Enzyme Inhibitor Combined with Chemotherapy Delays Glioblastoma Growth

 In animal experiments, a human-derived glioblastoma significantly regressed when treated with the combination of an experimental enzyme inhibitor and the standard glioblastoma chemotherapy drug, temozolomide.

The regression seen in this combination therapy of temozolomide and the inhibitor SLC-0111 — which targets the enzyme carbonic anhydrase 9, or CA9 — was greater than that seen with either SLC-0111 or temozolomide alone, says research leader Anita Hjelmeland, Ph.D., assistant professor in the Department of Cell, Developmental and Integrative Biology at the University of Alabama at Birmingham.

“Our experiments strongly suggest that a strategy to target a carbonic anhydrase that is increased in glioblastoma, CA9, will improve temozolomide efficacy,” Hjelmeland said. “We believe the drug combination could improve patient outcomes in glioblastomas sensitive to chemotherapy.”

Glioblastoma is the most common primary brain tumor seen in adults. Half of the tumors recur less than seven months after undergoing the standard treatment of surgery, temozolomide and radiation. The median survival after diagnosis of this deadly cancer is 12 to 14 months. Thus, new approaches to therapy are urgently needed.

Solid tumors like glioblastoma create microenvironments within and around themselves. A common condition is hypoxia, a shortage of oxygen as the tumor outgrows its blood supply. Tumor cells shift to making their energy through glycolysis, a method of metabolism that does not require oxygen. Glycolysis, in turn, changes the acid-base balance at the tumor — the extracellular space becomes more acidic and the tumor cell interiors become more alkaline, adapting to this change.

In the face of this hypoxia and acid stress, tumor cells over-produce CA9, a membrane enzyme that converts carbon dioxide and water to bicarbonate and protons. This reaction aids maintenance of the altered acid-base balance in the tumor microenvironment.

Thus, CA9 is a possible therapeutic target, and the inhibitor SLC-0111 shows more than 100-fold specificity against CA9, versus two other forms of human carbonic anhydrases, CA1 or CA2. Furthermore, collaborators on this project have previously shown that SLC-0111 exhibits effectiveness against breast cancer xenografts in animals. SLC-0111 has been tested in Phase I clinical safety trials sponsored by Welichem Biotech Inc. in Canada for patients with advanced solid tumors.

The research team led by Hjelmeland and co-first authors Nathaniel Boyd, Ph.D., and Kiera Walker, both working in Hjelmeland’s UAB lab, studied glioma cells in cell-culture that were derived from an aggressive pediatric primary glioblastoma and from an adult recurrent tumor. The researchers also studied the tumor in mice, using the adult recurrent glioblastoma.

One reason for recurrence of glioblastoma is a therapeutically resistant sub-population of glioma cells known as brain tumor initiating cells. Part of the focus of the Hjelmeland team was to look at the effect of the combination therapy on that subset of glioblastoma cells.

The researchers found that the combined treatment with temozolomide and SLC-0111 in cell culture experiments: 1) reduced glioblastoma cell growth, 2) induced arrest of the cell-division cell cycle by creating breaks in DNA, 3) shifted the tumor metabolism and intracellular acid-base balance by decreasing metabolic intermediates, and 4) inhibited enrichment of brain tumor initiating cells.

In experiments with mice, the combined treatment with temozolomide and SLC-0111: 1) delayed tumor growth of a patient-derived, recurrent glioblastoma xenograft implanted beneath the skin of immunocompromised mice, as compared to temozolomide alone, and 2) improved survival of the mice when the xenograft was implanted in the brain, a placement that more closely models glioblastoma in patients.

“Clinical trials in glioblastoma often initiate with patients that have a tumor recurrence, and we have demonstrated in vivo efficacy for SLC-0111 with temozolomide in a recurrent glioblastoma,” the researchers wrote in their study, published in JCI Insight. “Therefore, our data strongly suggest the translational potential of SLC-0111 for glioblastoma therapy.”

“With funds from the Southeastern Brain Tumor Foundation,” Hjelmeland said, “we continue to determine whether there are subtypes of glioblastomas that are most likely to respond to combinatorial therapy.

Rare Melanoma Type Highly Responsive to Immunotherapy

Desmoplastic melanoma is a rare subtype of melanoma that is commonly found on sun-exposed areas, such as the head and neck, and usually seen in older patients. Treatment is difficult because these tumors are often resistant to chemotherapy and lack actionable mutations commonly found in other types of melanoma that are targeted by specific drugs. However, Moffitt Cancer Center researchers report in the Jan. 10 issue of Nature that patients with desmoplastic melanoma are more responsive to immune-activating antiPD-1/PD-L1 therapies than previously assumed.

Drugs that reactivate a patient’s own immune system to target cancer cells are rapidly changing the face of cancer therapy. Pembrolizumab and nivolumab have been approved to treat melanoma, and others are in development. These drugs block the interaction between the proteins PD-1 and PD-L1. During cancer development, PD-1 and PD-L1 inhibit the immune system and allow tumor cells to escape detection and continue to grow. By blocking their interaction, immune-activating drugs restimulate the immune system to detect and destroy cancer cells.

Scientists previously believed that the tissue architecture of desmoplastic melanomas would reduce the ability of immune cells to infiltrate the tumor area and limit the effectiveness of immune-activating drugs. However, based on anecdotal reports of favorable responses, a group of researchers including Moffitt’s Zeynep Eroglu, M.D., Jane Messina, M.D., and Dae Won Kim, M.D., hypothesized that patients with desmoplastic melanoma may be more responsive to antiPD-1/PD-L1 therapies than previously assumed, and explored this in the largest group of immunotherapy-treated desmoplastic melanoma patients studied to date.

To test their hypothesis, the researchers analyzed 60 patients with advanced/metastatic desmoplastic melanoma who were previously treated with a drug that targets either PD-1 or PD-L1. They discovered that 42 patients had a significant response to treatment.  Approximately half of these patients had a complete response in which their tumors entirely disappeared, and the remainder had a partial response, with significant reduction of their tumors.  Seventy-four percent of patients were still alive more than two years after beginning treatment. This 70 percent response rate is one of the highest reported for antiPD-1/PD-L1 therapies to date, and is even higher than response rates commonly observed in patients with other subtypes of melanoma, which are approximately 35 to 40 percent.

In a collaborative effort involving 10 United States and international cancer centers including Moffitt and University of California Los Angeles, researchers wanted to determine the biological reasons why patients with desmoplastic melanoma may benefit from drugs that target PD-1 or PD-L1. They first confirmed that desmoplastic melanomas have high levels of DNA mutations, as they are highly associated with ultraviolet light DNA damage caused by sun exposure. NF-1 mutations were found as the most common driving genetic event.  They also demonstrated that desmoplastic melanomas have the pre-existing immune cells and proteins necessary to mount an immune response against cancer cells. They compared tissue biopsies from patients with desmoplastic melanoma and non-desmoplastic melanoma. They discovered that desmoplastic melanomas have more cells with high levels of the PD-L1 protein within both the tumor and the invading edges of the tumor. Desmoplastic melanomas also have high levels of immune cells called CD8 T cells that are critical for immune-activating drugs to be effective.

“Our findings challenge the previous school of thought that immunotherapy would offer little benefit to patients with desmoplastic melanoma due to the dense tissue architecture of these tumors. These tumors in fact have the necessary biological ingredients to be very effective targets for anti-PD-1 drugs,” said Eroglu, assistant member of the Cutaneous Oncology Department at Moffitt. “Often, combinations of two immunotherapy drugs are used to treat patients with melanoma to try to improve tumor response rates and survival above current reported rates.  However, these combinations can lead to significantly higher rate of severe side-effects than treatment with anti-PD-1 therapy alone.  Our data suggest that single-agent anti-PD-1 therapy may well be sufficient for patients with desmoplastic melanoma, potentially sparing them the increased toxicities generally observed with combinations of immunotherapies.”

Texas A&M Research Shows Biological Clocks Could Improve Brain Cancer Treatment

Biological clocks throughout the body play a major role in human health and performance, from sleep and energy use to how food is metabolized and even stroke severity. Now, Texas A&M University researchers found that circadian rhythms could hold the key to novel therapies for glioblastoma, the most prevalent type of brain cancer in adults—and one with a grim prognosis.

Scientists in the Texas A&M Center for Biological Clocks Research (CBCR) determined that the timed production of a particular protein, associated with tumor proliferation and growth, is disrupted in glioblastoma cells, and they believe that this may lead to a more effective technique to treat the cancerous cells without damaging the healthy surrounding tissue. These findings, which were supported in part by the National Institutes of Health, were published today (Jan. 10) in the international journal BMC Cancer.

Texas A&M biologist Deborah Bell-Pedersen, PhD, a co-corresponding author on the study, found in her previous research that the biological clock in the model fungal system Neurospora crassa controls daily rhythms in the activity of a signaling molecule, called p38 mitogen activated protein kinase (MAPK). This signaling protein plays a role in glioblastoma’s highly invasive and aggressive properties.

In the new research, David J. Earnest, PhD, a mammalian biological clocks expert at the Texas A&M College of Medicine and co-corresponding author on the study, collaborated with Bell-Pedersen to show that the clock controls daily rhythms in p38 MAPK activity in a variety of mammalian cells as well, including normal glial cells, the supporting “helper” cells surrounding neurons.

Furthermore, their work found that such regulation is absent in glioblastoma cells. “We tested to see if inhibition of this cancer-promoting protein in glioblastoma cells would alter their invasive properties,” said Bell-Pedersen, an internationally recognized leader in the fields of circadian and fungal biology. “Indeed, we found that inhibition of p38 MAPK at specific times of the day—times when the activity is low in normal glial cells under control of the circadian clock—significantly reduced glioblastoma cell invasiveness to the level of noninvasive glioma cells.”

These findings indicate that glioblastoma might be a good candidate for chronochemotherapy, meaning treating cancer at specific times of day to get the most impact.

“Chronotherapeutic strategies have had a significant positive impact on the treatment of many types of cancer by optimizing the specific timing of drug administration to improve the efficacy and reduce the toxicity of chemotherapy,” Bell-Pedersen said. “However, circadian biology has not been applied to the development of chronotherapeutic strategies for the treatment of glioblastoma, and clinical outcomes for this common primary brain tumor have shown limited improvement over the past 30 years.”

Glioblastomas gained some attention this summer when Senator John McCain was diagnosed with the condition. “A big reason for poor prognosis for patients with this aggressive type of tumor is that the glioblastoma cells rapidly and unabatedly invade and disrupt the surrounding brain cells,” said Gerard Toussaint, MD, a clinician and assistant professor at the Texas A&M College of Medicine who specializes in glioblastoma. Current treatments—including chemotherapy, surgical resection, immunotherapy and radiation—are largely ineffective in prolonging life expectancy beyond 18 months.

“We found that an inhibitor of p38 MAPK activity would make the cells behave less invasively, and if you can control the invasive properties, you can improve prognosis,” Earnest said. In addition, the team’s data indicate such treatment may be more effective and less toxic if administered at the appropriate time of the day.

This reduced toxicity is important, because a drug to inhibit the cancer-promoting activity of this protein was tested but found to be too harmful, with too many side effects. “If treatment with the drug can be timed to when the normal glial cells naturally have low activity of p38 MAPK, the addition of the drug might not be as toxic for these cells, and yet would still be very effective on the cancerous cells,” Earnest said.

Although promising, the current studies were done using cell cultures. The team’s next step is to test p38 inhibitor chronochemotherapy in an animal model for glioblastoma. If successful, they would then move on to clinical trials.

“We work on a model system, and the reason to do that is that we can make progress quickly, and we always hope that what we’re working on will lead to something useful, and I think this is a prime example of how putting effort into basic research can pay off,” Bell-Pedersen said. “We’re very hopeful and encouraged by our data that we’ll find a treatment.”

‘Decorated’ Stem Cells Could Offer Targeted Heart Repair

Although cardiac stem cell therapy is a promising treatment for heart attack patients, directing the cells to the site of an injury – and getting them to stay there – remains challenging. In a new pilot study using an animal model, North Carolina State University researcher Ke Cheng and his team show that “decorating” cardiac stem cells with platelet nanovesicles can increase the stem cells’ ability to find and remain at the site of heart attack injury and enhance their effectiveness in treatment.

“Platelets can home in on an injury site and stay there, and even in some cases recruit a body’s own naturally occurring stem cells to the site, but they are a double-edged sword,” says Cheng, associate professor of veterinary medicine and associate professor in the NC State/UNC Joint Department of Biomedical Engineering. “That’s because once the platelets arrive at the site of injury, they trigger the coagulation processes that cause clotting. In a heart-attack injury, blood clots are the last thing that you want.”

Cheng and his associates wondered if it would be possible to co-opt a platelet’s ability to locate and stick to an injury site without inducing clotting. They found that adhesion molecules (a group of glycoproteins) located on the platelet’s surface were responsible for its ability to find and bind to an injury. So the team created platelet nanovesicles from these molecules, and then decorated the surface of cardiac stem cells with the nanovesicles,

“The nanovesicle is like the platelet’s coat,” Cheng says. “There isn’t any internal cellular machinery that could activate clotting. When you place the nanovesicle on the stem cell, it’s like giving the stem cell a tiny GPS that helps it locate the injury so it can do its repair work without any of the side effects associated with live platelets.”

In a proof-of-concept study involving a rat model of myocardial infarction, twice as many platelet nanovesicle decorated cardiac stem cells, or PNV-CSCs, were retained in the heart than non-decorated cardiac stem cells. The rodents were monitored for four weeks. Overall, the rats in the PNV-CSC group showed nearly 20 percent or higher cardiac function than the control CSC group.

A small pilot study in a pig model also demonstrated higher rates of stem cell retention with PNV-CSCs, though the team did not perform functional studies. A future follow-up study is planned.

“Platelet nanovesicles do not affect the performance of the cardiac stem cells, and are free from any negative side effects,” Cheng says. “Hopefully we will be able to use this approach to improve cardiac stem cell therapy in clinical trials in the future.”

Immune Cells Play Key Role in Early Breast Cancer Metastasis Even Before a Tumor Develops

Mount Sinai researchers have discovered that normal immune cells called macrophages, which reside in healthy breast tissue surrounding milk ducts, play a major role in helping early breast cancer cells leave the breast for other parts of the body, potentially creating metastasis before a tumor has even developed, according to a study published in Nature Communications.

The macrophages play a role in mammary gland development by regulating how milk ducts branch out through breast tissue. Many studies have also proven the importance of macrophages in metastasis, but until now, only in models of advanced large tumors. By studying human samples, mouse tissues, and breast organoids, which are miniaturized and simplified versions of breast tissue produced in the lab, the new research found that in very early cancer lesions, macrophages are attracted to enter the breast ducts where they trigger a chain reaction that brings early cancer cells out of the breast, said lead researcher Julio Aguirre-Ghiso, PhD, Professor of Oncological Sciences, Otolaryngology, Medicine, Hematology and Medical Oncology at The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai.

This research shows that macrophages’ relationship with normal breast cells is co-opted by early cancer cells that activate the cancer-causing HER2 gene, helping in this newly-discovered role of these immune cells. The findings from this study could eventually help pinpoint biomarkers to identify cancer patients who may be at risk of carrying potential metastatic cells due to these macrophages and potentially lead to the development of novel therapies that prevent early cancer metastasis.

Early treatment of high-risk patients may prevent the formation of deadly metastasis better than the current standard of treating metastatic disease only once it has occurred, said key researcher Miriam Merad, MD, PhD, Director of the Precision Immunology Institute and the Human Immune Monitoring Center and co-leader of the Cancer Immunology program at The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai.

“Our study challenges the dogma that early diagnosis and treatment means sure cure,” Dr. Aguirre-Ghiso said. “In this study and in our previous studies, we present mechanisms governing early dissemination.  This work further sheds light onto the mysterious process of early dissemination and cancer of an unknown primary tumor.”

Researchers hope to build on this study by identifying which macrophages specifically control early dissemination. They also hope to further detail how early disseminated cancer cells interact with macrophages in the lungs where metastases eventually form and how this interaction can be targeted to prevent metastasis.

“Here, we have identified how macrophages and early cancer cells form a ‘microenvironment of early dissemination’ and show that by disrupting this interaction we can prevent early dissemination and ultimately deadly metastasis,” said Dr. Merad. “This sheds light onto the mysterious process of early dissemination and for patients who have metastasis cancer that came from an unknown source.”

Researchers Map Molecular Interaction That Prevents Aggressive Breast Cancer

Researchers in Italy have discovered how specific versions of a protein called Numb protect the key tumor suppressor p53 from destruction. The study, which will be published December 21 in the Journal of Cell Biology, suggests that the loss of these particular Numb proteins makes breast cancers more aggressive and resistant to chemotherapy, but points the way toward new therapeutic approaches that could improve patient outcome by preserving p53 levels.

Cells produce several alternative isoforms of Numb by differentially processing, or splicing, the mRNA encoding Numb to include or exclude specific regions of the protein. How this alternative splicing affects Numb’s various functions remains unclear.

In mammary gland stem cells, for example, Numb binds and inhibits an enzyme called Mdm2, preventing it from targeting p53 for degradation. Numb therefore stabilizes p53 and allows this tumor suppressor protein to limit stem cell proliferation. If the stem cells lose Numb, however, p53 levels plunge and the cells proliferate uncontrollably, leading to the emergence of cancer stem cells that drive the growth of breast tumors. Cancer cells that lack p53 are also more resistant to chemotherapy drugs that kill cells by damaging their DNA.

A team of researchers based in Milan set out to identify how Numb binds to Mdm2. The team was led by Pier Paolo Di Fiore of the FIRC Institute for Molecular Oncology (IFOM), the European Institute of Oncology (EIO), and The University of Milan, as well as Salvatore Pece of EIO and The University of Milan and Marina Mapelli of EIO.

The researchers found that a small region of Numb—comprising just 11 amino acids—is responsible for binding and inhibiting Mdm2. This region is present in Numb isoforms 1 and 2 but excluded from isoforms 3 and 4. Accordingly, depleting Numb-1 and -2 from breast cancer cells reduced the levels of p53, whereas depleting Numb-3 and -4 had no effect.

The researchers then compared tumor cells isolated from multiple different breast cancer patients and found that cells expressing lower amounts of Numb-1 and -2 were more resistant to the chemotherapy agent cisplatin. Treating these cells with an Mdm2 inhibitor boosted p53 levels and increased the cells’ sensitivity to cisplatin.

“We reasoned that breast cancers displaying reduced levels of Numb-1 and -2, being resistant to genotoxic agents, might also display poorer disease outcome,” explains Pece.

The team therefore analyzed the case history of 890 breast cancer patients and found that low Numb-1 and -2 levels correlated with an increased risk of aggressive, metastatic disease, particularly for the luminal subtype of breast cancers, which tend to retain a normal, functional copy of the p53 gene.

“Our results show how Numb splicing specifically impacts the regulation of p53 and breast cancer prognosis,” Mapelli says.

“We hope that it will be possible to exploit the knowledge of the molecular basis of the Numb–Mdm2 interaction in the rational design of molecules that can mimic the crucial region in Numb and inhibit Mdm2 to relieve p53 dysfunction in Numb-defective breast cancers,” Di Fiore says.

Harnessing Sperm to Treat Gynecological Diseases

Delivering drugs specifically to cancer cells is one approach researchers are taking to minimize treatment side effects. Stem cells, bacteria and other carriers have been tested as tiny delivery vehicles. Now a new potential drug carrier to treat gynecological conditions has joined the fleet: sperm. Scientistsreport in the journal ACS Nano that they have exploited the swimming power of sperm to ferry a cancer drug directly to a cervical tumor in lab tests.

Creating an effective way to target cancer cells with drugs is challenging on multiple fronts. For example, the drugs don’t always travel deeply enough through tissues, and they can get diluted in body fluids or sidetracked and taken up by healthy organs. To get around these issues, scientists have turned in some cases to loading pharmaceuticals into bacteria, which can effectively contain drug compounds and propel themselves. The microbes can also be guided by a magnetic field or other mechanism to reach a specific target. However, the body’s immune system can attack the microbes and destroy them before they reach their target. Looking for another self-propelled cell as an alternative drug carrier to bacteria, Mariana Medina-Sánchez and colleagues at the Leibniz Institute for Solid State and Materials Research—Dresden (IFW Dresden) turned to sperm.

The researchers packaged a common cancer drug, doxorubicin, into bovine sperm cells and outfitted them with tiny magnetic harnesses. Using a magnetic field, a sperm-hybrid motor was guided to a lab-grown tumor of cervical cancer cells. When the harness arms pressed against the tumor, the arms opened up, releasing the sperm. The sperm then swam into the tumor, fused its membrane with that of a cancer cell, and released the drug. When unleashed by the thousands, drug-loaded sperm killed more than 80 percent of a cancerous ball while leaking very little of their payload en route. Further work is needed to ensure the system could work in animals and eventually humans, but researchers say the sperm motors have the potential to one day treat cancer and other diseases in the female reproductive tract.

Researchers Identify Epigenetic Orchestrator of Pancreatic Cancer Cells

Genentech researchers have identified an enzyme that shifts pancreatic cancer cells to a more aggressive, drug-resistant state by epigenetically modifying the cells’ chromatin. The study, which will be published December 11 in the Journal of Cell Biology, suggests that targeting this enzyme could make pancreatic cancer cells more vulnerable to existing therapies that currently have only limited effect against this deadly form of cancer.

The vast majority of cancers originate in epithelial tissues, where cells are normally organized into tightly packed sheets. As cancers progress, however, many tumor cells lose their epithelial characteristics and transition to a so-called mesenchymal state in which they detach from neighboring cells and become more mobile, allowing them to invade and form secondary tumors in other tissues. Mesenchymal tumor cells are also more resistant to chemotherapy drugs than their epithelial counterparts, and many of them appear to have stem cell–like properties that allow them to drive tumor growth.

Given these unfavorable characteristics, researchers are interested in developing ways to reverse the epithelial-to-mesenchymal transition in tumors. This approach could be particularly beneficial in the treatment of pancreatic cancer, one of the deadliest forms of the disease that typically shows little response to existing chemo- and immunotherapies. “Priming pancreatic cancers with an epithelial-inducing agent might not only decrease invasion, metastasis, and limit stem cell–like behavior, but may also increase responses to existing cancer drugs,” explains Ira Mellman, vice president of cancer immunology at Genentech.

Researchers have already identified many of the proteins that regulate epithelial-to-mesenchymal transitions, but attempts at targeting these proteins in cancer patients to convert mesenchymal tumor cells into epithelial cells have so far proven unsuccessful. However, large-scale changes in cell state, such as epithelial–mesenchymal transitions, are often orchestrated by epigenetic regulators that control the expression of many different genes by chemically modifying their DNA or the histone proteins that package them into chromosomes.

Mellman and colleagues, including the study’s first author Manuel Viotti, screened 300 different epigenetic regulators and found that reducing the levels of a histone-modifying protein called SUV420H2 caused mesenchymal pancreatic cells grown in the laboratory to regain many of the characteristics of epithelial cells. Pancreatic cancer cells lacking SUV420H2 showed increased levels of epithelial cell–specific genes and lower levels of genes typically expressed by mesenchymal cells.

“The acquisition of these epithelial characteristics was sufficient to reduce cell invasion and motility and increase sensitivity to gemcitabine and 5-fluorouracil, two of the most commonly used chemotherapies in human pancreatic ductal adenocarcinoma,” says Viotti. The cells also appeared to lose their ability to act like stem cells capable of driving tumor growth.

In contrast, when the researchers boosted SUV420H2 levels, epithelial-like pancreatic cancer cells were converted into a mesenchymal-like state. Mellman and colleagues then examined human pancreatic adenocarcinoma samples and saw that SUV420H2 levels were low in healthy regions of the pancreas, slightly elevated during the early stages of tumorigenesis, and strongly increased in advanced, invasive portions of the tumor that had lost their epithelial characteristics.

Histone-modifying enzymes such as SUV420H2 are relatively easy to target with specific inhibitory drug molecules, but Mellman and colleagues caution that it is still unclear whether or not converting mesenchymal tumor cells into epithelial cells will be beneficial for cancer patients. “Nonetheless, promoting the epithelial state by targeting SUV420H2 in combination with conventional chemotherapies and decreasing resistance might prove to be an effective treatment for the devastating diagnosis of pancreatic cancer,” Mellman says.

Mitochondrial Protein in Cardiac Muscle Cells Linked to Heart Failure, Study Finds

Reducing a protein found in the mitochondria of cardiac muscle cells initiates cardiac dysfunction and heart failure, a finding that could provide insight for new treatments for cardiovascular diseases, a study led by Georgia State University has shown.

The researchers discovered that reducing an outer mitochondrial membrane protein, FUN14 domain containing 1 (FUNDC1), in cardiac muscle cells, also known as cardiomyocytes, activates and worsens cardiac dysfunction. Also, disrupting how FUNDC1 binds to a particular receptor inhibited the release of calcium from another cell structure, the endoplasmic reticulum (ER), into the mitochondria of these cells and resulted in mitochondrial dysfunction, cardiac dysfunction and heart failure. The findings are published in the journal Circulation.

Mitochondria play numerous roles in the body, including energy production, reactive oxygen species generation and signal transduction. Because the myocardium, the muscular wall of the heart, is a high-energy-demand tissue, mitochondria play a central role in maintaining optimal cardiac performance. Growing evidence suggests deregulated mitochondrial activity plays a causative role in cardiovascular diseases.

In the body, mitochondria and ER are interconnected and form their own endomembrane networks. The points where mitochondria and ER make physical contact and communicate are known as mitochondria-associated ER membranes (MAMs). MAMs play a major role in regulating the transfer of calcium between ER and mitochondria. Dysfunctional MAMs are involved in several neuronal disorders, including Alzheimer’s disease and Parkinson’s disease. Until now, the role of MAMs in cardiac pathologies has not been well understood.

“Our study found the formation of MAMs mediated by the mitochondrial membrane protein FUNDC1 was significantly suppressed in patients with heart failure, which provides evidence that FUNDC1 and MAMs actively participate in the development of heart failure,” said Dr. Ming-Hui Zou, director of the Center for Molecular and Translational Medicine at Georgia State and a Georgia Research Alliance Eminent Scholar in Molecular Medicine. “This work has important clinical implications and provides support that restoring proper function of MAMs may be a novel target for treating heart failure.”

The researchers used mouse neonatal cardiomyocytes, mice with a genetic deletion of the FUNDC1 gene, control mice with no genetic deficiencies and the cardiac tissues of patients with heart failure.

The cardiac functions of the mice were monitored using echocardiography at 10 weeks of age. Mice with the genetic deletion of FUNDC1 had markedly reduced ventricular filling velocities, prolonged left ventricular isovolumic relaxation time, diastolic dysfunction, decreased cardiac output (which indicates impaired systolic functions) and interstitial fibrosis of the myocardium, among other issues. The mitochondria in the hearts of mice with FUNDC1 gene deletion were larger and more elongated, a 2.5-fold increase of size compared to mitochondria in the control mice.

To determine if FUNDC1 reduction occurred in human hearts and contributed to heart failure in patients, the researchers examined four heart specimens from heart failure patients and four heart specimens from control donors. They found the levels of FUNDC1 were significantly reduced in patients with heart failure compared to control donors. Also, the contact between ER and mitochondria in failed hearts was significantly reduced. In addition, the mitochondria in heart failure hearts were more elongated compared to those in control donors.

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.