Podcasts about annexin v

BUFFALO, NY- March 25, 2024 – A new #research paper was #published in Oncotarget's Volume 15 on March 14, 2024, entitled, “ABT199/venetoclax synergism with thiotepa enhances the cytotoxicity of fludarabine, cladribine and busulfan in AML cells.” ABT199/venetoclax, an inhibitor of the pro-survival BCL-2 protein, has improved AML treatment. Its efficacy in hematopoietic stem cell transplantation (HSCT), when combined with other chemotherapeutic drugs, has not been thoroughly investigated. In this new study, researchers Benigno C. Valdez, Bin Yuan, David Murray, Jeremy L. Ramdial, Uday Popat, Yago Nieto, and Borje S. Andersson from The University of Texas MD Anderson Cancer Center and the University of Alberta demonstrate the synergistic cytotoxicity of ABT199/venetoclax with the DNA alkylator thiotepa (Thio) in AML cells. “The results may provide relevant information for the design of clinical trials using these drugs to circumvent recognized drug-resistance mechanisms when used as part of pre-transplant conditioning regimens for AML patients undergoing allogenic HSCT.” Cleavage of Caspase 3, PARP1 and HSP90, as well as increased Annexin V positivity, suggest potent activation of apoptosis by this two-drug combination; increased levels of γ-H2AX, P-CHK1 (S317), P-CHK2 (S19) and P-SMC1 (S957) indicate an enhanced DNA damage response. Likewise, the increased level of P-SAPK/JNK (T183/Y185) and decreased P-PI3Kp85 (Y458) suggest enhanced activation of stress signaling pathways. These molecular readouts were synergistically enhanced when ABT199/venetoclax and Thio were combined with fludarabine, cladribine and busulfan. The five-drug combination decreased the levels of BCL-2, BCL-xL and MCL-1, suggesting its potential clinical relevance in overcoming ABT199/venetoclax resistance. Moreover, this combination is active against P53-negative and FLT3-ITD-positive cell lines. Enhanced activation of apoptosis was observed in leukemia patient-derived cell samples exposed to the five-drug combination, suggesting a clinical relevance. “The results provide a rationale for clinical trials using these two- and five-drug combinations as part of a conditioning regimen for AML patients undergoing HSCT.” DOI - https://doi.org/10.18632/oncotarget.28563 Correspondence to - Benigno C. Valdez - mbalasik@yahoo.com Sign up for free Altmetric alerts about this article - https://oncotarget.altmetric.com/details/email_updates?id=10.18632%2Foncotarget.28563 Subscribe for free publication alerts from Oncotarget - https://www.oncotarget.com/subscribe/ Keywords - cancer, acute myeloid leukemia, aml, pre-transplant regimens, venetoclax, thiotepa, busulfan 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. Oncotarget is indexed and archived by PubMed/Medline, PubMed Central, Scopus, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science). To learn more about Oncotarget, please visit https://www.oncotarget.com and connect with us: Facebook - https://www.facebook.com/Oncotarget/ X - https://twitter.com/oncotarget Instagram - https://www.instagram.com/oncotargetjrnl/ YouTube - https://www.youtube.com/@OncotargetJournal LinkedIn - https://www.linkedin.com/company/oncotarget Pinterest - https://www.pinterest.com/oncotarget/ Reddit - https://www.reddit.com/user/Oncotarget/ Spotify - https://open.spotify.com/show/0gRwT6BqYWJzxzmjPJwtVh Media Contact MEDIA@IMPACTJOURNALS.COM 18009220957

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.24.059584v1?rss=1 Authors: Scott-Hewitt, N. J., Perrucci, F., Morini, R., Erreni, M., Mahoney, M., Witkowska, A., Carey, A., Faggiani, E., Schutz, L. T., Mason, S., Tamborini, M., Passoni, L., Filipello, F., Jahn, R., Stevens, B., Matteoli, M. Abstract: Neuronal circuits assembly requires the fine equilibrium between synapse formation and elimination. Microglia, through the elimination of supernumerary synapses, have an established role in this process. While the microglial receptor TREM2 and the soluble complement proteins C1q and C3 are recognized key players in this process, the neuronal molecular components that tag synapses to be eliminated are still undefined. Here we show that exposed phosphatidylserine (PS) represents a neuronal "eat-me" signal enabling microglial-mediated synapse pruning. In hippocampal neuron and microglia co-cultures, synapse elimination can be prevented by blocking accessibility of exposed PS using Annexin V or through microglial loss of TREM2. In vivo, exposed PS is detectable at both hippocampal and retinogeniculate synapses, where exposure coincides with the onset of synapse elimination and increased PS engulfment by microglia. Mice deficient in C1q, which fail to properly refine retinogeniculate connections, display elevated exposed PS and reduced PS engulfment by microglia. These data provide mechanistic insight into microglial-mediated synapse pruning and identify a novel role of developmentally regulated PS exposure that is common among developing brain structures. Copy rights belong to original authors. Visit the link for more info

Mutations in the gene coding for the ATP binding cassette protein A3 (ABCA3) are known as the most frequent genetic cause of fatal neonatal respiratory distress syndrome and chronic interstitial lung disease (ILD) of children. ABCA3 transporter is localized to the limiting membrane of lamellar bodies, organelles for assembly and storage of pulmonary surfactant in alveolar epithelial type II cells. It transports surfactant phospholipids into lamellar bodies and is essential for their biogenesis. ABCA3 mutations can result in either functional defects of the correctly localized ABCA3 or trafficking/folding defects where mutated ABCA3 remains in the endoplasmic reticulum (ER). This study showed previously not examined cellular dysfunction in cultured lung epithelial A549 cells overexpressing the three ABCA3 mutations R43L, R280C and L101P. All three mutations were found in children with ABCA3-associated lung disease either with fatal neonatal respiratory distress syndrome (L101P and R43L) or chronic pediatric ILD (R280C). Cell biology of R43L and R280C mutations was studied here for the first time. L101P mutation was used as a known example of the trafficking/folding defect leading to the ER retention of ABCA3 protein. Human lung epithelial A549 cells were transfected with vectors containing wild type ABCA3 or one of the three ABCA3 mutant forms, R43L, R280C and L101P, C-terminally tagged with YFP or hemagglutinin-tag. Localization/trafficking properties were analyzed by immunofluorescence and ABCA3 deglycosylation. Uptake of fluorescent NBD-labeled lipids into lamellar bodies was used as a functional assay. ER stress and apoptotic signaling were examined through RT-PCR based analyses of XBP1 splicing, immunoblotting or FACS analyses of stress- and apoptosis-proteins, Annexin V surface staining and determination of the intracellular glutathion level. Induction of epithelial-mesenchymal transition (EMT) was assessed by immunoblotting. It was demonstrated that two ABCA3 mutations, which affect ABCA3 protein trafficking/folding and lead to partial (R280C) or complete (L101P) retention of ABCA3 in the ER compartment, can elevate ER stress and susceptibility to it and induce apoptosis in A549 cells. A549 cells expressing L101P additionally gain a mesenchymal phenotype. R43L mutation, resulting in a functional defect of the properly localized ABCA3, had no effect on intracellular stress and apoptotic signaling. These data suggest that expression of partially or completely ER localized ABCA3 mutant proteins induce raised intracellular stress and apoptotic cell death of the affected cells, which are factors that might contribute to the pathogenesis of genetic ILD via a fatal ER-stress/apoptosis/fibrogenesis-axis.

Background: ABCA3 transporter (ATP-binding cassette transporter of the A subfamily) is localized to the limiting membrane of lamellar bodies, organelles for assembly and storage of pulmonary surfactant in alveolar epithelial type II cells (AECII). It transports surfactant phospholipids into lamellar bodies and absence of ABCA3 function disrupts lamellar body biogenesis. Mutations of the ABCA3 gene lead to fatal neonatal surfactant deficiency and chronic interstitial lung disease (ILD) of children. ABCA3 mutations can result in either functional defects of the correctly localized ABCA3 or trafficking/folding defects where mutated ABCA3 remains in the endoplasmic reticulum (ER). Methods: Human alveolar epithelial A549 cells were transfected with vectors expressing wild-type ABCA3 or one of the three ABCA3 mutant forms, R43L, R280C and L101P, C-terminally tagged with YFP or hemagglutinin-tag. Localization/trafficking properties were analyzed by immunofluorescence and ABCA3 deglycosylation. Uptake of fluorescent NBD-labeled lipids into lamellar bodies was used as a functional assay. ER stress and apoptotic signaling were examined through RT-PCR based analyses of XBP1 splicing, immunoblotting or FACS analyses of stress/apoptosis proteins, Annexin V surface staining and determination of the intracellular glutathion level. Results: We demonstrate that two ABCA3 mutations, which affect ABCA3 protein trafficking/folding and lead to partial (R280C) or complete (L101P) retention of ABCA3 in the ER compartment, can elevate ER stress and susceptibility to it and induce apoptotic markers in the cultured lung epithelial A549 cells. R43L mutation, resulting in a functional defect of the properly localized ABCA3, had no effect on intracellular stress and apoptotic signaling. Conclusion: Our data suggest that expression of partially or completely ER localized ABCA3 mutant proteins can increase the apoptotic cell death of the affected cells, which are factors that might contribute to the pathogenesis of genetic ILD.

Endothelial cell survival is indispensable to maintain endothelial integrity and initiate new vessel formation. We investigated the role of SHP-2 in proliferation, survival and sprouting of human microvascular- and umbilical vein endothelial cells (HMEC, HUVEC) using antisense oligonucleotides (AS-ODN) and a pharmacological SHP-2 inhibitor (PtpI IV). Knock-down of SHP-2 decreased bFGF and PDGF dependent endothelial cell proliferation (p

A broad variety of tumor cells express Hsp70 on their cell surface. These tumor cells are more sensitive to the lysis mediated by NK cells. Here, it was shown that the 14mer peptide TKD (TKDNNLLGRFELSG, aa450-463) derived from the C-terminus of Hsp70 is the minimal sequence of Hsp70 that has the capacity to activate NK cells. NK cells incubated with low dose IL-2 (100 IU/ml) plus TKD (2 µg/ml) showed an enhanced proliferative capacity and an enhanced cytolytic activity and migratory capacity against Hsp70 membrane-positive tumor cells. Furterhmore, secretion of the cytokines IFN-g and TNF-a was enhanced. TKD stimulated NK cells also showed enhanced intracellular levels of the serine protease granzyme B. Since binding of fulllength Hsp70 protein and TKD to NK cells was specific and concentration-dependent, an involvement of a Hsp70 specific receptor was hypothesized. It was shown that the C-type lectine receptor CD94 is involved in Hsp70/TKD-NK cell interaction: (i) CD94 was upregulated in NK cells after incubation with Hsp70/TKD; (ii) binding of Hsp70 could be inhibited by a CD94 specific antibody; (iii) Hsp70 reactivity correlated with CD94 expression on NK cells; and (iv) Hsp70 reactivity of NK cells could be inhibited by a CD94 specific antibody. Finally, the mechanism of lysis of Hsp70 membrane-positive tumor cells by NK cells could be elucidated. It was shown that the serine protease granzyme B binds to Hsp70/TKD on the cell surface of Hsp70 membrane-positive tumor cells and is specifically taken up by these cells. As demonstrated by different apoptosis assays (Annexin V staining, cytochrome c release, and DAPI staining) granzyme B causes apoptosis specifically in Hsp70 membrane-positive tumor cells, but not in their Hsp70 membrane-negative counterparts.