Cell Surface Protein May Offer Big Target in Treating High-Risk Childhood Cancers

Oncology researchers studying high-risk children’s cancers have identified a protein that offers a likely target for immunotherapy–harnessing the immune system in medical treatments. In cell cultures and animal models, a potent drug attached to an antibody selectively zeroes in on cancer cells without harming healthy cells.

“We have built a strong foundation for developing a completely new and hopefully much less toxic treatment for neuroblastoma, the most common cancer in infants,” said study supervisor John M. Maris, MD, a pediatric oncologist at Children’s Hospital of Philadelphia (CHOP). “Furthermore, our findings may also lend support to the development of other immune-based therapies, such as CAR T-cells, in children with multiple aggressive cancers in addition to neuroblastoma.”

Maris, along with study leader and first author Kristopher R. Bosse, MD, and colleagues published their study today in Cancer Cell, which featured their findings as the cover story.

Neuroblastoma is a cancer of the developing peripheral nervous system that usually occurs as a solid tumor in a child’s chest or abdomen, and is the most common cancer in infants. It accounts for a disproportionate share of cancer deaths in children. Over decades, CHOP clinicians and researchers have built one of the world’s leading programs in neuroblastoma.

The study team used sophisticated sequencing tools to first discover molecules that are much more commonly found on the surface of neuroblastoma cells than on normal cells. “Our rationale was to identify a cell-surface molecule that an immune-based therapy could target without damaging healthy tissues,” said Bosse. “Using this approach, we identified a protein called glypican-2, or GPC2.” GPC2 is one of a family of glypicans—cell-surface proteins that interact with growth factors and cell surface receptors, influencing many intracellular signaling pathways important in development and cancer.

In addition to GPC2’s presence on neuroblastoma cells, the study team also found that GPC2 is necessary for a neuroblastoma tumor to proliferate. Both of those facts implied that a compound that acted against GPC2 might kill cancer cells, spare healthy cells, and limit the possibility of these tumors developing “immune escape” mechanisms, in which cancer cells resist an immunotherapy by shedding the target. “Given GPC2’s critical role in the growth of neuroblastomas, we hope that tumors will not be able to simply downregulate this protein in order to escape recognition by our immunotherapies that target GPC2,” said Bosse.

After pinpointing GPC2 as a very promising target for therapy, the researchers next worked with their colleagues at the National Cancer Institute to search for a weapon. They developed an antibody-drug conjugate (ADC) called D3-GPC2-PBD, which combined a very specific antibody that recognizes GPC2 with a potent chemotherapy drug that is internalized specifically by cancer cells. The drug payload damages DNA in tumors, while sparing healthy tissues from its toxic effects.

In cell cultures and mouse models of neuroblastoma, the ADC robustly killed neuroblastoma cells with no discernible toxicity to normal cells. “These findings establish that this type of immunotherapy could be potentially safe and effective against neuroblastoma,” said Maris. “Our next steps will be to further evaluate this ADC and also develop other immune-based therapies directed against GPC2. Because other glypicans in addition to GPC2 are overexpressed in other childhood cancers, it may also be possible to apply this approach across various types of high-risk pediatric cancers.”

Accelerating the Development of Next-Generation Cancer Therapies

To accelerate the development of next-generation cancer therapies, the Gene Editing Institute of the Helen F. Graham Cancer Center & Research Institute at Christiana Care Health System has agreed to provide genetically modified cell lines to Analytical Biological Services, Inc. (ABS) of Wilmington, Delaware.

Under a three-year agreement, the Gene Editing Institute will act as sole provider of gene editing services and genetically modified cell lines to ABS for replication, marketing and distribution to leading pharmaceutical and biomedical research companies worldwide.

“This agreement with ABS will speed the progress in the discovery of effective cancer therapies and accelerate the path to prevention, diagnosis and treatment of many forms of cancer,” said Nicholas J. Petrelli, M.D., the Bank of America endowed medical director of the Helen F. Graham Cancer Center & Research Institute at Christiana Care Health System.

“This partnership greatly enhances our capability to provide the highest quality genetically engineered cells for drug discovery,” said ABS President and CEO Charles Saller, Ph.D. “Our partners at the Gene Editing Institute are advancing molecular medicine, and their expertise adds a new dimension to our efforts to speed up drug discovery.”

“One goal of The Gene Editing Institute is to develop community partnerships that can advance translational cancer research,” said Eric Kmiec, Ph.D., founder and director of the Gene Editing Institute. “The Gene Editing Institute is driving innovation in gene engineering, and ABS has the know-how to grow and expand the cells in sufficient quantities, as well as to market them to pharmaceutical and biotechnology clients for drug screening and research.”

The Gene Editing Institute is a worldwide leader in the design of the tools that scientists need to manipulate and alter human genetic material easier and more efficiently than ever before. Scientists at the Gene Editing Institute have designed and customized an expanding tool-kit for gene editing, including the renowned CRISPR-Cas9 system, to permanently disrupt or knock out genes, add or knock in DNA fragments and create point mutations in genomic DNA. Last year, scientists at the Gene Editing Institute described in the journal Scientific Reports how they combined CRISPR and short strands of synthetic DNA to greatly enhance the precision and reliability of the CRISPR gene editing technique. Called Excision and Corrective Therapy, or EXACT, this new tool acts as both a Band-Aid and a template during gene mutation repairs.

Genetically modified cells can help advance cancer research. By inactivating a single gene, scientists can test if it affects tumor formation or somehow alters the response to cancer therapies. Similarly, inserting a gene into a cell can produce a gene product that is a target for potential new drugs.

“Gene editing and the CRISPR technology is having a major impact on anticancer drug development because it allows us to validate the target of the candidate drug,” said Dr. Kmiec. “Pharmaceutical companies want to use gene editing tools to identify new targets for anti-cancer drugs and to validate the targets they already have identified.”

The Delaware BioScience Association helped connect the Gene Editing Institute with ABS. “The collaborative agreement between the Gene Editing Institute and ABS exemplifies the power of building a strong biotech community, flourishing further innovation, and keeping businesses engaged and thriving in the state of Delaware,” said Helen Stimson, president and CEO of The Delaware BioScience Association. “The Delaware BioScience Association is committed to fostering meaningful relationships, such as this one, among its members, and establishing strategic partnerships that bolster the state’s innovation economy,” she said.

“This is one of those times when the forces of nature align to bring two perfectly matched skill sets together,” said Dr. Kmiec. “There is no question that our collaboration with ABS will accelerate the pace of drug discovery around the world.”

About The Gene Editing Institute

The Gene Editing Institute of Christiana Care Health System’s Helen F. Graham Cancer Center & Research Institute is unlocking the genetic mechanisms that drive cancer that can lead to new therapies and pharmaceuticals to revolutionize cancer treatment. Gene editing in lung cancer research has already begun setting the stage for clinical trials.

The Gene Editing Institute is integrated into the Molecular Screening Facility at The Wistar Institute in Philadelphia, PA, where its innovative gene-editing technologies are available to research projects at Wistar and to external users. Working with Wistar scientists, the Gene Editing Institute has begun research to conduct a clinical trial in melanoma. With funding from the National Institutes of Health, the Gene Editing Institute is partnering with A.I. duPont/Nemours to develop a gene editing strategy for the treatment of sickle cell anemia and leukemia. Under a grant from the U.S.–Israel Binational Industrial Research & Development Foundation, the Gene Editing Institute is working with Jerusalem-based NovellusDx to improve the efficiency and speed of cancer diagnostic screening tools. This work could lead to earlier identification of genetic mechanisms responsible for both the onset and progression of many types of cancers and the development of individualized therapeutics.

Gene Editing Institute scientists also provide instruction in the design and implementation of genetic tools. Partnerships with Bio-Rad Inc. and the Delaware Technical and Community College are producing gene editing curricula and teacher training workshops for both community colleges and secondary schools.

Study Unlocks How Changes in Gene Activity Early During Therapy Can Establish the Roots of Drug-Resistant Melanoma

FINDINGS
A UCLA-led study of changes in gene activity in BRAF-mutated melanoma suggests these epigenomic alterations are not random but can explain how tumors are already developing resistance as they shrink in response to treatment with a powerful class of drugs called MAP kinase (MAPK)-targeted inhibitors. The discovery marks a potential milestone in the understanding of treatment-resistant melanoma and provides scientists with powerful targets for drug development and new clinical studies.

BACKGROUND
Approximately 50 percent of advanced melanoma tumors are driven to grow by the presence of BRAF mutations. The use of BRAF inhibitors, both alone and in combination with another MAPK pathway inhibitor called MEK, have shown unprecedented responses as a treatment for these types of tumors, rapidly shrinking them. However, BRAF-mutated tumors frequently show early resistance to treatment and respond only partially to BRAF inhibitors, leaving behind cancer cells that may evolve to cause eventual tumor regrowth.

The findings build upon research by Dr. Roger Lo, professor of medicine (dermatology) and molecular and medical pharmacology at the David Geffen School of Medicine, and lead author of the new study. Previously, he discovered that epigenomic alterations (via a regulatory mechanism called CpG methylation) accounted for a wide range of altered gene activities and behaviors in BRAF-mutant therapy-resistant melanoma tumor cells. The loss of tumor-fighting immune or T-cells in drug-resistant tumors may lead to resistance to subsequent salvage immunotherapy, Lo said, and drug resistance can grow at the same time that anti-tumor immune cells diminish and weaken.

This means that in some patients the melanoma might develop resistance to both MAP kinase-targeted therapy and anti-PD-L1 antibodies, which capitalize on the abundance of immune cells inside the tumor to unleash their anti-cancer activities. Lo concluded that non-genomic, epigenomic, and immunologic evolution of melanoma explain why patients relapse on MAPK-targeted therapies.

Along with co-first authors, Drs. Chunying Song, Marco Piva and Lu Sun, Lo hypothesized that epigenomic and immunologic resistance evident during clinical relapse may be developing already during the first few weeks of therapy as the tumors shrink and clinical responses are viewed as successes. If this proves to be true, then scientists could potentially identify combination treatments that suppress the earliest resistance-promoting activities.

METHOD
Lo’s team utilized state-of-the-art technologies to comprehensively profile recurrent patterns of gene activity changes. They analyzed 46 samples of patients’ melanoma tumors, both before and early during MAPK therapy. They also replicated the process outside of the human body, modeling both non-genomic drug resistance by growing melanoma cell lines from patients’ tumors and immunologic resistance in mouse melanoma. Patient-derived cell lines and mouse melanoma tumors were treated with drugs that block the MAP kinase pathway and sampled at various times over the course of the study to track gene activity changes.

The researchers found that MAPK therapies fostered CpG methylation and gene activity reprogramming of tumors. This reduced the tumor cells’ dependence on the mutated BRAF protein, and switched their growth and survival strategies to rely on proteins called receptor-tyrosine kinases and PD-L2. In addition, PD-L2 gene activity was found to be turned on in immune cells surrounding the tumor cells. They also demonstrated that blocking PD-L2 with an antibody could prevent the loss of T-cells in the tumor’s immune microenvironment and suppressing therapy resistance.

Lo’s team continues to identify other adaptations during this early phase of therapy that could be targets of future combination treatment regiments.

IMPACT
More than 87,000 new cases of melanoma will be diagnosed this year in the United States alone, and more than 9,500 people are expected to die of the disease.

The findings can prompt drug development and new clinical studies based on epigenetic or gene expression and immune targets in combination with mutation-targeted therapies. As scientists learn what these mechanisms of tumor resistance are, they can combine inhibitor drugs that block multiple resistance routes and eventually make the tumors shrink for much longer or go away completely, Lo said.

JOURNAL
The research is published online in Cancer Discovery, the peer-reviewed journal of the American Association of Cancer Research.

AUTHORS
UCLA’s Dr. Roger Lo is senior author. The co-first authors are Drs. Chunying Song, Marco Piva and Lu Sun at the David Geffen School of Medicine at UCLA. Other authors are Drs. Aayoung Hong, Gatien Moriceau, Xiangju Kong, Hong Zhang, Shirley Lomeli, Jin Qian, Clarissa Yu, Robert Damoiseaux, Philip Scumpia, Antoni Ribas and Willy Hugo at UCLA; and Mark Kelley, Kimberly Dahlman, Jeffrey Sosman, Douglas Johnson at Vanderbilt University. Lo, Damoiseaux, Scumpia and Ribas are members of UCLA’s Jonsson Comprehensive Cancer Center.

FUNDING
The research was supported by the National Institutes of Health, the American Cancer Society, the Melanoma Research Alliance, the American Skin Association, the American Association for Cancer Research, the National Cancer Center, the Burroughs Wellcome Fund, the Ressler Family Foundation, the Ian Copeland Melanoma Fund, the SWOG/Hope Foundation, the Steven C. Gordon Family Foundation, the Department of Defense Horizon Award, the Dermatology Foundation, and the ASCO Conquer Cancer Career Development Award.

Stabilizing TREM2 — a potential strategy to combat Alzheimer’s disease

A gene called triggering receptor expressed on myeloid cells 2, or TREM2, has been associated with numerous neurodegenerative diseases, such as Alzheimer’s disease, Frontotemporal lobar degeneration, Parkinson’s disease, and Nasu-Hakola disease. Recently, a rare mutation in the gene has been shown to increase the risk for developing Alzheimer’s disease.

Independently from each other, two research groups have now revealed the molecular mechanism behind this mutation. Their research, published today in EMBO Molecular Medicine, sheds light on the role of TREM2 in normal brain function and suggests a new therapeutic target in Alzheimer’s disease treatment.

Alzheimer’s disease, just like other neurodegenerative diseases, is characterized by the accumulation of specific protein aggregates in the brain. Specialized brain immune cells called microglia strive to counter this process by engulfing the toxic buildup. But as the brain ages, microglia eventually lose out and fail to rid all the damaging material.

TREM2 is active on microglia and enables them to carry out their protective function. The protein spans the microglia cell membrane and uses its external region to detect dying cells or lipids associated with toxic protein aggregates. Subsequently, TREM2 is cut in two. The external part is shed from the protein and released, while the remaining part still present in the cell membrane is degraded. To better understand TREM2 function, the two research groups took a closer look at its cleavage. They were led by Christian Haass at the German Center for Neurodegenerative Diseases at the Ludwig-Maximilians-University in Munich, Germany, and Damian Crowther of AstraZeneca’s IMED Neuroscience group in Cambridge, UK together with colleagues at the Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto and the Cambridge Institute for Medical Research, University of Cambridge, UK.

Using different technological approaches, both groups first determined the exact site of protein shedding and found it to be at amino acid 157. Amino acid 157 was no unknown. Only recently, researchers from China had uncovered that a mutation at this exact position, referred to as p.H157Y, increased the risk of Alzheimer’s disease. Together, these observations indicate that protein cleavage is perturbed in the p.H157 mutant and that this alteration promotes disease development.

As a next step, Haass and Crowther’s groups investigated the biochemical properties of the p.H157Y mutant protein more closely. They found that the mutant was cleaved more rapidly than a healthy version of the protein. “Our results provide a detailed molecular mechanism for how this rare mutation alters the function of TREM2 and hence facilitates the progression of Alzheimer’s disease,” said Crowther.

While most TREM2 mutations affect protein production, the mechanism behind p.H157Y is somewhat different. The p.H157Y mutation allows the protein to be correctly manufactured and transported to the microglia cell surface, but then it is cleaved too quickly. “The end result is the same. In both cases, there is too little full-length TREM protein on microglia,” said Haass. “This suggests that stabilizing TREM2, by making it less susceptible to cleavage, may be a viable therapeutic strategy.”

Repairing damaged hearts with self-healing heart cells

New research has discovered a potential means to trigger damaged heart cells to self-heal. The discovery could lead to groundbreaking forms of treatment for heart diseases. For the first time, researchers have identified a long non-coding ribonucleic acid (ncRNA) that regulates genes controlling the ability of heart cells to undergo repair or regeneration. This novel RNA, which researchers have named “Singheart”, may be targeted for treating heart failure in the future. The discovery was made jointly by A*STAR’s Genome Institute of Singapore (GIS) and the National University Health System (NUHS), and is now published in Nature Communications.

Unlike most other cells in the human body, heart cells do not have the ability to self-repair or regenerate effectively, making heart attack and heart failure severe and debilitating. Cardiovascular disease (CVD) is the leading cause of death worldwide, with an estimated 17.7 million people dying from CVD in 2015 (1). CVD also accounted for close to 30% of all deaths in Singapore in 2015 (2).

In this project, the researchers used single cell technology to explore gene expression patterns in healthy and diseased hearts. The team discovered that a unique subpopulation of heart cells in diseased hearts activate gene programmes related to heart cell division, uncovering the gene expression heterogeneity of diseased heart cells for the first time. In addition, they also found the “brakes” that prevent heart cells from dividing and thus self-healing. Targeting these “brakes” could help trigger the repair and regeneration of heart cells.

“There has always been a suspicion that the heart holds the key to its own healing, regenerative and repair capability. But that ability seems to become blocked as soon as the heart is past its developmental stage. Our findings point to this potential block that when lifted, may allow the heart to heal itself,” explained A/Prof Roger Foo, the study’s lead author, who is Principal Investigator at both GIS and NUHS’ Cardiovascular Research Institute (CVRI) and Senior Consultant at the National University Heart Centre, Singapore (NUHCS).

“In contrast to a skin wound where the scab falls off and new skin grows over, the heart lacks such a capability to self-heal, and suffers a permanent scar instead. If the heart can be motivated to heal like the skin, consequences of a heart attack would be banished forever,” added A/Prof Foo.

The study was driven by first author and former Senior Research Fellow at the GIS, Dr Kelvin See, who is currently a Postdoctoral Researcher and Mack Technology Fellow at University of Pennsylvania.

“This new research is a significant step towards unlocking the heart’s full regenerative potential, and may eventually translate to more effective treatment for heart diseases. Heart disease is the top disease burden in Singapore and strong funding remains urgently needed to enable similar groundbreaking discoveries,” said Prof Mark Richards, Director of CVRI.

Executive Director of GIS, Prof Ng Huck Hui added, “This cross-institutional research effort serves as a strong foundation for future heart studies. More importantly, uncovering barriers that stand in the way of heart cells’ self-healing process brings us another step closer to finding a cure for one of the world’s biggest killers.”

Skewing the aim of targeted cancer therapies

Headlines, of late, have touted the successes of targeted gene-based cancer therapies, such as immunotherapies, but, unfortunately, also their failures.

Broad inadequacies in a widespread biological concept that affects cancer research could be significantly deflecting the aim of such targeted drugs, according to a new study. A team exploring genetic mechanisms in cancer at the Georgia Institute of Technology has found evidence that a prevailing concept about how cells produce protein molecules, particularly when applied to cancer, could be erroneous as much as two-thirds of the time.

Prior studies by other researchers have also critiqued this concept about the pathway leading from genetic code to proteins, but this new study, led by cancer researcher John McDonald, has employed rare analytical technology to explore it in unparalleled detail. The study also turned up novel evidence for regulating mechanisms that could account for the prevailing concept’s apparent shortcomings.

RNA concept incomplete

The concept stems from common knowledge about the assembly line inside cells that starts with code in DNA, is transcribed to messenger RNA, then translated into protein molecules, the cell’s building blocks.

That model seems to have left the impression that cellular protein production works analogously to an old-style factory production line: That the amount of a messenger RNA encoded by DNA on the front end translates directly into the amount of a corresponding protein produced on the back end. That idea is at the core of how gene-based cancer drug developers choose their targets.

To put that assumed congruence between RNA production and protein production to the test, the researchers examined — in ovarian cancer cells donated by a patient — 4,436 genes, their subsequently transcribed messenger RNA, and the resulting proteins. The assumption, that proverbial factory orders passed down the DNA-RNA line determine in a straightforward manner the amount of a protein being produced, proved incorrect 62 percent of the time.

RNA skews drug cues

“The messenger RNA-protein connection is important because proteins are usually the targets of gene-based cancer therapies,” McDonald said. “And drug developers typically measure messenger RNA levels thinking they will tell them what the protein levels are.” But the significant variations in ratios of messenger RNA to protein that the researchers found make the common method of targeting proteins via RNA seem much less than optimal.

McDonald, Mengnan Zhang and Ronghu Wu published their results on August 15, 2017 in the journal Scientific Reports. The work was funded by the Ovarian Cancer Institute, The Deborah Nash Endowment, Atlanta’s Northside Hospital and the National Science Foundation. The spectrophotometric technology needed to closely identify a high number of proteins is rare and costly but is available in Wu’s lab at Georgia Tech.

Whereas many studies look at normal tissue versus cancerous tissue, this new study focused on cancer progression, or metastasis, which is what usually makes cancer deadly. The researchers looked at primary tumor tissue and also metastatic tissue.

Hiding drug targets

“The idea that any change in RNA level in cancerous development flows all the way up to the protein level could be leading to drug targeting errors,” said McDonald, who heads Georgia Tech’s Integrated Cancer Research Center. Drug developers often look for oddly high messenger RNA levels in a cancer then go after what they believe must be the resulting oddly high levels of a corresponding protein.

Taking messenger RNA as a protein level indicator could actually work some of the time. In the McDonald team’s latest experiment, in 38 percent of the cases, the rise of RNA levels in cancerous cells did indeed reflect a comparable rise of protein levels. But in the rest of cases, they did not.

“So, there are going to be many instances where if you’re predicting what to give therapeutically to a patient based on RNA, your prescription could easily be incorrect,” McDonald said. “Drug developers could be aiming at targets that aren’t there and also not shooting for targets that are there.”

RNA muted or magnified

The analogy of a factory producing building materials can help illustrate what goes wrong in a cancerous cell, and also help describe the study’s new insights into protein production. To complete the metaphor: The materials produced are used in the construction of the factory’s own building, that is, the cell’s own structures.

In cancer cells, a mutation makes protein production go awry usually not by deforming proteins but by overproducing them. “A lot of mutations in cancer are mutations in production levels. The proteins are being overexpressed,” said McDonald, who is also a professor in Georgia Tech’s School of Biological Sciences.

A bad factory order can lead to the production of too much of a good material and then force it into the structures of the cell, distorting it. The question is: Where in the production line do bad factory orders appear?

According to the new study, the answer is less straightforward than perhaps previously thought.

Micro RNA managing

The orders don’t all appear on the front end of the assembly line with DNA over-transcribing messenger RNA. Additionally, some mutations that do over-transcribe messenger RNA on the front end are tamped down or canceled by regulating mechanisms further down the line, and may never end up boosting protein levels on the back end.

Regulating mechanisms also appear to be making other messenger RNA, transcribed in normal amounts, unexpectedly crank out inordinate levels of proteins.

At the heart of those regulating systems, another RNA called micro RNA may be micromanaging how much, or little, of a protein is actually produced in the end.

“We have evidence that micro RNAs may be responsible for the non-correlation between the proteins and the RNA, and that’s completely novel,” McDonald said. “It’s an emerging area of research.”

Micro RNA, or miRNA, is an extremely short strand of RNA.

No one at fault

McDonald would like to see tissues from more cancer patients undergo similar testing. “Right now, with just one patient, the data is limited, but I also really think it shows that the phenomenon is real,” McDonald said.

“Many past studies have looked at one particular protein and a particular gene, or a particular handful. We looked at more than 4,000,” McDonald said. “What that brings up is that the phenomenon is probably not isolated but instead genome-wide.”

The study’s authors would also like to see rarely accessible, advanced protein detecting technology become more widely available to biomolecular researchers, especially in the field of cancer drug development. “Targeted gene therapy is a good idea, but you need the full knowledge of whether it’s affecting the protein level,” McDonald said.

He pointed out that no one is at fault for the possible incompleteness of commonly held concepts about protein production.

As science progresses, it naturally illuminates new details, and formerly useful ideas need updating. With the existence of new technologies, it may be time to flesh out this particular concept for the sake of cancer research progress.

Cell mechanism discovery could lead to ‘fundamental’ change in leukaemia treatment

Researchers have identified a new cell mechanism that could lead to a fundamental change in the diagnosis and treatment of leukaemia.

A team in the University of Kent’s pharmacy school conducted a study that discovered that leukaemia cells release a protein, known as galctin-9, that prevents a patient’s own immune system from killing cancerous blood cells.

Acute Myeloid Leukaemia (AML) — a type of blood cancer that affects over 250,000 people every year worldwide — progresses rapidly because its cells are capable of avoiding the patient’s immune surveillance. It does this by inactivating the body’s immune cells, cytotoxic T lymphocytes and natural killer (NK) cells.

Existing treatment strategies consist of aggressive chemotherapy and stem cell transplantation, which often do not result in effective remission of the disease. This is because of a lack of understanding of the molecular mechanisms that allow malignant cells to escape attack by the body’s immune cells.

Now the researchers at the Medway School of Pharmacy, led by Dr Vadim Sumbayev, Dr Bernhard Gibbs and Professor Yuri Ushkaryov, have found that leukaemia cells — but not healthy blood cells — express a receptor called latrophilin 1 (LPHN1). Stimulation of this receptor causes these cancer cells to release galectin-9, which then prevents the patient’s immune system from fighting the cancer cells.

The discovery of this cell mechanism paves the way for new ‘biomarkers’ for AML diagnosis, as well as potential targets for AML immune therapy, say the researchers.

‘Targeting this pathway will crucially enhance patients own immune defences, helping them to eliminate leukaemia cells’, said Dr Sumbayev. He added that the discovery has the potential to also be beneficial in the treatment of other cancers.

UC research examines lung cell turnover as risk factor & target for treatment of influenza pneumonia

Influenza is a recurring global health threat that, according to the World Health Organization, is responsible for as many as 500,000 deaths every year, most due to influenza pneumonia, or viral pneumonia. Infection with influenza most typically results in lung manifestations limited to dry cough and fever, and understanding how the transition to pneumonia occurs could shed light on interventions that reduce mortality. Research led by University of Cincinnati (UC) scientists takes a different approach to investigating how influenza spreads through the lungs by focusing on how resistant or susceptible cells lining the airway are to viral infection.

The work published today in the Proceedings of the National Academy of Sciences (PNAS) shows how stimuli that induce cell division in the lung promote spread of influenza from the airway to the gas exchanging units of the lung, known as the alveoli. The UC study also demonstrates that interventions that prevent alveolar cells from dividing reduce influenza mortality in animal models, suggesting a potential prophylactic and/or therapeutic strategy for influenza pneumonia.

“Almost all research into susceptibility or resistance to influenza focuses on host immune responses,” says Nikolaos Nikolaidis, PhD, research scientist in the Division of Pulmonary, Critical Care and Sleep Medicine in the Department of Internal Medicine at the UC College of Medicine and lead author on the paper. “Our approach was to examine factors that influence the vulnerability of alveolar cells to influenza infection, separate from how the immune system is dealing with the virus.”

“Less than 1 percent of alveolar cells are actively dividing at any given time in the healthy lung, rendering it naturally resistant to influenza infection,” says Frank McCormack, MD, Gordon and Helen Hughes Taylor Professor of Internal Medicine and director of the Division of Pulmonary, Critical Care and Sleep Medicine and senior author on the paper. “Recovery from lung injury due to supplemental oxygen therapy, cigarette smoke or scarring lung diseases is associated with expression of growth factors that result in multiplication of lung cells. Our work demonstrated that these mitogenically stimulated cells are rich targets for influenza infection while they are dividing.”

The researchers found that when sirolimus, which is FDA-approved for use as an anti-growth agent for the rare lung disease, lymphangioleiomyomatosis (LAM), was given to influenza-infected animal models, it prevented alveolar cells from dividing, and as a result, protected the mice from viral pneumonia and death.

“Although sirolimus also has off target immunosuppressive properties that could potentially pose added risks of side effects in virus-infected patients, trials of inhaled sirolimus could lead to approaches that do not entail systemic exposure,” says McCormack.

The McCormack lab expressed optimism that this observation has the potential to ultimately inform understanding of other unexplained risk factors for influenza, including very young age and pregnancy, and perhaps even to change medical management, such as more judicious use of supplemental oxygen in patients admitted with suspected viral pneumonia. Further, the team has hopes that the research could lead to a paradigm shift in the approach to therapy.

Nikolaidis says the next step in this research is to further explore why the multiplying alveolar epithelial cell is a better target for influenza. “Is it because the virus gets into the dividing cell more easily, because multiplying stimuli expand the pool of cellular machinery used by the virus to replicate, or because proliferation is associated with a reduction in innate cellular defenses? We are anxious to explore these and other potential mechanisms of viral susceptibility,” he adds.

Genetically enhanced, cord-blood derived immune cells strike B-cell cancers

Immune cells with a general knack for recognizing and killing many types of infected or abnormal cells also can be engineered to hunt down cells with specific targets on them to treat cancer, researchers at The University of Texas MD Anderson Cancer Center report in the journal Leukemia.

The team’s preclinical research shows that natural killer cells derived from donated umbilical cords can be modified to seek and destroy some types of leukemia and lymphoma. Genetic engineering also boosts their persistence and embeds a suicide gene that allows the modified cells to be shut down if they cause a severe inflammatory response.

A first-in-human phase I/II clinical trial of these cord-blood-derived, chimeric antigen receptor-equipped natural killer cells opened at MD Anderson in June for patients with relapsed or resistant chronic lymphocytic leukemia (CLL), acute lymphocytic leukemia (ALL), or non-Hodgkin lymphoma. All are cancers of the B cells, another white blood cell involved in immune response.

“Natural killer cells are the immune system’s most potent killers, but they are short-lived and cancers manage to evade a patient’s own NK cells to progress,” said Katy Rezvani, M.D., Ph.D., professor of Stem Cell Transplantation and Cellular Therapy.

“Our cord-blood derived NK cells, genetically equipped with a receptor that focuses them on B-cell malignancies and with interleukin-15 to help them persist longer — potentially for months instead of two or three weeks — are designed to address these challenges,” Rezvani said.

Moon Shots Program funds project

The clinical trial is funded by MD Anderson’s Moon Shots Program™, designed to more rapidly develop life-saving advances based on scientific discoveries.

The chimeric antigen receptor (CAR), so-called because it’s added to the cells, targets CD19, a surface protein found on B cells.

In cell lines and mouse models of lymphoma and CLL, CD19-targeted NK cells killed cancer cells and extended survival of animals compared to simply giving NK cells alone. Addition of IL-15 to the CD19 receptor was crucial for the longer persistence and enhanced activity of the NK cells against tumor cells.

NK cells are a different breed of killer from their more famous immune system cousins, the T cells. Both are white blood cells, but T cells are highly specialized hunters that look for invaders or abnormal cells that bear a specific antigen target, kill them and then remember the antigen target forever.

Natural killers have an array of inhibitory and activating receptors that work together to allow them to detect a wider variety of infected, stressed or abnormal cells.

“By adding the CD19 CAR, we’re also turning them into guided missiles,” said Elizabeth Shpall, M.D., professor of Stem Cell Transplantation and Cell Therapy.

Using a viral vector, the researchers transduce NK cells taken from cord blood with the CD19 CAR, the IL-15 gene, and an inducible caspase-9-based suicide gene.

Cell line tests found the engineered NK cells to be more efficient killers of lymphoma and CLL cells, compared to unmodified NK cells, indicating the engineered cells’ killing was not related to non-specific natural killer cell cytotoxicity.

Another experiment showed the engineered cord blood NK cells killed CLL cells much more efficiently than NK cells taken from CLL patients and engineered, highlighting the need to transplant CAR-engineered NK cells from healthy cord blood rather than use a patient’s own cells.

Suicide gene to counter cytokine release syndrome

Mouse model lymphoma experiments using a single infusion of low dose NK cells resulted in prolongation of survival. At a higher, double dose, none of the mice treated with the CD19/IL-15 NK cells died of lymphoma, with half surviving for 100 days and beyond. All mice treated with other types of NK cells died by day 41.

A proportion of mice treated with the higher dose of engineered NK cells died of cytokine release syndrome, a severe inflammatory response that also occurs in people treated with CAR T cells.

To counteract this toxicity, the researchers incorporated a suicide gene (iC9) that can be activated to kill the NK cells by treatment with a small-molecule dimerizer. This combination worked to swiftly reduce the engineered NK cells in the mouse model.

Subsequent safety experiments were conducted in preparation for the clinical trial. Rezvani, the principal investigator of the clinical trial, says the protocol calls for vigilance for signs of cytokine release syndrome, treatment with steroids and tocilizumab for low-grade CRS with AP1903 added to activate the suicide gene for grade 3 or 4 CRS.

NK CARs available off the shelf

T cells modified with chimeric antigen receptors against CD19 have shown efficacy in clinical trials. In these therapies, a patient’s own T cells are modified, expanded, and given back to the patient, a process that takes weeks. Finding a matched donor for T cells would be a challenge, but would be necessary because unmatched T cells could attack the recipient’s normal tissue – graft vs. host disease.

Rezvani and Shpall have given patients cord-blood derived NK cells in a variety of clinical trials and found that they do not cause graft vs. host disease, therefore don’t have to be matched. NK cells can be an off-the-shelf product, prepared in advance with the necessary receptor and given promptly to patients.

“CAR NK cells are scalable in a way that CAR T cells are not,” Rezvani noted.

A strength of T cells is the development of memory cells that persist and repeatedly attack cells bearing the specific antigen that return. NK cells do not seem to have a memory function, but Rezvani says the experience of the longer-lived mice, which are now more than a year old, raises the possibility that a prolonged NK cell attack will suffice.

Shpall, Rezvani and colleagues are developing cord blood NK CARs for other targets in a variety of blood cancers and solid tumors.

MD Anderson and the researchers have intellectual property related to the engineered NK cells, which is being managed in accordance with the institution’s conflict-of-interest rules.

Shpall founded and directs MD Anderson’s Cord Blood Bank, originally established to provide umbilical cord blood stem cells for patients who need them but cannot get a precise donor match. Donated by mothers who deliver babies at seven Houston hospitals and two others from California and Michigan, the bank now has 26,000 cords stored. MD Anderson researchers pioneered the extraction and expansion of NK cells from umbilical cords.

Promising new therapeutic approach for debilitating bone disease

An Australian-led research team has demonstrated a new therapeutic approach that can re-build and strengthen bone, offering hope for individuals with the debilitating bone cancer, multiple myeloma.

The findings were published today in the medical journal Blood, and were presented at an international meeting of bone biology experts in Brisbane earlier this month.

The researchers tested a new type of treatment that specifically targets a protein called sclerostin, which in healthy bones is an important regulator of bone formation. Sclerostin halts bone formation, and the researchers speculated that if they could inhibit the action of sclerostin, they could reverse the devastating bone disease that occurs with multiple myeloma.

Dr Michelle McDonald and Professor Peter Croucher, of the Bone Biology Division of the Garvan Institute of Medical Research in Sydney, led the study.

“Multiple myeloma is a cancer that grows in bone, and in most patients it is associated with widespread bone loss, and recurrent bone fractures, which can be extremely painful and debilitating,” says Dr McDonald.

“The current treatment for myeloma-associated bone disease with bisphosphonate drugs prevents further bone loss, but it doesn’t fix damaged bones, so patients continue to fracture. We wanted to re-stimulate bone formation, and increase bone strength and resistance to fracture.”

The new therapeutic approach is an antibody that targets and neutralises sclerostin, and in previous clinical studies of osteoporosis, such antibodies have been shown to increase bone mass and reduce fracture incidence in patients.

The researchers tested the anti-sclerostin antibody in mouse models of multiple myeloma, and found that not only did it prevent further bone loss, it doubled bone volume in some of the mice.

Dr McDonald says, “When we looked at the bones before and after treatment, the difference was remarkable – we saw less lesions or ‘holes’ in the bones after anti-sclerostin treatment.

“These lesions are the primary cause of bone pain, so this is an extremely important result.”

The researchers have a biomechanical method to test bone strength and resistance to fracture, and found that the treatment also made the bones substantially stronger, with more than double the resistance to fracture observed in many of the tests.

They then combined the new antibody with zoledronic acid, a type of bisphosphonate drug, the current standard therapy for myeloma bone disease.

“Bisphosphonates work by preventing bone breakdown, so we combined zoledronic acid with the new anti-sclerostin antibody, that re-builds bone. Together, the impact on bone thickness, strength and resistance to fracture was greater than either treatment alone,” says Dr McDonald.

The findings provide a potential new clinical strategy for myeloma. While this disease is relatively rare, with approximately 1700 Australians diagnosed every year, the prognosis is extremely poor, with less than half of those diagnosed expected to survive for more than five years.

Prof Croucher, Head of the Bone Biology Division at Garvan, says that preventing the devastating bone disease of myeloma is critical to improve the prognosis for these people.

“Importantly, myelomas, like other cancers, vary from individual to individual and can therefore be difficult to target. By targeting sclerostin, we are blocking a protein that is active in every person’s bones, and not something unique to a person’s cancer. Therefore, in the future, when we test this antibody in humans, we are hopeful to see a response in most, if not all, patients,” Prof Croucher says.

“We are now looking towards clinical trials for this antibody, and in the future, development of this type of therapy for the clinical treatment of multiple myeloma.

“This therapeutic approach has the potential to transform the prognosis for myeloma patients, enhancing quality of life, and ultimately reducing mortality.

“It also has clinical implications for the treatment of other cancers that develop in the skeleton.”

Study shows biomarkers can predict which ER-positive breast cancer patients respond best to first-line therapy

Two challenges in treating patients with estrogen-positive breast cancer (ER+) have been an inability to predict who will respond to standard therapies and adverse events leading to therapy discontinuation. A study at The University of Texas MD Anderson Cancer Center revealed new information about how the biomarkers retinoblastoma protein (Rb) and cytoplasmic cyclin E could indicate which patients will respond best to current first-line therapies.

The study also discovered that combining the current therapy with autophagy inhibitors will result in using one-fifth of the dosage of the standard treatment, which could significantly reduce side effects associated with this therapy. Findings were published in the June 27 issue of Nature Communications.

Standard treatment, consisting of palbociclib, often has adverse side effects and not all ER+ patients respond to the therapy. Palbociclib inhibits proteins called CDK4 and CDK6 (CDK4/6) and tumor cells escape this inhibition by activating autophagy, a process allowing cancer cells to thrive even when starved of nutrients. By combining palbocicilb with autophagy inhibitors in cells that express normal Rb and nuclear cyclin E, the dose of palbociclib was significantly reduced.

Khandan Keyomarsi, Ph.D., professor of Experimental Radiation Oncology, led a team that demonstrated how CDK4/6 and autophagy inhibitors synergistically induce cell senescence in Rb-positive cytoplasmic cyclin E-negative cancers. CDK4/6 inhibitors are approved by the Food and Drug Administration (FDA).

“Our findings could impact the majority of ER+ and HER2-negative breast cancers accounting for about 60 percent of advanced breast cancers,” said Keyomarsi. “We demonstrated for the first time evidence that Rb and cytoplasmic cyclin E status have a very strong effect on predicting response to the current standard first-line therapy for this population of patients, hormonal therapy plus palbociclib.We also discovered that by inhibiting the pathway such as autophagy that causes tumor cells to escape palbociclib growth inhibition, CDK4/6 inhibitor was more effective.”

Deregulation of cell cycle checkpoint proteins, such as CDK4/6, is a key hallmark of cancer, resulting in uncontrolled cellular growth and tumor formation. Some CDK4/6 inhibitors, including palbociclib, ribociclib and abemaciclib, have shown potential in pre-clinical and clinical studies in numerous solid tumors. Palbociclib has demonstrated benefits in Phase II and III trials in advanced ER+ breast cancers, doubling progression-free survival compared to drugs such as letrozole or fulvestrant, and is currently being evaluated clinically in other solid tumors.

“Data provided through The Cancer Genome Atlas revealed alterations in the CDK4/6/cyclin D pathway in about 35 percent of the patients, making them an ideal population for targeting CDK4/6,” said Keyomarsi. “Our study revealed that inhibition of CDK4/6 and autophagy pathways cooperate to induce sustained growth inhibition and senescence in vitro and in vivo, in breast and other solid tumors and showed how autophagy inhibition can significantly decrease the dose of palbociclib required to treat breast cancer patients. We believe this new strategy can improve the efficacy of other CDK4/6 inhibitor treatments like ribociclib and abemaciclib.”

The team’s findings indicated how Rb and cyclin E status predicts response to a combination of CDK4/6 and autophagy inhibition in pre-clinical models and that autophagy blockade is successful in reversing resistance to palbociclib.

“Palbociclib resistance is a significant limitation of this treatment which is not curative and does not prolong survival even though transient responses and prolongation of response have formed the basis of FDA approval,” said Keyomarsi. “Our study provides evidence that models of hormone receptor-negative cancer and even non-breast cancer malignancies can respond to the combination of palbociclib and autophagy inhibition, when selected based on Rb and cyclin E isoform status, representing a completely new therapeutic opportunity for these cancers.”

Keyomarsi and colleagues anticipate future clinical studies based on this pre-clinical and clinical evidence with the aim of developing translational and clinical applications.

Researching Radiosensitizers, a New Class of Drugs That Would Make Tumors More Vulnerable to Radiation Therapy

Two out of three cancer patients are treated with radiation, but the therapy often fails to wipe out the tumor or slow its growth. Southern Research is working to develop a new class of drugs that will help the radiation deliver a more powerful punch to the disease.

Dr. Bo Xu, M.D., Ph.D., Distinguished Fellow and Chair of Southern Research’s Oncology Department, said a radiosensitizer would greatly benefit cancer patients by improving the success rate of radiation by reducing resistance to the treatment.

“Our project focuses on making those tumor cells more vulnerable to radiation by targeting a critical survival mechanism that allows them to recover from the effects of radiation,” Xu said.

It’s a challenging project, in the works for almost a decade. It got started when Southern Research scientists began looking at fundamental biology concepts to identify a pathway that could play a role in the ability of cancer cells to survive radiation.

They discovered that disrupting the tumor’s self-protection mechanism – in this case, an interaction between two specific proteins – makes the cancer more sensitive to radiation treatment, Xu said.

“The whole idea is to use this strategy to find a new drug that can be used by patients who receive radiation. This drug wouldn’t have toxicity because if it got into the cell it wouldn’t mess up the major functions of the protein network,” he said.

“It would only work when radiation is delivered, and that radiation would be more effective. It’s like a catalyst.”

Using funding from the Alabama Drug Discovery Alliance (ADDA), a partnership with the University of Alabama at Birmingham, Southern Research scientists recently scanned thousands of compounds to identify potential drug candidates. The focus now is to validate the results of those scans and to identify lead compounds for more testing.

“Our hope is that in three years, we can identify a novel class of radiosensitizers that can help the approximately two-thirds of cancer patients who will eventually receive radiotherapy,” Xu said.

While some forms of cancer, such as lymphoma, are sensitive to radiation therapy, many others are not. Solid tumors with a low supply of oxygen, called hypoxic tumors, are tough to treat with radiation. So are cancer cells with a high DNA-repair capability.

To develop a radiosensitizer, Xu is taking aim at a protein that binds to DNA and recognizes the damage being done by radiation. The protein then joins forces with an enzyme to initiate a molecular repair job.

“If that recruitment is successful, then the DNA damage will be repaired, and the cancer cell will survive,” Xu said. “What we’re trying to do is to block this protein from finding the other one, so that the repair process will be diminished or affected. That way, the tumor cells will die.”

To prevent the DNA repair job from getting started, Xu is investigating a small peptide mimic, a small sequence of amino acids that is similar to a human protein but just a fraction of its size. These strands get to the site to block the interaction of the two natural, full-size proteins.

“This interference makes the cancer cell more vulnerable to radiation treatment,” he said.

Radiosensitizers are in demand, but they have proved difficult to develop. While the concept has been around for half a century, very few radiosensitizers have actually become available, according to Xu.

“While there are compounds that work synergistically with radiation, there are few drugs that were developed as a pure radiosensitizer,” he said.

In addition to the ADDA, the National Institutes of Health and the Department of Defense prostate cancer program have provided Southern Research with funding for this research over the years.

Cancer therapy shows promise for psoriasis treatment

HDAC inhibitors, already widely used to treat cancer, may be an effective therapy for psoriasis as well, scientists report.

They have shown that HDAC3 inhibitors are particularly adept at increasing expression of aquaporin-3, or AQP3, a channel that transports glycerin, a natural alcohol and water attractor, which helps skin look better and aids healthy production and maturation of high-turnover skin cells.

“We’ve found that HDAC3 normally inhibits expression of AQP3 and we think we can use this knowledge to treat patients with psoriasis,” said Dr. Vivek Choudhary, molecular biologist and physiologist in the Department of Physiology at the Medical College of Georgia at Augusta University.

MCG scientists knew that AQP3 levels were lower in psoriasis than in healthy skin, said Choudhary, corresponding author of the study in the Journal of Investigative Dermatology. The protein helps skin cells proliferate, differentiate into the right kind of cells and get to the right location in the body. It also aids the skin’s hydration, wound recovery and elasticity. Histone deacetylase, which they found suppresses AQP3, helps regulate gene expression and protein function.

Since the immune system is believed to play a key role in psoriasis, many current treatments generally suppress the immune response, which increases the risk of infections, even cancer. MCG scientists hope they can one day instead directly enhance the presence of AQP3 or maybe its key cargo glycerin.

Psoriasis is one of the most common skin disorders, with red, flaky patches most often erupting on the elbows, knees, scalp and back, said Dr. Wendy B. Bollag, cell physiologist in the MCG Department of Physiology and the study’s senior author.

Like cancer, inflammation and excessive proliferation of cells are a psoriasis hallmark. That common ground and other emerging clues got the scientists thinking about the treatment potential of HDAC inhibitors. But first they had to establish a relationship.

When they introduced a broad-acting HDAC inhibitor to normal skin cells, or keratinocytes, – both mouse and human – they found expression of AQP3 went up within 24 hours, the first time the relationship had been noted.

They reiterated that AQP3 was critical because when it was missing, there was no commensurate increase in glycerin. AQP3 knockout mice also further clarified AQP3’s role in skin hydration, elasticity and wound healing and that it is glycerin – rather than water – that is most key to these healthy functions.

They also found that p53, a known, natural tumor suppressor that also supports cell differentiation, helps the HDAC inhibitors enable more AQP3 and ultimately more glycerin, Choudhary said. HDACs also are known to inhibit p53 activity. However overexpressing p53 by itself did not result in increased functional levels of AQP3, the scientists found.

The MCG scientists first used the HDAC inhibitor, suberoylanilide hydroxamic acid, or SAHA, which was approved by the Food and Drug Administration more than a decade ago to treat cutaneous T cell lymphoma, which has symptoms that can include dry, itchy skin as well as enlarged lymph nodes.

“We think this is one of the ways it works,” Bollag said of SAHA and their new findings. They also used several other HDAC inhibitors and found the ones that suppressed HDAC3 were also most effective at increasing AQP3.

AQP3 is adept at hauling glycerin, the backbone of many lipids and typically a key ingredient in skin lotion. Bollag’s lab reported in the Journal of Investigative Dermatology in 2003 that glycerin helps skin cells mature properly. Inside skin cells, phospholipase D – an enzyme that converts fats or lipids in the external protective cell membrane into cell signals – and AQP3 interact. AQP3 hands off glycerin, which produces phosphatidylglycerol, which, in turn, aids skin cell differentiation.

“We think phosphatidylglycerol is the key,” Bollag said of the positive results. “If you don’t have enough, you may have psoriasis.”

The Bollag lab and others also had found that AQP3, which is present in psoriasis, appears rather immature and out of place, largely inside the cell cytoplasm instead of on the protective, outer cell membrane. The inner location puts quite a damper on its normal mature function of transporting glycerin, water and other substances through the membrane.

“If you use antibodies to visualize where AQP3 is in the keratinocytes, you will see it nicely outlining the cells because it’s right there on the plasma membrane,” Bollag said. “So clearly it’s normally expressed in keratinocytes but the fact that we can upregulate it even more with an HDAC3 inhibitor suggests that normally HDAC3 keeps it in check.”

Cambridge, Massachusetts-based biotech company Shape Pharmaceuticals Inc., currently has a topical version of an HDAC inhibitor in clinical trials for cutaneous T cell lymphoma. If psoriasis patients end up taking HDAC inhibitors, low doses or a topical application likely would help avoid some side effects, including nausea, Bollag said.

One way HDAC inhibitors help fight cancer is by temporarily loosening DNA, increasing the expression of tumor-suppressing genes and making the tumor more vulnerable. HDAC inhibitors also are being explored for their potential in treating neurological diseases such as Huntington’s.

Others have provided evidence that dysregulation of AQP3 contributes to psoriasis and AQP3 is linked to other skin diseases as well like atopic dermatitis – the most common type of eczema and vitiligo, which results in white patches on the skin.

Interestingly, even though psoriatic cells are known for their propensity to replicate, it’s hard to grow an adequate number of cells for scientific study: they increase a certain amount then go quiet. There also is no real animal model of psoriasis. Moving forward, the MCG scientists may try developing a model using a topical drug for genital warts since some patients who take it develop psoriasis.

Better treatment for kidney cancer thanks to new mouse model

Roughly 2-3 percent of all people suffering from cancer have kidney cancer. The most common form of this disease is called clear cell renal cell carcinoma (ccRCC). In roughly half of all patients with this disease, the tumor develops metastases and generally cannot be cured.

New Mouse Model for Investigating Kidney Cancer

The research of different types of cancer and the testing of new treatments depends on accurate mouse models. This is because the tumors in mice mirror the genetics as well as the molecular and cellular properties of tumors in humans. Despite decades of effort, however, researchers were unable to develop a mouse model of renal cell carcinoma – until now. Scientists conducting a long-term research project at the University of Zurich were able to develop a mouse model. The study was led by Sabine Harlander and her colleagues at the Institute of Physiology of the University of Zurich in the lab of Professor Ian Frew, who has recently joined the University of Freiburg in Germany. The researchers began by identifying the genes that often mutate in human renal cell carcinomas. They then mutated three of these genes simultaneously in renal cells of mice, which then developed renal cancer.

Gene Mutations Promote Uncontrolled Cell Division

The progression from gene mutation in the renal cells to the development of a tumor took eight to twelve months. This lengthy period of time, compared to a mouse’s lifetime, indicates that additional factors play a role in tumor development. The researchers therefore decided to take a closer look at the protein-encoding genes in the mouse tumors. They discovered that in all of the tumors at least one of the many genes responsible for the correct functioning of the primary cilium had mutated. The primary cilium is a hair-like structure found on the cell’s surface and is responsible for coordinating cell signaling, among other things.

Based on this finding, the researchers found that similar mutations also occur in renal cell carcinomas in humans. The scientists now believe that the loss of normal function in the primary cilium leads to the uncontrollable division of renal epithelial cells, which contributes to the formation of ccRCC. “This research project is a prime example of how mouse models can help us to better understand cancer diseases in human beings,” says Sabine Harlander.

Mouse Model Enables Development of Better Treatments

The new mouse model will make it possible to develop better therapies for renal cancer. For example, in the case of patients with renal carcinoma metastasis who are given different medications, some patients respond to the medications, while others do not. The same phenomenon can be observed when mice with renal cancer are treated with the same drugs as the humans. Some tumors shrink, while others do not. Now researchers can investigate the factors that contribute to why certain tumours respond to certain medications and not to others. “We hope that our mouse model, which allows us to combine drug testing and genetic analysis, will provide a deeper understanding of why tumors are sensitive or resistant to drugs,” states Ian Frew. Such vital information could be used to better adjust treatments to the characteristics of each patient.

The mouse model could also contribute to the further development of immunotherapies – a method in which the body’s immune system is stimulated, so that it intensifies its fight against tumor cells. In the last few years, much progress has been made in this field of cancer research, also for the treatment of renal cell carcinomas. Now, thanks to the new mouse model, it will be possible to study how renal tumors are able to develop in an environment with a normal immune system, and how cancer cells manage to evade the immune system’s attacks. Ultimately, the researchers’ goal is to use these new findings to improve the effectiveness of immunomodulatory treatments.

Study redefines HPV-related head and neck cancers

Much of what we thought we knew about the human papilloma virus (HPV) in HPV-related head and neck cancers may be wrong, according to a newly published study by Virginia Commonwealth University (VCU) researchers that analyzed data from The Human Cancer Genome Atlas. Head and neck cancers involving HPV are on the rise, and many experts believe we are seeing the start of an epidemic that will only get worse in the coming years.

The Cancer Genome Atlas is a collaboration between the National Cancer Institute (NCI) and the National Human Genome Research (NHGR) Institute that makes publicly available genomic information on tumor samples from 33 different types of cancers. Its aim is to help the cancer research community improve the prevention, diagnosis and treatment of cancer.

It is thought that there are two main forms of HPV-related cancers, episomal and integrated. In episomal variants, the HPV genome replicates independently. Integrated HPV has become part of the DNA of the host cell and relies on it for replication. Previously, it was believed that most HPV-related head and neck cancers had integrated HPV, as is what is believed with HPV-related cervical cancers. However, Windle’s study, recently published in the journal Oncotarget, found that HPV DNA is maintained separate from the human genome in the majority of HPV-related head and neck cancers, though, in many cases, the HPV genome can acquire a small piece of human DNA making it look like integrated HPV. This viral-human hybrid represents a new category of episomal HPV in HPV-related cancers.

“Our work challenges the idea that finding HPV DNA joined to human DNA means that HPV is integrated. With this new view of the state of HPV, we conclude that episomal HPV is the predominant state in HPV-related head and neck cancers,” says Brad Windle, member of the Cancer Molecular Genetics research program at VCU Massey Cancer Center, professor at the Philips Institute for Oral Health Research at the VCU School of Dentistry and co-principle investigator on the study. “This is an important distinction because patients with episomal HPV cancer respond better to therapy than patients with integrated HPV cancer.”

Windle’s team analyzed the genomes of all 520 HNC samples in The Cancer Genome Atlas and found that 72 were HPV positive. The large majority of these cancers had a common type of the virus known as HPV16 present, so they focused on that virus type. The data showed that 75 percent of the HPV16 samples had the HPV genome in the episomal state, and about half of the genomes contained a piece of human DNA within their circular structure.

The researchers also found that 73 percent of the tumor samples were still dependent on proteins known as E1 and E2 for replication. This is important because when the HPV genome integrates with human DNA, expression of the HPV E2 protein–essential for independent replication–is lost. The presence of E2, or lack thereof, in tumor biopsies could be a reliable way for physicians to determine the cancer type and provide a more accurate prognosis.

“Perhaps our most striking outcome is the potential to target the E1 and E2 proteins for diagnosis and treatment,” says Windle. With nearly three quarters of these cancers dependent on E1 and E2 for replication, we could develop drugs that target these proteins and promote cell death.”

Windle’s team plans to continue studying the integration of HPV in HPV-related head and neck cancers, and suggests that viral-human DNA hybrid HPV should be further explored in HPV-related cervical cancers. His team is currently working with Massey clinicians in order to use this information to assess patients’ prognosis in the clinic.

Epilepsy drug therapies to be improved by new targeted approach

New research from the University of Liverpool, in collaboration with the Mario Negri Institute in Milan, published today in the Journal of Clinical Investigation, has identified a protein that could help patients with epilepsy respond more positively to drug therapies.

Epilepsy continues to be a serious health problem and is the most common serious neurological disease. Despite 30 years of drug development, approximately 30% of people with epilepsy do not become free of fits (also called seizures) with currently available drugs.

New, more effective drugs are therefore required for these individuals. We do not fully understand why some people develop seizures, why some go onto develop epilepsy (continuing seizures), and most importantly, why some patients cannot be controlled with current drugs.

Inflammation

There is now increasing body of evidence suggesting that local inflammation in the brain may be important in preventing control of seizures. Inflammation refers to the process by which the body reacts to insults such as having a fit. In most cases, the inflammation settles down, but in a small number of patients, the inflammation continues.

The aim of the research, undertaken by Dr Lauren Walker while she was a Medical Research Council (MRC) Clinical Training Fellow, was to address the important question of how can inflammation be detected by using blood samples, and whether this may provide us with new ways of treating patients in the future to reduce the inflammation and therefore improve seizure control.

The research focused on a protein called high mobility group box-1 (HMGB1), which exists in different forms in tissues and bloodstream (called isoforms), as it can provide a marker to gauge the level of inflammation present.

Predicting drug response

The results showed that there was a persistent increase in these isoforms in patients with newly-diagnosed epilepsy who had continuing seizure activity, despite anti-epileptic drug therapy, but not in those where the fits were controlled.

An accompanying drug study also found that HMGB1 isoforms may predict how an epilepsy patient’s seizures will respond to anti-inflammatory drugs.

Dr Lauren Walker, said: “Our data suggest that HMGB1 isoforms represent potential new drug targets, which could also identify which patients will respond to anti-inflammatory therapies. This will require evaluation in larger-scale prospective trials.”

Innovative scheme

Professor Sir Munir Pirmohamed, Director of the MRC Centre for Drug Safety Science and Programme lead for the MRC Clinical Pharmacology scheme, said: “The MRC Clinical Pharmacology scheme is a highly successful scheme to train “high flyers” who are likely to become future leaders in academia and industry.

“Dr Walker’s research is testament to this and shows how this innovative scheme, which was jointly funded by the MRC and Industry, can tackle areas of unmet clinical need, and identify new ways of treating patients with epilepsy using a personalised medicine approach”.

Stem Cell Trial for Stroke Patients Suffering Chronic Motor Deficits Begins at UTHealth

A clinical trial to evaluate the safety and efficacy of a stem cell product injected directly into the brain to treat chronic motor deficits from ischemic stroke has begun at McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth).

McGovern Medical School at UTHealth is the only site in Texas and the central south portion of the country to open enrollment for the multi-institutional, phase 2B study – the first in the U.S. for chronic stroke. Surgeries will be conducted at Memorial Hermann-Texas Medical Center.

“This trial is one of the first randomized, sham-controlled studies to test the efficacy of administering adult-derived stem cells in patients disabled with a chronic stroke,” said Sean I. Savitz, M.D., professor and the Frank M. Yatsu Chair in Neurology at McGovern Medical School and director of the UTHealth Institute for Stroke and Cerebrovascular Disease. “We were chosen as one of only a handful of referral centers in the nation and patients from all over the country will be referred to our center for this trial. Overall, the study adds to our growing regenerative medicine program for patients with neurological disorders.”

In the double-blind, sham-surgery controlled study, patients randomized to the study intervention will receive a stem cell product made by SanBio and patients must have chronic motor deficits from an ischemic stroke to be eligible for the study. The product, administered through tiny holes bored into the skull and placed near the site of the damage, came from the bone marrow of two healthy adult donors. Enrollment is limited to patients who are between six and 60 months post-stroke and have a chronic motor neurological deficit.

Results of a phase 1/2A study of the stem cell product, presented at the International Society of Stem Cell Research Meeting and published in the journal, Stroke, showed statistically significant improvements in motor function and no safety concerns.

The UTHealth Stroke Program at McGovern Medical School, led by Savitz, is one of the most active research and clinical programs in the country. It was one of the lead sites in the National Institute of Neurological Disease and Stroke’s (NINDS) tPA stroke study; was one of eight centers in the country funded by the NIH to conduct specialized translational research to develop novel acute stroke therapies; and receives NINDS fellowship funding to train the next generation of academic leaders in cerebrovascular disease.

Trigger for autoimmune disease identified

Researchers at National Jewish Health have identified a trigger for autoimmune diseases such as lupus, Crohn’s disease and multiple sclerosis. The findings, published in the April 2017 issue of Journal of Clinical Investigation, help explain why women suffer autoimmune disease more frequently than men, and suggest a therapeutic target to prevent autoimmune disease in humans.

“Our findings confirm that Age-associated B Cells (ABCs) drive autoimmune disease,” said Kira Rubtsova, PhD, an instructor in biomedical science at National Jewish Health. “We demonstrated that the transcription factor T-bet inside B cells causes ABCs to develop. When we deleted T-bet inside B cells, mice prone to develop autoimmune disease remained healthy. We believe the same process occurs in humans with autoimmune disease, more often in elderly women.”

Autoimmune diseases occur when the immune system attacks and destroys the organs and tissue of its own host. Dozens of autoimmune diseases afflict millions of people in the United States. Several autoimmune diseases, including lupus, rheumatoid arthritis and multiple sclerosis strike women two to 10 times as often as men. Overall, about 80 percent of autoimmune patients are women. There is no cure for autoimmune disease.

B cells are important players in autoimmune disease. The National Jewish Health research team, led by Chair of Biomedical Science Philippa Marrack, PhD, previously identified a subset of B cells that accumulate in autoimmune patients, autoimmune and elderly female mice. They named the cells Age-associated B cells, or ABCs. Subsequent research showed that the transcription factor T-bet plays a crucial role in the appearance of ABC.

Transcription factors bind to DNA inside cells and drive the expression of one or several genes. Researchers believe that T-bet appears inside cells when a combination of receptors on B-cell surfaces — TLR7, Interferon-gamma and the B-cell receptor — are stimulated.

Through breeding and genetic techniques the research team eliminated the ability of autoimmune-prone mice to express T-bet inside their B cells. As a result, ABCs did not appear and the mice remained healthy. Kidney damage appeared in 80 percent of mice with T-bet in the B cells and in only 20 percent of T-bet-deficient mice. Seventy-five percent of mice with T-bet in their B cells died by 12 months, while 90 percent of T-bet-deficient mice survived 12 months.

“Our findings for the first time show that ABCs are not only associated with autoimmune disease, but actually drive it,” said Dr. Rubtsova.

ABCs have attracted increasing interests since their discovery in 2011. Dr. Rubtsova and her colleagues at National Jewish Health have expanded their study of ABCs beyond autoimmune disease and are looking at their involvement in sarcoidosis, hypersensitivity pneumonitis and chronic beryllium disease.

New Progress Toward Finding Best Cells for Liver Therapy

Study shows transplanted fetal rat liver cells multiply and give rise to new cells in injured adult liver.

In a new study, researchers demonstrate successful transplantation of fetal rat liver cells to an injured adult rat liver. The work is an important step toward using transplanted cells to treat liver failure, which currently requires an organ transplant.

Jennifer Sanders, PhD, assistant professor of pediatrics at Brown University, will present the new research at the American Society for Investigative Pathology annual meeting during the Experimental Biology 2017 meeting, to be held April 22–26 in Chicago.

“There are too few donor livers, so many people die of liver diseases such as hepatitis and cirrhosis without ever getting a transplant,” said Sanders. “Understanding the behavior of fetal liver cells may lead to ways to select the best cells for transplantation into people whose livers are failing.”

In the new study, the researcher removed liver cells from a rat fetus near the end of gestation and transplanted them into an injured adult rat liver. In the new liver, the transplanted cells multiplied for a long period and gave rise to new hepatocytes—the main cell type found in the liver—as well as the cells that form the bile ducts and line the blood vessels. Adult rat liver cells cannot multiply and differentiate after transplantation.

“Most previous studies have used very immature fetal rat cells and have not attempted to characterize the cell population prior to transplantation,” said Sanders.  “We are using late-gestation fetal rat hepatocytes that can carry out many of the functions of adult liver cells, and we characterized the cells based on expression of markers on their surface.”

To better understand how fetal and adult hepatocytes differ, the researchers examined proteins called histones that regulate DNA structure. They identified histone differences that may allow the fetal cells to grow and survive when transplanted into an injured adult liver.

“Our prior studies have shown that fetal rat hepatocyte proliferation, growth and gene-expression regulation are different than in adult rat hepatocytes,” said Sanders. “This has led us to believe that maintenance of DNA structure is very important for the behavior of fetal rat hepatocytes and the ability of these cells to repopulate an injured adult liver.”

In addition to this work’s implications for cell-based liver therapies, better understanding of how DNA structure, gene expression and protein function are regulated together in the normal fetal liver cell could help scientists understand the events that lead to liver cancer.

As a next step, the researchers are working to determine how the adult liver environment affects transplanted fetal cells. They want to find out whether transplanted fetal cells differentiate in a way that makes them indistinguishable from normal adult hepatocytes.

Breast Cancer Drug Dampens Immune Response, Protecting Light-Sensing Cells of the Eye

Tamoxifen could be repurposed to treat degenerative diseases of the retina

The breast cancer drug tamoxifen appears to protect light-sensitive cells in the eye from degeneration, according to a new study in mice. The drug prevented immune cells from removing injured photoreceptors, the light-sensitive cells of the retina in the back of the eye. The study, recently reported in the Journal of Neuroscience, suggests tamoxifen might work for the treatment of age-related macular degeneration (AMD) and retinitis pigmentosa (RP), blinding diseases that lack good treatment options. The study was conducted by researchers at the National Eye Institute (NEI), part of the National Institutes of Health.

Although commonly used for cancer treatment, tamoxifen is used in the laboratory as a tool to activate specific genes in genetically engineered mice. The tool allows researchers to turn genes on and off in specific tissues at will. Wai Wong, M.D., Ph.D., chief of NEI’s Unit on Neuron-Glia Interactions in Retinal Disease, and his team were using tamoxifen for this purpose when they noticed something odd. Xu Wang, Ph.D., staff scientist in the Wong laboratory and lead author of the study, observed that mice treated with tamoxifen gained resistance to light-induced eye injuries. Light injury, induced by exposing mice to short-duration, high-intensity light, normally leads to degeneration of photoreceptors. But in the tamoxifen-treated mice, the team unexpectedly observed little to no photoreceptor degeneration.

The team investigated the effects of tamoxifen on light-induced photoreceptor degeneration in normal mice and mice with a disease similar to RP. Live retinal imaging and tissue analyses showed significantly lower levels of photoreceptor degeneration, compared to control mice that did not received tamoxifen. Tamoxifen-treated mice also demonstrated higher photoreceptor function, compared to controls.

How was tamoxifen exerting this protective effect? In an earlier study in 2015, Wong showed that light injury triggers a neurotoxic immune response in the retina. “The immune system becomes alerted to the stressed photoreceptors and goes into culling mode, clearing them out of the retina,” he explained. Wong and his team surmised that tamoxifen was inhibiting this immune response, rather than protecting the photoreceptors directly.

To investigate this hypothesis, Wong’s team cultured microglia — immune cells in the retina — and found that tamoxifen reduced their ability to remove and kill photoreceptor cells. Tamoxifen also reduced levels of inflammatory cytokines — signaling molecules that trigger inflammation — produced by the microglia.

Tamoxifen did not appear to directly influence the physiology of photoreceptors or protect photoreceptors in the absence of microglia, suggesting that the inhibition of microglia is a key mechanism underlying tamoxifen’s protective effect. The investigators are currently studying at molecular level how tamoxifen is able to inhibit the microglia.

In August 2016, Wong’s laboratory filed a patent for use of tamoxifen in retinal degenerative disorders. The new use of the drug is unexpected, as tamoxifen’s only previously known association with the retina had been a low risk of retinopathy among breast cancer patients.

RP is a group of rare genetic disorders affecting the retina. Worldwide, RP affects about 1 in 4,000 people. Symptoms typically appear during childhood and slowly progress over many years, often causing blindness. AMD is a leading cause of vision loss among people age 50 and older. About two million Americans have AMD, which affects central vision.

The tamoxifen dose used in Wong’s mouse study was equivalent to eight times the FDA-approved dose for breast cancer. The researchers are currently investigating whether the protective effects are retained at lower doses.

The work “sets us up for a clinical trial in the not-so-distant future,” said Wong. “Translation to the clinic can happen reasonably rapidly because tamoxifen, as an FDA-approved drug, already has a well-characterized safety profile,” he explained.