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2 episodes with vegfr2
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.06.547994v1?rss=1 Authors: Carey, A. M., Parodi, R., Vazquez, R., Canepa, E., Fossati, S. Abstract: Cerebrovascular dysfunction has been implicated as a major contributor to Alzheimers Disease (AD) pathology, with cerebral endothelial cell (cEC) stress promoting ischemia, cerebral-blood flow impairments and blood-brain barrier (BBB) permeability. Recent evidence suggests that cardiovascular (CV)/cerebrovascular risk factors, including hyperhomocysteinemia (Hhcy), exacerbate AD pathology and risk. Yet, the underlying molecular mechanisms for this interaction remain unclear. Our lab has demonstrated that amyloid beta 40 (A{beta}40) species, and particularly A{beta}40-E22Q (vasculotropic Dutch mutant), promote death receptor 4 and 5 (DR4/DR5)-mediated apoptosis in human cECs, barrier permeability and angiogenic impairment. Previous studies show that Hhcy also induces EC dysfunction, but it remains unknown whether A{beta} and homocysteine function through common molecular mechanisms. We tested the hypotheses that Hhcy exacerbates A{beta}-induced cEC DR4/5-mediated apoptosis, barrier dysfunction, and angiogenesis defects. This study was the first to demonstrate that Hhcy specifically potentiates A{beta}40-E22Q-mediated activation of the DR4/5-mediated extrinsic apoptotic pathway in cECs, including DR4/5 expression, caspase 8/9/3 activation, cytochrome-c release and DNA fragmentation. Additionally, we revealed that Hhcy intensifies the deregulation of the same cEC junction proteins mediated by A{beta}, precipitating BBB permeability. Furthermore, Hhcy and A{beta}40-E22Q, impairing VEGF-A/VEGFR2 signaling and VEGFR2 endosomal trafficking, additively decrease cEC angiogenic capabilities. Overall, these results show that the presence of the CV risk factor Hhcy exacerbates A{beta}-induced cEC apoptosis, barrier dysfunction, and angiogenic impairment. This study reveals specific mechanisms through which amyloidosis and Hhcy jointly operate to produce brain EC dysfunction and death, highlighting new potential molecular targets against vascular pathology in comorbid AD/CAA and Hhcy conditions. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.19.537575v1?rss=1 Authors: Zink, J., Froemel, T., Boon, R. A., Fleming, I., Benz, P. M. Abstract: Endothelial tip cells are essential for VEGF-induced angiogenesis, but underlying mechanisms are elusive. Endothelial-specific deletion of EVL, a member of the mammalian Ena/VASP protein family, reduced the expression of the tip cell marker protein endothelial cell specific molecule-1 (Esm1) and compromised the radial sprouting of the vascular plexus in the postnatal mouse retina. The latter effects could at least partly be attributed to reduced VEGF receptor 2 (VEGFR2) internalization and signaling but the underlying mechanisms(s) are not fully understood. In the present study, we revealed that the expression of the long non-coding RNA H19 was significantly reduced in endothelial cells from postnatal EVL-/- mice and in siRNA-transfected human endothelial cells under hypoxic conditions. H19 was recently shown to promote VEGF expression and bioavailability via Esm1 and hypoxia inducible factor 1 (HIF-1). Similar to EVL-/- mice, the radial outgrowth of the vascular plexus was significantly delayed in the postnatal retina of H19-/- mice. In summary, our data suggests that loss of EVL not only impairs VEGFR2 internalization and downstream signaling, but also impairs VEGF expression and bioavailability in the hypoxic retina via downregulation of lncRNA H19. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.29.534783v1?rss=1 Authors: Bychkov, I., Topchu, I., Makhov, P., Kudinov, A., Patel, J. D., Boumber, Y. Abstract: Lung cancer is the most frequently diagnosed cancer type and the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) represents most of the lung cancer. Vascular endothelial growth factor receptor-2 (VEGFR2) is a member of the VEGF family of receptor tyrosine kinase proteins, expressed on both endothelial and tumor cells which is one of the key proteins contributing to cancer development and involved in drug resistance. We previously showed that Musashi-2 (MSI2) RNA-binding protein is associated with NSCLC progression by regulating several signaling pathways relevant to NSCLC. In this study, we performed Reverse Protein Phase Array (RPPA) analysis of murine lung cancer which nominated VEGFR2 protein as strongly positively regulated by MSI2. Next, we validated VEGFR2 protein regulation by MSI2 in several human NSCLC cell line models. Additionally, we found that MSI2 affected AKT signaling via negative PTEN mRNA translation regulation. In silico prediction analysis suggested that both VEGFR2 and PTEN mRNAs have predicted binding sites for MSI2. We next performed RNA immunoprecipitation coupled with quantitative PCR which confirmed that MSI2 directly binds to VEGFR2 and PTEN mRNAs, suggesting direct regulation mechanism. Finally, MSI2 expression positively correlated with VEGFR2 and VEGF-A protein levels in human NSCLC samples. We conclude that MSI2/VEGFR2 axis contributes to NSCLC progression and is worth further investigations and therapeutic targeting. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC
A new research paper was published in Aging (listed as "Aging (Albany NY)" by MEDLINE/PubMed and "Aging-US" by Web of Science) Volume 15, Issue 1, entitled, “Genetic deficiency and pharmacological modulation of RORα regulate laser-induced choroidal neovascularization.” Choroidal neovascularization (CNV) causes acute vision loss in neovascular age-related macular degeneration (AMD). Genetic variations of the nuclear receptor RAR-related orphan receptor alpha (RORα) have been linked with neovascular AMD, yet its specific role in pathological CNV development is not entirely clear. In this new study, researchers Chi-Hsiu Liu, Felix Yemanyi, Kiran Bora, Neetu Kushwah, Alexandra K. Blomfield, Theodore M. Kamenecka, John Paul SanGiovanni, Ye Sun, Laura A. Solt, and Jing Chen from Harvard Medical School, UF Scripps Biomedical Research and University of Arizona showed that Rora was highly expressed in the mouse choroid compared with the retina, and genetic loss of RORα in Staggerer mice (Rorasg/sg) led to increased expression levels of Vegfr2 and Tnfa in the choroid and retinal pigment epithelium (RPE) complex. “Here, we investigated whether RORα regulates CNV using a mouse model of laser-induced CNV, mimicking the neovascular features of wet AMD. We found that expression of RORα was enriched in the mouse choroid/RPE complex and upregulated in laser-induced CNV.” In a mouse model of laser-induced CNV, RORα expression was highly increased in the choroidal/RPE complex post-laser, and loss of RORα in Rorasg/sg eyes significantly worsened CNV with increased lesion size and vascular leakage, associated with increased levels of VEGFR2 and TNFα proteins. Pharmacological inhibition of RORα also worsened CNV. In addition, both genetic deficiency and inhibition of RORα substantially increased vascular growth in isolated mouse choroidal explants ex vivo. RORα inhibition also promoted angiogenic function of human choroidal endothelial cell culture. “Together, our results suggest that RORα negatively regulates pathological CNV development in part by modulating angiogenic response of the choroidal endothelium and inflammatory environment in the choroid/RPE complex.” DOI: https://doi.org/10.18632/aging.204480 Corresponding Author: Jing Chen - jing.chen@childrens.harvard.edu Keywords: age-related macular degeneration, angiogenesis, choroidal neovascularization, inflammation, nuclear receptors, RORα, VEGFR2, TNFα Sign up for free Altmetric alerts about this article: https://aging.altmetric.com/details/email_updates?id=10.18632%2Faging.204480 About Aging-US: Launched in 2009, Aging (Aging-US) publishes papers of general interest and biological significance in all fields of aging research and age-related diseases, including cancer—and now, with a special focus on COVID-19 vulnerability as an age-dependent syndrome. Topics in Aging go beyond traditional gerontology, including, but not limited to, cellular and molecular biology, human age-related diseases, pathology in model organisms, signal transduction pathways (e.g., p53, sirtuins, and PI-3K/AKT/mTOR, among others), and approaches to modulating these signaling pathways. Please visit our website at www.Aging-US.com and connect with us: SoundCloud – https://soundcloud.com/Aging-Us Facebook – https://www.facebook.com/AgingUS/ Twitter – https://twitter.com/AgingJrnl Instagram – https://www.instagram.com/agingjrnl/ YouTube – https://www.youtube.com/agingus LinkedIn – https://www.linkedin.com/company/aging/ Reddit – https://www.reddit.com/user/AgingUS Pinterest – https://www.pinterest.com/AgingUS/ For media inquiries, please contact media@impactjournals.com.
A new research paper was published in Oncotarget's Volume 13 on October 19, 2022, entitled, “Platelet-derived growth factor (PDGF) cross-signaling via non-corresponding receptors indicates bypassed signaling in colorectal cancer.” Platelet-derived growth factor (PDGF) signaling, besides other growth factor-mediated signaling pathways like vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF), seems to play a crucial role in tumor development and progression. Previously, researchers Romana Moench, Martin Gasser, Karol Nawalaniec, Tanja Grimmig, Amrendra K. Ajay, Larissa Camila Ribeiro de Souza, Minghua Cao, Yueming Luo, Petra Hoegger, Carmen M. Ribas, Jurandir M. Ribas-Filho, Osvaldo Malafaia, Reinhard Lissner, Li-Li Hsiao, and Ana Maria Waaga-Gasser, from Harvard Medical School, Shenzhen Traditional Chinese Medicine Hospital, University of Wuerzburg, and Mackenzie Evangelical Faculty of Paraná, recently provided evidence for upregulation of PDGF expression in UICC stage I–IV primary colorectal cancer (CRC) and demonstrated PDGF-mediated induction of PI3K/Akt/mTOR signaling in CRC cell lines. In their new study, the researchers sought to follow up on our previous findings and explore the alternative receptor cross-binding potential of PDGF in CRC. “Our analysis of primary human colon tumor samples demonstrated upregulation of the PDGFRβ, VEGFR1, and VEGFR2 genes in UICC stage I-III tumors.” Immunohistological analysis revealed co-expression of PDGF and its putative cross-binding partners, VEGFR2 and EGFR. The team then analyzed several CRC cell lines for PDGFRα, PDGFRβ, VEGFR1, and VEGFR2 protein expression. They found these receptors to be variably expressed amongst the investigated cell lines. Interestingly, whereas Caco-2 and SW480 cells showed expression of all analyzed receptors, HT29 cells expressed only VEGFR1 and VEGFR2. However, stimulation of HT29 cells with PDGF resulted in upregulation of VEGFR1 and VEGFR2 expression despite the absence of PDGFR expression and mimicked the effect of VEGF stimulation. Moreover, PDGF recovered HT29 cell proliferation under simultaneous treatment with a VEGFR or EGFR inhibitor. “Our results provide some of the first evidence for PDGF cross-signaling through alternative receptors in colorectal cancer and support anti-PDGF therapy as a combination strategy alongside VEGF and EGF targeting even in tumors lacking PDGFR expression.” DOI: https://doi.org/10.18632/oncotarget.28281 Correspondence to: Ana Maria Waaga-Gasser - awaaga@bwh.harvard.edu Keywords: PDGF, VEGFR, EGFR, bypassed signaling, colorectal cancer About Oncotarget: Oncotarget (a primarily oncology-focused, peer-reviewed, open access journal) aims to maximize research impact through insightful peer-review; eliminate borders between specialties by linking different fields of oncology, cancer research and biomedical sciences; and foster application of basic and clinical science. To learn more about Oncotarget, visit Oncotarget.com and connect with us on social media: Twitter - https://twitter.com/Oncotarget Facebook - https://www.facebook.com/Oncotarget YouTube – www.youtube.com/c/OncotargetYouTube Instagram - https://www.instagram.com/oncotargetjrnl/ LinkedIn - https://www.linkedin.com/company/oncotarget/ Pinterest - https://www.pinterest.com/oncotarget/ LabTube - https://www.labtube.tv/channel/MTY5OA SoundCloud - https://soundcloud.com/oncotarget For media inquiries, please contact: media@impactjournals.com. Oncotarget Journal Office 6666 East Quaker Str., Suite 1A Orchard Park, NY 14127 Phone: 1-800-922-0957 (option 2)
This month on Episode 32 of Discover CircRes, host Cynthia St. Hilaire highlights four original research articles featured in the January 7 and January 21 issues of Circulation Research. This episode also features a conversation with Ms Natalie Harris and Dr Kathleen Caron from the University of North Carolina Chapel Hill about their study, VE-Cadherin Is Required for Cardiac Lymphatic Maintenance and Signaling. Article highlights: Carlson, et al. AKAP18δ Controls CaMKIIδ Activity Gan, et al. sEV and Adipocyte ER Stress Following MI/R Khan, et al. Long-term Risk Prediction of Heart Failure Awan, et al. Wnt5a Is Essential for Cholesterol Homeostasis Cindy St. Hilaire: Hi, and welcome to Discover CircRes, the podcast of the American Heart Association's journal Circulation Research. I'm your host, Dr Cindy St. Hilaire from the Vascular Medicine Institute at the University of Pittsburgh. Today, I'm going to be highlighting the articles from our January issues of Circulation Research. I'm also going to speak with Ms Natalie Harris and Dr Kathleen Caron from the University of North Carolina Chapel Hill about their study, VE-Cadherin Is Required for Cardiac Lymphatic Maintenance and Signaling. Cindy St. Hilaire: The first article I want to share is titled AKAP18δ Anchors and Regulates CaMKII Activity at Phospholamban-SERCA2 and Ryanodine Receptors. The first and corresponding author for this article is Cathrine Carlson, and the study was conducted at University of Ohio. In cardiac muscle cells, calcium is continuously released and taken up by the sarcoplasmic reticulum to drive alternating contractions and relaxations. The kinase, CaMKII, regulates this calcium signaling via phosphorylation of the sarcoplasmic reticulum proteins ryanodine receptors also called RYR. Cindy St. Hilaire: These receptors promote calcium release, and phospholamban promotes calcium uptake via the transporter SERCA, but how CaMKII localizes to and associates with these sarcoplasmic reticulum factors was unclear. Because AKAP18 delta enables phosphorylation of phospholamban and calcium uptake into the sarcoplasmic reticulum, this group suspected it might be involved. The team's immuno precipitation and functional experiments in rodent cardiomyocytes show that AKAP18 delta associates with CaMKII and phospholamban SERCA2 as well as with CaMKII and ryanodine receptors, and that these interactions are linked to CaMKII activity. Cindy St. Hilaire: The team identified two separate CaMKII binding domains within the AKAP18 delta protein, one that inhibits the kinase and one that actuates it, suggesting they may somehow serve to fine tune CaMKII activity. While such regulatory details remain to be resolved, the isolated domains may be utilized as tools for studying calcium handling in cardiomyocytes, and for developing therapeutic CaMKII regulating reagents for treating arrhythmia. Cindy St. Hilaire: The second article I want to share is titled Ischemic Heart-Derived Small Extracellular Vesicles Impair Adipocyte Function. The first author is Lu Gan, and the corresponding authors are Yajing Wang and Yu Cao from Thomas Jefferson University. While diabetes and obesity increase a person's risk of myocardial infarction, suffering a myocardial infarction itself can lead to metabolic dysfunction. One of the main regulators of systemic metabolic homeostasis is the body's adipose tissue, but whether and how an injured heart communicates with adipocytes was unclear. Cindy St. Hilaire: The infarcted heart is known to release microRNA containing extracellular vesicles, also called EVs, and so this group hypothesized that these EVs might constitute a heart-to-fat communication system. They isolated circulating EVs before and after myocardial infarction in mice, and incubated these vesicles with cultured adipocytes. After 24 hours, differences in adipocyte gene and protein expression were apparent. Notably, a key cardioprotective metabolic factor called adiponectin was downregulated in cells treated with the extracellular vesicles from myocardial infarcted mice, while genes involved in endoplasmic reticulum stress were increased. Cindy St. Hilaire: Analysis of the myocardial infarction extracellular vesicle content showed an increased abundance of specific microRNAs, and the team went on to show that inhibiting production of these microRNAs or the EVs themselves, prevented adipocyte ER stress and adiponectin production in mice after myocardial infarction. Together, these data hints that such microRNA inhibition may be a clinical strategy that can be used to prevent infarction-associated metabolic dysfunction in humans. Cindy St. Hilaire: The next article I want to share is titled Development and Validation of A Long-Term Incident Heart Failure Risk Model. The first and corresponding author of this study is Sadiya Khan from Northwestern University. Heart failure contributes to approximately 1.2 million hospitalizations, and 300,000 deaths in the U.S. annually. Heart failure also has an estimated healthcare cost of over $10 billion. With both the incident rates and costs expected to rise in the future, a method for predicting an individual's heart failure risk would enable preventative interventions such as diet and blood pressure treatments to be initiated early, thus prolonging the number of healthy years. Cindy St. Hilaire: To develop such a prediction tool, this group studied decades of health data from over 24,000 individuals that was collected as part of five separate, long-running national heart, lung and blood institute studies. The individuals included in the model for development were at baseline aged between 20 and 59 years old, and had no cardiovascular disease diagnosis at that time. Analysis of their body mass indices, blood pressures, total cholesterol levels, high density lipoprotein levels, smoking statuses, diabetes diagnoses, and other cardiovascular health data over several decades enabled the team to develop an equation for predicting an individual's likelihood of developing heart failure in the next 30 years. The hope is such personalized risk assessments will help to guide patient-doctor discussions regarding cardiovascular health, lifestyle choices and medical interventions. Cindy St. Hilaire: The last article I want to share is titled Wnt5a Promotes Lysosomal Cholesterol Egress and Protects Against Atherosclerosis. The first authors are Sarah Awan and Magalie Lambert, and the corresponding author is Philippe Boucher from the University of Strasbourg. The Wnt family of signaling proteins drives many developmental processes, such as cell fate determination, proliferation and migration. Recently, Wnt signaling has been implicated in lipid homeostasis. Mutations that impair Wnt signaling have been shown to cause hyperlipidemia in mice, and in humans, decreased Wnt signaling activity inversely correlates with atherosclerosis severity. Cindy St. Hilaire: Because the protein Wnt5a in particular has been shown to inhibit cholesterol accumulation in cells, this group investigated the role of Wnt5a protein in mice and human cells. Mice whose vascular smooth muscle cells lacked Wnt5a developed more severe atherosclerosis compared to control animals, and human smooth muscle cells lacking Wnt5a accumulated far greater amounts of cholesterol in the lysosomes than did cells with normal levels of Wnt5a. The group then showed that Wnt5a normally associates with lysosomes, where it promotes the catabolism of lysosomal cholesterol via activating lysosomal lipase, and promoting cholesterol egress via the endoplasmic reticulum. In revealing how cholesterol efflux is trafficked by Wnt5a, these findings may help to inform future cholesterol regulating therapies. Cindy St. Hilaire: Today, Natalie Harris and Dr Kathleen Caron from the University of North Carolina Chapel Hill are here with me to discuss their study, VE-Cadherin Is Required for Cardiac Lymphatic Maintenance and Signaling, which is featured in our January 7th issue of Circulation Research. Thank you both for joining me today. Kathleen Caron: Thanks, Cindy, for having us. We're really honored and excited to talk with you. Cindy St. Hilaire: I'm excited too, because I think this is my first lymphatic paper I'm talking about. That's where I'm going to start my questions. Your study is investigating cardiac lymphatics. But like I said, I haven't talked a lot about lymphatics here, so I was wondering if you could at least give a little bit of background about what the role is of the lymphatic system, especially because I feel like it's the unappreciated member of the circulation, and also give us a little bit of background on what cardiac lymphatics are. Kathleen Caron: That's a really great question. We sometimes talk about lymphatic vessels as the third vascular system or the understudied vascular system. I'm hoping that that's not the case so much anymore, because the lymphatic field has really boomed in the past 15 years or so. I think where we are right now in the field is in early days, we and others had discovered key signaling molecules, and transcription factors, and growth factors that are important and specific to the lymphatic vasculature as compared to blood endothelial cells. Through those unique tools, now, the field has fast forwarded where we're starting to look into organ-specific functions of lymphatics. Kathleen Caron: We're appreciating that perhaps a little unlike the blood vascular system, which has one main function of delivering blood, lymphatics actually have very different functions depending on the organ that they're in. Some of the more common ones that you'll read about in textbooks in about a paragraph in a medical textbook are that lymphatics are important for immune cell trafficking through the lymph nodes, so they're the major route of trafficking for immune cells and for their maturation. Lymphatics are also important for draining interstitial fluid, and maintaining the homeostasis of tissue fluid balance. Kathleen Caron: A third really big one, which is sometimes underappreciated, is that lymphatics are the key vessels within the intestine that absorb lipid, and so all of our dietary lipids are absorbed through lymphatic vessels as opposed to the blood vasculature. Those three hallmark functions of lymphatics are the cornerstone of what they do throughout our body. But when you start to look into different organs and recognizing the different extrinsic and intrinsic forces that govern the function of these endothelial cells and different organs, you start to realize that they're even more complex, and that brings us to the heart. Kathleen Caron: The heart just has this beautiful network of lymphatic vessels that begin in the subendocardial space, and then project out and cover the subepicardial surface of the heart. And because the heart is always pumping, and because lymphatic vessels don't have an intrinsic mechanism for the flow of fluid through them, they rely on the movement of the tissue that they're in to help propel the fluid. So, this really raises the question of how are lymphatics functioning physically within a myocardium that is pumping with a very strong extrinsic force, and what is the function of those vessels if the heart is a very dense, thick organ that is not necessarily prone to edema necessarily as maybe our peripheral tissue and our skin is? Kathleen Caron: We've been studying this for many years now, and we've had several studies exploring genetic factors that are important for the growth and development of cardiac lymphatics. That's the focus of this paper today. They're quite unique and very different vessels. Cindy St. Hilaire: Reading your paper, I definitely learned a lot about lymphatics in general. One of the things I was thinking about, obviously, you're looking at VE-Cadherin, which is an endothelial cell marker. When I think of VE-Cadherin, and when I think of endothelial cells, my mind goes primarily to those that are in arteries and veins. In those conduits, their role is to really keep a tight seal to keep things out. But in the lymphatic system, it's very different, so how exactly different are the endothelial cells in the lymphatic tissue, and are they different, say, in the cardiac lymphatics versus, like you said, the mesenteric lymphatic? Kathleen Caron: Lymphatics are very different than the blood vasculature. First of all, the lymphatic vasculature has key differences in terms of its architecture and structure. The lymphatic endothelial cells themselves, as they exist in vessels, don't put down a basement membrane, and in general, the dermal capillaries or the initial collector lymphatics that are the ones that are taking in fluid also don't have smooth muscle cells surrounding them like our typical vasculature does. All of this is guided and precedented by the differences in gene expression patterns of these very specialized endothelial cells. Kathleen Caron: They also have very different cell-cell junctions. So when we think of a blood endothelial cell, we typically think of these tight junctions that bring them together, but the lymphatic endothelial cells have oak leaf shaped overlapping junctions. They're really beautiful to see on an EM, and they're very different than the blood vasculature, because, Cindy, as you mentioned, the function is very different. You're supposed to let things leak out, and big things too, right, like immune cells and large proteins. Cindy St. Hilaire: One of the neat things that really made your study possible is this really nice PROX1 inducible CRE that you crossed with the flox-cadherin5 gene. I was wondering a little bit about that protein. Is that one of these, I guess, markers that allows lymphatic EC to be a lymphatic EC, and how specific is that protein for those specific ECs? Natalie Harris: The PROX1 CRE that we use is based off of the PROX1 transcription factor, which we consider to be one of the master transcription factors of lymphatics. In fact, that was one of the very first lymphatic specific transcription factors that help maintain the lymphatic identity. So in this case, PROX1 turns on from blood endothelial cells, because many lymphatics are of venous origin, so actually, PROX1 turning on is a hallmark of them becoming a lymphatic endothelial cell. Natalie Harris: Those are really great CRE specifically to look at lymphatics in this case, and it actually is a perfect model system because VE-Cadherin itself is only expressed in lymphatics and blood vessels, and then we have PROX1 as our free driver. Therefore, it will only be lymphatic, so it's a very specific lymphatic knockout of VE-Cadherin. Cindy St. Hilaire: That's so wonderful when we discover things that are so specific like that. So using this really nice model that's also Tamoxifen inducible, you then have control to look at things temporally. One of the neat things that you did was you looked at this in terms of an embryonic level knockout, but then another one postnatally, and then another one, it was an adult mouse, which not a lot of people do that intricate, temporal spacing of things. So I was wondering if you could just share with us what you were thinking behind doing that, and then really importantly, what those different models actually taught you about the cardiac lymphatics? Kathleen Caron: That's a great question, Cindy. It would take me 20 minutes to answer. It really represents work by all of the co-authors. Really, it's the first effort to look at the different stages. That's because the growth and development of lymphatics, particularly within the myocardium, differs a lot during embryogenesis, and then the vessels themselves are quiescent in an adult animal. Then of course, we were interested in seeing what might happen in an injured myocardium, and that was also part of the study. Kathleen Caron: We felt that it was important to address the changing and dynamic role of this protein in a developing lymphatic, because it's growing and forming these nascent vessels, and then as it's starting to remodel an early life, and then in adulthood when it's in a quiescence state. That was the rationale for looking at this. It was also... Sometimes, science just takes you where it takes you, and it was a co-author of ours, and collaborator of ours, who had noted a phenotype in the hearts of these animals that he generated and suggested that maybe it would be a good idea to look early in development. Then as one thing leads to another, you start looking later in development and so on and so forth, so the science just kind of… Cindy St. Hilaire: Sometimes tells you where to go on its own. Kathleen Caron: Exactly. It was a long project. Natalie Harris: Part of the reason too is that the cardiac lymphatics have been shown to have a little bit of a different development and maintenance and pruning cycle than some of the other lymphatics. Some other lymphatics are totally fully formed in embryonic development, but the cardiac lymphatics have been shown to develop through birth and a little bit postnatally as well. That makes them a little bit unique in the sense that their maturation is very prolonged, so that's part of the reason as well we wanted to look both in embryonic development as well as that postnatal period. Cindy St. Hilaire: That's so interesting. There are a lot of little nuggets that my antennas would perk up as I read your paper, really neat observations. One of them was that I think it was the postnatal and the adults. There was lymphatic endothelial cells in the cardiac tissue were disrupted. They were discontinuous and fragmented, yet there was no cardiac edema. I thought that was interesting because normally, you'd think about any of these mice with lymphatic issues. You think of edema. You think of swelling, and yet it wasn't happening in the heart. What do you think that means either about the lymphatic system in the heart or in lymphatics as a whole? Kathleen Caron: That's a really great question, and one that we think about all the time. I think it goes back to the first question or the first comment about the really remarkable differences in the functions of lymphatics and different tissues, right? And within the myocardium, because it is continuously moving and pumping with great force, the extrinsic forces within that tissue will help to mitigate the formation of edema. This is not to say that you can't get myocardial edema, and we've actually developed surgical models in our lab to form myocardial edema in mice. Kathleen Caron: It is a very common clinical condition in humans as well, but the lymphatics themselves being fully invested within this myocardium probably are being regulated differently in their function in draining fluid than, for example, the lymphatics that you might have in the skin or in your thigh or in other organs in your body. The fact that there wasn't edema, even though you had leaky vessels, didn't alarm us too much because we knew and sensed that with this constant pressure and pumping of the myocardium, that in itself helps to keep the tissue fluid balanced. Natalie Harris: That might be another reason why we're not seeing such extremes in edema, and then going back to what Kathrine said, again, because lymphatics have multiple functions, perhaps it's more in the immune cell realm or even other functions we haven't uncovered yet. Cindy St. Hilaire: One of the other neat observations you had was that you were doing a myocardial infarction model on the adult animals, and you noticed that the infarct size and the fibrosis was indeed larger in the knockouts, but the cardiac function wasn't exactly affected. What does this mean, and were you surprised by this? Kathleen Caron: Yeah, we were surprised. We absolutely were surprised, and we think that's actually one of the key big reveals for the field. To balance this, to counterbalance the absence of a phenotype, that was really remarkable to us, and I hope to many others as well, is that other studies including work from our lab and Paul Riley's lab and Eva Brackinham's lab have very convincingly shown in multiple different ways that if you stimulate lymphangiogenesis after injury, if you have a model, either genetic or induced, where there are more lymphatics for whatever reason, that's a beneficial thing. That's a great thing, and having more lymphatics is positive and beneficial to improving heart repair, and mitigating heart injury, and helping in the context of myocardial infarction. Kathleen Caron: Of course, it was really surprising that now we have a mouse model where we essentially have little to no lymphatics with very little to no function, and yet the ejection fractional shorting of the heart was doing just fine. I think that was a big moment and a big discovery for us, but very convincing. Then I think it leads us to really asking while more might be better, what really could be the critical function of the lymphatics in an injured myocardium? As Natalie just mentioned previously, it might be related to immune cell trafficking. Paul Riley's group has made some really seminal discoveries in that regard. Natalie Harris: It's just very interesting, because it's really against everything that you would expect from, again, all the previous studies. It just goes to show again that the lymphatics are so heterogeneous in their organ level function that that's really worth exploring more, because maybe if you can figure out strategies to selectively target certain beds, you can really do a treat on the disease by disease, organ by organ basis. That makes the lymphatics just really cool in my opinion, because they are so different, but it's all the same system, so it's just a very interesting organ, in my opinion. Kathleen Caron: I should also say serendipitously or right about a few months ago... Shout out to Mark Kahn's lab at University of Pennsylvania. They had a recent paper, I believe, in JCI that had a similar finding to ours. It's always gratifying when another lab says, "Oh, wow, really?" Their study was very different than ours and on a different series of signaling molecules, but similarly, they ablated or reduced cardiac lymphatics through different mechanisms, and then had an injury model. Also, were rather surprised to see that it didn't have this negative effect. Cindy St. Hilaire: It's so neat. The whole observations that you saw with these knockouts was a paper in itself, but the next half of the paper, you dig into the mechanism, which is also interesting. Can you share a little bit about the links that you found between VE-Cadherin and the VEGF receptor signaling, and is your mechanism you think specific to all lymphatic ECs or even all ECs, or is it specific just to the cardiac lymphatic ECs? Kathleen Caron: Yes, the mechanism, I find one of the funnest parts of this paper, because I think it really synergizes a lot of the key signaling molecules within our field. Also, I think it bridges together a G-protein-coupled-receptor signaling pathway that my lab has been interested in for decades now, and that is a pathway with the VEGFR3 signaling pathway. I think that's been a big open question in the field. How do these two critical requisite signaling paradigms for lymphatics converge together to maintain lymphatic function development? Kathleen Caron: I think we've really made some really great inroads in the study, and VE-Cadherin is central to that because it forms a structural scaffold to keep a GPCR signaling pathway in register with the receptor tyrosine kinase signaling pathway, and basically allow for the transactivation of these two really powerful pathways. The mechanism really is gratifying to be able to finally pull how these molecules all interface together and regulate one another. Natalie Harris: It's very interesting in the fact that VE-Cadherin, it's not necessarily like a lymphatic-specific molecule, but a lot of work in terms of VE-Cad has been more in studying mechanosensing and mechanotransductions. That's where a lot of little nuggets about maybe our mechanism has occurred that we know from really just on protein level studies that VE-Cadherin does interact with VEGFR2 and VEGFR3 by the transmembrane domain interaction. That was clue number one, and then clue number two is that we know that a lot of different mechanical signals that might affect VEGFR3 happened in the presence of VE-Cad. Natalie Harris: So in a sense, this particular paper is just piecing together a lot of these nuggets of information, and it all makes sense. One thing that you were saying in terms of maybe specific to the heart, going back to some of the earlier studies on these papers on these mice, that we found very vessel-bed-specific effects. One of the vessel beds that is really impacted is the lacteals and the mesentery, so the gut lymphatics. We do know that these lymphatic beds are very sensitive to VEGFC. In fact, they require constant VEGFC signaling. So if you're not having VEGFR3 stable at the membrane to receive these signals, it makes sense if you would have really extreme effects. That might be, again, some of the case in the heart as well. We do know after a cardiac injury, we do see an increase in things like adrenomedullin, and an increase in VEGFC has been shown to increase lymphangiogenesis, so perhaps also the heart, the gut lymphatics also has a special requirement for VEFGR3 signaling. Cindy St. Hilaire: So in terms of, I guess, the future of this line of research and maybe thinking about translation, what do you see as maybe a role for this in terms of developing therapeutic strategies or even preventative measures, I guess, specifically in the cardiac lymphatic area? Natalie Harris: Like we mentioned earlier, there's been a lot of studies in mice that have looked at increasing lymphangiogenesis post-injury, so it would be interesting to see more when those hit the clinical end, and if you're seeing similar effects. Then the other thing that's interesting about lymphatics, you can think of them as both a target and also as a drug delivery route. There's a huge, huge field totally dedicated to using the lymphatics to deliver drugs like nanoparticles. That's very big in the cancer realm, and pretty much for any kind of drug delivery, if you can imagine using that as a super highway to deliver drugs as well. Natalie Harris: That could be a potential avenue in terms of the heart as well, getting a more specific administration of cardiovascular drugs to the heart. So whether or not we're thinking of them as being modulated by disease, we can also use them to modulate the disease itself by delivering drugs as well, so it's interesting. You can think of the lymphatics as a therapeutic target and as a therapeutic administrator. That's going to be really interesting to see where the field goes. Cindy St. Hilaire: I like that, a new super highway to deliver drugs. Thank you so much, soon to be Dr Harris and Dr Caron from UNC Chapel Hill. This was a wonderful conversation and a beautiful paper. Congratulations on all the hard work. Kathleen Caron: Well, thanks so much, Cindy, and to the whole Circ Research team. We really appreciate your advocacy for our work and giving us this wonderful opportunity. Natalie Harris: Thank you so much. Cindy St. Hilaire: That's it for the highlights from our January issues of Circulation Research. Thank you for listening. Please check out the CircRes Facebook page, and follow us on Twitter and Instagram with the handle @CircRes and #DiscoverCircRes. Thank you to our guests, Natalie Harris and Dr Kathleen Caron. This podcast was produced by Ashara Ratnayaka, edited by Melissa Stoner, and supported by the editorial team of Circulation Research. Some of the copy text for highlighted articles was provided by Ruth Williams. I'm your host, Dr Cindy St. Hilaire, and this is Discover CircRes, your on-the-go source for the most up-to-date and exciting discoveries in basic cardiovascular research. Cindy St. Hilaire: This program is copyright of the American Heart Association, 2022. The opinions expressed by speakers on this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more information, visit ahajournals.org.
On this episode, we're discussing a phase III trial that showed improved progression-free survival with VEGFR2 inhibition in certain patients with thyroid cancer. Then, we'll hear about a report on outcomes of breakthrough COVID-19 infection among fully vaccinated patients with cancer.Coverage of stories discussed this week on ascopost.com:Apatinib for Advanced Radioactive Iodine–Refractory Differentiated Thyroid CancerStudy Finds Fully Vaccinated Patients With Cancer and Breakthrough COVID-19 Infection Remain at High Risk for Severe OutcomesTo listen to more podcasts from ASCO, visit asco.org/podcasts.
In this podcast episode, Jean-Yves Blay, MD, PhD, and Robin L. Jones, BSc, MBBS, MRCP, MD(Res), discuss the most important clinical trial data on leveraging TKIs as monotherapy and in combination with chemotherapy or immune checkpoint inhibitors for treatment of soft tissue sarcoma and osteosarcoma.Presenters:Jean-Yves Blay, MD, PhDProfessor of Medical OncologyDepartment of MedicineCentre Leon BerardLyon, FranceRobin L. Jones, BSc, MBBS, MRCP, MD(Res)ProfessorSarcoma UnitRoyal Marsden Hospital and Institute of Cancer ResearchLondon, United KingdomLink to full program, including accompanying downloadable slidesets:https://bit.ly/2ZL9bxq
Vidcast: https://youtu.be/LsH7UZN_Fz4 Today's medical discoveries that point to future therapy: Ultrasonic Patch Warns Of Strokes and Heart Attacks Electromagnetic Helmet Helps Shrink Brain Tumor Copper Tranporter Gene Triggers Blood Vessel Repair New Cancer Immunotherapy Emerging Nanodressing Turbocharges Wound Healing UC-San Diego have developed a soft, flexible ultrasound generating patch that, when worn on the skin of the neck or chest, can report blood flow problems major arteries feeding the brain and heart. The phased array of ultrasound transducers in the patch work continuously to measure blood flow in vessels as deep as 6 inches within the body. The ultrasound beam may also be electronically tilted for measurements of vessels not directly beneath the patch. An oscillating magnetic field generated within a wearable helmet has driven shrinkage of an otherwise untreatable brain tumor by 30%. Neurosurgical investigators at the Houston Methodist Research Institute report the case of a 53 year old man with an end-stage, recurrent frontal lobe glioblastoma given this electromagnetic therapy for 5 weeks. Looks for more work in this arena. Medical College of Georgia cardiologists report that the gene responsible for copper transport and utilization also promotes the healing of ailing blood vessels. In a biochemical cascade, the product of this gene, ATP7A, triggers activity of the blood vessel growth factor VEGFR2. Acquiring control over this process could help halt vascular deterioration in diabetics and others with chronic vascular disease. There are new cancer immunotherapy agents in town called anti-TIGIT antibodies, and they prevent TIGIT from dialing down killer T cell activity against cancer cells. The major drug companies are all battling to get their hands on these experimental agents. GlaxoSmithKline just bought rights to EOS-448, BristolMyersSquibb bought AGEN1777, Gilead AB154, and Roche has already tested its tiragolumab in combination with another checkpoint inhibitor in phase 2 trials. Stay tuned on this one. A wound nanodressing composed of thin threads of natural materials including collagen as well as wound healing promotion agents may provide a cost effective means of helping diabetics and others with chronic vascular disease. Michigan State bioengineers helmed a multinational group that has developed these dressings aiming to keep the eventual cost as low as $20 per unit by employing readily available biopolymers. These and other cutting edge solutions are coming to your doctor's office and our hospitals…….some day soon! https://www.nature.com/articles/s41551-021-00763-4 https://www.frontiersin.org/articles/10.3389/fonc.2021.708017/full https://www.nature.com/articles/s41467-021-23408-1 https://cen.acs.org/pharmaceuticals/biologics/GSK-buy-iTeosanti-TIGIT-antibody/99/i23 https://pubmed.ncbi.nlm.nih.gov/31828774/ https://pubs.acs.org/doi/10.1021/acs.molpharmaceut.1c00400 #ultrasoundpatch #oncomagnetictherapy #glioblastoma #TIGIT #antitigit #checkpointinhbitor #wounds #diabetes
Dr. Jason Luke, director of the Cancer Immunotherapeutics Center at UPMC Hillman Cancer Center, discusses advances in immunotherapy across the spectrum of malignancies featured at the 2021 ASCO Annual Meeting. Transcript: ASCO Daily News: Welcome to the ASCO Daily News podcast. I'm Geraldine Carroll, a reporter for the ASCO Daily News. My guest today is Dr. Jason Luke, the director of the Cancer Immunotherapeutics Center at UPMC Hillman Cancer Center. Dr. Luke also serves as associate professor of medicine at the University of Pittsburgh School of Medicine. His clinical focus is on immunotherapy for advanced solid tumors, as well as cutaneous malignancies and melanoma. He joins me to discuss advances in immunotherapy featured at the 2021 ASCO Annual Meeting. Dr. Luke has relationships with most of the pharmaceutical companies that have funded the research discussed in this episode. His full disclosures are available on the transcript of this episode. Dr. Luke, always great to have you on the podcast. Dr. Jason Luke: Well, thanks so much for the invitation today. ASCO Daily News: Well, there was an abundance of novel therapies and practice-changing studies presented during this year's [ASCO] Annual Meeting. Did you detect any themes among all of the great studies presented during the meeting? Dr. Jason Luke: Well, I agree. And as I was sort of taking the fire-hose of abstracts in this year, I thought there were four themes that really seemed to stand out to me. And when I was thinking through them, I think the first one was the validation of a new checkpoint, or a third validated checkpoint for use in clinical practice. A second one was really the emergence of immunotherapy, now being used in the curative setting, meaning either in adjuvant studies or in neoadjuvant studies. And the third area was advancements in this management of metastatic disease with practice-changing trials. And then the fourth area, which is always near and dear to me, is novel therapeutics with the development of the next generation of immunotherapies, and those early data that might give us a hint towards what might be coming next. ASCO Daily News: OK, so let's first look at the third validated checkpoint for use in clinical practice. That's Abstract 9503. Dr. Jason Luke: Yeah, absolutely. So this year at ASCO, we saw the results of a clinical trial described as the RELATIVITY-047 study, which was a global randomized double blind phase II/III study comparing anti-PD-1 antibody with nivolumab (nivo) versus a combination of nivolumab with the anti-LAG-3 antibody relatlimab. And so LAG-3 is a molecule that many will be familiar with, but perhaps not everyone. And LAG-3 is another receptor on T cells that can become up-regulated as T cells become dysfunctional in the tumor microenvironment. And so all are aware of the concept that infiltrating lymphocytes can get into tumors, and then they get blocked by these immune checkpoints. And so LAG-3 is another immune checkpoint expressed on these tumor infiltrating lymphocytes. And I don't have time to go into all of this, but in the preclinical space, blocking LAG-3 with an antibody is actually, in many mouse models, more effective than blocking a PD-1 or PD-L1. And so there's been a lot of interest. LAG-3 was one of the first targets to really develop as a co-target to PD-1. And just to zoom forward then to the clinical trial, this was a study where patients with advanced, untreated, metastatic melanoma were randomized one to one to either get relatlimab plus nivolumab, in what they are describing as a fixed dose combination, meaning that there's an infusion of the dose once a month, relatlimab 160 milligrams plus nivolumab 480 milligrams. And that was the same dose. And so it's only one infusion, even though it's two drugs, one infusion. That was compared with nivolumab. And there were a number of stratification factors, et cetera, in the study. And they're useful to get into the minutia, but right now, I think not so important. This, like I said, was a gated study, meaning they did a phase II trial first, to try to prove that there was a benefit in a smaller sample of patients. And if they hit the endpoint, they then went on to a phase III trial. And that's exactly what happened. So in this trial, progression-free survival (PFS) was the primary endpoint. And, interestingly, it was evaluated by blinded independent central radiology. And that may sound like a mouthful, but we'll come back to why that's important a little bit later. And there was a hierarchical testing strategy, such that the PFS had to be established first, before the investigators can look at overall survival and overall response rate. But given that background, there really was a quite substantial and clinically impressive difference between these two arms. And so we call relatlimab "rela" for short. So rela plus nivo demonstrated a substantial improvement, markedly statistically significant improvement, compared with nivolumab monotherapy, so that at 1 year, at 12 months, the progression-free survival for the combination arm was 47.7%, compared to 36% for nivolumab. And the median PFS was 10.1 months for the combination versus 4.6 months from nivolumab. So you can see that's more than a doubling of progression-free survival, with a hazard ratio at 0.75 and a p value at 0.006 or 0.0055. So why does that matter? Well, we have thought for a long time in the field about combination immunotherapy, and people think of PD-1 and CTLA-4 combination. And these data, when compared sort of across trial comparison, which is always a little dangerous, but they look very similar to what we saw with nivolumab plus ipilimumab (ipi), in terms of the absolute improvement in the benefit in terms of median progression-free survival, between relatlimab plus nivo, as compared with ipi plus nivo in the CheckMate-067 study. And I mentioned this blinded independent central radiology, that complicates things a little bit, because the landmark comparisons between having the radiologist evaluate the scans and having the investigators evaluate the scans, actually gives a little bit of variation in terms of the outcomes. But if you just compare them on a high level, they actually look very similar. And along those lines, the really important thing is that relatlimab plus nivolumab is much better tolerated with much less side effects than nivolumab plus ipilimumab. So, in fact, in this clinical trial, we see that the rates of grade 3-4 adverse events are on the order of what we saw with nivolumab monotherapy in CheckMate-067. Now, interestingly, in this study, RELATIVITY-047, the rates of grade 3 adverse events for nivolumab monotherapy were actually about half of what they had been seen in the previous phase III trial. And I think that that just suggests that all of us, as a field, are getting better at managing these immune therapy toxicities. One other piece of information that was very interesting to look at was when the outcomes were broken down by subgroups, particularly the biomarkers of PD-L1 positivity, and LAG-3 positivity. These biomarkers actually did not inform the outcomes, in which case, I mean, that nivolumab plus relatlimab was actually effective across all the subgroups. And so one might have hypothesized, going into this, that patients with high LAG-3 would do better with a LAG-3 treatment. That was not what was seen. In fact, all patients benefited with the combination. And that's relevant to clinical practice, because, as we think about applying this treatment, I do not think we're going to be able to use biomarkers, at least initially, to be able to differentiate who should get what. And rather this just suggests that basically all patients who are going to get PD-1 monotherapy would be better served by giving the combination. So I was the discussant actually for this abstract, and one of the questions I tried to get at was, well, does that mean that you would just essentially replace PD-1 monotherapy across the board in melanoma with this combination? And I think the answer is, not quite yet, but maybe someday. And what I mean by that, is that there are still some very high-risk patients that we treat. And particularly those are patients with high lactate dehydrogenase, brain metastases, rapid progression, et cetera. And those are the patients where, at least I, predominantly use nivolumab plus ipilimumab, or nivo plus ipi. And that's because nivo plus ipi is the treatment for which we have the best long-term data, and we know the most about it in terms of treating high risk patients. So I would continue to use that until this trial, at least. Is more mature, so that we can get data about the response rate, the overall survival, and so on and so forth. But I think there's really no question, looking at this relatlimab plus nivolumab data, that it does change the standard of care in melanoma, and that, for most patients, who would have gotten PD-1 monotherapy, they're now going to be directed towards this combination, given it's well tolerated and appears to be highly active. And I think, thinking beyond melanoma now, if this is now a second, a third checkpoint, but a second one we can combine with nivolumab with little toxicity, I think it opens up a huge new world of clinical investigation, possibly adding doublet checkpoint to chemotherapy. Basically everyone everywhere we've seen PD-1 combined with chemotherapy, and obviously that's quite exciting just thinking about improving outcomes. And we're going to discuss all the different ways that PD-1's been impacting the standard of care across different settings. ASCO Daily News: Excellent. Well, let's shift our focus now to the curative use of immunotherapy. Let's start in the adjuvant setting with the KEYNOTE-564 study. That's LBA 5. Dr. Jason Luke: So plenary presentation for the KEYNOTE-564 study, which was adjuvant pembrolizumab versus placebo in high-risk renal clear cell renal cell carcinoma. And so this is an important trial, because there have been decades, actually, of immunotherapy clinical trials in the adjuvant setting, which have not demonstrated a benefit. That also includes actually VEGF-TKIs, which also did not show a benefit. But in this large study, so almost 1,000 patients, 994 patients, they were randomized one to one to receive pembrolizumab or placebo. And the eligibility population were pathological T2 with intermediate and high risk features all the way through metastatic disease that's been fully resected. And the outcomes here, again, I think were very impressive. And so the disease-free survival was statistically significant, with a hazard ratio of 0.68. And what does that mean in reality? Well, the 2 year disease-free survival was 77.3% for the patients getting pembrolizumab compared to 68.1% for those getting the placebo. So you can see basically a 10% 2 year improvement in disease-free survival. And though the data were quite immature, the early analysis of overall survival also suggested a statistically significant benefit. So p value was 0.02 and hazard ratio was 0.54. Now we'll be very interested to see how that matures over time. But I think again these are practice-changing data, to suggest that, basically, all high-risk patients with clear cell renal cell cancer are now going to be receiving anti-PD-1 immunotherapy in the adjuvant setting. I think it does raise the question, and we'll discuss it now across other diseases as well, in terms of, are we over-treating patients. But this has been a constant struggle in medical oncology for many, many years. But it's very hard to see a treatment like this, with such a benefit, and not think that you want to give this basically to almost all the patients. But, hopefully, biomarkers to inform which patients benefit most will be coming over the relatively near future for renal cell. But I think those are becoming a little bit more obvious in some other diseases. ASCO Daily News: Looking at non--small cell lung cancer, Abstract 8500, that's the IMPOWER-10 trial, that caught a lot of attention. That was trending on Twitter for a while. What are your thoughts on that trial? Dr. Jason Luke: Yeah, absolutely, so the IMPOWER-010 or 010 study, this study looked at PD-L1 inhibition in the adjuvant setting, versus a placebo. So this was another very large trial where patients with early to later high-risk disease, so stage 1b to 3a, they received standard chemotherapy as adjuvant treatment, but then were randomly assigned to get PD-L1 versus best supportive care. And this was an interesting clinical trial, [ and] had a complicated statistical design where the first analysis was to look at the impact in PD-L1 positive patients. Secondarily, then, they looked at randomized patients. And then thirdly, they looked at intention-to-treat. And this was a positive study. So in the disease-free, in the PD-L1 high patient population, the disease-free survival did not reach the median, with a 2 year benefit at 74.6% versus 61%, so again a 13% improvement in 2 year disease-free survival. And that was highly statistically significant, hazard at 0.66. And, again, that's the PD-L1 high population. So, thinking about biomarkers then, it looks clear that the PD-L1 positive group is the one that disproportionately benefits, because as we went through the rest of the hierarchical testing, the disease-free survival in randomly assigned patients, and then in intention-to-treat patients, those numbers got a little less strong. And it really probably suggests that the PD-L1 positive group is the one that's going to drive almost all of the benefit. So it'll be interesting to see how this data matures, and how it's interpreted in the community. I mean, you mentioned the discussions on Twitter, which I sometimes participate in. And I'm going to come back to a little later how it's very interesting to see how thought leaders for various malignancies sort of take these data into consideration. I think clearly in GU cancers, when we talked about the KEYNOTE-564 pembrolizumab data, the sense was, this is an immediate change in the standard of care. When we look at this data for non--small cell lung cancer, however, the sense I've gotten from some investigators is, this is early data. And they really do want to see that overall survival before that's really going to have high uptake. But we'll have to kind of see how that goes. Maybe selecting for PD-L1 in that population would make that difference, to really let you feel confident. But it'll be interesting again, like I said, as more time passes and as we see more data, and as other PD-1, PD-L1 agents come into this same space, if there's reproducible data that will help them feel more confident. ASCO Daily News: Right, well, another trial that attracted a lot of attention was CheckMate-577. That's Abstract 4003. Do you think this trial will move the needle in esophageal or esophagogastric junction (GEJ) cancers? Dr. Jason Luke: So I think this is a real important trial, because we've historically thought of certain tumor types as immunotherapy sensitive versus not sensitive, melanoma, lung cancer, et cetera. And gastrointestinal (GI) tumors predominantly have fallen into that latter group, where we think where there isn't as much of a benefit. Obviously there are approvals for esophageal and gastric cancers, but I think this study really shows how we can move the needle in terms of maybe curing more patients. So CheckMate-577 looked at adjuvant nivolumab. And these were stage II and stage III patients with esophageal or GEJ, and they got neoadjuvant chemoradiation treatment and then surgery, all of that being standard of care, but then went on to get a randomization 2 to 1 to either nivolumab or placebo. And again, as you mentioned, this is an important trial. The disease-free survival (DFS) was statistically and substantially improved for the patients getting nivolumab versus placebo, after that definitive therapy. So in the group receiving nivolumab, the median disease-free survival was 22.4 months, compared to only 11 months in the patients getting the placebo. That was a hazard of 0.69 and a p value at 0.003. And, again, thinking about biomarkers here, there was a broad population of patients treated. But when you look at the breakdown of who benefited the most, the patients benefiting in this trial were almost entirely those patients who had a PD-L1 composite signature at greater than 5, combined positive score (CPS) greater than 5. And so it's really the case that the PD-L1 positive patients with esophageal cancer seemed to benefit the most. And so I don't know how you think this doesn't impact the standard of care. In the total population there was a doubling of DFS, and in the PD-L1 high it was actually almost a tripling. And so I think, immediately, at least for PD-L1 high patients, they should go on to get adjuvant PD-1 after definitive chemotherapy, radiotherapy (RT), then surgery. And I think this is really exciting, when we think about, this is disease, obviously, it's very, very difficult to treat. And outcomes in metastatic disease are not what we want. And this really suggests we may be able to really benefit a lot of patients moving forward. ASCO Daily News: Excellent. So what are your takeaways from Abstract 9500, the KEYNOTE-054 trial of adjuvant pembrolizumab for melanoma? Dr. Jason Luke: Yeah. Thanks, so in melanoma we've had immunotherapy with checkpoint blockade now for a decade. And adjuvant clinical trials have been ongoing for most of that decade. And it's been standard of care to give our patients checkpoint blockade again for several years. I think what was really interesting about the update for KEYNOTE-054, which was the study of pembrolizumab (pembro) versus placebo in stage III melanoma, was the authors on this update looked at the impact of crossover after initial progression. So in the clinical trial, patients were randomized one to one to either receive pembro or placebo. And at the time of progression, they could then cross over and get the other treatment, right? So this trial was the first trial to be designed to be able to ask that question, immunotherapy now versus immunotherapy later. And what we observed in this study was that the response rate to getting pembrolizumab in the metastatic setting, if you had gotten the placebo on the adjuvant trial, was approximately similar. It was right around 40% And that's actually what we saw on the KEYNOTE-006 study that got pembrolizumab registered. So that was really, really interesting. And it suggested that if patients progress in the adjuvant setting and get treatment with PD-1 in the frontline metastatic, and they're still in good shape, they actually can have similar outcomes than what we would have expected if they had not had that adjuvant experience. And so I think this is really important. It doesn't actually answer the question about overall survival, which is really what we want to know. Does adjuvant immunotherapy improve overall survival? But it does suggest that patients can have this benefit, even if they wait for treatment. One thing that was really interesting to see was that, for those patients who had pembrolizumab, in the adjuvant setting, and then had a progression event, who went on to get pembrolizumab again, actually had much lower outcomes. And so I think that that's something to be cautious about. I think if patients progress on adjuvant PD-1, the data from this trial really suggest that going back to PD-1, even if there's been a period of time, is not a real great idea. And many of us in the field have kind of advocated of going to CTLA-4 combination in those patients anyway. But I would think these data really do suggest that that's important. So broadly speaking, then, I think these data are important to suggest that if you wait to give immunotherapy, you can still get a good benefit, at least in melanoma. And what I thought was really interesting across all of these abstracts, so for kidney cancer, lung cancer, esophageal, melanoma, was we saw, I think, based on the investigator feedback, or the thought leaders in the field, was that disease-free survival or relapse-free survival was really interpreted somewhat differently in different settings. And so I think, in melanoma, I think we have for a long time thought that adjuvant therapy was important, despite the fact, we don't have overall survival for PD-1 antibodies. In the renal cell data, again, where immunotherapy has been a backbone, albeit with IL-2 and various different immunotherapies, again, a lot of enthusiasm. When we looked at lung cancer and esophageal cancer, where I think investigators are more used to biomarker selection, they were a little more nitpicky about which populations we should treat. And so I'm very interested to see how this entire field sort of develops, and how the thought leaders for each disease take these data in. But, if you take a step back, on a really high level, when we think about giving PD-1 checkpoint blockade, it's generally speaking a low-toxicity treatment. And there's a tremendous impact on recurrence and potentially cure in the adjuvant setting. And that is just so exciting when we think about truly making a difference on cancer. We're talking about people never having recurrence and never dying of metastatic disease. And if we think about the outliers among the thousands of patients that have these diseases, and just go out to 5 years, 10 years from now, that's going to be a lot of people alive because they got immunotherapy after surgery. ASCO Daily News: Well, that would be fantastic. Thanks, Dr. Luke, for your great analysis of the adjuvant setting. Let's focus now on the neoadjuvant setting. Abstract 8503, the CheckMate-816 trial, seems to be on everyone's radar. What can you tell us about it? Dr. Jason Luke: Absolutely, so I think we just got done talking about adjuvant therapy. But an alternative would be to say, is there a way that we can deliver this immunotherapy, perhaps to enhance the immunotherapy and either improve the surgery or actually maybe even avoid the surgery, moving into the future. And so that is a really exciting paradigm as well. And so the first of these was in non--small cell lung cancer, the CheckMate-816 study. And the initial results of this study were actually presented at AACR earlier this year, but now updated here at ASCO. And what we saw was that there was a major improvement, 10 times improvement, in pathologic complete response for giving nivolumab plus chemotherapy. I mean literally 2% pathologic complete response with chemotherapy, up to more than 20% with this combination with immunotherapy. And what the investigators updated here was a number of details around the surgical plans, showing that the surgeries were easier, and the patients had better time recovering, due to lower disease burden for those that got the combination with immunotherapy. And I think that's really, really exciting, because, I mean, it suggests a paradigm in the future where we can reduce the amount of surgery. So one of the things was they looked at the number of open thoracotomies versus VATS procedures. And a number of patients who got immunotherapy had a much lower surgical burden. So, I think those data are really exciting. They're not quite ready for prime time yet, because I think we need larger studies to prove this, but I think the trend is, we'll talk through these different disease settings, really does suggest that immunotherapy is going to really change all of oncology, in terms of surgical paradigms, how we follow patients, et cetera. ASCO Daily News: Excellent. Dr. Luke, you spoke earlier about the phase III study of relatlimab and nivolumab. There's another study, Abstract 9502 in the neoadjuvant setting, right? Dr. Jason Luke: Yep, and so, in addition to the phase III data for relatlimab, there was also a neoadjuvant study from The University of Texas MD Anderson Cancer Center group, which I think was really, really useful in helping us feel more confident actually about the metastatic disease data, and about understanding where the field in melanoma is going. So, in melanoma, that's where, sort of taking a step back quickly to note that there have been a whole bunch of neoadjuvant clinical trials done over the last 3 to 4 years, and actually so many that we've already started to have meta-analyses to look and see and observe, I should say, that those patients actually who have major pathologic responses, and those with complete responses, generally speaking, don't recur. And this is really exciting. It's actually even led to clinical trial designs where we're actually deferring surgery in melanoma, where we give neoadjuvant therapy. We take out one node. And if it's a complete response (CR) we don't even do the surgery. So in the Abstract 9502, again relatlimab, the anti-LAG-3 antibody was combined with nivolumab. And I think what the important thing to highlight here was that the rates of pathologic complete response and major partial response actually looked very similar to what we saw with nivo plus ipi in previous clinical trials. So if you remember, the relatlimab data in the metastatic setting was only the PFS data, due to the statistical plan. But what we see here is that in the neoadjuvant setting, very similar outcomes for relatlimab plus nivo as what would have been expected for ipi plus nivo. And I think that gives us, again, more strength and more confidence that this is a very active combo, again, with lower toxicity relative to nivo plus ipi. ASCO Daily News: OK, well, Abstracts 4503 and Abstract 4504 looked at alternative management strategies in bladder cancer. Can you tell us about these data? Dr. Jason Luke: So these were two really interesting abstracts, I thought, from my perspective. And they really looked at management, alternative management strategies for muscle invasive bladder cancer. And so the first one, 4503, was the Hoosier Oncology GU study 16-257. And this was a study that looked at neoadjuvant nivolumab plus gemcitabine and cisplatin, with an evaluation for clinical outcome. So what I mean by that was, after the patients got this treatment, they were evaluated for whether or not they had had a clinical complete response, and then they were offered the opportunity to either not pursue cystectomy, which obviously is highly morbid, or to continue to be followed. And, very interesting, the study, for those patients who were deemed to have had a complete clinical response, 70% of them did not recur. And that's really exciting, because if you think about the population of patients with bladder cancer, many of them elderly, those cystectomies are highly morbid surgeries. And this suggests that we may be able to move into a future where we could give them upfront medical therapy and actually potentially avoid that surgery. The other abstract I thought was really interesting was sort of married to that, which was the 4504 abstract. And that was a clinical trial that looked at the neoadjuvant administration of pembrolizumab plus gemcitabine chemotherapy and radiation treatment. And, again, what they observed in that study was very high rates of pathologic complete response, and longer term outcomes that looked very exciting. And I think what both of these studies show, as phase II studies, is the possibility that medical therapy might actually be curative in some patients. And there are a number of phase III efforts now ongoing to try to amplify these trials and actually confirm them on a larger scale. ASCO Daily News: Shifting our focus now to practice-changing trials in metastatic disease, GI oncologists were very pleased to see the data from CheckMate-648. What was observed in this trial, LBA 4001? Dr. Jason Luke: So CheckMate-648 in esophageal cancer was a study in the frontline metastatic setting, looking at the impact of immunotherapy plus chemotherapy, or immunotherapy alone versus chemotherapy. And so what I mean by that was one arm in the study looked at nivolumab with standard chemotherapy, compared to chemotherapy, and the other arm looked at nivolumab plus ipilimumab versus chemotherapy. And, very briefly, what was observed was that both of the active arms, so the immunotherapy containing arms, the nivo plus chemotherapy or the nivo plus ipi, both of them improved outcomes compared with chemotherapy. And so, moving forward, there's really no question now that the standard of care in the frontline management of esophageal cancer should include immunotherapy, either as a combination with chemotherapy, or possibly with leaving out the chemotherapy and giving just nivolumab plus ipilimumab. Now the sub-stratification of patients and their outcomes by sub-stage was important in this study, and again emphasized that it's mostly the PD-L1 positive patients who benefited the most from immunotherapy. So but the idea of potentially having a regimen that's chemotherapy-free for frontline esophageal cancer, I think is really exciting. And I'd be really interested to follow where this field goes in terms of which patients are getting selected for the nivo chemotherapy versus ipi plus nivo arms, in standard practice kind of moving into the future. And obviously further biomarkers will be really important. But I think this is really a practice-changing trial, again, to emphasize that all patients with esophageal cancer should be getting immunotherapy in the frontline, moving forward. ASCO Daily News: Indeed, what can you tell us about Abstract 6000 using camrelizumab for nasopharyngeal carcinoma (NPC)? Dr. Jason Luke: Yeah, absolutely. So I think that this is a really interesting study and I think important. This is a study actually looking at the impact of adding immunotherapy to chemotherapy in nasopharyngeal carcinoma. So all the oncologists in the United States will be like NPC, oh, yeah, I heard about that during fellowship. But this is actually a major source of morbidity and mortality throughout the rest of the world, especially in the developing world. And so this clinical trial to me is very interesting. So the short story here is that adding camrelizumab improved outcomes relative to chemotherapy, which I think is probably not surprising, because across many other settings we've seen that adding PD-1 to chemotherapy would improve outcomes. I think the difference here was that this is an antibody that was developed in China. And is it part of a growing trend to see competitor PD-1 PD-L1 antibodies entering the space. So to close the loop on NPC, I think these data really strongly suggest that we should be giving immunotherapy in combination with chemotherapy in the frontline to these patients. But I think, more broadly, start to open this conversation about how are we going to evaluate new drugs that are getting developed, say, only in China, or in other parts of the world where there are no patients from the United States that are actually participating in the clinical trial. Are those drugs going to get approved by the U.S Food and Drug Administration (FDA)? And if they do get approved by the FDA, how are they going to get priced, because as we're moving into the era now of more than 10 anti-PD-1, PD-L1 antibodies that have shown a benefit in the metastatic setting in phase III trials, one could imagine the time has finally come for price control, and not control, but price competition. It'll be really interesting to see whether or not that actually comes true. I don't know the answer yet. But this trial, I think, is very important in that regard. ASCO Daily News: And back to melanoma, can you tell us about advances in the metastatic setting? Dr. Jason Luke: Absolutely. So I think there were two to hit on quickly. Obviously there were more, but two quickly to hit on. One was Abstract 9506, which was the long term update, 6 and a half years of CheckMate-067, which people remember was the nivolumab plus ipilimumab versus ipi trial. And just to summarize this quickly, it really was amazing to see that now at 6 and a half years, we finally hit the median for overall survival for patients with metastatic melanoma in the frontline setting. And the median was 49%. So it just barely went under the median. But I just can't emphasize, when I was a fellow, and actually I'm a melanoma oncologist, and coming into this, the outcomes for patients at that time, the median survival was 9 months. And now we're talking about 10 years later, and the median is basically, it's 6 and a half years, almost 50%. So it's just outstanding. And I can't emphasize it enough. Clearly not good enough. We still have 50% of patients who need better treatments. But it's pretty exciting. The other abstract I wanted to highlight, because I think it differentiates where things stand, was the Abstract 9505, which was the tumor infiltrating lymphocyte (TIL) lifileucil in melanoma. And, again, just to highlight this, 36.5% response rate to re-infusion of TIL with interleukin-2. And I think that that's going to be an important part of the armamentarium for melanoma management, moving into the future. One final metastatic disease abstract to highlight was the development of T cell receptor (TCR) T cells for synovial sarcoma. So this was a really important abstract as well, going along with the lifileucil abstract, because I think this showed that this is a really active regimen with adoptive cell transfer for synovial sarcoma. And I would very much expect to see that both the TCR T cells and the TIL product get approved by the FDA within the coming year. ASCO Daily News: Excellent, well, before we wrap up the podcast, can you share some highlights from your main research area, developmental therapeutics? Dr. Jason Luke: Yeah, finally, so in the realm of developmental therapeutics, which is my major research area, there's always a lot going on. And I think this year's ASCO Annual Meeting I would just highlight a few things. So one is the continued development of VEGFR2 tyrosine kinase inhibitors (TKIs) with immunotherapy, we saw long term updates with lenvatinib and pembrolizumab in melanoma (Abstract 9504). And we saw other updates with new combinations in colorectal cancer. Another area in terms of considerations were small molecule inhibitors. And so there was a really interesting abstract about an MDM2 inhibitor. And people will remember that's a regulator of P-53, being combined with pembrolizumab. And preclinically and translationally, in this abstract, it appears that modulating the P-53 pathway via MDM2 actually has immunomodulatory effects. So it'll be very interesting to see where alrizomadlin goes (Abstract 2506). There are a number of other novel targets. And there's so many abstracts on these that I'm not going to really go through them in a lot of detail. But TLR-7/8 agonism with checkpoint blockade looks interesting (Abstract 2512). There were a number of abstracts around transforming growth factor, TGF beta. And this is a really important target in cancer. And it'll be interesting to see how that gets developed out further. There were a number of approaches looking at targeting of human papillomavirus or HPV, one of them, which was a triplet regimen of an HPV vaccine plus a cytokine plus a PD-L1 antibody, and another one which was some viral vectors expressing HPV proteins. So all of this, I think, very interesting and taking sort of orthogonal to checkpoint approaches in terms of immunotherapy, vaccines, cytokines, viral vectors, et cetera. And then the final area, just to highlight, there was one very interesting Abstract 2507, which was a novel CAR T-cell product, which included a 41BB activation domain, attached actually to a bispecific CAR that binds to both CD19 and CD20. And this was Abstract 2507, and what I thought was very interesting was the rates of response for this molecule are really high, almost 100%. And that even included patients who had previously progressed on other CAR T products. So not enough time to go and give justice to any of these, but there's so much going on in developmental therapy for immuno-oncology. And I think that just emphasizes how bright the future is, building on this tremendous benefit in the standard of care setting in the adjuvant and metastatic settings. So, very excited to see where all these molecules go, and hopefully to advance the outcomes for all of our patients. ASCO Daily News: Indeed. Dr. Luke, thank you, as always, for your fantastic insight on some tremendous advances in immunotherapy, across the spectrum of malignancies. Our listeners will find links to all of the studies that you discussed in the transcript of this episode. Thank you, Dr. Luke. Dr. Jason Luke: Well, thanks so much for the opportunity. ASCO Daily News: And thanks to our listeners for joining us today. If you enjoyed this episode of the podcast, please take a moment to rate and review us wherever you get your podcasts. Disclosures: Dr. Jason Luke Stock and Other Ownership Interests: Actym Therapeutics, Mavu Pharmaceutical, Pyxis, Alphamab Oncology, Tempest Therapeutics, Kanaph Therapeutics, Onc.AI, and Arch Oncology Consulting or Advisory Role: Bristol-Myers Squibb, Merck, EMD Serono, Novartis, 7 Hills Pharma, Janssen, Reflexion Medical, Tempest Therapeutics, Alphamab Oncology, Spring Bank, Abbvie, Astellas Pharma, Bayer, Incyte, Mersana, Partner Therapeutics, Synlogic, Eisai, Werewolf, Ribon Therapeutics, Checkmate Pharmaceuticals, CStone Pharmaceuticals, Nektar, Regeneron, Rubius, Tesaro, Xilio, Xencor, Alnylam, Crown Bioscience, Flame Biosciences, Genentech, Kadmon, Immunocore, KSQ Therapeutics, Inzen, Pfizer, Silicon Therapeutics, TRex Bio Research Funding (Institution): Merck, Bristol-Myers Squibb, Incyte, Corvus Pharmaceuticals, Abbvie, Macrogenics, Xencor, Research Funding: Array BioPharma, Agios, Astellas Pharma, EMD Serono, Immatics, Kadmon, Moderna Therapeutics, Nektar, Spring bank, Trishula, KAHR Medical, Fstar, Genmab, Ikena Oncology, Numab, Replimmune, Rubius Therapeutics, Synlogic, Takeda, Tizona Therapeutics, Inc., Trishula Therapeutics, BioNTech AG, Scholar Rock Patents, Royalties, Other Intellectual Property: Serial #15/612,657 (Cancer Immunotherapy), Serial #PCT/US18/36052 (Microbiome Biomarkers for Anti-PD-1/PD-L1 Responsiveness: Diagnostic, Prognostic and Therapeutic Uses Thereof) Travel, Accommodations, Expenses: Bristol-Myers Squibb, Array BioPharma, EMD Serono, Janssen, Merck, Novartis, Reflexion Medical, Mersana, Pyxis, Xilio Disclaimer: The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.
Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.22.308783v1?rss=1 Authors: Perez-Miller, S., Patek, M., Moutal, A., Cabel, C. R., Thorne, C. A., Campos, S. K., Khanna, R. Abstract: Neuropilin-1 (NRP-1) is a multifunctional transmembrane receptor for ligands that affect developmental axonal growth and angiogenesis. In addition to a role in cancer, NRP-1 is a reported entry point for several viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19). The furin cleavage product of SARS-CoV-2 Spike protein takes advantage of the vascular endothelial growth factor A (VEGF-A) binding site on NRP-1 which accommodates a polybasic stretch ending in a C-terminal arginine. This site has long been a focus of drug discovery efforts for cancer therapeutics. We recently showed that interruption of the VEGF-A/NRP-1 signaling pathway ameliorates neuropathic pain and hypothesize that interference of this pathway by SARS-CoV-2 spike protein interferes with pain signaling. Here, we report hits from a small molecule and natural product screen of nearly 0.5 million compounds targeting the VEGF-A binding site on NRP-1. We identified nine chemical series with lead- or drug-like physico-chemical properties. Using an ELISA, we demonstrate that six compounds disrupt VEGF-A-NRP-1 binding more effectively than EG00229, a known NRP-1 inhibitor. Secondary validation in cells revealed that almost all tested compounds inhibited VEGF-A triggered VEGFR2 phosphorylation. Two compounds displayed robust inhibition of a recombinant vesicular stomatitis virus protein that utilizes the SARS-CoV-2 Spike for entry and fusion. These compounds represent a first step in a renewed effort to develop small molecule inhibitors of the VEGF-A/NRP-1 signaling for the treatment of neuropathic pain and cancer with the added potential of inhibiting SARS-CoV-2 virus entry. Copy rights belong to original authors. Visit the link for more info
Dr Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and it's editors. We're your co-hosts, I'm Dr Carolyn Lam, associate editor from The National Heart Center and Duke National University of Singapore. Dr Greg Hundley: And I'm Greg Hundley, associate editor for Circulation and director of The Pauley Heart Center at VCU Health in Richmond, Virginia. Dr Carolyn Lam: Guess what Greg? Right after this we have a double feature discussion. It is all about dapagliflozin with some really, really important self-analyses from the DECLARED-TIMI 58 trial and about heart failure in Type 2 Diabetes with dapagliflozin. But, all of that coming right up only after we have our chat. So Greg, what do you have for us today? Dr Greg Hundley: My first article is going to be from Dr Mintu Turakhia at the VA Palo Alto healthcare system at Stanford University and is going to discuss the practice variation in anticoagulation prescription and outcomes after device-detected atrial fibrillation. It's a study that has insights from the VA Health Administration. This study evaluated the relationship between oral anticoagulant prescription practice variation in response to new device detected atrial fibrillation and the association to outcomes. As you know Carolyn, there are no clearly defined thresholds of AF burden, for which to initiate oral anticoagulation. Dr Carolyn Lam: Interesting, so what did they find, how did they do this? Dr Greg Hundley: Carolyn, the investigators performed a retrospective cohort analysis using data from the Veterans Health Administration linked to remote monitoring data that included day level AF burden. They included patients with cardiac implantable electronic devices and remote monitoring from the years 2011 through 2014. A CHA2DS2-VASc score of greater or equal to 2, and no prior stroke or oral anticoagulant receipt in the preceding 2 years. They determined the proportion of patients prescribed oral anticoagulants within 90 days following new device-detected AFib across a range of AFib thresholds. Greater than or equal to 6 minutes, all the way up to greater than 24 hours. And they examined sight variation in oral anticoagulation prescription. Dr Carolyn Lam: And so? What did they find? Dr Greg Hundley: Well, you ask among 10,212 patients with defibrillators, proportion receiving oral anticoagulation varied based on device detected AF burden. For example, for those greater than or equal to 6 minutes, it was roughly 13% of individuals, for those greater than 24 hours, 27% of individuals received oral anticoagulants. Importantly, there was a substantial sight variation in oral anticoagulation prescription after device-detected atrial fibrillation, for example, greater than one hour. The median was 16%, but it ranged from as low as 3% up to highs of 67%. And so, in adjusted models, oral anticoagulant prescription after device-detected AFib of greater than 24 hours was associated with reduced stroke risk and has a ratio of 0.28, p-value's 0.02, although, the propensity adjusted model was significant when AFib lasted at least 6 minutes. So, in conclusion, among veterans with implanted devices, device-detected atrial fibrillation is common. There is large practice variation in 90-day oral anticoagulation initiation after new device-detected AFib with low rates of treatment overall, even for episodes greater than 24 hours. Remember, we said that rate was 27%. The strongest association of oral anti-coagulation with reduction in stroke was observed after device-detected Afib of greater than 24 hours. And what this study shows, is that randomized trials are needed to perform these observational findings. So, Carolyn, how about your next study? Dr Carolyn Lam: Well, from anti-coagulants to anti-hypertensives. I'm going to tell you about the 6-month results if the RADIANCE Hypertension Solo Trial. Dr Greg Hundley: Oh, so, what was the RADIANCE Hypertension Solo Trial? Can you remind us? Dr Carolyn Lam: Glad you asked. So the trial was the one that demonstrated a greater reduction in daytime ambulatory systolic blood pressure at 2 months by endovascular ultrasound renal denervation compared with a sham procedure among patients who were not treated with anti-hypertensive medications. So the current paper, led by Michel Azizi from Université Paris-Descartes and colleagues, now report the 6-month results following the addition of a recommended, standardized, stepped-care anti-hypertensive treatment to the randomized endovascular procedure under continued blinding to the initial treatment. Now, remember these were patients with uncontrolled combined systolic and diastolic hypertension who were initially off medications for two months following randomization. Now, between two and five months, if the monthly measured home blood pressure was more than 135/85, the stepped-care antihypertensive treatment approach was recommended and consisted of sequential addition of, for example, amlodipine 5mg a day, then a standard dose of an angiotensin-converting-enzyme inhibitor, or an ARB, and hydrochlorothiazide at 12.5mg a day, followed by sequential uptitration of the hydrochlorothiazide and amlodipine. So, what did they find? At 6 months, 65% of the patients in the original renal denervation group were being treated by this stepped-care approach, versus 84.5 in the sham group. And the average number of antihypertension medications and defined-daily doses were all less in the renal denervation group than the sham group. Now, despite less intensive antihypertensive treatment, the renal denervation group had reduced daytime ambulatory systolic blood pressure to a great extent than the sham group. Importantly, there were no major adverse events in either group through 6 months. The blood pressure lowering effect of endovascular ultrasound renal denervation was maintained at 6 months with less prescribed antihypertension medications compared with the sham control. And what this means is if safety is maintained in larger studies with longer follow-up, renal denervation could be a promising adjunct therapy for patients with hypertension. Dr Greg Hundley: Wow, so we're getting back toward renal denervation? How about that? Carolyn, my next paper jumps into the world of basic science. This is a study from Kari Alitalo at the University of Helsinki, and it involves endothelial cells and how they regulate physiological cardiomyocyte growth versus VEGFR2 mediated paracrine signaling. The study evaluates the role of bidirectional endothelial cells and cardiomyocyte cross-talk via cardiokine and angiocrine signaling as it pertains to the regulation of cardiac growth and homeostasis in pathological cardiac hypertrophy. The expansion of the cardiac vasculature to maintain adequate supply of oxygen and nutrients is a key determinant of whether the heart grows in a physiological compensated manner, or a pathological decompensated manner. Understanding how an excess of angiogenesis induces cardiac hypertrophy and how endothelial cells regulate cardiomyocyte homeostasis, could provide novel therapeutic targets for heart failure. Dr Carolyn Lam: Ah, this is something very close to my heart. So Greg tell us, how did they establish the link between the endothelial cells and cardiomyocytes? Dr Greg Hundley: The investigators demonstrated that both endothelial cell deletion of vascular endothelial growth factor receptor 1 and AAV-mediated delivery of the VEGFR1's specific ligands, VEGF-B or BGIF, into the myocardium increased the coronary vasculature and induced cardiomyocyte hypertrophy in adult mice. The resulting cardiac hypertrophy was a physiological as indicated by preserved cardiac function and exercise capacity and lack and pathological gene activation. Also, the investigators demonstrated that the reported changes were mediated by increased VEGF signaling via endothelial VEGFR2 and found that the notch and ERBb pathways are involved in transducing signals for endothelial cell cardiomyocyte cross-talk in response to angiogenesis. So clinically, the relevance of the findings are highlighted nicely in an editorial by professor Issei Komuro at the University of Tokyo Hospital. First, he emphasizes that cross-talk between the endothelial cell VEGFR2 and cardiomyocyte ErbB signaling pathways coordinates cardiomyocyte hypertrophy with angiogenesis and contributes to physiological cardiac growth. And understanding whether factors could modify this process may impact the treatment down the road of pathologic hypertrophy. Dr Carolyn Lam: Oh interesting! Well you know what, Greg, I've got a preclinical one for you too, and this time looking at the role of inflammation in atherosclerosis and specifically at the role of the adaptive immune response and T-cells. So, Greg, let me remind you that when we looked at CANTOS and Canakinumab we were actually looking at the role of the innate immune response. And here is where I had planned this very nice, complicated quiz for you, Greg, about the innate versus the adaptive immune response in the various cells. Would you like to take the quiz? Dr Greg Hundley: You know what? I think I'm going to pledge that I'm already going to get a D or an F, so why don't you enlighten us? Dr Carolyn Lam: Now alright, remember that the CD4 T-cells are assumed to be activated by our antigens derived from modified proteins such as oxidized LDL, and these are presented via MHC class II molecules in the context of cytokine signaling, remember those? What I didn't realize is that it hadn't been assumed that atherosclerosis involves a loss of tolerance against these modified self-antigens, generated in response to hypercholesterolemia and that presentation of such antigens on these MHC class II cells, then lead to activation of proatherogenic Th1 cells. So, that was the assumptions, but this was really studied in detail by the authors, Dr Wigren from Scania University Hospital and Lund University in Sweden and their colleagues, who addressed the role of CD4 T-cells in a real novel, unconventional way. And they did this by crossing MHC class ii deficient mice with atherosclerosis-prone ApoE-deficient mice. Now the result of these double deficient mice was almost complete void of CD4 T-cells. However, despite the lack of these T-cells and inflammation, these mice developed larger atherosclerotic lesions in the aortic root area of the heart than their ApoE-deficient counterparts. Cell transfer and blocking antibody studies also, then supported these findings and suggested that loss of regulatory T-cells is the most important cause of aggravated atherosclerosis in the double-deficient mice. So, overall these observations demonstrate that deficiency of activation of the adaptive immune responses through MHC class ii is associated with increased development of atherosclerosis, and the findings have important implications for our understanding the possible risks and benefits of immunosuppressive therapy in patients with cardiovascular disease. Now this is discussed in a beautiful editorial by Dr Slütter and Kuiper and they are from Leiden, the Netherlands. So, Greg, interesting stuff, huh? Dr Greg Hundley: You bet! Let's go on and here a little bit more about diabetes. Dr Carolyn Lam: And dapagliflozin coming right up. Today's feature discussion is all about SGLT2 inhibitors both in heart failure and atherosclerotic disease. A huge discussion because we have two papers, and they're all coming from the DECLARE-TIMI 58 trial. I am so pleased to have the corresponding author, Dr Stephen Wiviott from the TIMI study group at Brigham Women's hospital in Boston, Massachusetts, as well as the first author of one of the papers, and that is Dr Eri Kato, who was at the TIMI study group and is now at Kyoto University, as well as the editorialist for these two papers, Dr Subodh Verma from University of Toronto, and our deputy editor, Dr Darren McGuire from UT Southwestern. All-star cast, all-star papers. So, Steve, could you start by telling us about the DECLARE-TIMI 58 trial, just to set the background please? Dr Stephen Wiviott: So DECLARE, for people who don't know, was a large, randomized trial of 17,000+ patients with diabetes, comparing the SGLT2 inhibitor dapagliflozin to placebo. And the patients could be enrolled if the patients had either an established cardiovascular disease, meaning secondary prevention, or simply risk factors for cardiovascular disease with primary prevention. Patients that were treated with dapagliflozin or placebo were followed for a period of just over 4 years and there were co-primary endpoints. Those were cardiovascular death and hospitalization for heart failure, and the second co-primary endpoint was MACE, major adverse cardiovascular events, a combination of cardiovascular death, MI, or stroke. And what we saw, initially, this was a safety trial to demonstrate the safety of this diabetes agent according to worldwide guidelines. We saw that there was certainly non-inferiority for MACE, so it was safe with regard to MACE, but we did see a statistically significant reduction in cardiovascular death and hospitalization for heart failure driven predominantly by a large reduction in hospitalization for heart failure, and we also saw consistent with the other SGLT2 inhibitors, a significant reduction in the progression of renal disease. And so we had the opportunity to follow up with a couple of important papers that were published in circulation. Dr Carolyn Lam: Thanks, Steve. And at this point I would love to invite Eri to tell us, because we just heard that the heart failure hospitalization signal is very strong. What did you do in your analysis? Dr Eri Kato: So previously, SGLT2 inhibitors including dapagliflozin have shown to reduce hospitalization for heart failure, now we wanted to take a step further and explore those who are at high risk. So, the aim of our study was to evaluate whether the clinical benefit of dapagliflozin is greater in patients with HFrEF, heart failure with reduced ejection fraction, compared with patients without HFrEF. So, we used data from the DECLARE-TIMI 58, which you just heard, which included a broad spectrum of patients with Type 2 diabetes, and was also unique that it is the only SGLT trial to date that has detailed the information of these ejection fractions. So, for this study, for our study trying to find patients by the presence or absence of HFrEF, which was defined as having ejection fraction less than 45%, which is pre-specified ejection fraction couplings, and the key outcome in each was cardiovascular death or hospitalization for heart failure, its components, and of course, mortality. But we also additionally looked at MACE and renal composite endpoints. There are several interesting findings. First, is that dapagliflozin reduced the risk of hospitalization for heart failure regardless of ejection fraction, including those with preserved ejection fraction. Second, is we have observed lower rates of cardiovascular death in all-cause mortality with dapagliflozin in patients with HFrEF, but not in those without HFrEF. So, in patients with HFrEF, there was a significant 45% reduction in cardiovascular death, and 41% reduction in all all-cause mortality with dapagliflozin. And I'd like to highlight that these were achieved on top of high-proportional use of conventional evidence-based heart failure therapies, and that it did not increase any adverse events. And third, and finally, there were lower rates of renal composite endpoints with dapagliflozin regardless rejection fraction, and once again, it improves patients with preserved rejection fraction. So, to summarize, our results showed a robust mortality benefit in patients with HFrEF, but also showed that dapagliflozin is beneficial in full spectrum patients with diabetes, regardless of ejection fraction. Dr Carolyn Lam: Thank you Eri, that's beautifully summarized, but could I just clarify? These were patients not just with a reduced ejection fraction, but with heart failure? And how was that determined? Dr Eri Kato: We collected data at the baseline and the heart failure was collected based on the medical record. Dr Carolyn Lam: So, I just wanted to clarify that it wasn't just rEF, but HFrEF, but the HF part was a medical record. So, Darren, I know you thought a lot about this stuff, so what do you think? Is there still equipoise for these heart failure trials, or how do you think this adds? Dr Darren McGuire: First, as deputy editor of Circulation, I'm thrilled that were attracting these excellent diabetes-related publications, we've had a track record of several years now of capturing many of the key analyses and certainly these two papers we're talking about today qualify among the very best we've had, and I've also had the privilege of working with these investigators on the executive committee at DECLARE. And to the investigators and the credit of the sponsor, we observed these heart failure signals in other trials as DECLARE was ongoing, and we actually made a modification during the trial to begin to collect as much as we could pre-randomization ejection fraction data. And we were able to capture on roughly one-third of the patients, pre-trial EF data and we took any way it was measured and any time of when it was measured, and there are some limitations to that, but this now represents the largest data set where we can stratify the outcomes by some measure of ejection fraction. And I have to say I was really surprised by these results; that the cardiovascular death benefits were amplified in patients with heart failure with reduced ejection fraction, but not in those with heart failure with preserved ejection fraction, as these medications are relatively modest, diuretic agents I anticipated the opposite, honestly, that heart failure would preserve ejection fraction that is much more volume-sensitive may have incremental benefits from these medications. So, I was surprised by this, it was a little bit upside-down from what I expected. I know Subodh and Carolyn you've both thought a lot about this as well, I'd be interested in your opinions. Did you expect that heart failure with reduced ejection fraction would drive these clinical results? Dr Carolyn Lam: Subodh, I'm going to let you go first. Dr Subodh Verma: First and foremost, I appreciate the opportunity the circulation gave both myself and Professor McMurray to write the editorial to these very important pre-specified analyses from DECLARE. I actually see the results not only as interesting and tantalizing as you already discussed, but I actually see a lot of consistency between the two phenotypes, if I may, in that there is a heart failure signal or reduction in heart failure hospitalizations that appears to be consistent between the two groups, right? People with an EF of less than 45 with or without heart failure and then on the other side, people without reduced ejection fraction. They're both responsive in terms of reductions in heart failure hospitalization, so it brings into question that is this differences that we're seeing with respect to mortality, a reflection of a difference in phenotypic responsiveness to an SGLT2 inhibitor, or is this simply a reflection of increasing placebo event rates and a response based on baseline of entry in one group versus the other. So, as has been nicely outlined by the authors, the placebo event rate for CB death and heart failure and the placebo group would have pass, if I may, was about 5 times lower than those with heart failure with reduced ejection fraction. And it might be that as we go up the pyramid of risk, whether that risk is defined based on a TIMI risk score, whether it's based on a post-MI versus stable CAV risk score, or whether it's defined based on GFR, or whether, finally, it's defined based on the event rates for CV death and heart failure, that the higher the event rate, the higher the probability of demonstrating a CV death benefit, but that old strategies are actually demonstrating a consistent benefit on the overall driver of that outcome, which in this case, is a reduction in heart failure. So, that's what we sort of said in the editorial as well that we think that it may be a bit premature at this point to reach a conclusion that one group is responsive, and the other group is not responsive. But, as you rightfully said, Darren, it is entirely feasible through these analyses to hypothesize that one of the alternative hypotheses could be that there is a greater responsiveness in HFrEF compared to HFpEF. I actually don't understand the mechanisms of it, if that was the pieces I would have a difficult time explaining it based on the overall biology and sort of current understanding of these agents. But, I would say let’s wait: dapa heart failure is just around the corner. That trial will enroll people with documented heart failure with reduced ejection fraction. I think 4,774 patients that are being randomized on top of base, on top of RNA, on top of MRA, etc. who still have heart failure and who have a BP that's elevated so the definitive proof for this, at least from a rough standpoint, will be forthcoming. And then there are numerous HFpEF studies that are ongoing. There's Emperor Preserve and there's Deliver, and they have characterized the HFpEF population with a little bit more granularity and clarity. And I think we will be able to then look at, specifically, is there a HFpEF group that has the same event rate for CV death and heart failure, and compare that population to a HFrEF group at the same level of risk and whether there is differences in the responsiveness to be definitive about whether this is a matter of risk, threshold, or whether this is a true representation phenotypically. Dr Carolyn Lam: Subodh is a hard act to follow. So, I will answer your question directly, but maybe not with so many words, because it's already been said, Darren. And I'll just say I expected this benefit to be in both, I wouldn't have said one versus the other, but because we do know that in trials and with prospective studies that HFpEF outcomes are lower, especially mortality is lower, compared to HFrEF. I do wonder if it's a power issue, but the most important message--and this is coming from me also being on the steering on the committee of both DELIVER and EMPEROR Preserve--that please, this doesn't mean that we don't need the trials. I really really think that there's equipoise there still and we need to look at the DEDICATED HFpEF trials. But, moving on from the concept of risk stratification, I would like to go on and talk about the next paper. About the DECLARE sub-study of those with a prior MI. So, Steve, could you tell us, why did you do this, and what did you find? Dr Stephen Wiviott: I think that what we've seen as a pattern across the three SGLT2 inhibitor trials including CANVAS, EMPEROR, Outcome, and DECLARE, was that there seems to be, as Subodh has said, reductions that are relatively consistent in heart failure and renal outcomes. But there was what appears to be ischemic outcomes, the MACE outcomes, cardiovascular death, MI and stroke. In fact, in a meta-analysis that we published at the same time as the primary paper for DECLARE, we demonstrated that there was an interaction between the primary prevention in the population, those without established cardiovascular disease, and the secondary prevention population as it relates to MACE, where the benefits for MACE seem to be in the secondary prevention population. So, this was seen in DECLARE as well, and so we hypothesized that the population of patients who had myocardial infarction as their entering condition may be particularly at high risk for MACE and it may potentially be that that was driving the benefit. And so, what we did was we stratified the patients based on history of prior myocardial infarction versus none, turned out that there was about 3,500 patients in the trial who had had a prior myocardial infarction. As would be expected from what's known about the conditions, the event rates for those patients in the placebo arm were much higher, about 2.5 times higher than patients without myocardial infarction for MACE, also true for CV death and hospitalization for heart failure. And then what we saw when we looked at the treatment outcomes was that there tended to be a greater reduction in MACE for patients with prior myocardial infarction. In fact, for the MACE outcome, we saw about a 16% reduction in MACE with patients with prior MI compared to reduction with patients without prior MI. And so, the combination of this higher risk, also a tendency towards a greater relative benefit lead to a much greater absolute benefit, where, in fact, we saw about a 2.5% reduction in MACE over the four-year period for patients with prior MI, compared to a 0% reduction for patients without prior MI. And, in fact, when we broke this down to three groups: patients with prior MI, patients with atherosclerotic cardiovascular disease without prior MI, and then patients with no atherosclerotic vascular disease, essentially, we saw the same thing, which is that patients with MI were the ones who had the greatest benefit in terms of MACE. And this was almost entirely driven by reductions in myocardial infarction. Now, I would say in contradistinction, as we look at heart failure reductions, the relative benefits for heart failure were similar among these groups, but because the risk was higher in the patients with prior MI, and of course the absolute benefits were greater in the MI population, and similar for renal outcome. So, I think that this sort of extends what we have previously known that patients with atherosclerotic cardiovascular disease were at higher risk intended to have greater benefit with the SGLT2 inhibitors on MACE events that the core of that appears to be those patients with myocardial infarction. Dr Carolyn Lam: Thanks, Steve, that was just so clearly explained. Darren, in the last couple of minutes could I ask you to give us the take-home messages from these two studies, and maybe just, what next? Dr Darren McGuire: I think the take-home message from these two studies in the context of the overall field of SGLT2 inhibitor data, I think the picture's becoming relatively clear and Subodh stated in eloquently before and is reviewed in the editorial is that I think across the board, and independent of how you define higher versus lower risk subsets, this class of medications in general and dapagliflozin, and these studies appear to have augmented benefit, the greater the risk. Whether that greater risk is defined by prior myocardial infarction, or heart failure with reduced ejection fraction, or decreased EGFR, these are all states where various sub studies have consistently shown across the three compounds where we have outcomes data that the treatment benefits are amplified in the higher risk patients. And it's not just an absolute risk reduction that's augmented based on baseline risk, but there appears to be an interaction where the relative risk reduction is also amplified. And so, it's really a remarkable field and it's providing therapeutic options in these really high-risk subsets of patients where we've really been handicapped up until now with these antihyperglycemic therapies for type ii diabetes. Dr Carolyn Lam: Thank you everybody for joining us today. This was truly a bonanza feature discussion, didn't I tell you? You've been listening to Circulation on the Run, thank you for listening today and don't forget to tune in again next week. This program is copyright American Heart Association 2019
Dr Escudier talks to ecancertv at ASCO GU 2016 about how patients with advanced kidney cancer live for nearly twice as long without their disease progressing if they are treated with cabozantinib, a small molecule tyrosine kinase inhibitor (TKI) that targets c-MET, VEGFR2 and AXL. In the interview he discusses the results of the open-label METEOR trial, which compared the TKI against everolimus, a standard of care in mRCC. The METEOR trial met its primary endpoint of improved progression free survival, and subgroup analyses of the endpoints progression free survival and overall response rate generally favoured cabozantinib over everolimus in patients with advanced RCC.
Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 06/06
Endothelial cell (EC) migration is an essential process in angiogenesis as ECs sprout from preexisting vessels, following chemotactic gradients. However, most of the data obtained about EC migration has been acquired in artificial two dimensional (2D) cell culture environments. Recent reports showed that migration in fibrillary environments can be mimicked by spatial confinement, achieved by micro patterning techniques (Doyle et al. 2009). In the first part of this work it was investigated whether a model system based on linearly structured surfaces allows to draw conclusions about the migration of ECs in fibrillary 3D collagen matrices. In order to estimate the cellular behavior of ECs on linearly structured surfaces, a comprehensive cell biological analysis was performed. ECs on narrow 3 µm wide tracks (also termed 1D in the following) migrated less efficient in comparison to ECs on broader tracks in regard to mean velocity, persistence, and run velocity. Additionally, ECs in 1D displayed a distinct actin cytoskeleton architecture, compressed nuclei, and different orientation of the centrosome in comparison to ECs on wider tracks. The frequent directional changes of ECs on narrow tracks were accompanied by pronounced membrane blebbing, while migrating and elongated cells displayed a lamellipodium as cellular protrusion. This behavior was contractility-dependent as both modes were provoked by using Blebbistatin or Calyculin A, respectively. The comparison between 1D and 3D migrating cells revealed a striking similarity in actin cytoskeleton architecture and in switching between two morphological modes. Cells migrating in 3D moved slower but more persistent after Blebbistatin treatment, which was likewise the case for cells migrating in 1D. In contrast to this, cells in the 2D system migrated faster but less persistent after Blebbistatin treatment. A Rac1 inhibitor used in this study showed the tendency to influence the migratory potential similarly in 1D and 3D, in contrast to 2D. However, a microtubule disrupting agent displayed different effects in 1D and 3D. These experiments demonstrated that the 1D system allows to draw conclusions about certain aspects of 3D migration. Thus, using this 1D migration system, important aspects of 3D migration can be mimicked in a highly controlled setting. In the second part of this work, a system for artificial tip cell formation was investigated. For the analysis of tip and stalk cells specifically structured surfaces were designed. These structures provided areas allowing only a restricted number of cell-cell contacts and areas allowing a high number of cell-cell contacts. ECs with a low number of cell-cell contacts displayed increased VEGFR2 expression levels in comparison to cells with a high number of cell-cell contacts, a phenomenon which was inhibited by using a Notch signaling inhibitor. This system will be a useful tool in the future to decipher tip and stalk cell competition within a defined cellular population and a defined microscopic frame
Prof Toni Choueiri - Dana-Farber Cancer Institute, Boston, USA Prof Choueiri talks to ecancertv at ECC 2015 about how patients with advanced kidney cancer live for nearly twice as long without their disease progressing if they are treated with cabozantinib, a small molecule tyrosine kinase inhibitor (TKI) that targets c-MET, VEGFR2 and AXL.. In the interview he discussed the results of the open-label METEOR trial, which compared the TKI against everolimus, a standard of care in mRCC.
Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 04/06
Tue, 27 Jul 2010 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/11876/ https://edoc.ub.uni-muenchen.de/11876/1/Suphansa_Sawamiphak.pdf Sawamiphak, Suphansa ddc:570, ddc:500, Fakultät für Biolo
Fakultät für Biologie - Digitale Hochschulschriften der LMU - Teil 03/06
Tue, 16 Mar 2010 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/12090/ https://edoc.ub.uni-muenchen.de/12090/1/Jellbauer_Stefan.pdf Jellbauer, Stefan
Marco Presta, Department Biomedical Sciences and Biotechnology, School of Medicine, University of Brescia, ITALY speaks on "The pro-angiogenic cystine-knot protein rm/gremlin-1 is a novel VEGFR2 agonist". This seminar has been recorded by ICGEB
Fakultät für Chemie und Pharmazie - Digitale Hochschulschriften der LMU - Teil 03/06
Efficient and safe protein nanoparticles for the targeted delivery of small molecule, protein and oligonucleotide based drugs will play a key role in the field of science in the upcoming years. Whereas viral and liposomal formulations have been extensively tested throughout the last two decades, their inherent and in the case of viruses sometimes even fatal obstacles not seldom seem impossible to conquer. The time for the development of a new therapeutic option in form of an advanced drug delivery system within pharmaceutical technology, biopharmacy and clinical studies has come. In our eyes gelatin based nanoparticles with polysaccharide and peptide modifications are an optimum to fulfil this need and will therefore be the center of the research presented in this work. Basically, nanoparticles with a size from 150 to 300 nm were prepared by desolvating a clear solution of gelatin through dropwise addition of an organic anti-solvent under heavy stirring. A subsequent destabilization of the water soluble protein chains resulted in round particles with a homogenous size distribution and an even surface. Initially, the polymers used for the formulation of the nanoparticles were characterized by such methods like asymmetric flow field-flow fractionation and nuclear magnetic resonance spectroscopy. Furthermore, established measurement and calculation algorithms were revised into state-of-the-art technology and applied as so called automatic microviscosimetry for in- depth protein analysis. The development of novel nanoparticle formulations based on these polymers was done in a second step using diethyl-amino-ethanol-dextran, polysorbate and polyethylene glycol, as well as methylation and acetylation chemistry. While the modified dextran mainly increased the zeta potential of the nanoparticles, the other modifications were intended to change the pharmacokinetic distribution patterns towards e.g. prolonged circulation times. In novel nanoparticle cytology science the use of a flow chamber device for cell cultivation allowed us to study the interaction patterns of nanoparticles with adherent cells under near to physiological conditions simulating blood vessels, junctions and shear stress. This in-vitro model can be used for online preclinical and high-throughput screenings of new nanoparticle and protein formulations with cell monolayers. The hindrances in traditional static cell culture models were shown to be overcome by comparing several nanoparticle formulations in a static and in a flow model. Proper nanoparticle formulations were tested further in innovative preclinical in-vivo models like the hamster dorsal skin fold chamber and the mouse cremaster model to elucidate their body distribution and targeting properties with a focus on kinetics, blood cell interaction and novel fluorescence detection techniques. In addition, the potential of gelatin nanoparticles as therapeutic options in a model for antigen induced arthritis was demonstrated. Finally, hybrid (sandwich) nanoparticles were formulated by combining gelatin nanoparticle preformulations with the endosomolytic peptide Melittin from bee venom and loading them with small interfering RNA molecules against VEGFR2 and luciferase. The novel hybrid carriers were extensively tested in cell cultures towards their efficiency to induce a protein knock-down based on RNA interference. With these results the door for further, more profound in-vivo studies in the field of oncology might be opened.
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