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News Article | January 27, 2017
Site: www.medicalnewstoday.com

When a cell is dividing, two identical structures, called centrosomes, move to opposite sides of the cell to help separate its chromosomes into the new cells. More than 100 years ago, scientists observed that cancer cells often have more than two centrosomes, but they couldn't untangle whether the extra structures were a result of the cancer - or part of its cause. Now, biologists at Johns Hopkins have solved that conundrum, finding that extra centrosomes can single-handedly promote tumor formation in mice. Beyond revealing more about cancer initiation, the researchers believe that their mice represent a model for cancer research that more closely mimics the traits of human cancer than previously available strains. "Mouse models of cancer are usually produced by altering a single gene or a combination of genes known to fuel a particular type of cancer," says Andrew Holland, Ph.D., assistant professor of molecular biology and genetics at the Johns Hopkins University School of Medicine and member of the Johns Hopkins Kimmel Cancer Center. "That often produces tumors in which every cell is genetically similar. But human tumors contain lots of variety, which may explain why they often don't respond to drugs the same way mice do." Michelle Levine, a Ph.D. candidate and the primary researcher on the project, adds, "Extra centrosomes generate genetic diversity in the mice, which creates tumors much more similar to human tumors." A summary of Holland's group's findings appears online in the journal Developmental Cell. During cell division, centrosomes help properly distribute chromosomes. When chromosome distribution goes wrong, each new cell inherits either too many or too few chromosomes. Holland says the condition, called aneuploidy, can be found in more than 90 percent of solid tumors in humans, suggesting a causal link. But, until now, there hadn't been a way to test how extra centrosomes contribute to aneuploidy and tumor formation. Previous experiments in lab-grown cells showed that elevated levels of the protein Plk4 caused an increase in centrosome numbers. Holland's team wanted to see if the same would happen in mice genetically engineered to produce extra Plk4, but the researchers knew that aneuploidy would be lethal during the delicate process of embryonic development. They engineered mice that would only produce extra Plk4 after being given the antibiotic doxycycline and waited until the mice were a month old to give them their first dose in their drinking water. After a month of doxycycline treatment, the researchers assessed the number of centrosomes in the mouse tissues. As suspected, they found many instances of excess centrosomes - in the skin, spleen, intestine, thymus, liver, pancreas and stomach. When they assessed chromosome numbers in cells from the skin and spleen, they found that up to one-third of them were aneuploid, indicating that the extra centrosomes were contributing to improper chromosome distribution. Holland says: "Faulty chromosome distribution causes an imbalance in how many copies of each gene a cell inherits. It also increases the chances of chromosomes being broken and subsequently swapping parts with each other. "Human cancers usually develop over decades," he says. "Some initial error - extra centrosomes, in this case - weakens the faithfulness with which chromosomes are duplicated and passed on to daughter cells. Then, every cell division is a chance for a cancer-promoting mutation to occur. Eventually, enough of these accumulate in a given tissue, and a tumor forms." Strikingly, half of the mice with high Plk4 levels developed cancer within nine to 18 months - when they were middle-aged - while none of the normal mice did. And each case of cancer originated in a tissue with elevated centrosome numbers, specifically the thymus, spleen and skin. "The evidence strongly suggests that it was extra centrosomes, not some unknown function of Plk4, that caused these tumors to form," says Holland. "First, we performed an experiment where we only increased levels of Plk4 for one month. In this case, extra centrosomes persisted after the excessive levels of Plk4 had declined, and the mice still developed tumors over a year later. Second, nearly every tissue in their bodies experienced high levels of Plk4, but it was only in those with extra centrosomes that we saw tumors form." Holland notes that not every tissue with extra centrosomes formed tumors - for example, the intestine. "While extra centrosomes can be sufficient to initiate tumor formation, they are not able to do so in every tissue," he says. "We don't yet know why this is, but we hope to address this in future studies." Additionally, some tissues, like the lungs and kidney, didn't make extra centrosomes, even though their levels of Plk4 were high. These tissues also failed to form tumors. Levine explains that extra centrosomes form only in dividing cells. The lungs and kidneys are relatively stable in an adult mouse, she says, so even though they did show high levels of Plk4, cells were not dividing frequently, and there was less centrosome multiplication. "That said, cells in the liver, pancreas and stomach showed high numbers of centrosomes but low rates of cell division, so there are probably unique things about each tissue that also contribute to the differences," she adds. Levine suggests that other mice could be genetically engineered to make extra centrosomes specifically in some of the tissues that didn't make them in this study. Ultimately, she thinks mice with extra centrosomes will become an invaluable tool for studying how cancer begins and how it can be defeated. Other authors of the report include Julia Moyett and James Lu of the Johns Hopkins University School of Medicine; Bjorn Bakker, Diana Spierings, Peter Lansdorp and Floris Foijer of the University of Groningen; Bram Boeckx and Diether Lambrechts of the Vesalius Research Center; Benjamin Vitre of the University of Montpellier; and Don Cleveland of the Ludwig Institute for Cancer Research. This work was supported by grants from Pew-Stewart Scholar Award, the Kimmel Cancer Center, a Johns Hopkins University School of Medicine Innovation Award, the National Institute of Diabetes and Digestive and Kidney Diseases (P30DK09086), the National Institute of General Medical Sciences (GM 114119, GM 29513), the American Cancer Society (RSG-16-156-01-CCG), the Dutch Cancer Society (2012-RUG-5549) and the European Research Council (ROOTS-Grant Agreement 294740). Article: Centrosome Amplification Is Sufficient to Promote Spontaneous Tumorigenesis in Mammals, Andrew J. Holland et al., Developmental Cell, doi: 10.1016/j.devcel.2016.12.022, published 26 January 2017.


News Article | February 27, 2017
Site: www.eurekalert.org

(PRINCETON, N.J., Feb. 27, 2017) - Bristol-Myers Squibb Company (NYSE:BMY) today announced that Columbia University Medical Center and Peter MacCallum Cancer Centre (Peter Mac) have joined the International Immuno-Oncology Network (II-ON), a global peer-to-peer collaboration between Bristol-Myers Squibb and academia that aims to advance Immuno-Oncology (I-O) science and translational medicine to improve patient outcomes. Launched in 2012 by Bristol-Myers Squibb, the II-ON was one of the first networks to bring academia and industry together to further the scientific understanding of I-O, and has expanded from 10 to 15 sites including more than 250 investigators working on over 150 projects across 20 tumor types. The II-ON has generated cutting-edge I-O data that have informed the development of new I-O agents, yielded publications and produced some of the earliest findings on a variety of biomarkers and target identification and validation. "Bristol-Myers Squibb has long believed the future of cancer research is dependent on investments in science and partnerships. We formed the II-ON to facilitate innovation in I-O science and drug discovery by providing a streamlined framework for peer-to-peer collaboration among global cancer research leaders," said Nils Lonberg, Head of Oncology Biology Discovery at Bristol-Myers Squibb. "The significant discoveries generated by the II-ON over the past five years have not only informed our robust early I-O pipeline, but also serve to advance the entire field. We are proud to collaborate with Columbia University Medical Center and Peter Mac, and together with the entire II-ON will continue to lead pioneering research and heighten our collective understanding of the science behind I-O." Through the II-ON, Bristol-Myers Squibb is collaborating with leading cancer research institutions around the world to generate innovative I-O science, launch biology-driven trials and seek out cutting-edge technologies with the goal of translating research findings into clinical trials and, ultimately, clinical practice. "I-O research may be transforming the way we treat cancer," said Charles G. Drake, MD, PhD, Professor of Medicine at Columbia University Medical Center and Director of Genitourinary Oncology and Associate Director for Clinical Research at the Herbert Irving Comprehensive Cancer Center at New York-Presbyterian/Columbia. "The II-ON offers a tremendous opportunity to work smarter and faster along with our colleagues to address fundamental scientific questions in I-O." "We believe the collective knowledge and research power of the II-ON will generate groundbreaking findings in I-O with the potential to improve outcomes for people affected by cancer," said Professor Joe Trapani, Executive Director Cancer Research and Head of the Cancer Immunology Program at Peter MacCallum Cancer Centre, Melbourne, Australia. Building on the success of the II-ON, Bristol-Myers Squibb has invested in several other models of scientific collaboration with academic partners across the globe, including the Global Expert Centers Initiative (GECI) and the Immuno-Oncology Integrated Community Oncology Network (IO-ICON). "We believe a one-size-fits-all research approach does not facilitate innovation," said Lonberg. "Our tailored collaborations with academic centers expand our research capabilities and accelerate our collective ability to deliver potentially life-changing results for patients." The II-ON, formed in 2012, is a global peer-to-peer collaboration between Bristol-Myers Squibb and academia advancing the science of Immuno-Oncology (I-O) through a series of preclinical, translational and biology-focused research objectives. The research in the collaboration is focused on three fundamental scientific pillars: understanding the mechanisms of resistance to immunotherapy; identifying patient populations likely to benefit from immunotherapy; and exploring novel combination therapies that may enhance anti-tumor response through complementary mechanisms of action. The II-ON facilitates the translation of scientific research findings into drug discovery and development, with the goal of introducing new treatment options into clinical practice. In addition to Bristol-Myers Squibb, the II-ON currently comprises 15 leading cancer research institutions, including: Clinica Universidad Navarra, Dana-Farber Cancer Institute, The Earle A. Chiles Research Institute (Providence Health & Services), Institut Gustave Roussy, Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione G. Pascale", Bloomberg-Kimmel Institute for Cancer Immunotherapy at the Johns Hopkins Kimmel Cancer Center, Memorial Sloan Kettering Cancer Center, National Cancer Center Japan, The Netherlands Cancer Institute, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, University College London, The University of Chicago, West German Cancer Center/University Hospital Essen, and now Columbia University Medical Center and Peter MacCallum Cancer Centre. Bristol-Myers Squibb: At the Forefront of Immuno-Oncology Science & Innovation At Bristol-Myers Squibb, patients are at the center of everything we do. Our vision for the future of cancer care is focused on researching and developing transformational Immuno-Oncology (I-O) medicines that will raise survival expectations in hard-to-treat cancers and will change the way patients live with cancer. We are leading the scientific understanding of I-O through our extensive portfolio of investigational and approved agents - including the first combination of two I-O agents in metastatic melanoma - and our differentiated clinical development program, which is studying broad patient populations across more than 20 types of cancers with 12 clinical-stage molecules designed to target different immune system pathways. Our deep expertise and innovative clinical trial designs uniquely position us to advance the science of combinations across multiple tumors and potentially deliver the next wave of I-O combination regimens with a sense of urgency. We also continue to pioneer research that will help facilitate a deeper understanding of the role of immune biomarkers and inform which patients will benefit most from I-O therapies. We understand making the promise of I-O a reality for the many patients who may benefit from these therapies requires not only innovation on our part, but also close collaboration with leading experts in the field. Our partnerships with academia, government, advocacy and biotech companies support our collective goal of providing new treatment options to advance the standards of clinical practice. Bristol-Myers Squibb is a global biopharmaceutical company whose mission is to discover, develop and deliver innovative medicines that help patients prevail over serious diseases. For more information about Bristol-Myers Squibb, visit us at BMS.com or follow us on LinkedIn, Twitter, YouTube and Facebook. This press release contains "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995 regarding the research, development and commercialization of pharmaceutical products. Such forward-looking statements are based on current expectations and involve inherent risks and uncertainties, including factors that could delay, divert or change any of them, and could cause actual outcomes and results to differ materially from current expectations. No forward-looking statement can be guaranteed. Forward-looking statements in this press release should be evaluated together with the many uncertainties that affect Bristol-Myers Squibb's business, particularly those identified in the cautionary factors discussion in Bristol-Myers Squibb's Annual Report on Form 10-K for the year ended December 31, 2016 in our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K. Bristol-Myers Squibb undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise.


PRINCETON, N.J.--(BUSINESS WIRE)--Bristol-Myers Squibb Company (NYSE:BMY) today announced that Columbia University Medical Center and Peter MacCallum Cancer Centre (Peter Mac) have joined the International Immuno-Oncology Network (II-ON), a global peer-to-peer collaboration between Bristol-Myers Squibb and academia that aims to advance Immuno-Oncology (I-O) science and translational medicine to improve patient outcomes. Launched in 2012 by Bristol-Myers Squibb, the II-ON was one of the first networks to bring academia and industry together to further the scientific understanding of I-O, and has expanded from 10 to 15 sites including more than 250 investigators working on over 150 projects across 20 tumor types. The II-ON has generated cutting-edge I-O data that have informed the development of new I-O agents, yielded publications and produced some of the earliest findings on a variety of biomarkers and target identification and validation. “Bristol-Myers Squibb has long believed the future of cancer research is dependent on investments in science and partnerships. We formed the II-ON to facilitate innovation in I-O science and drug discovery by providing a streamlined framework for peer-to-peer collaboration among global cancer research leaders,” said Nils Lonberg, Head of Oncology Biology Discovery at Bristol-Myers Squibb. “The significant discoveries generated by the II-ON over the past five years have not only informed our robust early I-O pipeline, but also serve to advance the entire field. We are proud to collaborate with Columbia University Medical Center and Peter Mac, and together with the entire II-ON will continue to lead pioneering research and heighten our collective understanding of the science behind I-O.” Through the II-ON, Bristol-Myers Squibb is collaborating with leading cancer research institutions around the world to generate innovative I-O science, launch biology-driven trials and seek out cutting-edge technologies with the goal of translating research findings into clinical trials and, ultimately, clinical practice. “I-O research may be transforming the way we treat cancer,” said Charles G. Drake, MD, PhD, Professor of Medicine at Columbia University Medical Center and Director of Genitourinary Oncology and Associate Director for Clinical Research at the Herbert Irving Comprehensive Cancer Center at New York-Presbyterian/Columbia. “The II-ON offers a tremendous opportunity to work smarter and faster along with our colleagues to address fundamental scientific questions in I-O.” “We believe the collective knowledge and research power of the II-ON will generate groundbreaking findings in I-O with the potential to improve outcomes for people affected by cancer,” said Professor Joe Trapani, Executive Director Cancer Research and Head of the Cancer Immunology Program at Peter MacCallum Cancer Centre, Melbourne, Australia. Building on the success of the II-ON, Bristol-Myers Squibb has invested in several other models of scientific collaboration with academic partners across the globe, including the Global Expert Centers Initiative (GECI) and the Immuno-Oncology Integrated Community Oncology Network (IO-ICON). "We believe a one-size-fits-all research approach does not facilitate innovation,” said Lonberg. “Our tailored collaborations with academic centers expand our research capabilities and accelerate our collective ability to deliver potentially life-changing results for patients." The II-ON, formed in 2012, is a global peer-to-peer collaboration between Bristol-Myers Squibb and academia advancing the science of Immuno-Oncology (I-O) through a series of preclinical, translational and biology-focused research objectives. The research in the collaboration is focused on three fundamental scientific pillars: understanding the mechanisms of resistance to immunotherapy; identifying patient populations likely to benefit from immunotherapy; and exploring novel combination therapies that may enhance anti-tumor response through complementary mechanisms of action. The II-ON facilitates the translation of scientific research findings into drug discovery and development, with the goal of introducing new treatment options into clinical practice. In addition to Bristol-Myers Squibb, the II-ON currently comprises 15 leading cancer research institutions, including: Clinica Universidad Navarra, Dana-Farber Cancer Institute, The Earle A. Chiles Research Institute (Providence Health & Services), Institut Gustave Roussy, Istituto Nazionale per lo Studio e la Cura dei Tumori “Fondazione G. Pascale”, Bloomberg-Kimmel Institute for Cancer Immunotherapy at the Johns Hopkins Kimmel Cancer Center, Memorial Sloan Kettering Cancer Center, National Cancer Center Japan, The Netherlands Cancer Institute, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, University College London, The University of Chicago, West German Cancer Center/University Hospital Essen, and now Columbia University Medical Center and Peter MacCallum Cancer Centre. Bristol-Myers Squibb: At the Forefront of Immuno-Oncology Science & Innovation At Bristol-Myers Squibb, patients are at the center of everything we do. Our vision for the future of cancer care is focused on researching and developing transformational Immuno-Oncology (I-O) medicines that will raise survival expectations in hard-to-treat cancers and will change the way patients live with cancer. We are leading the scientific understanding of I-O through our extensive portfolio of investigational and approved agents – including the first combination of two I-O agents in metastatic melanoma – and our differentiated clinical development program, which is studying broad patient populations across more than 20 types of cancers with 12 clinical-stage molecules designed to target different immune system pathways. Our deep expertise and innovative clinical trial designs uniquely position us to advance the science of combinations across multiple tumors and potentially deliver the next wave of I-O combination regimens with a sense of urgency. We also continue to pioneer research that will help facilitate a deeper understanding of the role of immune biomarkers and inform which patients will benefit most from I-O therapies. We understand making the promise of I-O a reality for the many patients who may benefit from these therapies requires not only innovation on our part, but also close collaboration with leading experts in the field. Our partnerships with academia, government, advocacy and biotech companies support our collective goal of providing new treatment options to advance the standards of clinical practice. Bristol-Myers Squibb is a global biopharmaceutical company whose mission is to discover, develop and deliver innovative medicines that help patients prevail over serious diseases. For more information about Bristol-Myers Squibb, visit us at BMS.com or follow us on LinkedIn, Twitter, YouTube and Facebook. This press release contains “forward-looking statements” as that term is defined in the Private Securities Litigation Reform Act of 1995 regarding the research, development and commercialization of pharmaceutical products. Such forward-looking statements are based on current expectations and involve inherent risks and uncertainties, including factors that could delay, divert or change any of them, and could cause actual outcomes and results to differ materially from current expectations. No forward-looking statement can be guaranteed. Forward-looking statements in this press release should be evaluated together with the many uncertainties that affect Bristol-Myers Squibb’s business, particularly those identified in the cautionary factors discussion in Bristol-Myers Squibb’s Annual Report on Form 10-K for the year ended December 31, 2016 in our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K. Bristol-Myers Squibb undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise.


News Article | February 28, 2017
Site: www.eurekalert.org

In a rigorous study of tumor tissue collected from 125 patients with aggressive brain cancers, researchers at Johns Hopkins say they have found no evidence of cytomegalovirus (CMV) infection and conclude that a link between the two diseases, as claimed by earlier reports, likely does not exist. The Johns Hopkins team cautioned that studies to confirm this finding are needed to absolutely rule out any role for the common CMV in glioblastoma and other cancers that arise in neurological support cells called glial cells. But they say their study substantially weakens the likelihood of that role. "We have found no evidence of CMV in these tissues, and if there is no virus, targeting that virus to affect cancer using antiviral drugs or tailored vaccines doesn't make biological sense," says Angelo M. De Marzo, M.D., Ph.D., professor of pathology, oncology and urology at the Johns Hopkins Kimmel Cancer Center. A report on the research was published Dec. 29, 2016 in Clinical Cancer Research. As early as 2002, the Johns Hopkins team says, several studies reported that tumor cells isolated within glioblastomas and other gliomas were infected with CMV, a herpes virus that infects more than half of all adults by age 40 and is related to viruses that cause chickenpox and mononucleosis. Because other viruses are associated with some cancers, notably HPV, which causes most cervical and some head and neck cancers; and Epstein-Barr virus, which causes some lymphomas, those earlier findings generated excitement about the potential for antiviral therapies to improve the usually poor outlook for people with gliomas. However, explains Matthias Holdhoff, M.D., Ph.D., associate professor of oncology and neurosurgery at the Johns Hopkins Kimmel Cancer Center, other laboratories found no evidence of the virus in these types of tumors. "Significant resources have already gone into this field of study," he says, "making it very important to definitively answer the question of whether there's an association between CMV and gliomas or not." To investigate, Holdhoff and De Marzo, along with Ravit Arav-Boger, M.D., associate professor of pediatrics and oncology at the Johns Hopkins University School of Medicine, and their colleagues used several techniques to test tumor and other tissues from 99 men and women and 26 children with glioblastoma and other high-grade gliomas preserved and stored in different ways. Some of the tissues were stored as fresh frozen tissue, and some in paraffin wax blocks of tissue first soaked in a preservative known as formalin (formalin-fixed/paraffin embedded or FFPE), using either standard pathology slides or a tissue microarray (a collection of several small samples placed in the same paraffin wax block). What they called an "exhaustive" study design was crafted to determine presence of CMV in different ways, says De Marzo. The researchers ran these samples through different analytical techniques to look for CMV. Fresh frozen and FFPE samples underwent real-time PCR (a technique used to amplify copies of CMV's viral DNA) or chromogenic in situ hybridization, a technique that looks for the presence of specific nucleic acids that make up DNA. The FFPE samples and those in a tissue microarray underwent immunohistochemistry, a process that looks for certain CMV-derived proteins. Using one or more of these techniques on all of the samples from the 125 patients, the researchers found no evidence of CMV in any of them. Additionally, the researchers took blood samples from 18 recently diagnosed patients before they received standard radiation to treat their cancer and periodically after their treatment. The scientists tested the portion of blood called plasma of these patients using real-time PCR and their serum using a method known as the IgG avidity index, which looks for antibodies to a virus and can indicate the presence of a latent or previous infection. Eight of 15 patients, for which blood serum was available, had signs of CMV in their serum, similar to rates in the general population. None had signs of the virus in their tumors, including those who tested positive for the virus in their serum, report the researchers. The scientists say that more research using large numbers of tumor tissues from patients throughout the world, coordinated by independent laboratories with no stake in the presence of CMV in gliomas, will be necessary before CMV can definitely be ruled out as a player in these cancers. There are several types of high-grade gliomas, including glioblastoma, the most common, which is a type of astrocytoma and the most common among primary brain cancers in adults. The American Brain Tumor Association predicts that more than 12,000 cases of glioblastoma will be diagnosed in the U.S. in 2017. Median survival for this disease is 14.6 months with the current standard of care, which includes radiation and chemotherapy. Other Johns Hopkins researchers who participated in this study include Gunes Guner, Fausto J. Rodriguez, Jessica Hicks, Qizhi Zheng, Michael S. Forman, Xiaobu Ye, Stuart A. Grossman, Alan K. Meeker, Christopher M. Heaphy and Charles G. Eberhart. This research was funded by the National Institutes of Health's National Cancer Institute (P30CA006973), Wendy Jachman, the Robert H. Gross Memorial Fund and the Retired Professional Fire Fighters Cancer Fund Inc.


News Article | March 1, 2017
Site: www.eurekalert.org

Working with yeast and human cells, researchers at Johns Hopkins say they have discovered an unexpected route for cells to eliminate protein clumps that may sometimes be the molecular equivalent of throwing too much or the wrong trash into the garbage disposal. Their finding, they say, could help explain part of what goes awry in the progression of such neurodegenerative diseases as Parkinson's and Alzheimer's. Proteins in the cell that are damaged or folded incorrectly tend to form clumps or aggregates, which have been thought to dissolve gradually in a cell's cytoplasm or nucleus thanks to an enzyme complex called the proteasome, or in a digestive organelle called the lysosome. But in experiments on yeast, which has many structures similar to those in human cells, the Johns Hopkins scientists unexpectedly found that many of those protein clumps break down in the cell's energy-producing powerhouses, called mitochondria. They also found that too many misfolded proteins can clog up and damage this vital structure. The team's findings, described March 1 in Nature, could help explain why protein clumping and mitochondrial deterioration are both hallmarks of neurodegenerative diseases. Rong Li, Ph.D., professor of cell biology, biomedical engineering and oncology at the Johns Hopkins University School of Medicine and a member of the Johns Hopkins Kimmel Cancer Center, who led the study, likens the disposal system to the interplay between a household's trash and a garbage disposal in the kitchen sink. The disposal is handy and helps keep the house free of food scraps, but the danger is that with too much trash, especially tough-to-grind garbage, the system could get clogged up or break down. In a previous study, Li and her team found protein aggregates, which form abundantly under stressful conditions, such as intense heat, stuck to the outer surface of mitochondria. In this study, they found the aggregates bind to proteins that form the pores mitochondria normally use to import proteins needed to build this organelle. If these pores are damaged by mutations, then aggregates cannot be dissolved, the researchers report. These observations led the team to hypothesize that misfolded proteins in the aggregates are pulled into mitochondria for disposal, much like food scraps dropped into the garbage disposal. Testing this hypothesis was tricky, Li says, because most of the misfolded proteins started out in the cytoplasm, and most of those that enter mitochondria quickly get ground up. As a consequence, Li and her team used a technique in which a fluorescent protein was split into two parts. Then, they put one part inside the mitochondria and linked the other part with a misfolded and clumping protein in the cytoplasm. If the misfolded protein entered the mitochondria, the two parts of the fluorescent protein could come together and light up the mitochondria. This was indeed what happened. "With any experiment," Li says, "you have a hypothesis, but in your head, you may be skeptical, so seeing the bright mitochondria was an enlightening moment." To see what might happen in a diseased system, the team then put into yeast cells a protein implicated in the neurodegenerative disease known as amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease. After a heat treatment that caused the ALS protein to misfold, it also wound up in the mitochondria. The researchers then did an experiment in which a lot of proteins in the cytoplasm were made to misfold and found that when too much of these proteins entered mitochondria, they started to break down. The team wanted to make sure that the phenomenon it had observed in the yeast cells could also happen in human cells, so the scientists used the same split-fluorescent protein method to observe misfolded proteins to enter the mitochondria of lab-grown human retinal pigmented epithelial cells. As observed in yeast, misfolded proteins, but not those that were properly folded, entered and lit up mitochondria. Biological systems are in general quite robust, but there are also some Achilles' heels that may be disease prone, Li says, and relying on the mitochondrial system to help with cleanup may be one such example. While young and healthy mitochondria may be fully up to the task, aged mitochondria or those overwhelmed by too much cleanup in troubled cells may suffer damage, which could then impair many of their other vital functions. Other researchers involved in the study include Linhao Ruan, Erli Jin and Andrei Kucharavy, all of Johns Hopkins, as well as Chuankai Zhou, Zhihui Wen and Laurence Florens of Stowers Institute for Medical Research in Kansas City, Missouri. This work was funded by the National Institute of General Medical Science (grant number R35 GM118172) and the American Heart Association.


News Article | March 2, 2017
Site: www.biosciencetechnology.com

Working with yeast and human cells, researchers at Johns Hopkins say they have discovered an unexpected route for cells to eliminate protein clumps that may sometimes be the molecular equivalent of throwing too much or the wrong trash into the garbage disposal. Their finding, they say, could help explain part of what goes awry in the progression of such neurodegenerative diseases as Parkinson’s and Alzheimer’s. Proteins in the cell that are damaged or folded incorrectly tend to form clumps or aggregates, which have been thought to dissolve gradually in a cell’s cytoplasm or nucleus thanks to an enzyme complex called the proteasome, or in a digestive organelle called the lysosome. But in experiments on yeast, which has many structures similar to those in human cells, the Johns Hopkins scientists unexpectedly found that many of those protein clumps break down in the cell’s energy-producing powerhouses, called mitochondria. They also found that too many misfolded proteins can clog up and damage this vital structure. The team’s findings, described March 1 in Nature, could help explain why protein clumping and mitochondrial deterioration are both hallmarks of neurodegenerative diseases. Rong Li, Ph.D., professor of cell biology, chemical and biomolecular engineering, and oncology at the Johns Hopkins University and a member of the Johns Hopkins Kimmel Cancer Center, who led the study, likens the disposal system to the interplay between a household’s trash and a garbage disposal in the kitchen sink. The disposal is handy and helps keep the house free of food scraps, but the danger is that with too much trash, especially tough-to-grind garbage, the system could get clogged up or break down. In a previous study, Li and her team found protein aggregates, which form abundantly under stressful conditions, such as intense heat, stuck to the outer surface of mitochondria. In this study, they found the aggregates bind to proteins that form the pores mitochondria normally use to import proteins needed to build this organelle. If these pores are damaged by mutations, then aggregates cannot be dissolved, the researchers report. These observations led the team to hypothesize that misfolded proteins in the aggregates are pulled into mitochondria for disposal, much like food scraps dropped into the garbage disposal. Testing this hypothesis was tricky, Li says, because most of the misfolded proteins started out in the cytoplasm, and most of those that enter mitochondria quickly get ground up. As a consequence, Li and her team used a technique in which a fluorescent protein was split into two parts. Then, they put one part inside the mitochondria and linked the other part with a misfolded and clumping protein in the cytoplasm. If the misfolded protein entered the mitochondria, the two parts of the fluorescent protein could come together and light up the mitochondria. This was indeed what happened. “With any experiment,” Li says, “you have a hypothesis, but in your head, you may be skeptical, so seeing the bright mitochondria was an enlightening moment.” To see what might happen in a diseased system, the team then put into yeast cells a protein implicated in the neurodegenerative disease known as amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease. After a heat treatment that caused the ALS protein to misfold, it also wound up in the mitochondria. The researchers then did an experiment in which a lot of proteins in the cytoplasm were made to misfold and found that when too much of these proteins entered mitochondria, they started to break down. The team wanted to make sure that the phenomenon it had observed in the yeast cells could also happen in human cells, so the scientists used the same split-fluorescent protein method to observe misfolded proteins to enter the mitochondria of lab-grown human retinal pigmented epithelial cells. As observed in yeast, misfolded proteins, but not those that were properly folded, entered and lit up mitochondria. Biological systems are in general quite robust, but there are also some Achilles’ heels that may be disease prone, Li says, and relying on the mitochondrial system to help with cleanup may be one such example. While young and healthy mitochondria may be fully up to the task, aged mitochondria or those overwhelmed by too much cleanup in troubled cells may suffer damage, which could then impair many of their other vital functions.


News Article | February 22, 2017
Site: www.eurekalert.org

Working with human breast cancer cells and mice, researchers at Johns Hopkins say they have identified a biochemical pathway that triggers the regrowth of breast cancer stem cells after chemotherapy. The regrowth of cancer stem cells is responsible for the drug resistance that develops in many breast tumors and the reason that for many patients, the benefits of chemo are short-lived. Cancer recurrence after chemotherapy is frequently fatal. "Breast cancer stem cells pose a serious problem for therapy," says lead study investigator Gregg Semenza, M.D., Ph.D., the C. Michael Armstrong Professor of Medicine, director of the Vascular Biology Program at the Johns Hopkins Institute for Cell Engineering and a member of the Johns Hopkins Kimmel Cancer Center. "These are the cells that can break away from a tumor and metastasize; these are the cells you most want to kill with chemotherapy. Paradoxically, though, cancer stem cells are quite resistant to chemotherapy." Semenza says previous studies have shown that resistance to chemotherapy arises from the hardy nature of cancer stem cells, which are often found in the centers of tumors, where oxygen levels are quite low. Their survival is made possible through proteins known as hypoxia-inducible factors (HIFs), which turn on genes that help the cells survive in a low-oxygen environment. In this new study, described Feb. 21 in Cell Reports, Semenza and his colleagues conducted gene expression analysis of multiple human breast cancer cell lines grown in the laboratory after exposure to chemotherapy drugs, like carboplatin, which stops tumor growth by damaging cancer cell DNA. The team found that the cancer cells that survived tended to have higher levels of a protein known as glutathione-S-transferase O1, or GSTO1. Experiments showed that HIFs controlled the production of GSTO1 in breast cancer cells when they were exposed to chemotherapy; if HIF activity was blocked in these lab-grown cells, GSTO1 was not produced. Semenza notes that GSTO1 and related GST proteins are antioxidant enzymes, but GSTO1's role in chemotherapy resistance did not require its antioxidant activity. Instead, following exposure to chemotherapy, GSTO1 binds to a protein called the ryanodine receptor 1, or RYR1, that triggers the release of calcium, which causes a chain reaction that transforms ordinary breast cancer cells into cancer stem cells. To more directly assess the role of GSTO1 and RYR1 in the breast tumor response to chemotherapy, the researchers injected human breast cancer cells into the mammary gland of mice and then treated the mice with carboplatin after tumors had formed. In addition to using normal breast cancer cells in the experiments, the team also used cancer cells that had been genetically engineered to lack either GSTO1 or RYR1. Loss of either GSTO1 or RYR1, the researchers report, decreased the number of cancer stem cells in the primary tumor, blocked metastasis of cancer cells from the primary tumor to the lungs, decreased the duration of chemotherapy required to induce remission and increased the duration of time after chemotherapy was stopped that the mice remained tumor-free. Although the study showed that blocking the production of GSTO1 may improve the efficacy of chemotherapy drugs, such as carboplatin, GSTO1 is only one of many proteins that are produced under the control of HIFs in breast cancer cells that have been exposed to chemotherapy. The Semenza lab is working to develop drugs that can block the action of HIFs, with the hope that HIF inhibitors will make chemotherapy more effective. Other authors of the report include Haquin Li, Ivan Chen, Larissa Shimoda, Youngrok Park, Chuanzhao Zhang, Linh Tran and Huimin Zhang of the Johns Hopkins University School of Medicine. This work was supported by an Impact Award from the Department of Defense (grant number W81XWH-12-1-0464) and a Research Professor Award from the American Cancer Society.

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