Podcasts about cdk2

The most enthralling conversation I've ever had with anyone on cancer. It's with Charlie Swanton who is a senior group leader at the Francis Crick Institute, the Royal Society Napier Professor in Cancer and medical oncologist at University College London, co-director of Cancer Research UK.Video snippet from our conversation. Full videos of all Ground Truths podcasts can be seen on YouTube here. The audios are also available on Apple and Spotify.Transcript with audio links and many external linksEric Topol (00:07):Well, hello, this is Eric Topol with Ground Truths, and I am really fortunate today to connect us with Charlie Swanton, who is if not the most prolific researcher in the space of oncology and medicine, and he's right up there. Charlie is a physician scientist who is an oncologist at Francis Crick and he heads up the lung cancer area there. So Charlie, welcome.Charles Swanton (00:40):Thank you, Eric. Nice to meet you.Learning from a FailureEric Topol (00:43):Well, it really is a treat because I've been reading your papers and they're diverse. They're not just on cancer. Could be connecting things like air pollution, it could be Covid, it could be AI, all sorts of things. And it's really quite extraordinary. So I thought I'd start out with a really interesting short paper you wrote towards the end of last year to give a sense about you. It was called Turning a failing PhD around. And that's good because it's kind of historical anchoring. Before we get into some of your latest contributions, maybe can you tell us about that story about what you went through with your PhD?Charles Swanton (01:26):Yeah, well thank you, Eric. I got into research quite early. I did what you in the US would call the MD PhD program. So in my twenties I started a PhD in a molecular biology lab at what was then called the Imperial Cancer Research Fund, which was the sort of the mecca for DNA tumor viruses, if you like. It was really the place to go if you wanted to study how DNA tumor viruses worked, and many of the components of the cell cycle were discovered there in the 80s and 90s. Of course, Paul Nurse was the director of the institute at the time who discovered cdc2, the archetypal regulator of the cell cycle that led to his Nobel Prize. So it was a very exciting place to work, but my PhD wasn't going terribly well. And sort of 18, 19 months into my PhD, I was summoned for my midterm reports and it was not materializing rapidly enough.(02:25):And I sat down with my graduate student supervisors who were very kind, very generous, but basically said, Charlie, this isn't going well, is it? You've got two choices. You can either go back to medical school or change PhD projects. What do you want to do? And I said, well, I can't go back to medical school because I'm now two years behind. So instead I think what I'll do is I'll change PhD projects. And they asked me what I'd like to do. And back then we didn't know how p21, the CDK inhibitor bound to cyclin D, and I said, that's what I want to understand how these proteins interact biochemically. And they said, how are you going to do that? And I said, I'm not too sure, but maybe we'll try yeast two-hybrid screen and a mutagenesis screen. And that didn't work either. And in the end, something remarkable happened.(03:14):My PhD boss, Nic Jones, who's a great guy, still is, retired though now, but a phenomenal scientist. He put me in touch with a colleague who actually works next door to me now at the Francis Crick Institute called Neil McDonald, a structural biologist. And they had just solved, well, the community had just solved the structure. Pavletich just solved the structure of cyclin A CDK2. And so, Neil could show me this beautiful image of the crystal structure in 3D of cyclin A, and we could mirror cyclin D onto it and find the surface residue. So I spent the whole of my summer holiday mutating every surface exposed acid on cyclin D to an alanine until I found one that failed to interact with p21, but could still bind the CDK. And that little breakthrough, very little breakthrough led to this discovery that I had where the viral cyclins encoded by Kaposi sarcoma herpes virus, very similar to cyclin D, except in this one region that I had found interactive with a CDK inhibitor protein p21.(04:17):And so, I asked my boss, what do you think about the possibility this cyclin could have evolved from cyclin D but now mutated its surface residues in a specific area so that it can't be inhibited by any of the control proteins in the mammalian cell cycle? He said, it's a great idea, Charlie, give it a shot. And it worked. And then six months later, we got a Nature paper. And that for me was like, I cannot tell you how exciting, not the Nature paper so much as the discovery that you were the first person in the world to ever see this beautiful aspect of evolutionary biology at play and how this cyclin had adapted to just drive the cell cycle without being inhibited. For me, just, I mean, it was like a dream come true, and I never experienced anything like it before, and I guess it's sizes the equivalent to me of a class A drug. You get such a buzz out of it and over the years you sort of long for that to happen again. And occasionally it does, and it's just a wonderful profession.Eric Topol (05:20):Well, I thought that it was such a great story because here you were about to fail. I mean literally fail, and you really were able to turn it around and it should give hope to everybody working in science out there that they could just be right around the corner from a significant discovery.Charles Swanton (05:36):I think what doesn't break you makes you stronger. You just got to plow on if you love it enough, you'll find a way forward eventually, I hope.Tracing the Evolution of Cancer (TRACERx)Eric Topol (05:44):Yeah, no question about that. Now, some of your recent contributions, I mean, it's just amazing to me. I just try to keep up with the literature just keeping up with you.Charles Swanton (05:58):Eric, it's sweet of you. The first thing to say is it's not just me. This is a big community of lung cancer researchers we have thanks to Cancer Research UK funded around TRACERx and the lung cancer center. Every one of my papers has three corresponding authors, multiple co-first authors that all contribute in this multidisciplinary team to the sort of series of small incremental discoveries. And it's absolutely not just me. I've got an amazing team of scientists who I work with and learn from, so it's sweet to give me the credit.Eric Topol (06:30):I think what you're saying is really important. It is a team, but I think what I see through it all is that you're an inspiration to the team. You pull people together from all over the world on these projects and it's pretty extraordinary, so that's what I would say.Charles Swanton (06:49):The lung community, Eric, the lung cancer community is just unbelievably conducive to collaboration and advancing understanding of the disease together. It's just such a privilege to be working in this field. I know that sounds terribly corny, but it is true. I don't think I recall a single email to anybody where I've asked if we can collaborate where they've said, no, everybody wants to help. Everybody wants to work together on this challenge. It's just such an amazing field to be working in.Eric Topol (07:19):Yeah. Well I was going to ask you about that. And of course you could have restricted your efforts or focused on different cancers. What made you land in lung cancer? Not that that's only part of what you're working on, but that being the main thing, what drew you to that area?Charles Swanton (07:39):So I think the answer to your question is back in 2008 when I was looking for a niche, back then it was lung cancer was just on the brink of becoming an exciting place to work, but back then nobody wanted to work in that field. So there was a chair position in thoracic oncology and precision medicine open at University College London Hospital that had been open, as I understand it for two years. And I don't think anybody had applied. So I applied and because I was the only one, I got it and the rest is history.(08:16):And of course that was right at the time when the IPASS draft from Tony Mok was published and was just a bit after when the poster child of EGFR TKIs and EGFR mutant lung cancer had finally proven that if you segregate that population of patients with EGFR activating mutation, they do incredibly well on an EGFR inhibitor. And that was sort of the solid tumor poster child along with Herceptin of precision medicine, I think. And you saw the data at ASCO this week of Lorlatinib in re-arranged lung cancer. Patients are living way beyond five years now, and people are actually talking about this disease being more like CML. I mean, it's extraordinary the progress that's been made in the last two decades in my short career.Eric Topol (09:02):Actually, I do want to have you put that in perspective because it's really important what you just mentioned. I was going to ask you about this ASCO study with the AKT subgroup. So the cancer landscape of the lung has changed so much from what used to be a disease of cigarette smoking to now one of, I guess adenocarcinoma, non-small cell carcinoma, not related to cigarettes. We're going to talk about air pollution in a minute. This group that had, as you say, 60 month, five year plus survival versus what the standard therapy was a year plus is so extraordinary. But is that just a small subgroup within small cell lung cancer?Charles Swanton (09:48):Yes, it is, unfortunately. It's just a small subgroup. In our practice, probably less than 1% of all presentations often in never smokers, often in female, never smokers. So it is still in the UK at least a minority subset of adenocarcinomas, but it's still, as you rightly say, a minority of patients that we can make a big difference to with a drug that's pretty well tolerated, crosses the blood-brain barrier and prevents central nervous system relapse and progression. It really is an extraordinary breakthrough, I think. But that said, we're also seeing advances in smoking associated lung cancer with a high mutational burden with checkpoint inhibitor therapy, particularly in the neoadjuvant setting now prior to surgery. That's really, really impressive indeed. And adjuvant checkpoint inhibitor therapies as well as in the metastatic setting are absolutely improving survival times and outcomes now in a way that we couldn't have dreamt of 15 years ago. We've got much more than just platinum-based chemo is basically the bottom line now.Revving Up ImmunotherapyEric Topol (10:56):Right, right. Well that actually gets a natural question about immunotherapy also is one of the moving parts actually just amazing to me how that's really, it's almost like we're just scratching the surface of immunotherapy now with checkpoint inhibitors because the more we get the immune system revved up, the more we're seeing results, whether it's with vaccines or CAR-T, I mean it seems like we're just at the early stages of getting the immune system where it needs to be to tackle the cancer. What's your thought about that?Charles Swanton (11:32):I think you're absolutely right. We are, we're at the beginning of a very long journey thanks to Jim Allison and Honjo. We've got CTLA4 and PD-1/PDL-1 axis to target that's made a dramatic difference across multiple solid tumor types including melanoma and lung cancer. But undoubtedly, there are other targets we've seen LAG-3 and melanoma and then we're seeing new ways, as you rightly put it to mobilize the immune system to target cancers. And that can be done through vaccine based approaches where you stimulate the immune system against the patient's specific mutations in their cancer or adoptive T-cell therapies where you take the T-cells out of the tumor, you prime them against the mutations found in the tumor, you expand them and then give them back to the patient. And colleagues in the US, Steve Rosenberg and John Haanen in the Netherlands have done a remarkable job there in the context of melanoma, we're not a million miles away from European approvals and academic initiated manufacturing of T-cells for patients in national health systems like in the Netherlands.(12:50):John Haanen's work is remarkable in that regard. And then there are really spectacular ways of altering T-cells to be able to either migrate to the tumor or to target specific tumor antigens. You mentioned CAR-T cell therapies in the context of acute leukemia, really extraordinary developments there. And myeloma and diffuse large B-cell lymphoma as well as even in solid tumors are showing efficacy. And I really am very excited about the future of what we call biological therapies, be it vaccines, an antibody drug conjugates and T-cell therapies. I think cancer is a constantly adapting evolutionary force to be reckoned with what better system to combat it than our evolving immune system. It strikes me as being a future solution to many of these refractory cancers we still find difficult to treat.Eric Topol (13:48):Yeah, your point is an interesting parallel how the SARS-CoV-2 virus is constantly mutating and becoming more evasive as is the tumor in a person and the fact that we can try to amp up the immune system with these various means that you just were reviewing. You mentioned the other category that's very hot right now, which is the antibody drug conjugates. Could you explain a bit about how they work and why you think this is an important part of the future for cancer?Antibody-Drug ConjugatesCharles Swanton (14:26):That's a great question. So one of the challenges with chemotherapy, as you know, is the normal tissue toxicity. So for instance, neutropenia, hair loss, bowel dysfunction, diarrhea, epithelial damage, essentially as you know, cytotoxics affect rapidly dividing tissues, so bone marrow, epithelial tissues. And because until relatively recently we had no way of targeting chemotherapy patients experienced side effects associated with them. So over the last decade or so, pioneers in this field have brought together this idea of biological therapies linked with chemotherapy through a biological linker. And so one poster chart of that would be the drug T-DXd, which is essentially Herceptin linked to a chemotherapy drug. And this is just the most extraordinary drug that obviously binds the HER2 receptor, but brings the chemotherapy and proximity of the tumor. The idea being the more drug you can get into the tumor and the less you're releasing into normal tissue, the more on tumor cytotoxicity you'll have and the less off tumor on target normal tissue side effects you'll have. And to a large extent, that's being shown to be the case. That doesn't mean they're completely toxicity free, they're not. And one of the side effects associated with these drugs is pneumonitis.(16:03):But that said, the efficacy is simply extraordinary. And for example, we're having to rewrite the rule books if you like, I think. I mean I'm not a breast cancer physician, I used to be a long time ago, but back in the past in the early 2000s, there was HER2 positive breast cancer and that's it. Now they're talking about HER2 low, HER2 ultra-low, all of which seem to in their own way be sensitive to T-DXd, albeit to a lower extent than HER2 positive disease. But the point is that there doesn't seem to be HER2 completely zero tumor group in breast cancer. And even the HER2-0 seem to benefit from T-DXd to an extent. And the question is why? And I think what people are thinking now is it's a combination of very low cell service expression of HER2 that's undetectable by conventional methods like immunohistochemistry, but also something exquisitely specific about the way in which HER2 is mobilized on the membrane and taken back into the cell. That seems to be specific to the breast cancer cell but not normal tissue. So in other words, the antibody drug conjugate binds the tumor cell, it's thought the whole receptor's internalized into the endosome, and that's where the toxicity then happens. And it's something to do with the endosomal trafficking with the low level expression and internalization of the receptor. That may well be the reason why these HER2 low tumors are so sensitive to this beautiful technology.Eric Topol (17:38):Now I mean it is an amazing technology in all these years where we just were basically indiscriminately trying to kill cells and hoping that the cancer would succumb. And now you're finding whether you want to call it a carry or vector or Trojan horse, whatever you want to call it, but do you see that analogy of the HER2 receptor that's going to be seen across the board in other cancers?Charles Swanton (18:02):That's the big question, Eric. I think, and have we just lucked out with T-DXd, will we find other T-DXd like ADCs targeting other proteins? I mean there are a lot of ADCs being developed against a lot of different cell surface proteins, and I think the jury's still out. I'm confident we will, but we have to bear in mind that biology is a fickle friend and there may be something here related to the internalization of the receptor in breast cancer that makes this disease so exquisitely sensitive. So I think we just don't know yet. I'm reasonably confident that we will find other targets that are as profoundly sensitive as HER2 positive breast cancer, but time will tell.Cancer, A Systemic DiseaseEric Topol (18:49):Right. Now along these lines, well the recent paper that you had in Cell, called embracing cancer complexity, which we've talking about a bit, in fact it's kind of those two words go together awfully well, but hallmarks of systemic disease, this was a masterful review, as you say with the team that you led. But can you tell us about what's your main perspective about this systemic disease? I mean obviously there's been the cancer is like cardiovascular and cancers like this or that, but here you really brought it together with systemic illness. What can you say about that?Charles Swanton (19:42):Well, thanks for the question first of all, Eric. So a lot of this comes from some of my medical experience of treating cancer and thinking to myself over the years, molecular biology has had a major footprint on advances in treating the disease undoubtedly. But there are still aspects of medicine where molecular biology has had very little impact, and often that is in areas of suffering in patients with advanced disease and cancer related to things like cancer cachexia, thrombophilia. What is the reason why patients die blood clots? What is the reason patients die of cancer at all? Even a simple question like that, we don't always know the answer to, on death certificates, we write metastatic disease as a cause of cancer death, but we have patients who die with often limited disease burden and no obvious proximal cause of death sometimes. And that's very perplexing, and we need to understand that process better.(20:41):And we need to understand aspects like cancer pain, for example, circadian rhythms affect biological sensitivity of cancer cells to drugs and what have you. Thinking about cancer rather than just sort of a single group of chaotically proliferating cells to a vision of cancer interacting both locally within a microenvironment but more distantly across organs and how organs communicate with the cancer through neuronal networks, for example, I think is going to be the next big challenge by setting the field over the next decade or two. And I think then thinking about more broadly what I mean by embracing complexity, I think some of that relates to the limitations of the model systems we use, trying to understand inter-organ crosstalk, some of the things you cover in your beautiful Twitter reviews. (←Ground Truths link) I remember recently you highlighted four publications that looked at central nervous system, immune cell crosstalk or central nervous system microbiome crosstalk. It's this sort of long range interaction between organs, between the central nervous system and the immune system and the cancer that I'm hugely interested in because I really think there are vital clues there that will unlock new targets that will enable us to control cancers more effectively if we just understood these complex networks better and had more sophisticated animal model systems to be able to interpret these interactions.Eric Topol (22:11):No, it's so important what you're bringing out, the mysteries that still we have to deal with cancer, why patients have all these issues or dying without really knowing what's happened no less, as you say, these new connects that are being discovered at a remarkable pace, as you mentioned, that ground truths. And also, for example, when I spoke with Michelle Monje, she's amazing on the cancer, where hijacking the brain cells and just pretty extraordinary things. Now that gets me to another line of work of yours. I mean there are many, but the issue of evolution of the tumor, and if you could put that in context, a hot area that's helping us elucidate these mechanisms is known as spatial omics or spatial biology. This whole idea of being able to get the spatial temporal progression through single cell sequencing and single cell nuclei, all the single cell omics. So if you could kind of take us through what have we learned with this technique and spatial omics that now has changed or illuminated our understanding of how cancer evolves?Charles Swanton (23:37):Yeah, great question. Well, I mean I think it helps us sort of rewind a bit and think about evolution in general. Genetic selection brought about by diverse environments and environmental pressures that force evolution, genetic evolution, and speciation down certain evolutionary roots. And I think one can think about cancers in a similar way. They start from a single cell and we can trace the evolutionary paths of cancers by single cell analysis as well as bulk sequencing of spatially separated tumor regions to be able to reconstruct their subclones. And that's taught us to some extent, what are the early events in tumor evolution? What are the biological mechanisms driving branched evolution? How does genome instability begin in tumors? And we found through TRACERx work, whole genome doubling is a major route through to driving chromosome instability along with mutagenic enzymes like APOBEC that drive both mutations and chromosomal instability.(24:44):And then that leads to a sort of adaptive radiation in a sense, not dissimilar to I guess the Cambrian explosion of evolutionary opportunity upon which natural selection can act. And that's when you start to see the hallmarks of immune evasion like loss of HLA, the immune recognition molecules that bind the neoantigens or even loss of the neoantigens altogether or mutation of beta 2 microglobulin that allow the tumor cells to now evolve below the radar, so to speak. But you allude to the sort of spatial technologies that allow us to start to interpret the microenvironments as well. And that then tells us what the evolutionary pressures are upon the tumor. And we're learning from those spatial technologies that these environments are incredibly diverse, actually interestingly seem to be converging on one important aspect I'd like to talk to you a little bit more about, which is the myeloid axis, which is these neutrophils, macrophages, et cetera, that seem to be associated with poor outcome and that will perhaps talk about pollution in a minute.(25:51):But I think they're creating a sort of chronic inflammatory response that allows these early nascent tumor cells to start to initiate into frankly tumor invasive cells and start to grow. And so, what we're seeing from these spatial technologies in lung cancer is that T-cells, predatory T-cells, force tumors to lose their HLA molecules and what have you to evade the immune system. But for reasons we don't understand, high neutrophil infiltration seems to be associated with poor outcome, poor metastasis free survival. And actually, those same neutrophils we've recently found actually even tracked to the metastasis sites of metastasis. So it's almost like this sort of symbiosis between the myeloid cells and the tumor cells in their biology and growth and progression of the tumor cells.Eric Topol (26:46):Yeah, I mean this white cell story, this seems to be getting legs and is relatively new, was this cracked because of the ability to do this type of work to in the past everything was, oh, it's cancer's heterogeneous and now we're getting pinpoint definition of what's going on.Charles Swanton (27:04):I think it's certainly contributed, but it's like everything in science, Eric, when you look back, there's evidence in the literature for pretty much everything we've ever discovered. You just need to put the pieces together. And I mean one example would be the neutrophil lymphocyte ratio in the blood as a hallmark of outcome in cancers and to checkpoint inhibitor blockade, maybe this begins to explain it, high neutrophils, immune suppressive environment, high neutrophils, high macrophages, high immune suppression, less benefit from checkpoint inhibitor therapy, whereas you want lymphocyte. So I think there are biomedical medical insights that help inform the biology we do in the lab that have been known for decades or more. And certainly the myeloid M2 axis in macrophages and what have you was known about way before these spatial technologies really came to fruition, I think.The Impact of Air PollutionEric Topol (28:01):Yeah. Well you touched on this about air pollution and that's another dimension of the work that you and your team have done. As you well know, there was a recent global burden of disease paper in the Lancet, which has now said that air pollution with particulate matter 2.5 less is the leading cause of the burden of disease in the world now.Charles Swanton (28:32):What did you think of that, Eric?Eric Topol (28:34):I mean, I was blown away. Totally blown away. And this is an era you've really worked on. So can you put it in perspective?Charles Swanton (28:42):Yeah. So we got into this because patients of mine, and many of my colleagues would ask the same question, I've never smoked doctor, I'm healthy. I'm in my mid 50s though they're often female and I've got lung cancer. Why is that doctor? I've had a good diet, I exercise, et cetera. And we didn't really have a very good answer for that, and I don't want to pretend for a minute we solved the whole problem. I think hopefully we've contributed to a little bit of understanding of why this may happen. But that aside, we knew that there were risk factors associated with lung cancer that included air pollution, radon exposure, of course, germline genetics, we mustn't forget very important germline variation. And I think there is evidence that all of them are associated with lung cancer risk in different ways. But we wanted to look at air pollution, particularly because there was an awful lot of evidence, several meta-analysis of over half a million individuals showing very convincingly with highly significant results that increasing PM 2.5 micron particulate levels were associated with increased risk of lung cancer.(29:59):To put that into perspective, where you are on the west coast of the US, it's relatively unpolluted. You would be talking about maybe five micrograms per meter cubed of PM2.5 in a place like San Diego or Western California, assuming there aren't any forest fires of course. And we estimate that that would translate to about, we think it's about one extra case of never smoking lung cancer per hundred thousand of the population per year per one microgram per meter cube rise in the pollution levels. So if you go to Beijing for example, on a bad day, the air pollution levels could be upwards of a hundred micrograms per meter cubed because there are so many coal fired power stations in China partly. And there I think the risk is considerably higher. And that's certainly what we've seen in the meta-analyses in our limited and relatively crude epidemiological analyses to be the case.(30:59):So I think the association was pretty certain, we were very confident from people's prior publications  this was important. But of course, association is not causation. So we took a number of animal models and showed that you could promote lung cancer formation in four different oncogene driven lung cancer models. And then the question is how, does air pollution stimulate mutations, which is what I initially thought it would do or something else. It turns out we don't see a significant increase in exogenous like C to A carcinogenic mutations. So that made us put our thinking caps on. And I said to you earlier, often all these discoveries have been made before. Well, Berenblum in 1947, first postulated that actually tumors are initiated through a two-step process, which we now know involves a sort of pre initiated cell with a mutation in that in itself is not sufficient to cause cancer.(31:58):But on top of that you need an inflammatory stimulus. So the question was then, well, okay, is inflammation working here? And we found that there was an interleukin-1 beta axis. And what happens is that the macrophages come into the lung on pollution exposure, engulf phagocytose the air pollutants, and we think what's happening is the air pollutants are puncturing membranes in the lung. That's what we think is happening. And interleukin-1 beta preformed IL-1 beta is being released into the extracellular matrix and then stimulating pre-initiated cells stem cells like the AT2 cells with an activating EGFR mutation to form a tumor. But the EGFR mutation alone is not sufficient to form tumors. It's only when you have the interleukin-1 beta and the activated mutation that a tumor can start.(32:49):And we found that if we sequence normal lung tissue in a healthy adult 60-year-old adult, we will find about half of biopsies will have an activating KRAS mutation in normal tissue, and about 15% will have an activating mutation in EGFR in histologically normal tissue with nerve and of cancer. In fact, my friend and colleague who's a co-author on the paper, James DeGregori, who you should speak to in Colorado, fascinating evolutionary cancer biologists estimates that in a healthy 60-year-old, there are a hundred billion cells in your body that harbor an oncogenic mutation. So that tells you that at the cellular level, cancer is an incredibly rare event and almost never happens. I mean, our lifetime risk of cancer is perhaps one in two. You covered that beautiful pancreas paper recently where they estimated that there may be 80 to 100 KRAS mutations in a normal adult pancreas, and yet our lifetime risk of pancreas cancer is one in 70. So this tells you that oncogenic mutations are rarely sufficient to drive cancer, so something else must be happening. And in the context of air pollution associated lung cancer, we think that's inflammation driven by these white cells, these myeloid cells, the macrophages.Cancer BiomarkersEric Topol (34:06):No, it makes a lot of sense. And this, you mentioned the pancreas paper and also what's going in the lung, and it seems like we have this burden of all you need is a tipping point and air pollution seems to qualify, and you seem to be really in the process of icing the mechanism. And like I would've thought it was just mutagenic and it's not so simple, right? But that gets me to this is such an important aspect of cancer, the fact that we harbor these kind of preconditions. And would you think that cancer takes decades to actually manifest most cancers, or do we really have an opportunity here to be able to track whether it's through blood or other biomarkers? Another area you've worked on a lot whereby let's say you could define people at risk for polygenic risk scores or various cancers or genome sequencing for predisposition genes, whatever, and you could monitor in the future over the course of those high-risk people, whether they were starting to manifest microscopic malignancy. Do you have any thoughts about how long it takes for the average person to actually manifest a typical cancer?Charles Swanton (35:28):That's a cracking question, and the answer is we've got some clues in various cancers. Peter Campbell would be a good person to speak to. He estimates that some of the earliest steps in renal cancer can occur in adolescence. We've had patients who gave up smoking 30 or so years ago where we can still see the clonal smoking mutations in the trunk of the tumor's evolutionary tree. So the initial footprints of the cancer are made 30 years before the cancer presents. That driver mutation itself may also be a KRAS mutation in a smoking cigarette context, G12C mutation. And those mutations can precede the diagnosis of the disease by decades. So the earliest steps in cancer evolution can occur, we think can precede diagnoses by a long time. So to your point, your question which is, is there an opportunity to intervene? I'm hugely optimistic about this actually, this idea of molecular cancer prevention.An Anti-Inflammatory Drug Reduces Fatal Cancer and Lung Cancer(36:41):How can we use data coming out of various studies in the pancreas, mesothelioma, lung, et cetera to understand the inflammatory responses? I don't think we can do very much about the mutations. The mutations unfortunately are a natural consequence of aging. You and I just sitting here talking for an hour will have accumulated multiple mutations in our bodies over that period, I'm afraid and there's no escaping it. And right now there's not much we can do to eradicate those mutant clones. So if we take that as almost an intractable problem, measuring them is hard enough, eradicating them is even harder. And then we go back to Berenblum in 1947 who said, you need an inflammatory stimulus. Well, could we do something about the inflammation and dampen down the inflammation? And of course, this is why we got so excited about IL-1 beta because of the CANTOS trial, which you may remember in 2017 from Ridker and colleagues showed that anti IL-1 beta used as a mechanism of preventing cardiovascular events was associated with a really impressive dose dependent reduction in new lung cancer primaries.(37:49):Really a beautiful example of cancer prevention in action. And that data weren't just a coincidence. The FDA mandated Novartis to collect the solid tumor data and the P-values are 0.001. I mean it's very highly significant dose dependent reduction in lung cancer incidents associated with anti IL-1 beta. So I think that's really the first clue in my mind that something can be done about this problem. And actually they had five years of follow-up, Eric. So that's something about that intervening period where you can treat and then over time see a reduction in new lung cancers forming. So I definitely think there's a window of opportunity here.Eric Topol (38:31):Well, what you're bringing up is fascinating here because this trial, which was a cardiology trial to try to reduce heart attacks, finds a reduction in cancer, and it's been lost. It's been buried. I mean, no one's using this therapy to prevent cancer between ratcheting up the immune system or decreasing inflammation. We have opportunities that we're not even attempting. Are there any trials that are trying to do this sort of thing?Charles Swanton (39:02):So this is the fundamental problem. Nobody wants to invest in prevention because essentially you are dealing with well individuals. It's like the vaccine challenge all over again. And the problem is you never know who you are benefiting. There's no economic model for it. So pharma just won't touch prevention with a barge pole right now. And that's the problem. There's no economic model for it. And yet the community, all my academic colleagues are crying out saying, this has got to be possible. This has got to be possible. So CRUK are putting together a group of like-minded individuals to see if we can do something here and we're gradually making progress, but it is tough.Eric Topol (39:43):And it's interesting that you bring that up because for GRAIL, one of the multicenter cancer early detection companies, they raised billions of dollars. And in fact, their largest trial is ongoing in the UK, but they haven't really focused on high-risk people. They just took anybody over age 50 or that sort of thing. But that's the only foray to try to reboot how we or make an early microscopic diagnosis of cancer and track people differently. And there's an opportunity there. You've written quite a bit on you and colleagues of the blood markers being able to find a cancer where well before, in fact, I was going to ask you about that is, do you think there's people that are not just having all these mutations every minute, every hour, but that are starting to have the early seeds of cancer, but because their immune system then subsequently kicks in that they basically kind of quash it for that period of time?Charles Swanton (40:47):Yeah, I do think that, I mean, the very fact that we see these sort of footprints in the tumor genome of immune evasion tells you that the immune system's having a very profound predatory effect on evolving tumors. So I do think it's very likely that there are tumors occurring that are suppressed by the immune system. There is a clear signature, a signal of negative selection in tumors where clones have been purified during their evolution by the immune system. So I think there's pretty strong evidence for that now. Obviously, it's very difficult to prove something existed when it doesn't now exist, but there absolutely is evidence for that. I think it raises the interesting question of immune system recognizes mutations and our bodies are replete with mutations as we were just discussing. Why is it that we're not just a sort of epithelial lining of autoimmunity with T-cells and immune cells everywhere? And I think what the clever thing about the immune system is it's evolved to target antigens only when they get above a certain burden. Otherwise, I think our epithelial lining, our skin, our guts, all of our tissues will be just full of T-cells eating away our normal clones.(42:09):These have to get to a certain size for antigen to be presented at a certain level for the immune system to recognize it. And it's only then that you get the immune predation occurring.Forever Chemicals and Microplastics Eric Topol (42:20):Yeah, well, I mean this is opportunities galore here. I also wanted to extend the air pollution story a bit. Obviously, we talked about particulate matter and there's ozone and nitric NO2, and there's all sorts of other air pollutants, but then there's also in the air and water these forever chemicals PFAS for abbreviation, and they seem to be incriminated like air pollution. Can you comment about that?Charles Swanton (42:55):Well, I can comment only insofar as to say I'm worried about the situation. Indeed, I'm worried about microplastics actually, and you actually cover that story as well in the New England Journal, the association of microplastics with plaque rupture and atheroma. And indeed, just as in parenthesis, I wanted to just quickly say we currently think the same mechanisms that are driving lung cancer are probably responsible for atheroma and possibly even neurodegenerative disease. And essentially it all comes down to the macrophages and the microglia becoming clogged up with these pollutants or environmental particulars and releasing chronic inflammatory mediators that ultimately lead to disease. And IL-1 beta being one of those in atheroma and probably IL-6 and TNF in neurodegenerative disease and what have you. But I think this issue that you rightly bring up of what is in our environment and how does it cause pathology is really something that epidemiologists have spent a lot of time focusing on.(43:56):But actually in terms of trying to move from association to causation, we've been, I would argue a little bit slow biologically in trying to understand these issues. And I think that is a concern. I mean, to give you an example, Allan Balmain, who works at UCSF quite close to you, published a paper in 2020 showing that 17 out of 20 environmental carcinogens IARC carcinogens class one carcinogens cause tumors in rodent models without driving mutations. So if you take that to a logical conclusion, in my mind, what worries me is that many of the sort of carcinogen assays are based on driving mutagenesis genome instability. But if many carcinogen aren't driving DNA mutagenesis but are still driving cancer, how are they doing it? And do we actually have the right assays to interpret safety of new chemical matter that's being introduced into our environment, these long-lived particles that we're breathing in plastics, pollutants, you name it, until we have the right biological assays, deeming something to be safe I think is tricky.Eric Topol (45:11):Absolutely. And I share your concerns on the nanoplastic microplastic story, as you well know, not only have they been seen in arteries that are inflamed and in blood clots and in various tissues, have they been seen so far or even looked for within tumor tissue?Charles Swanton (45:33):Good question. I'm not sure they have. I need to check. What I can tell you is we've been doing some experiments in the lab with fluorescent microplastics, 2.5 micron microplastics given inhaled microplastics. We find them in every mouse organ a week after. And these pollutants even get through into the brain through the olfactory bulb we think.Charles Swanton (45:57):Permeate every tissue, Eric.Eric Topol (45:59):Yeah, no, this is scary because here we are, we have these potentially ingenious ways to prevent cancer in the future, but we're chasing our tails by not doing anything to deal with our environment.Charles Swanton (46:11):I think that's right. I totally agree. Yeah.Eric Topol (46:15):So I mean, I can talk to you for the rest of the day, but I do want to end up with a topic that we have mutual interest in, which is AI. And also along with that, when you mentioned about aging, I'd like to get your views on these two, how do you see AI fitting into the future of cancer? And then the more general topic is, can we actually at some point modulate the biologic aging process with or without help with from AI? So those are two very dense questions, but maybe you can take us through them.Charles Swanton (46:57):How long have we got?Eric Topol (46:59):Just however long you have.A.I. and CancerCharles Swanton (47:02):AI and cancer. Well, AI and medicine actually in general, whether it's biomedical research or medical care, has just infinite potential. And I'm very, very excited about it. I think what excites me about AI is it's almost the infinite possibilities to work across scale. Some of the challenges we raised in the Cell review that you mentioned, tackling, embracing complexity are perfectly suited for an AI problem. Nonlinear data working, for instance in our fields with CT imaging, MRI imaging, clinical outcome data, blood parameters, genomics, transcriptomes and proteomes and trying to relate this all into something that's understandable that relates to risk of disease or potential identification of a new drug target, for example. There are numerous publications that you and others have covered that allude to the incredible possibilities there that are leading to, for instance, the new identification of drug targets. I mean, Eli Van Allen's published some beautiful work here and in the context of prostate cancer with MDM4 and FGF receptor molecules being intimately related to disease biology.(48:18):But then it's not just that, not just drug target identification, it's also going all the way through to the clinic through drug discovery. It's how you get these small molecules to interact with oncogenic proteins and to inhibit them. And there are some really spectacular developments going on in, for instance, time resolved cryo-electron microscopy, where in combination with modeling and quantum computing and what have you, you can start to find pockets emerging in mutant proteins, but not the wild type ones that are druggable. And then you can use sort of synthetic AI driven libraries to find small molecules that will be predicted to bind these transiently emerging pockets. So it's almost like AI is primed to help at every stage in scientific investigation from the bench all the way through to the bedside. And there are examples all the way through there in the literature that you and others have covered in the last few years. So I could not be more excited about that.Eric Topol (49:29):I couldn't agree with you more. And I think when we get to multimodal AI at the individual level across all their risks for conditions in their future, I hope someday will fulfill that fantasy of primary prevention. And that is getting me to this point that I touched on because I do think they interact to some degree AI and then will we ever be able to have an impact on aging? Most people conflate this because what we've been talking about throughout the hour has been age-related diseases, that is cancer, for example, and cardiovascular and neurodegenerative, which is different than changing aging per se, body wide aging. Do you think we'll ever changed body wide aging?Charles Swanton (50:18):Wow, what a question. Well, if you'd asked me 10 years ago, 15 years ago, do you think we'll ever cure melanoma in my lifetime, I'd have said definitely not. And now look where we are. Half of patients with melanoma, advanced melanoma, even with brain metastasis curd with combination checkpoint therapy. So I never say never in biology anymore. It always comes back to bite you and prove you wrong. So I think it's perfectly possible.Charles Swanton (50:49):We have ways to slow down the aging process. I guess the question is what will be the consequences of that?Eric Topol (50:55):That's what I was going to ask you, because all these things like epigenetic reprogramming and senolytic drugs, and they seem to at least pose some risk for cancer.Charles Swanton (51:09):That's the problem. This is an evolutionary phenomenon. It's a sort of biological response to the onslaught of these malignant cells that are potentially occurring every day in our normal tissue. And so, by tackling one problem, do we create another? And I think that's going to be the big challenge over the next 50 years.Eric Topol (51:31):Yeah, and I think your point about the multi-decade challenge, because if you can promote healthy aging without any risk of cancer, that would be great. But if the tradeoff is close, it's not going to be very favorable. That seems to be the main liability of modulation aging through many of the, there's many shots on goal here, of course, as you well know. But they do seem to pose that risk in general.Charles Swanton (51:58):I think that's right. I think the other thing is, I still find, I don't know if you agree with me, but it is an immense conundrum. What is the underlying molecular basis for somatic aging, for aging of normal tissues? And it may be multifactorial, it may not be just one answer to that question. And different tissues may age in different ways. I don't know. It's a fascinating area of biology, but I think it really needs to be studied more because as you say, it underpins all of these diseases we've been talking about today, cardiovascular, neurodegeneration, cancer, you name it. We absolutely have to understand this. And actually, the more I work in cancer, the more I feel like actually what I'm working on is aging.(52:48):And this is something that James DeGregori and I have discussed a lot. There's an observation that in medicine around patients with alpha-1 antitrypsin deficiency who are at higher risk of lung cancer, but they're also at high risk of COPD, and we know the associations of chronic obstructive pulmonary disease with lung cancer risk. And one of the theories that James had, and I think this is a beautiful idea, actually, is as our tissues age, and COPD is a reflection of aging, to some extent gone wrong. And as our tissues age, they become less good at controlling the expansion of these premalignant clones, harboring, harboring oncogenic mutations in normal tissue. And as those premalignant clones expand, the substrate for evolution also expands. So there's more likely to be a second and third hit genetically. So it may be by disrupting the extracellular matrices through inflammation that triggers COPD through alpha-1 antitrypsin deficiency or smoking, et cetera, you are less effectively controlling these emergent clones that just expand with age, which I think is a fascinating idea actually.Eric Topol (54:01):It really is. Well, I want to tell you, Charlie, this has been the most fascinating, exhilarating discussion I've ever had on cancer. I mean, really, I am indebted to you because not just all the work you've done, but your ability to really express it, articulate it in a way that hopefully everyone can understand who's listening or reading the transcript. So we'll keep following what you're doing because you're doing a lot of stuff. I can't thank you enough for joining me today, and you've given me lots of things to think about. I hope the people that are listening or reading feel the same way. I mean, this has been so mind bending in many respects. We're indebted to you.Charles Swanton (54:49):Well, we all love reading your Twitter feeds. Keep them coming. It helps us keep a broader view of medicine and biological research, not just cancer, which is why I love it so much.******************************************The Ground Truths newsletters and podcasts are all free, open-access, without ads.Please share this post/podcast with your friends and network if you found it informativeVoluntary paid subscriptions all go to support Scripps Research. Many thanks for that—they greatly helped fund our summer internship programs for 2023 and 2024.Thanks to my producer Jessica Nguyen and Sinjun Balabanoff tor audio and video support at Scripps Research.Note: you can select preferences to receive emails about newsletters, podcasts, or all I don't want to bother you with an email for content that you're not interested in. Get full access to Ground Truths at erictopol.substack.com/subscribe

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.24.550435v1?rss=1 Authors: Bradley, R. A., Wolff, I. D., Cohen, P. E., Gray, S. Abstract: During prophase I of meiosis, DNA double-strand breaks form throughout the genome, with a subset repairing as crossover events, enabling the accurate segregation of homologous chromosomes during the first meiotic division. The mechanism by which DSBs become selected to repair as crossovers is unknown, although the crossover positioning and levels in each cell indicate it is a highly regulated process. One of the proteins that localises to crossover sites is the serine/threonine cyclin-dependent kinase CDK2. Regulation of CDK2 occurs via phosphorylation at tyrosine 15 (Y15) and threonine 160 (T160) inhibiting and activating the kinase, respectively. In this study we use a combination of immunofluorescence staining on spread spermatocytes and fixed testis sections, and STA-PUT gravitational sedimentation to isolate cells at different developmental stages to further investigate the temporal phospho regulation of CDK2 during prophase I. Western blotting reveals differential levels of the two CDK2 isoforms (CDK233kDa and CDK239kDa) throughout prophase I, with inhibitory phosphorylation of CDK2 at Y15 occurring early in prophase I, localising to telomeres and diminishing as cells enter pachynema. Conversely, the activatory phosphorylation on T160 occurs later, specifically the CDK233kDa isoform, and T160 signal is detected in spermatogonia and pachytene spermatocytes, where it co-localises with the Class I crossover protein MLH3. Taken together, our data reveals intricate control of CDK2 both with regards to levels of the two CDK2 isoforms, and differential regulation via inhibitory and activatory phosphorylation. 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/2023.03.17.533218v1?rss=1 Authors: Armstrong, C., Passanisi, V. J., Ashraf, H. M., Spencer, S. L. Abstract: Faithful DNA replication requires that cells fine-tune their histone pool in coordination with cell-cycle progression. Replication-dependent histone biosynthesis is initiated at a low level upon cell-cycle commitment, followed by a burst at the G1/S transition, but it remains unclear how exactly the cell regulates this change in histone biosynthesis as DNA replication begins. Here, we use single-cell timelapse imaging to elucidate the mechanisms by which cells modulate histone production during different phases of the cell cycle. We find that CDK2-mediated phosphorylation of NPAT at the Restriction Point triggers histone transcription, which results in a burst of histone mRNA precisely at the G1/S phase boundary. Excess soluble histone protein further modulates histone abundance by promoting the degradation of histone mRNA for the duration of S phase. Thus, cells regulate their histone production in strict coordination with cell-cycle progression by two distinct mechanisms acting in concert. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Cyclacel Pharmaceuticals is a clinical-stage, biopharmaceutical company, developing innovative cancer medicines based on cell cycle, transcriptional regulation, and mitosis biology with a focus on oncology and hematology indications. Their lead drug candidate, fadraciclib is a dual CDK2/9 inhibitor currently undergoing investigation of dose escalation in a Phase 1/2 trial.Spiro Rombotis is the founding CEO of Cyclacel. Prior to joining Cyclacel, Spiro served in a number of management positions at public and private biotechs including Centocor, Bristol Myers Squibb, and the Liposome Company. He earned his MBA at Northwestern University's Kellogg School of Business.In this episode, we discuss cell cycle dysregulation in cancer, precision targeting of proteins in the drug design process, and unique clinical trial design.Hosted by Joe Varriale.

2:40 Labiotech.eu news4:58 SOTIO Biotech13:43 Eversana19:37 Carl Borrebaeck36:42 Concarlo TherapeuticsThis week, we have four interviews: Franjo Hanzl, vice president commercial development Europe at Eversana; Stacy Blain, founder and CEO of Concarlo Therapeutics; Jens Hennecke, chief business officer at SOTIO Biotech; and Carl Borrebaeck, chairman of the board of directors of Immunovia and professor at the Department of Immunotechnology at the University of Lund in Sweden.Concarlo TherapeuticsConcarlo Therapeutics is a U.S.-based preclinical-stage precision-medicine oncology company. It is developing a novel therapy for drug-resistant metastatic breast cancer as a first indication.Concarlo's patented IpY, a novel therapeutic peptide, will be the first to hit two targets, both CDK4/6- driven cell proliferation and CDK2-driven drug resistance at the same time, and the first to target p27. It is a specific cellular pathway to kill cancer cells rather than just slowing their proliferation.The novel approach relies on the role of p27Kpi, a natural inhibitor, an  "on-off" switch that regulates the activities of the major cancer-related proteins, CDK6, CDK4, and CDK2. EversanaEversana is a provider of global services to the life sciences industry. Its integrated solutions are rooted in the patient experience and span all stages of the product life cycle to deliver long-term, sustainable value for patients, prescribers, channel partners and payers. The company serves more than 500 organizations, including start-ups and established pharmaceutical companies, to advance life sciences solutions.Labiotech spoke with Franjo Hanzl, vice president commercial development Europe, at the Medicon Valley Alliance annual summit in Copenhagen, Denmark.Medicon VillageDuring NLS Days, Labiotech visited Medicon Village, in Lund, Sweden. While there, we had the opportunity to chat with Carl Borrebaeck. To say he's involved in biotech would be an understatement. He is chairman of the board of directors of Immunovia and professor at the Department of Immunotechnology at the University of Lund in Sweden, as well as being director of Create Health. Borrebaeck, former vice president of the University of Lund, has been involved in many companies throughout his career, including Alligator Bio, SenzaGen and PainDrainer. He received the AKZONobel Science Award 2009, for contributions to cancer proteomics and antibody-based therapy, a Research! Sweden Award 2012 for his medical research of value for patients and health organizations, and the Royal Academy of Engineering Sciences Gold Medal 2012 for outstanding contributions to biomedical science. He was honored as the Biotech Builder of the Year in 2017.SOTIO BiotechSOTIO Biotech is a clinical stage immuno-oncology company owned by PPF Group based in Prague, Czechia. The company is building a pipeline of oncology programs by pursuing promising early-stage candidates through strategic licensing, M&A and in-house discovery efforts. SOTIO has been active in the clinic in 2022. The company initiated two clinical trials, the first was a phase 2 study for its lead IL-15 superagonist, SOT101. The initiation of the AURELIO-04 trial comes on the heels of positive phase 1/1b data, which showed 15 of 19 patients with advanced/metastatic solid tumors demonstrated clinical benefit with SOT101 in combination with pembrolizumab. The company also plans to enter the CAR-T space with the initiation of its BOXR trial in Q4 2022.  SOTIO is well funded into 2023 and plans to use those funds for posting more data across its already promising programs.We spoke with SOTIO Biotech at BIO-Europe.  

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.04.514246v1?rss=1 Authors: Bea-Mascato, B., Giudice, G., Pinheiro-de-Sousa, I., Petsalaki, E., Valverde, D. Abstract: BACKGROUND: The primary cilium is a sensory organelle that extends from the plasma membrane. It plays a vital role in physiological and developmental processes by controlling different signalling pathways such as WNT, Sonic hedgehog (SHh), and transforming growth factor {beta} (TGF-{beta}). Ciliary dysfunction has been related to different pathologies such as Alstrom (ALMS) or Bardet-Biedl (BBS) syndrome. The leading cause of death in adults with these syndromes is chronic kidney disease (CKD), which is characterised by fibrotic and inflammatory processes often involving the TGF-{beta} pathway. METHODS: Using genomic editing with CRISPR-CAS9 and phosphoproteomics we have studied the TGF- {beta} signalling pathway in knockout (KO) models for ALMS1 and BBS1 genes. We have developed a network diffusion-based analysis pipeline to expand the data initially obtained and to be able to determinate which processes were deregulated in TGF-{beta} pathway. Finally, we have analysed protein-protein interactions to prioritise candidate genes in the regulation of the TGF-{beta} pathway in Alstrom and Bardet-Biedl syndrome. RESULTS: Analysis of differentially phosphorylated proteins identified 10 candidate proteins in the ALMS1 KO model and 41 in the BBS1 KO model. After network expansion using a random walk with a restart model, we were able to obtain processes related to TGF-{beta} signalling such as endocytosis in the case of ALMS1 or extracellular matrix regulation in BBS1. Protein interaction analyses demonstrated the involvement of CDC42 as a central protein in the interactome in ALMS1 and CDK2 in the case of BBS1. CONCLUSION: In conclusion, the depletion of ALMS1 and BBS1 affects the TGF-{beta} signalling pathway, conditioning the phosphorylation and activation of several proteins, including CDC42 in the case of ALMS1 and CDK2 in the case of BBS1. KEYWORDS: ALMS1, BBS1, ciliopathies, TGF-{beta}, phosphoproteomics, Alstrom syndrome, Bardet-Biedl syndrome. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

It's the circle of life: the cell cycle is a molecular merry-go-round for the propagation of all cells, including tumor cells. This process is regulated by cyclin-dependent kinases (CDKs), thus, CDK inhibition has long been a goal of drug developers. However, until very recently, toxicity has remained an issue. Early clinical results suggest that Cyclacel Pharmaceuticals has potentially overcome this hurdle. Tune in as Spiro Rombotis, CEO of Cyclacel Pharmaceuticals, describes Cyclacel's Phase 1/2 studies with its two clinical stage molecules, including lead asset fadraciclib, a CDK2/9 inhibitor, in patients with solid tumor cancers and hematological malignancies.

With a lack of clear standards of care in the post CDK4/6 inhibitor setting, a new study aims to address this unmet need. Dr. Timothy Yap from the University of Texas MD Anderson Cancer Center shares clinical trial data and its impact on cancer patients.

Are you a lover of Wikipedia? Well, this one is for you. I bring Abir Majumdar, PhD on to the Sound to talk about his thesis research on CDK2 and we tie it to the hit song "Doing It to Death" by James Brown and the JBs. We laugh and chill as we have all the feels since he is heading to Dallas, Texas.Song of the Sound: Miracles by SAULTInstagram @scientificallysound Twitter: 4theSci_SoundEmail : 4thescientificallysound@gmail.com

This week's cover paper of Oncotarget (Volume 12, Issue 14) is entitled, "Esomeprazole enhances the effect of ionizing radiation to improve tumor control," by researchers from Baylor College of Medicine, University of Texas MD Anderson Cancer Center, and Texas Children's Hospital. Abstract: The resistance of cancer cells to radiation-based treatment is a major clinical challenge confounding standard of care in cancer. This problem is particularly notable in many solid tumors where cancer cells are only partially responsive to radiation therapy. Combination of radiation with radiosensitizers is able to enhance tumor cell killing. However, currently available radiosensitizers are associated with significant normal tissue toxicity. Accordingly, there is an unmet need to develop safer and more effective radiosensitizers to improve tumor control. Here, we evaluated the radiosensitizing effect of the FDA-approved drug esomeprazole in normal and radioresistant human head and neck squamous cell carcinoma (HNSCC) cells in vitro, and in a mouse model of HNSCC. For the in vitro studies, we used cancer cell colony formation (clonogenicity) assay to compare cancer cell growth in the absence or presence of esomeprazole. To determine mechanism(s) of action, we assessed cell proliferation and profiled cell cycle regulatory proteins. In addition, we performed reverse phase protein array (RPPA) study to understand the global effect of esomeprazole on over 200 cancer-related proteins. For the in vivo study, we engrafted HNSCC in a mouse model and compared tumor growth in animals treated with radiation, esomeprazole, and combination of radiation with esomeprazole. We found that esomeprazole inhibits tumor growth and dose-dependently enhances the cell killing effect of ionizing radiation in wildtype and p53-mutant radioresistant cancer cells. Mechanistic studies demonstrate that esomeprazole arrests cancer cells in the G1 phase of the cell cycle through upregulation of p21 protein and inhibition of cyclin-dependent kinases (Cdks) type 1 (Cdk1) and type 2 (Cdk2). In vivo data showed greater tumor control in animals treated with combination of radiation and esomeprazole compared to either treatment alone, and that this was associated with inhibition of cell proliferation in vivo. In addition, combination of esomeprazole with radiation significantly impaired repair following radiation-induced DNA damage. Our studies indicate that esomeprazole sensitizes cancer cells to ionizing radiation, and is associated with upregulation of p21 to arrest cells in the G1 phase of the cell cycle. Our findings have significant therapeutic implications for the repurposing of esomeprazole as a radiosensitizer in HNSCC and other solid tumors. Sign up for free Altmetric alerts about this article - https://oncotarget.altmetric.com/details/email_updates?id=10.18632%2Foncotarget.28008 DOI - https://doi.org/10.18632/oncotarget.28008 Full text - https://www.oncotarget.com/article/28008/text/ Correspondence to - Yohannes T. Ghebre - yohannes.ghebre@bcm.edu Keywords - esomeprazole, proton pump inhibitors, ionizing radiation, radiosensitization, tumor control About Oncotarget Oncotarget is a bi-weekly, peer-reviewed, open access biomedical journal covering research on all aspects of oncology. To learn more about Oncotarget, please visit https://www.oncotarget.com or connect with: SoundCloud - https://soundcloud.com/oncotarget Facebook - https://www.facebook.com/Oncotarget/ Twitter - https://twitter.com/oncotarget YouTube - https://www.youtube.com/c/OncotargetYouTube/ LinkedIn - https://www.linkedin.com/company/oncotarget Pinterest - https://www.pinterest.com/oncotarget/ Reddit - https://www.reddit.com/user/Oncotarget/ Oncotarget is published by Impact Journals, LLC please visit https://www.ImpactJournals.com or connect with @ImpactJrnls Media Contact MEDIA@IMPACTJOURNALS.COM 18009220957

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.08.329599v1?rss=1 Authors: Salamina, M., Montefiore, B. C., Liu, M., Wood, D. J., Heath, R., Ault, J. R., Wang, L.-Z., Korolchuk, S., Basle, A., Pastok, M. W., Reeks, J., Tatum, N. J., Sobott, F., Arold, S. T., Pagano, M., Noble, M. E. M., Endicott, J. A. Abstract: The SCFSKP2 ubiquitin ligase relieves G1 checkpoint control of CDK-cyclin complexes by promoting p27KIP1 degradation. We describe reconstitution of stable complexes containing SKP1-SKP2 and CDK1-cyclin B or CDK2-cyclin A/E, mediated by the CDK regulatory subunit CKS1. We further show that a direct interaction between a SKP2 N-terminal motif and cyclin A can stabilize SKP1-SKP2-CDK2-cyclin A complexes in the absence of CKS1. We identify the SKP2 binding site on cyclin A and demonstrate the site is not present in cyclin B or cyclin E. This site is distinct from but overlapping with features that mediate binding of p27KIP1 and other G1 cyclin regulators to cyclin A. We propose that the capacity of SKP2 to engage with CDK2-cyclin A by more than one structural mechanism provides a way to fine tune the degradation of p27KIP1 and distinguishes cyclin A from other G1 cyclins to ensure orderly cell cycle progression. Copy rights belong to original authors. Visit the link for more info

Spiro Rombotis, President and Chief Executive Officer, Cyclacel Pharmaceuticals dives into the insights about cell cycle check point control that have led to the development of fadraciclib, a potent orally and intravenously available inhibitor of CDK2 and CDK9 cancer pathways. Drawing on the vision of the company's founding scientist, Professor Sir David Lane, the mission of Cyclacel is to provide cancer patients with a treatment that allows them to live with their cancer and not die from it. #Cyclacel #fadra #cancer #solidtumors Cyclacel.com Download the transcript here  

Spiro Rombotis, President and Chief Executive Officer, Cyclacel Pharmaceuticals dives into the insights about cell cycle check point control that have led to the development of fadraciclib, a potent orally and intravenously available inhibitor of CDK2 and CDK9 cancer pathways. Drawing on the vision of the company's founding scientist, Professor Sir David Lane, the mission of Cyclacel is to provide cancer patients with a treatment that allows them to live with their cancer and not die from it. #Cyclacel #fadra #cancer #solidtumors Cyclacel.com Listen to the podcast here  

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.27.223008v1?rss=1 Authors: Wang, Y., Hsu, A. Y., Walton, E. M., Syahirah, R., Wang, T., Zhou, W., Ding, C., Lemke, A. P., Tobin, D. M., Deng, Q. Abstract: Tissue-specific knockout techniques are widely applied in biological studies to probe the tissue-specific roles of specific genes in physiology, development, and disease. CRISPR/Cas9 is a widely used technology to perform fast and efficient genome editing in vitro and in vivo. Here, we report a robust CRISPR-based gateway system for tissue-specific gene inactivation in zebrafish. A transgenic fish line expressing Cas9 under the control of a neutrophil-restricted promoter was constructed. As proof of principle, we transiently disrupted rac2 or cdk2 in neutrophils using plasmids driving the expression of sgRNAs from U6 promoters. Loss of the rac2 or cdk2 gene in neutrophils resulted in significantly decreased cell motility, which could be restored by re-expressing Rac2 or Cdk2 in neutrophils in the corresponding knockout background. The subcellular location of Rac activation and actin structure and stress in the context of neutrophil migration was determined in both the wild-type and rac2 knockout neutrophils in vivo. In addition, we evaluated an alternative approach where the Cas9 protein is ubiquitously expressed while the sgRNA is processed by ribozymes and expressed in a neutrophil-restricted manner. Cell motility was also reduced upon rac2 sgRNA expression. Together, our work provides a potent tool that can be used to advance the utility of zebrafish in identification and characterization of gene functions in neutrophils. Copy rights belong to original authors. Visit the link for more info

Pituitary adenomas are benign neoplasms accounting for 15% of all intracranial tumors. They are associated with significant clinical syndromes due to the hormonal excess they produce or to visual/cranial disturbances because of their considerable intracranial mass. Surgery is the primary means for the management of pituitary tumor mass, but it comes with considerable side effects to the patients and their quality of life. Tumor shrinkage by pharmacological agents currently used in neuroenocrinology, such as, somatostatin analogs (SSA) is not observed in a large fraction of pituitary adenomas. Therefore, efforts are taken to investigate how to overcome the resistance to existing treatments and to identify new cytostatic therapeutic agents. The PI3K/Akt/mTOR signaling pathway is frequently overactivated in a variety of tumors rendering them resistant to chemo- and radiotherapy. The present study shows that Akt overactivation confers resistance to the antiproliferative action of the SSA octreotide in pituitary tumor cells. Blocking the Akt pathway downstream with rapamycin rendered those cells sensitive to octeotide’s antiproliferative action. However, the efficacy of the combined treatment was not due to the antiproliferative action of rapamycin, since most of the tumors did not respond to this pharmacological agent. Rapamycin and its analogs (rapalogs) have a cytostatic effect in various tumors. However, resistance to rapalog treatment is reported with increasing frequency due to the elimination of the negative feedback loop exerted by the mTOR substrate p70/S6K on IRS-1. Rapamycin, by inhibiting mTOR and p70/S6K, decreases the inhibitory IRS-1 serine phosphorylation, activates IRS-1 and increases Akt-Ser473 phosphorylation. The present study shows for the first time that activating the G protein-coupled receptor Sstr2 with octreotide blocks the rapamycin-induced IRS-1 activation by increasing its inhibitory serine and decreasing its stimulatory tyrosine phosphorylation. This leads to decreased Akt-Ser473 phosphorylation in a mechanism involving the phosphotyrosine phosphatase SHP-1. Both octreotide and rapamycin are cytostatic agents blocking the G1/S cell cycle transition and herein it is seen that their potent antiproliferative action depends on the more potent upregulation of the Cdk2 inhibitor p27/Kip1. A novel drug able to co-target the PI3K pathway up- and downstream is the dual class PI3K/mTOR inhibitor, NVP-BEZ235, which has shown high antiproliferative efficacy in tumors with the overactivated PI3K pathway. In the present study NVP-BEZ235 treatment dramatically decreased cell viability by suppressing the cell cycle activators cyclin E and Cdk2 and upregulating the cell cycle progression inhibitor p27/Kip1. The remarkable sensitivity of pituitary adenomas to NVP-BEZ235 highlights the importance of the Akt dysregulation in their tumor maintenance. Altogether, these data provide new therapeutic cytostatic schemes that could prove beneficial for the management of pituitary macroadenomas. In addition they provide the biochemical basis for combating resistance to rapalog treatment also in other tumor types by concomitant administration of biologicals able to inhibit the PI3K pathway upstream.

gamma-Aminobutyric acid (GABA) is an emerging signalling molecule in endocrine organs, since it is produced by endocrine cells and acts via GABA(A) receptors in a paracrine/autocrine fashion. Testicular Leydig cells are producers and targets for GABA. These cells express GABA(A) receptor subunits and in the murine Leydig cell line TM3 pharmacological activation leads to increased proliferation. The signalling pathway of GABA in these cells is not known in this study. We therefore attempted to elucidate details of GABA(A) signalling in TM3 and adult mouse Leydig cells using several experimental approaches. TM3 cells not only express GABA(A) receptor subunits, but also bind the GABA agonist {[}H-3] muscimol with a binding affinity in the range reported for other endocrine cells (K-d = 2.740 +/- 0.721 nM). However, they exhibit a low B-max value of 28.08 fmol/mg protein. Typical GABA(A) receptor-associated events, including Cl- currents, changes in resting membrane potential, intracellular Ca2+ or cAMP, were not measurable with the methods employed in TM3 cells, or, as studied in part, in primary mouse Leydig cells. GABA or GABA(A) agonist isoguvacine treatment resulted in increased or decreased levels of several mRNAs, including transcription factors (c-fos, hsf-1, egr-1) and cell cycle-associated genes (Cdk2, cyclin D1). In an attempt to verify the cDNA array results and because egr-1 was recently implied in Leydig cell development, we further studied this factor. RT-PCR and Western blotting confirmed a time-dependent regulation of egr-1 in TM3. In the postnatal testis egr-1 was seen in cytoplasmic and nuclear locations of developing Leydig cells, which bear GABA(A) receptors and correspond well to TM3 cells. Thus, GABA acts via an untypical novel signalling pathway in TM3 cells. Further details of this pathway remain to be elucidated. Copyright (c) 2005 S. Karger AG, Basel

We present here the first evidence linking CD44 signaling to c-Jun expression and cell cycle progression in myeloid cell line models. CD44 ligation with the anti-CD44 monoclonal antibodies have been shown to induce differentiation and inhibit the proliferation of human acute myeloid leukemia (AML) cells, and c-Jun is involved in the regulation of these processes. The effects of anti-CD44 monoclonal antibody A3D8, on myeloid cells were associated with specific disruption of cell cycle events and induction of G0/G1 arrest. Induction of G0/G1 arrest was accompanied by an increase in the expression of p21, attenuation of pRb phosphorylation and associated with decreased CDK2 and CDK4 kinase activities. We observed that A3D8 treatment of AML patient blasts and HL60/U937 cells led to the downregulation of c-Jun expression at mRNA and protein level. Transient transfection studies showed the inhibition of c-jun promoter activity by A3D8, involving both AP-1 sites. Furthermore, A3D8 treatment caused a decrease in JNK protein expression and a decrease in the level of phosphorylated c-Jun. Ectopic overexpression of c-Jun in HL60 cells was able to induce proliferation and prevent the anti-proliferative effects of A3D8. Targeting of G1 regulatory proteins and the resulting induction of G1 arrest by A3D8 may provide new insights into anti-proliferative and differentiation therapy of AML.

Der eukaryontische Zellzyklus wird durch die Aktivität verschiedener Cyclinabhängiger Kinasen (CDKs) reguliert. Die zelluläre Menge des CDK-Inhibitorproteins p27Kip1 spielt eine entscheidende Rolle beim Übergang der Zelle von der G1- zur SPhase. Die Menge von p27Kip1 steigt während der G0- oder der G1-Phase an und nimmt zu Beginn der S-Phase rasch wieder ab. Die Bindung von p27Kip1 an die CDKKomplexe der G1-Phase inaktiviert diese und verhindert dadurch die Initiation der SPhase. Eine verminderte Menge von p27Kip1 am G1/S-Phaseübergang findet man dagegen häufig in verschiedenen Tumorgeweben. Die geringere zelluläre Menge des Inhibitors ist dabei mit einer hohen Patientensterblichkeit und einem aggressiven Verlauf der Erkrankung verbunden. Die zelluläre Aktivität und Menge von p27Kip1 wird entscheidend durch Proteine reguliert, die mit p27Kip1 interagieren. In dieser Arbeit wurden deshalb mit Hilfe von rekombinantem p27Kip1 Interaktionspartner des Inhibitors in HeLa-Zellextrakt identifiziert. Es konnte gezeigt werden, daß p27Kip1 an die CDK-Proteine und an Grb2 bindet. Grb2 ist ein Adapterprotein der Signaltransduktion. Die Interaktion zwischen p27Kip1 und Grb2 könnte damit, nach Stimulation der Zelle durch verschiedene Mitogene, die Signalweitergabe mit der Zellzyklusmaschinerie verbinden. Die zu dieser Interaktion notwendige Domäne in p27Kip1 konnte in weiteren Analysen auf eine acht Aminosäuren lange Prolin-reiche Region eingegrenzt werden. Auf der anderen Seite interagiert Grb2 vornehmlich über seine C-terminale SH3-Domäne mit p27Kip1. Die beiden mit p27Kip1 nah verwandten Inhibitorproteine p21Cip1 und p57Kip2 interagieren dagegen nicht mit Grb2. In einer erweiterten Analyse wurden 41 verschiedene rekombinante SH3-Domänen auf eine Interaktion mit p27Kip1 hin getestet. Es konnte gezeigt werden, daß p27Kip1 nur mit der C-terminalen SH3-Domäne von Grf40/Mona und der SH3-Domäne der Tyrosinkinase Lyn wechselwirkt. Die Interaktion der Tyrosinkinase Lyn in vivo führte zur Hypothese, daß p27Kip1 durch Lyn phosphoryliert werden könnte. Im zweiten Teil dieser Arbeit wurde deshalb die Tyrosinphosphorylierung von p27Kip1 untersucht. In Phosphoaminosäureanalysen mit metabolisch markierten Zellen konnte gezeigt werden, daß p27K i p 1 in vivo an Tyrosinresten phosphoryliert wird. Diese Zusammenfassung 13 Phosphorylierung konnte durch rekombinant hergestellte Tyrosinkinasen und verschiedene Tyrosin/Phenylalanin-Austausche in p27Kip1 auf Tyrosin 88 und 89 eingegrenzt werden. Nach Kristallstrukturdaten des trimeren Komplexes aus p27Kip1, CDK2 und Cyclin A kommt der Tyrosinrest 88 von p27Kip1 in der ATP-Bindetasche der Kinase zu liegen und blockiert diese. Es wurde deshalb untersucht, inwieweit eine Phosphorylierung von p27Kip1 an Tyrosin 88 oder 89 Einfluß auf die Aktivität des Inhibitors hat. Die Tyrosinphosphorylierung von p27Kip1 verhindert nicht die Bindung an den CDK-Komplex. Allerdings konnte mit in vitro-phosphoryliertem p27Kip1 gezeigt werden, daß eine Tyrosinphosphorylierung zu einer etwa 40%-igen Reduktion der Aktivität des Inhibitors führt. Diese Ergebnis konnte in vivo bestätigt werden. Interessanterweise verstärkt die Tyrosinphosphorylierung des Inhibitors die Phosphorylierung von p27Kip1 an Threonin 187 durch den gebundenen CDK-Komplex. Die Phosphorylierung von p27Kip1 an Threonin 187 ist in der Zelle ein initiales Signal zum Abbau von p27Kip1 durch das 26S-Proteasom. Das so markierte p27Kip1 wird von einem E3-Ligase-Komplex erkannt und ubiquitiniert. Es wurde deshalb untersucht, welchen Einfluß die Tyrosinphosphorylierung auf den Abbau von p27Kip1 besitzt. In Halbwertszeitbestimmungen mit einer SH3-bindedefizienten Form von p27Kip1 und einer Tyrosin/Phenylalanin-Austauschform von p27Kip1 konnte zeigten werden, daß beide Formen, im Vergleich zu unverändertem p27Kip1, eine höhere Stabilität aufweisen. Die Interaktion von p27Kip1 mit der Tyrosinkinase Lyn und die Inaktivierung des Inhibitors durch die Phosphorylierung von Tyrosinresten zeigt eine Möglichkeit auf wie p27Kip1, in Abhängigkeit von mitogenen Stimuli, reguliert werden kann. Die in dieser Arbeit gefundene Interaktion von Grb2, Grf40 und Lyn mit p27Kip1 verbindet damit die Signaltransduktion mit der Zellzykluskontrolle.