New Player in Alzheimer’s Disease Pathogenesis Identified

Scientists at Sanford Burnham Prebys Medical Discovery Institute (SBP) have shown that a protein called membralin is critical for keeping Alzheimer’s disease pathology in check. The study, published in Nature Communications, shows that membralin regulates the cell’s machinery for producing beta-amyloid (or amyloid beta, Aβ), the protein that causes neurons to die in Alzheimer’s disease.

“Our results suggest a new path toward future treatments for Alzheimer’s disease,” says Huaxi Xu, Ph.D., the Jeanne and Gary Herberger Leadership Chair of SBP’s Neuroscience and Aging Research Center. “If we can find molecules that modulate membralin, or identify its role in the cellular protein disposal machinery known as the endoplasmic reticulum-associated degradation (ERAD) system, this may put the brakes on neurodegeneration.”

ERAD is the mechanism by which cells get rid of proteins that are folded incorrectly in the ER. It also controls the levels of certain mature, functional proteins. Xu’s team found that one of the fully formed, working proteins that ERAD regulates is a component of an enzyme called gamma secretase that generates Aβ.

This discovery helps fill in the picture of how Alzheimer’s disease, an incredibly complicated disorder influenced by many genetic and environmental factors. No therapies have yet been demonstrated to slow progression of the disease, which affects around 47 million people worldwide. Until such drugs are developed, patients face a steady, or sometimes rapid, decline in memory and reasoning.

Memory loss in Alzheimer’s results from the toxic effects of Aβ, which causes connections between neurons to break down. Aβ is created when gamma secretase cuts the amyloid precursor protein into smaller pieces. While Aβ is made in all human brains as they age, differences in the rate at which it is produced and eliminated from the brain and in how it affects neurons, means that not everyone develops dementia.

“We were interested in membralin because of its genetic association with Alzheimer’s, and in this study we established the connection between membralin and Alzheimer’s based on findings from the laboratory of a former colleague at SBP, Professor Dongxian Zhang,” Xu explains. “That investigation showed that eliminating the gene for membralin leads to rapid motor neuron degeneration, but its cellular function wasn’t clear.”

Using proteomics, microscopic analysis, and functional assays, the group provided definitive evidence that membralin functions as part of the ERAD system. Later, they found that membralin-dependent ERAD breaks down a protein that’s part of the gamma secretase enzyme complex, and that reducing the amount of membralin in a mouse model of Alzheimer’s exacerbates neurodegeneration and memory problems.

“Our findings explain why mutations that decrease membralin expression would increase the risk for Alzheimer’s,” Xu comments. “This would lead to an accumulation of gamma secretase because its degradation is disabled, and the gamma-secretase complex would then generate more Aβ. Those mutations are rare, but there may be other factors that cause neurons to make less membralin.”

Xu and colleagues also observed lower levels of membralin, on average, in the brains of patients with Alzheimer’s than in unaffected individuals, demonstrating the relevance of their findings to humans.

“Previous studies have suggested that ERAD contributes to many diseases where cells become overwhelmed by an irregular accumulation of proteins, including Alzheimer’s,” says Xu. “This study provides conclusive, mechanistic evidence that ERAD plays an important role in restraining Alzheimer’s disease pathology. We now plan to search for compounds that enhance production of membralin or the rate of ERAD to test whether they ameliorate pathology and cognitive decline in models of Alzheimer’s. That would further support the validity of this mechanism as a drug target.”

Targeting a microRNA shows potential to enhance effectiveness of diabetes drugs

Over the past 15 years, University of Alabama at Birmingham endocrinologist Anath Shalev, M.D., has unraveled a crucial biological pathway that malfunctions in diabetes.

Her latest discovery in this beta-cell pathway, published in the journal Diabetes, shows the potential to enhance the effectiveness of existing diabetes drugs, as well as reduce some of the unwelcome side effects of those drugs.

The need for improved treatment is great. Diabetes is a disorder characterized by elevated blood sugar that afflicts one of every 10 U.S. adults and doubles the risk of early death. More than 30 million people in the United States have diabetes, which is the seventh-leading cause of death and also leads to blindness and lower-limb amputations.

In 2013, the UAB researchers found that either diabetes or elevated production of the protein TXNIP induced beta-cell expression of microRNA-204, or miR-204, and this microRNA, in turn, blocked insulin production. The Shalev group has now found another vital role for miR-204 — regulating the cell surface receptor that is the target of many of the newer type 2 diabetes drugs, such as Byetta, Victoza, Trulicity, Januvia, Onglyza and Tradjenta. This drug target is the glucagon-like peptide 1 receptor, or GLP1R. Activation of GLP1R with these drugs helps the beta cell produce and secrete more insulin.

Shalev’s new work was performed in rat beta cells, genetically modified mice, mouse pancreatic islets and human pancreatic islets. Healthy beta cells, which are found in the pancreatic islets, produce insulin to control blood sugar levels; in diabetes the beta cells are impaired and dysfunctional, and have lower GLP1R levels.

In the Diabetes study, Shalev and colleagues found that overexpression of miR-204 decreased expression of GLP1R in rat beta cells and in mouse and human pancreatic islets. Conversely, knock-down of miR-204 increased expression of GLP1R in those cells and pancreatic islets.

Greater GLP1R expression is beneficial because it helps transfer a signal to the beta cell to secrete more insulin, such as after a meal. Also, many of the newer diabetes drugs act as agonists to activate GLP1R. Higher expression can allow use of a lower-drug dose to treat diabetes, thus reducing dose-dependent side effects.

In mice, the UAB researchers found that a deletion of miR-204 caused enhanced GLP1R expression, and also better insulin secretion and glucose control. Furthermore, the knockout mice were more responsive to a GLP1R agonist in glucose tolerance tests. When the GLP1R knockout mice were used in a model of diabetes, where beta cells are damaged by low doses of the toxin streptozotocin, the diabetic mice showed improved glucose control and increased serum insulin levels.

These results suggest that downregulating miR-204, now revealed as an upstream regulator of GLP1R, could lead to better treatment of diabetes.

One key fact about miR-204 may further aid improved treatment. This microRNA is highly expressed in beta cells, but it is not highly expressed in the rest of the pancreas or in cells of the gastrointestinal tract that also express GLP1R and therefore respond to GLP1R agonists. Thus, an inhibitor of miR-204 would be relatively selective for beta cells.

“This novel concept of inhibiting a microRNA in a non-targeted manner, but taking advantage of its restricted tissue distribution and thereby selectively upregulating its target genes in that tissue, may have far reaching implications for microRNA biology and tissue-specific gene targeting in general,” Shalev said.

“Since miR-204 is expressed primarily in pancreatic beta cells, manipulating its levels allows for preferential upregulation of GLP1R in the beta cell, where it helps secrete insulin, rather than in the gastrointestinal system, where it can cause nausea and impaired gastric emptying, or in the pancreas, where it can increase the risk for pancreatitis,” Shalev said. “So by inhibiting miR-204, one could increase the effects of GLP1R agonist drugs on insulin secretion, thereby lowering the necessary dose and avoiding some of the dose-dependent adverse effects.”

The mechanism by which miR-204 downregulates expression of GLP1R is binding of the microRNA to the 3-prime-untranslated region of GLP1R messenger RNA. Such binding is a known method to control gene expression by microRNAs. The UAB researchers discovered this specific binding using microRNA target prediction software. They found two binding sites for miR-204 in the messenger RNA for human GLP1R and one binding site in the messenger RNA for mouse GLP1R. When they mutated those binding sites, it eliminated the regulatory effect of miR-204.

Additionally, the Shalev group showed a novel link between TXNIP and GLP1R signaling. Mice with a beta cell-specific knockout of the protein TXNIP had lower miR-204 levels and higher GLP1R expression, and the mice showed enhanced insulin secretion and glucose control in response to an agonist of GLP1R. Thus, through both control of insulin production and regulation of GLP1R, as well as regulation of the unfolded protein response and beta cell apoptosis, miR-204 appears to play a linchpin role to control the function of beta cells in the pancreas.

Study Finds a New Way to Shut Down Cancer Cells’ Ability to Consume Glucose

Cancer cells consume exorbitant amounts of glucose, a key source of energy, and shutting down this glucose consumption has long been considered a logical therapeutic strategy. However, good pharmacological targets to stop cancers’ ability to uptake and metabolize glucose are missing. In a new study published in Cell Reports, a team of University of Colorado Cancer Center researchers, led by Matthew Galbraith, PhD, and Joaquin Espinosa, PhD, finally identifies a way to restrict the ability of cancer to use glucose for energy.

Over-expression of the gene CDK8 is linked to the development of many cancers including colorectal cancer, melanoma, and breast cancer, where it regulates pathways that drive the growth and survival of cancer cells. Although a number of drugs aimed at blocking CDK8 activity are currently being developed, it is not yet clear how effective they are at treating various cancers. Galbraith and Espinosa have been working to better understand the role of CDK8 in cancer biology in the hopes of aiding the introduction of CDK8-based therapies as cancer treatments.

Their most recent study, which was funded in part by the Cancer League of Colorado and the Mary Miller and Charlie Fonfara-Larose Leukemia in Down Syndrome Fund, demonstrates that CDK8 plays a critical role in allowing cancer cells to use glucose as an energy source.

The finding takes place against the backdrop of the tissue conditions in which tumors grow – as cancer cells rapidly multiply, their growth often outstrips their blood supply, leading to depletion of oxygen (i.e. hypoxia) and other nutrients such as glucose. In 2013, the group published a paper showing that CDK8 is important for activation of many genes switched on in hypoxic conditions. During adaptation to these conditions, cancer cells must alter their metabolism to consume more glucose through a process called glycolysis. In fact, many cancer cells have permanent increases in glycolysis, maintained even in conditions of plentiful oxygen, a phenomenon known as the Warburg effect, which was described as far back as 1924. Consequently, many cancers are heavily dependent on glucose metabolism for their growth and survival. This is true to the point that doctors use glucose isotopes and PET scans to pinpoint the exact location of a tumor and its metastases within the human body – where there are abnormally high levels of glucose being used, chances are there is a cancerous growth.

When Galbraith used a sophisticated chemical genetics approach to specifically switch off CDK8 activity in colorectal cancer cells, he saw that the cells failed to activate glycolysis genes and took up much less glucose. He confirmed this in experiments showing that blocking CDK8 activity leads to a lower rate of glucose use.

“Because of this role of CDK8 in glycolysis, I reasoned that the cells with impaired CDK8 activity should be more susceptible to drugs that block glycolysis,” Galbraith says. Sure enough, treating cancer cells with drugs that block both CDK8 and glycolysis slowed their growth more effectively than either approach alone.

“These are very exciting discoveries. The Warburg effect and consequent addiction to glucose is a hallmark of cancerous tissues, something that distinguishes cancer cells from most normal tissues. Therefore, combining drugs that block CDK8 activity with those that block glycolysis may enable specific targeting of cancer cells without harmful effects on normal cells,” says Espinosa, the paper’s senior author.

The team was recently awarded a grant from the Denver chapter of Golfers Against Cancer to advance their findings through pre-clinical research in mouse models, a necessary step to test the clinical value of this new strategy targeting CDK8 and glucose metabolism.

Insights from a rare genetic disease may help treat multiple myeloma

A new class of drugs for blood cancers such as leukemia and multiple myeloma is showing promise. But it is hobbled by a problem that also plagues other cancer drugs: targeted cells can develop resistance. Now scientists, reporting in ACS Central Science, have found that insights into a rare genetic disease known as NGLY1 deficiency could help scientists understand how that resistance works — and potentially how drugs can outsmart it.

A class of compounds called proteasome inhibitors that include bortezomib and carfilzomib — both approved by the U.S. Food and Drug Administration — have been effective at treating certain types of blood cancers. The drugs work by jamming some of cancer cells’ machinery to induce cell death. But the drugs have been limited by cancer cells ability to development resistance, as well as the inhibitors inability to fight solid tumors effectively. Studies have suggested that resistance could be linked to a protein called Nrf1. When proteasome inhibitors go into action, Nrf1 is spurred into overdrive to restore the cells’ normal activities and keep them alive. If researchers could figure out how to block Nrf1, they might be able to address the resistance problem. Carolyn Bertozzi and colleagues, through studying NGLY1 deficiency, a seemingly unrelated condition, may have hit upon an approach to do this.

The researchers were investigating how lacking the enzyme NGLY1 causes a host of debilitating symptoms. They found that NGLY1 is responsible for activating Nrf1, the protein that is suspected of weakening proteasome inhibitors’ effectiveness against cancer. Further testing showed that dampening NGLY1 allowed a proteasome inhibitor to continue doing its work killing cancer cells without interference from Nrf1. This finding, the authors note, holds great promise for the development of combination therapeutics for blood cancers in the future.

German research advances in cancer and blood disorders reported in human gene therapy

Virotherapy capable of destroying tumor cells and activating anti-tumor immune reactions, and the use of engineered hematopoietic stem cells (HSCs) to deliver replacement genes that have the potential to cure blood diseases are among the key areas of gene therapy being advanced by German researchers and highlighted in a special issue of Human Gene Therapy, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The issue is available free on the Human Gene Therapy website.

The special focus issue entitled “German Gene Therapy Research — Part 1 ,” was developed by Guest Editors Christof von Kalle, MD, Boris Fehse, PhD, and Hildegard Büning, PhD. Dr. Büning, Hannover Medical School, is Editor of Human Gene Therapy Methods and serves as Chair of the 25th Anniversary ESGCT Congress, October 17-20, in Berlin.

In the special issue, Guy Ungerechts and Christine Engeland led a team of colleagues from Germany and Luxembourg in coauthoring the review article entitled “Virotherapy Research in Germany: From Engineering to Translation.” The researchers present the latest preclinical and clinical research activities to engineer oncolytic viruses, which selectively infect tumor cells, for use in tumor-targeted gene therapy. They discuss the different types of virus platforms being investigated–including adenovirus, arenavirus, measles vaccine virus, parvovirus, and vaccinia virus — and the potential to take advantage of the immunotherapeutic properties of oncolytic viruses and of their use in combination with other types of pharmaco-, radio-, and immunotherapy.

In the review article “Promises and Challenges in Hematopoietic Stem Cell Gene Therapy,” Saskia Kohlscheen, Halvard Bonig, and Ute Modlich, Paul-Ehrlich-Institute (Langen), Goethe University (Frankfurt), German Red Cross Blood Service Baden-Württemberg-Hessen (Frankfurt), Germany, and University of Washington, Seattle, describe the state-of-the-art in HSC-directed gene therapy, including viral vector delivery systems, transduction of HSCs, and protocols prior to HSC transplantation. The researchers discuss the main targets for this innovative approach, focusing on immunodeficiencies and inborn errors of metabolism, what has been learned to date from the limiting clinical studies performed, and how best to move forward to overcome the challenges the field still faces.

“The rapid pace of innovation among gene and cell therapy researchers in Germany is striking and significant,” says Editor-in-Chief Terence R. Flotte, MD, Celia and Isaac Haidak Professor of Medical Education and Dean, Provost, and Executive Deputy Chancellor, University of Massachusetts Medical School, Worcester, MA. “We are very proud to reflect the impact of German gene therapy science in this special issue of Human Gene Therapy.”

By Decoding How HPV Causes Cancer, Researchers Find a New Potential Treatment Strategy

A study that teases apart the biological mechanisms by which human papillomaviruses (HPV) cause cancer has found what researchers at Georgetown University Medical Center say is a new strategy that might provide targeted treatment for these cancers.

HPVs are responsible for the majority of cervical cancer and a substantial portion of head and neck and anal cancers, but therapy available to date is surgery and non-specific chemotherapy.

The new study, published Oct. 2 in the journal Oncotarget, found that E6, an oncoprotein produced by the virus, interacts with several other molecules in host cells in a manner that ensures infected cells cannot die. If they are immortal and continue to multiply, cancer develops.

“There is no targeted treatment now for these cancers since German virologist Harald zur Hausen, PhD, discovered in 1983 that HPV can cause cervical cancer. Recently, the numbers of HPV-linked head and neck cancers have increased in the U.S. Now we have a chance to develop and test a very specific, potentially less toxic way to stop these cancers,” says the study’s lead author, Xuefeng Liu, MD, associate professor of pathology at Georgetown University Medical Center.  Liu is director of Telomeres and Cell Immortalization for the medical center’s Center for Cell Reprogramming.

Liu and his team have previously found that the HPV E6 oncoprotein interferes with the well-known p53 tumor suppressor to increase telomerase activity that extends the life span of infected cells. A telomerase is a protein that allows a cell to divide indefinitely when it would have stopped after a certain number of divisions.

In this study, researchers found that E6 also interacts with myc, a protein produced by the Myc gene, which controls gene expression in all healthy cells. They concluded that telomerase activity is dependent on E6-myc proteins hooking on to each other.

This means, says Liu, that designing a small molecule that stops E6 from joining up with myc should shut down persistent activation of telomerase. A small molecule could bind to E6 in the same spot that myc would, or bind on to myc in the same spot that E6 would, thus preventing an E6-myc complex.

“This small molecule would not be toxic to all normal cells or, importantly, to master stem cells, because myc would not be affected,” says Liu. “It could be a unique treatment, targeted specifically to HPV cancers.”

Georgetown researchers are now working on a prototype chemical to interfere with E6/Myc binding.

Prostaglandin E1 Inhibits Leukemia Stem Cells Targeting leukemia stem cells in combination with standard chemotherapy may improve treatment for chronic myeloid leukemia

Two drugs, already approved for safe use in people, may be able to improve therapy for chronic myeloid leukemia (CML), a blood cancer that affects myeloid cells, according to results from a University of Iowa study in mice.

CML is a relatively common cancer. The American Cancer Society estimates that in 2017 there will be about 8,950 new cases and about 1,080 people will die of the disease.

In its initial, chronic stage, CML is relatively easy to treat. Drugs called tyrosine kinase inhibitors (TKIs) are generally successful at controlling the cancer. However, patients need to continue the expensive treatment for their lifetime. In some cases, even with that treatment, the cancer can progress to a more advanced stage that is no longer controlled.

One reason for this, explains Hai-Hui (Howard) Xue, MD, PhD, UI professor of microbiology and immunology, is that there are two kinds of tumor cells—bulk leukemia cells that can be killed by TKI drugs, and a subset of cells called leukemia stem cells, which are resistant to TKIs and to chemotherapy.

“A successful treatment is expected to kill the bulk leukemia cells and at the same time get rid of the leukemic stem cells. Potentially, that could lead to a cure,” says Xue, who is senior author of the study published in the September issue of the journal Cell Stem Cell as the cover story.

With that goal in mind, Xue and his team joined forces with Chen Zhao, MD, PhD, UI assistant professor of pathology, and used their understanding of CML genetics to look for small molecules or drug compounds that might be able to eradicate the leukemia stem cells.

Focusing on two proteins known as transcription factors, the researchers showed that genetically removing the two transcription factors, Tcf1 and Lef1, in mice is sufficient to prevent leukemia stem cells from persisting. Importantly, this genetic alteration did not affect normal hematopoietic (blood) stem cells.

Next the researchers used an informatics method called connectivity maps to identify drugs or small molecules that can replicate the gene expression pattern that occurs when the two transcription factors are removed. This screening test identified a drug called prostaglandin E1 (PGE1).

The team tested a combination of PGE1 and the TKI drug called imatinib in a mouse model of CML. The mice lived longer than control mice; 30 percent lived longer than 80 days compared to mice treated with only imatinib, all of which died within 60 days.

The team also looked at a different mouse model of CML, where human CML cells were transplanted into an immunocompromised mouse. When the mice received no treatment or were treated with imatinib alone, the human leukemia stem cells propagated and grew to relatively large numbers. In contrast, when the animals were treated with a combination of imatinib and PGE1, those numbers were greatly reduced, and mice did not develop leukemia.

“The results are a pleasant surprise,” says Xue who also is a member of Holden Comprehensive Cancer Center at the UI. “We do these kinds of genetic studies all the time—looking at transcription factors and what they do. This is a good opportunity to connect what we do at the bench to something that could be useful clinically.”

Investigating how the PGE1 works to suppress the leukemia stem cells, the team found that the effect relies on a critical interaction between PGE1 and its receptor EP4. They then tested the effect of a second drug molecule called misoprostol, which also interacts with EP4, and showed that misoprostol also has the ability to combine with TKI and significantly reduce the number of leukemia stem cells.

Both PGE1 and misoprostol are currently approved by the FDA for use in people. PGE1 is an injectable drug that is used to treat erectile dysfunction. Misoprostol is a pill that is used to treat ulcers.

“We would like to be able to test these compounds in a clinical trial,” Xue says. “If we could show that the combination of TKI with PGE1, or misoprostol, can eliminate both the bulk tumor cells and the stem cells that keep the tumor going, that could potentially eliminate the cancer to the point where a patient would no longer need to depend on TKI.”

Drug combination may improve impact of immunotherapy in head and neck cancer

Checkpoint inhibitor-based immunotherapy has been shown to be very effective in recurrent and metastatic head and neck cancer but only in a minority of patients. University of California San Diego School of Medicine researchers may have found a way to double down on immunotherapy’s effectiveness.

In a paper published in the journal JCI Insights on September 21, researchers report that a combination of toll-like receptors (TLR) agonists — specialized proteins that initiate immune response to foreign pathogens or, in this case, cancer cells — and other immunotherapies injected directly into a tumor suppresses tumor growth throughout the whole body.

“The mechanism reverses the phenotype of a tumor by changing its inherit properties to make the tumor more immunogenic,” said Ezra E.W. Cohen, MD, professor of medicine at UC San Diego School of Medicine and associate director for translational science at UC San Diego Moores Cancer Center and senior author on the paper. “In this study, the combination of immunotherapy drugs resulted in the complete elimination of cancer cells and even when re-challenged the tumors did not recur.”

Macrophages are specialized immune cells that destroy targeted cells. They are supposed to present antigens to the immune system to get it started, but in cancer they stop doing that so the immune system is unable to recognize the cancer. The combination of drugs restored the ability of macrophages to initiate a tumor response and allow the immune system to eliminate the cancer.

To improve the efficiency of checkpoint inhibitor immunotherapy on human papillomavirus-negative and HPV-positive head and neck cancers, the team of researchers combined synthetic TLR7 and TLR9 that were developed by Dennis Carson, MD, Professor Emeritus at UC San Diego School of Medicine, with an inhibitor of the protein called programmed death-1 receptor (PD-1) which is responsible for turning off T cells.

TLR agonists cause an innate immune response — that is, the rapid response to a foreign substance in the body. This immediate protection comes at a cost since the nonspecific immune response may harm healthy cells if activation of the immune systems persists. PD-1 inhibitors stimulate an adaptive response calling on B cells and T cells to respond to a specific target, but this process takes longer to go into effect.

In mouse models, the combined TLR agonists and PD-1 inhibitors injected directly into a tumor incited a tumor-specific response by T cells which prevented metastasis or the spread of the cancer. When cancer had already spread, the TLR and anti-PD-1 combo eliminated the primary tumor as well as distant tumors. The combination therapy was more effective than either agent alone.

The next step should be to study these drugs in a clinical setting for head and neck cancer using FDA-approved immunotherapy. In addition, Cohen suggests studying these agents with other combinations such as chemotherapy and radiation therapy.

“As we make the tumor more immunogenic we should be making other therapies more effective and eliminate the cancer completely,” said Cohen.

Immune Cells Produce Wound Healing Factor, Could Lead To New IBD Treatment

Specific immune cells have the ability to produce a healing factor that can promote wound repair in the intestine, a finding that could lead to new, potential therapeutic treatments for inflammatory bowel disease (IBD), according to a new research study.

The research team, led by Georgia State University and the University of Michigan, wanted to understand how a wound heals in the intestine because in IBD, which includes Crohn’s disease and ulcerative colitis, damage to the intestinal epithelial barrier allows bacteria in the intestine to go across the barrier and stimulate the body’s immune system. This can lead to excessive inflammation and IBD. Efficient repair of the epithelial barrier is critical for suppressing inflammation and reestablishing intestinal homeostasis.

In this study, the researchers found that a specific population of immune cells called macrophages have the ability to secrete or produce a protective or healing factor known as Interleukin-10 (IL-10), which can interact with receptors on intestinal epithelial cells to promote wound healing. The findings are published in The Journal of Clinical Investigation.

“Understanding how wounds can be healed is believed to be very important and a potential therapeutic avenue for the treatment of inflammatory bowel disease,” said Dr. Tim Denning, associate professor in the Institute for Biomedical Sciences at Georgia State. “In this study, we tried to understand some of the cellular mechanisms that are required for optimal wound healing in the intestine. To do this, we used a cutting-edge system, a colonoscope with biopsy forceps, to create a wound in mice. This is analogous to colonoscopies in humans. This cutting-edge system allowed us to begin to define what cells and factors contribute to wound healing in the mouse model.”

The researchers used a small, fiber optic camera and forceps to pinch the mouse’s intestine and take a small biopsy, just as how colonoscopies are done in humans. This small pinch created a wound, which the researchers observed as it healed. The study compared intestinal wound healing in two groups of mice: 1) typical mice (wild type) found in nature and 2) mice genetically deficient in the healing factor IL-10, specifically in macrophages, which impairs their ability to have normal wound repair.

The team also analyzed the effects of IL-10 on epithelial wound closure in vitro using an intestinal epithelial cell line.

They concluded that macrophages are a main source of IL-10 in the wound bed, and IL-10 stimulates in vitro intestinal epithelial wound healing and increases in expression during in vivo intestinal epithelial wound repair. In vitro, exposure to IL-10 increased wound repair within 12 hours and the response was further enhanced after 24 hours.

“Basically, you have a wound, and you have an immune cell that comes in,” Denning said. “That’s the macrophage. The macrophage can produce a factor (IL-10), and that factor can then cause the cells that are around the wound to start closing the wound.”

In addition, the researchers defined some of the signaling pathways that IL-10 uses to orchestrate wound repair. They found IL-10 promotes intestinal epithelial wound repair through the activation of cAMP response element-binding protein (CREB) signaling at the sites of injury, followed by synthesis and secretion of the WNT1-inducible signaling protein 1 (WISP-1).

“The implications are that understanding these cells, the factors and the pathways may offer us the ability to modulate this pathway during inflammatory bowel disease, which could lead to treatment and promote healing and recovery from inflammatory bowel disease,” Denning said. “There are different ways we think about it, but perhaps we could deliver the beneficial compounds (IL-10 and the downstream signaling pathways) to those patients, orally or even intravenously, or somehow drive the natural production of those compounds.”

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.