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.

Bioengineered Soft Microfibers Improve T-Cell Production

Columbia engineers bioengineer soft microfibers to improve T-cell production.

T cells play a key role in the body’s immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, chemical-based approaches. These “living drugs” are poised to transform medicine, with a growing number of cellular therapies receiving FDA-approval.

A current bottleneck in these approaches and other Adoptive T-cell Therapies (ACTs) is the production of sufficient numbers of high quality T cells. As a starting material, cells are isolated from the patient and then modified and grown outside the body in a bioreactor. This is still a new manufacturing challenge in medicine, and lack of a therapeutic number of cells is a frequent point of failure in ACT. In addition to technical challenges faced in consistent production of cells, T cells from patients undergoing treatment for cancer often show reduced function due to the disease, and are particularly difficult to grow.

A Columbia Engineering team has developed a new method for improving T-cell manufacture by focusing on the materials involved in this process. The team is a collaboration between Biomedical Engineering faculty Lance C. Kam and Helen H. Lu, whose research programs include immune engineering and smart biomaterial design. Their study, which is published today in Advanced Biosystems, uses a polymer mesh to activate the T cells, a critical step for their production. This approach simplifies processing compared to systems in use today. In addition, making the fibers out of a mechanically soft material improved T-cell growth, outperforming the current gold standard on several fronts.

“Our report shows that this soft mesh material increases the number of functional cells that can be produced in a single step,” Kam says. “In fact, our system provided nearly an order of magnitude more cells in a single process. What’s especially exciting is that we’ve been able to expand cells isolated from patients undergoing treatment for leukemia. These cells are often very difficult to activate and expand, and this has been a barrier to using cellular immunotherapy for the people who need it.”

In testing the effect of a softer material on T-cell production, the team was inspired by the field of mechanobiology. Researchers have known that other cell types can sense the mechanical stiffness of a material. For example, the rigidity of a material used to culture stem cells can direct differentiation, with a softer material promoting production of neuron while a stiffer substrate encourages bone cell differentiation. This effect can be as strong as the chemicals normally used to direct differentiation. However, a similar effect was unexpected in T cells for activation.

“This makes sense for cells normally involved in force-related activities, like muscle cells or fibroblasts that are involved in wound closure and healing. Our group was one of the first to explore this possibility for T cells, which are not associated with such functions,” Kam notes. These early experiments, involving his Microscale Biocomplexity Laboratory group, discovered that T-cells can sense the mechanical rigidity of the materials commonly used in the laboratory. To turn this into a clinically useful system, his group partnered with Lu’s Biomaterials and Interface Tissue Engineering Laboratory to create a microfiber-based platform.

Beyond simplifying the process of cell expansion and improving T-cells expansion, Kam and Lu envision that the mesh platform will have applications beyond immunotherapy. They are refining their platform and exploring how T cells from cancer patients respond to their materials. Says Lu, “It is truly exciting to see how these bioinspired matrices can direct cell function and be successfully used for T-cell therapy.”

More Evidence of Link Between Severe Gum Disease and Cancer Risk

Data collected during a long-term health study provides additional evidence for a link between increased risk of cancer in individuals with advanced gum disease, according to a new collaborative study led by epidemiologists Dominique Michaud at Tufts University School of Medicine and Elizabeth Platz of the Johns Hopkins Bloomberg School of Public Health and Kimmel Cancer Center.

The study, published in the Journal of the National Cancer Institute, used data from comprehensive dental exams performed on 7,466 participants from Maryland, Minnesota, Mississippi, and North Carolina, as part of their participation in the Atherosclerosis Risk in Communities (ARIC) study who were then followed from the late 1990s until 2012. During the follow-up period, 1,648 new cancer cases were diagnosed.

The research team found a 24 percent increase in the risk of developing cancer among participants with severe periodontitis, compared to those with mild to no periodontitis at baseline. Among patients who had no teeth—which can be a sign of severe periodontitis—the increase in risk was 28 percent. The highest risk was observed in cases of lung cancer, followed by colorectal cancer.

When the researchers did sub-group analyses, they found that participants with severe periodontal disease had more than double the risk of developing lung cancer, compared with no/mild periodontitis. An 80 percent increase in risk of colon cancer observed for participants who were edentulous at baseline, which is consistent with prior findings, and among never smokers, a two-fold higher risk was noted for participants with severe periodontitis, compared to those who had no/mild periodontitis.

“This is the largest study addressing the association of gum disease and cancer risk using dental examinations to measure gum disease prior to cancer diagnosis,” said first and corresponding author Dominique Michaud, Sc.D., professor of public health and community medicine at Tufts University School of Medicine. “Additional research is needed to evaluate if periodontal disease prevention and treatment could help alleviate the incidence of cancer and reduce the number of deaths due to certain types of cancer.”

Michaud noted that the findings were particularly interesting in light of research, including a recent study in Science, which determined that colorectal cancer tissues contain bacteria that are present in the mouth, including bacteria that have been associated with periodontal disease.

The researchers also uncovered a small increase in the risk of pancreatic cancer in patients with severe periodontitis. Although not significant statistically, the association has been seen in other similar studies, including a number of studies led by Michaud of Tufts.

The research team accounted for the impact of smoking among the participants, since people who smoke are more likely to get periodontal disease, and smoking raises the risk of lung and colon cancers.

“When we looked at data for the people who had never smoked, we also found evidence that having severe periodontal disease was related to an increased risk of lung cancer and colorectal cancer,” said Elizabeth Platz, Sc.D., deputy chair of the department of epidemiology at the Johns Hopkins Bloomberg School of Public Health and co-leader of the Cancer Prevention and Control Program at the Johns Hopkins Kimmel Cancer Center.

The ARIC data were especially useful to study because unlike most previous research linking gum disease and cancer risk, periodontitis cases were determined from dental examinations performed as part of the ARIC study rather than participants’ self-reports of the disease. The dental exams provided detailed measurements of the depth of the pocket between the gum and tooth in several locations in the mouth. The ARIC data include both Caucasian and African-American participants.

The researchers found no links between increased risk of breast, prostate or blood/lymphatic cancer and periodontitis. The link between periodontitis and increased cancer risk was weaker or not apparent in African-American participants from the ARIC study, except in cases of lung and colorectal cancer. “Additional research is needed to understand cancer-site specific and racial differences in findings,” wrote the authors. The researchers caution that the study was limited in size for subgroup analyses, and less common cancers. The findings, however, suggest the need for further study.

Michaud and Platz said the study also points to the importance of expanding dental insurance to more individuals. “Knowing more about the risks that come about with periodontal disease might give more support to having dental insurance in the way that we should be offering health insurance to everyone,” Platz said.

Advanced gum disease, also called periodontitis, is caused by bacterial infection that damages the soft tissue and bone that support the teeth. Previous research has shown a link between periodontitis and increased cancer risk, although the mechanism connecting the two diseases is still uncertain.

Flipping the Switch: Dietary Fat, Changes in Fat Metabolism May Promote Prostate Cancer Metastasis

Prostate tumors tend to be what scientists call “indolent” – so slow-growing and self-contained that many affected men die with prostate cancer, not of it. But for the percentage of men whose prostate tumors metastasize, the disease is invariably fatal. In a set of papers out today in the journals Nature Genetics and Nature Communications, researchers at the Cancer Center at Beth Israel Deaconess Medical Center (BIDMC) shed new light on the genetic mechanisms that promote metastasis in the mouse model and also implicated the typical Western high-fat diet as a key environmental factor driving metastasis.

“Although it is widely postulated that a Western diet can promote prostate cancer progression, direct evidence supporting a strong association between dietary lipids and prostate cancer has been lacking,” said first author Ming Chen, PhD, a research fellow in the laboratory of Pier Paolo Pandolfi, MD, PhD, Director of the Cancer Center and Cancer Research Institute at BIDMC.

Epidemiological data links dietary fats (and obesity) to many types of cancer, and rates of cancer deaths from metastatic cancers including prostate cancer are much higher in the United States than in nations where lower fat diets are more common. While prostate cancer affects about ten percent of men in Asian nations, that rate climbs to about 40 percent when they immigrate to the U.S., mirroring the rates among the native born U.S. population. That points to an environmental culprit that may work in concert with genetic factors to drive this aggressive, fatal disease.

“The progression of cancer to the metastatic stage represents a pivotal event that influences patient outcomes and the therapeutic options available to patients,” said senior author Pandolfi. “Our data provide a strong genetic foundation for the mechanisms underlying metastatic progression, and we also demonstrated how environmental factors can boost these mechanisms to promote progression from primary to advanced metastatic cancer.”

The tumor suppressor gene PTEN is known to play a major role in prostate cancer; its partial loss occurs in up to 70 percent of primary prostate tumors. Its complete loss is linked to metastatic prostate disease, but animal studies suggest the loss of PTEN alone is not enough to trigger progression. Pandolfi and colleagues sought to identify an additional tumor suppressing gene or pathway that may work in concert with PTEN to drive metastasis.

Looking at recent genomic data, Pandolfi and colleagues noticed that another tumor suppressor gene, called PML, tended to be present in localized (non-metastatic) prostate tumors, but was absent in about a third of metastatic prostate tumors. Moreover, about 20 percent of metastatic prostate tumors lack both PML and PTEN.

When they compared the two types of tumor – the localized ones lacking only the PTEN gene versus the metastatic tumors lacking both genes – the researchers found that the metastatic tumors produced huge amounts of lipids, or fats. In tumors that lacked both PTEN and PML tumor suppressing genes, the cells’ fat-production machinery was running amok.

“It was as though we’d found the tumors’ lipogenic, or fat production, switch,” said Pandolfi. “The implication is, if there’s a switch, maybe there’s a drug with which we can block this switch and maybe we can prevent metastasis or even cure metastatic prostate cancer,” he added.

Such a drug already exists. Discovered in 2009, a molecule named “fatostatin” is currently being investigated for the treatment of obesity. Pandolfi and colleagues tested the molecule in lab mice. “The obesity drug blocked the lipogenesis fantastically and the tumors regressed and didn’t metastasize.”

In addition to opening the door to new treatment for metastatic prostate cancer, these findings also helped solve a long-standing scientific puzzle. For years, researchers had difficulty modeling metastatic prostate cancer in mice, making it hard to study the disease in the lab. Some speculated that mice simply weren’t a good model for this particular disease. But the lipid production finding raised a question in Pandolfi’s mind.

“I asked, ‘What do our mice eat?’” Pandolfi recalled.

It turned out, the mice ate a vegetable-based chow – essentially a low-fat vegan diet that bore little resemblance to that of the average American male. When Pandolfi and colleagues increased the levels of saturated fats – the kind found in fast food cheeseburgers and fries – in the animals’ diet, the mice developed aggressive, metastatic tumors.

The findings could result in more accurate and predictive mouse models for metastatic prostate cancer, which in turn could accelerate discovery of better therapies for the disease. Additionally, physicians could soon be able to screen their early-stage prostate cancer patients for those whose tumors lack both PTEN and PML tumor suppressing genes, putting them at increased risk for progressing to metastatic disease. These patients may be helped by starving these tumors of fat either with the fat-blocking drug or through diet.

“The data are tremendously actionable, and they surely will convince you to change your lifestyle,” Pandolfi said.

Photographed: Pier Paolo Pandolfi, MD, PhD, Director of the Cancer Center and Cancer Research Institute at BIDMC

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.”

New Polygenic Hazard Score Predicts When Men Develop Prostate Cancer

An international team, led by researchers at the University of California San Diego School of Medicine, has developed and validated a genetic tool for predicting age of onset of aggressive prostate cancer, a disease that kills more than 26,000 American men annually.

The tool, described in the January 11 online issue of the BMJ (formerly the British Medical Journal), may potentially be used to help guide decisions about who to screen for prostate cancer and at what age.

Currently, detection of prostate cancer relies primarily upon the prostate-specific antigen (PSA) screening blood test. But PSA testing is not very good as a screening tool. While it reduces deaths from prostate cancer, indiscriminate PSA screening also produces false positive results and encourages over-detection of non-aggressive, slow-growing tumors.

“The existing PSA test is useful, but it is not precise enough to be used indiscriminately on all men,” said the study’s first author, Tyler M. Seibert, MD, PhD, chief resident physician in the Department of Radiation Medicine and Applied Sciences at UC San Diego School of Medicine. “As a result, it may prompt medical interventions like biopsy, surgery or radiotherapy that might not be necessary.”

Seibert, senior author Anders Dale, PhD, professor and co-director of the Center for Translational Imaging and Precision Medicine at UC San Diego School of Medicine, and colleagues in Europe, Australia and the United States, used genome-wide association studies (GWAS) to determine whether a man’s genetic predisposition to developing prostate cancer could be used to predict his risk of developing the aggressive and lethal form of the disease.

GWAS search individual genomes for small variations, called single-nucleotide polymorphisms (SNPs), that occur more frequently in people with a particular disease than in people without the disease. Hundreds or thousands of SNPs can be evaluated at the same time in large groups of people. In this case, researchers used data from over 200,000 SNPs from 31,747 men of European ancestry participating in the ongoing international PRACTICAL consortium project.

Using a method developed at UC San Diego, the researchers combined information from GWAS and epidemiological surveys to assess quantification for genetic risk at age of disease onset. “Polygenic Hazard Score methodology is specialized in finding age-dependent genetic risks and has already been proven to be very useful in predicting age of onset for Alzheimer’s disease”, said study co-author Chun Chieh Fan, MD, PhD, in the Department of Cognitive Science at UC San Diego.

“The polygenic hazard score is very versatile and can be applied to many age-related diseases,” said Fan. “In this case, the polygenic hazard score of prostate cancer captures the age variations of aggressive prostate cancer.”

Genotype, prostate cancer status and age were analyzed to select SNPs associated with prostate cancer diagnosis. Then the data was incorporated into the polygenic hazard score, which involves survival analysis to estimate SNPs’ effects on age at diagnosis of aggressive prostate cancer. The results led to a polygenic hazard score for prostate cancer that can estimate individual genetic risk. This score was then tested against an independent dataset, from the recent UK ProtecT trial, for validation.

“The polygenic hazard score was calculated from 54 SNPs and proved to be a highly significant predictor of age at diagnosis of aggressive prostate cancer,” said Seibert. “When men in the ProtecT dataset with a high polygenic hazard score were compared to those with average PHS, their risk of aggressive prostate cancer was at least 2.9 times greater.”

“And when we account statistically for the effect of the GWAS having disproportionately high numbers of men with disease compared to the general population, we estimate that the risk defined by the polygenic hazard score is 4.6 times greater.”

The study authors note that an individual’s genotype does not change with age, so the polygenic hazard score can be calculated at any time and used as a tool for men deciding whether and when to undergo screening for prostate cancer. This is especially critical for men at risk of developing prostate cancer at a very young age, before standard guidelines recommend consideration of screening.

“This kind of genetic risk stratification is a step toward individualized medicine,” said Dale, who also noted that PSA tests are much more predictive of aggressive prostate cancer in men with high polygenic hazard score than in those with low polygenic hazard score. This suggests that polygenic hazard score can help physicians determine whether to order a PSA test for a given patient, in the context of the patient’s general health and other risk factors.

Investigators caution that further study of the clinical benefits are needed before the polygenic hazard score is ready for routine use.

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.”

Researchers Seek Blood Test for Early Lung Cancer Detection

Researchers at Rush University Medical Center are trying to answer that question by working to develop a blood test for early detection of lung cancer. National Institutes of Health awarded this endeavor a two-year $275,000 grant on Jan. 1.

The availability of a simple and cost-effective blood test could change early detection of lung cancer, which is often undiagnosed until symptoms become apparent in a more serious, advanced stage of the disease.

“Our goal is to improve the way lung cancer is diagnosed using a simple blood test to detect the disease earlier and reduce the number of late-stage diagnoses,” said biochemist Jeffrey A. Borgia, PhD. “We are aiming to identify those who are at a higher risk by looking for a specific ‘signature’ of cancer-specific molecules (or biomarkers) in the blood.

“Currently there are screening guidelines for those who are at risk — people who have a history of smoking and are 55 to 80 years old — but what about a nonsmoking young person who gets lung cancer?”

According to the American Cancer Society, as many as 20 percent of the people who die from lung cancer in the United States every year have never smoked or used any other form of tobacco. This translates to about 30,000 Americans in 2017.

Blood test would improve on and complement CT screenings

Currently, people at risk for lung cancer are advised to receive a low-dose computed tomography (CT) scan of their lungs to detect early-stage cancers.

“It is an effective screening tool, but most of the nodules we identify with CT scanning will turn out to be benign,” said Dr. Christopher Seder, a thoracic surgeon at Rush. “We are trying to develop a better way to determine whether the nodule is malignant or not.”

Also, while low-dose CT scanning currently is the best method for catching lung cancer early, the established guidelines for screening exclude many people who may still be diagnosed with the disease.

“The blood test ideally could be used as a detection method that will complement current CT imaging technology,” Borgia said.

Biomarkers are key to cancer test

Cancer cells release a series of proteins and other biomolecules into the bloodstream that are unique to the type of cancer, known as biomarkers.

Using one of the world’s largest institutional repositories of blood and tissue samples from patients with benign and malignant thoracic tumors at Rush, Borgia’s team has identified several biomarkers in the blood that may be able to identify non-small cell lung cancer with about 90 percent accuracy.

Thanks to the cell samples from patients — about 10 percent of whom fall outside current CT screening criteria — the team also is searching for biomarkers that could lead to a “prescreening” blood test designed to detect additional populations that might benefit from CT screening but do not meet current criteria, outlined above.

Rush University Medical Center has been on the leading edge of the lung cancer CT screening and lung cancer treatment. Rush is an American College of Radiology-designated screening center as well as a Lung Cancer Alliance Screening Center of Excellence.

Rush’s preventive low-dose screening program, created in 2015, resulted in more than 3 percent cancer diagnoses found at earlier stages than when lung cancers are typically found. For these early-stage cancers, Dr. Michael Liptay and his thoracic surgical colleagues at Rush were able to perform minimally invasive procedures that gave these patients a better chance at survival.

Beta Blockers May Boost Immunotherapy, Help Melanoma Patients Live Longer

A common, inexpensive drug that is used to prevent heart attacks and lower blood pressure may also help melanoma patients live longer.

Researchers at Penn State found that melanoma patients who received immunotherapy while taking a specific type of beta blocker lived longer than patients who received immunotherapy alone. In a follow-up experiment with mice, the researchers saw the same results.

Todd Schell, professor of microbiology and immunology at Penn State College of Medicine, said that because beta blockers are already widely available, the findings – published in the journal OncoImmunology – could indicate a simple way for physicians to better treat their patients.

“The type of beta blocker we found to be effective against melanoma – pan beta blockers – was actually the least prescribed,” Schell said. “Most patients are either prescribed beta 1 selective blockers or are not taking beta blockers at all. This means there’s a large population of patients who may be eligible to take pan beta blockers while being treated with immunotherapy. And because beta blockers are already FDA approved, it’s something we know is safe and can be very quickly implemented in patient care.”

Patients with metastatic melanoma, or melanoma that has spread to other parts of the body, often have a poor prognosis, and while some forms of immunotherapy – treatments that boost the body’s immune system to fight disease – are promising, response rates are less than 35 percent.

Previous research has shown that physiological stress prevents the immune system from fighting tumors effectively, while lower stress boosts the benefits of anti-cancer treatments. The researchers were curious about whether lowering stress with beta blockers would improve outcomes in patients treated with immunotherapies.

“Beta blockers slow your heart rhythm, but they can also affect immune cells and improve immune function,” Schell said. “We wanted to see if there would be a correlation between the beta blockers patients were taking for another condition and their response to immunotherapy. For metastatic melanoma, there are currently three different types of immunotherapy approved for use, and we specifically looked at that population of people.”

In studies developed by Dr. Kathleen Kokolus, a postdoctoral fellow, the researchers analyzed data from 195 metastatic melanoma patients who were treated with immunotherapy between 2000 and 2015, 62 of which were also taking beta blockers. They compared survival between the patients taking beta one-selective blockers, pan beta blockers and no beta blockers.

While there was little difference in how long patients taking beta one-selective blockers or no beta blockers lived, the results indicate that patients taking pan beta blockers lived significantly longer than the others. Five years after immunotherapy, about 70 percent of patients receiving pan beta blockers were still alive, versus about 25 percent of those taking beta one-selective blockers or no beta blockers at all.

To help explain the results, the team performed a parallel experiment in mice with melanoma. They treated the mice with immunotherapy and with or without the pan beta blocker propranolol. The researchers found that the propranolol significantly delayed tumor growth and increased survival when combined with immunotherapy.

Dr. Joseph Drabick, professor of medicine, said the results suggest that reducing physiological stress with beta blockers can help improve the effectiveness of immunotherapy and survival for melanoma patients.

“These new immunotherapies are great, but they don’t work for everyone,” Drabick said. “So how can we make these treatments better? We saw that for patients taking pan beta blockers, there was a dramatic improvement in survival, and we were able to duplicate these findings in mice and see the exact same phenomenon.”

Drabick also said the study was a good example of the benefits of finding new uses for drugs that have been around awhile.

“The benefit of this is that beta blockers already have a long history of safety in people, and they’re cheap and generic,” Drabick said. “And now they have the potential to augment some of these newer immunotherapy drugs to help people with cancer.”

Schell said that in the future, they’ll be working on a clinical trial to further explore and understand the role of beta blockers in treating cancer.

BriaCell Provides Clinical Update on its Lead Immunotherapy Drug in Advanced Breast Cancer

BriaCell, an immuno-oncology focused biotechnology company with a proprietary targeted immunotherapy technology, has provided a clinical update regarding its ongoing clinical trials of Bria-IMT™ (formerly referred to as SV-BR-1-GM).

BriaCell currently is enrolling patients in two separate but related clinical trials. Trial WRI-GEV-007 (listed in ClinicalTrials.gov as NCT03066947) is a Phase I/IIa clinical study designed to evaluate the safety and efficacy of Bria-IMT™ in metastatic or locally recurrent breast cancer patients.  In this study, Bria-IMT™ is given in a regimen including low-dose pre-dose cyclophosphamide (to reduce suppression of the immune response) and post-dose interferon-alpha (to boost the immune response).  The second clinical trial, BRI-ROL-001 (listed in ClinicalTrials.gov as NCT03328026), is a rollover study of Bria-IMT™ in combination with Keytruda® [pembrolizumab] or Yervoy® [ipilimumab].

Patient recruitment is on schedule despite interruption due to temporary shutdown of some clinical sites, affected by wildfires and hurricanes. Seven patients have enrolled in the WRI-GEV-007 clinical trial with 6 treated to date (1 patient dropped out after cyclophosphamide pre-treatment and did not receive Bria-IMT™). Based on results to-date, Bria-IMT™ has been very well tolerated and the majority of adverse events were limited to expected minor local irritation at the injection sites.  No serious adverse events related to Bria-IMT™ have been reported and no new or unexpected safety issues related to Bria-IMT™ have been observed.  The Phase I portion of the study has been successfully completed, and the Phase IIa portion is currently enrolling.

One patient is worth discussing in detail. This 73-year-old woman had breast cancer diagnosed in 1995.  She developed liver metastases in 2010, and then lung metastases in 2017. Prior treatments included surgery, radiation therapy, hormonal therapy and seven rounds of chemotherapy with 8 different chemotherapy agents. She received 5 cycles of Bria-IMT™ over the first 3 months of treatment, then 3 additional cycles over the following 3 months (6 months total).  Evaluation was performed after 3 months and 6 months. After 3 months, despite the extensive prior therapy, her scans noted that, “there has been a clear response in the multiple bilateral pulmonary nodules” indicating that several lung tumors had disappeared or decreased in size.  This response was maintained after 6 months of treatment with Bria-IMT™.  The liver tumors were stable to slightly increased at 3 months, and then progressed after 6 months.

Like the patient reported previously by Dr. Wiseman, BriaCell’s Scientific Founder, in a proof-of-concept clinical study, this patient is a double match with Bria-IMT™ at two specific biomarkers (HLA-A and HLA-DRB3).  This is highly significant, as it supports our BriaDX™ hypothesis that these biomarkers can be used to select the patients most likely to respond to Bria-IMT™ therapy.  We also noted in this patient that, while circulating tumor-associated cells decreased following the initial treatment, the expression of PD-L1, a molecule that suppresses the immune response, increased during treatment. This suggests that treating this patient (and other similar patients) with Bria-IMT™ in combination with a potent PD-1 inhibitor such as Keytruda® [pembrolizumab] may be a highly effective method to improve the efficacy of the treatment and patient outcomes.

A third clinical site was recently added to the study and several patients are being evaluated for the WRI-GEV-007 study. Discussions are ongoing with two additional clinical sites which are expected to be added in the near future. The combination rollover study, BRI-ROL-001, is available to enroll patients.

Other activities remain on track.  The companion diagnostic, BriaDX™, has been bolstered by the important supporting data for the HLA biomarker matching hypothesis noted above.  BriaCell is also developing an off-the-shelf, personalized immunotherapy (Bria-OTS™) to treat a much wider patient population (with ~90% of the population being a double-match with Bria-OTS™).  In collaboration with University of Zurich, Switzerland, BriaCell is testing other drugs/product candidates that are expected to boost the effectiveness of Bria-IMT™ and Bria-OTS™.

Ongoing work in the small molecule program to select protein kinase C delta inhibitors for cancer and fibrotic diseases is also progressing according to our timelines. The medicinal chemistry work is being performed at Colorado State University where the current library of compounds available is being augmented.

BriaCell is an immuno-oncology focused biotechnology company developing a targeted and safe approach to the management of cancer. Immunotherapy has come to the forefront of the fight against cancer, harnessing the body’s own immune system in recognizing and selectively destroying cancer cells while sparing normal ones. Immunotherapy, in addition to generally being more targeted and less toxic than commonly used types of chemotherapy, is also thought to be a potent approach with the potential to prevent cancer recurrence.

Bria-IMT™ (SV-BR-1-GM), the Company’s lead product candidate, is derived from a breast cancer cell line genetically engineered to release granulocyte-macrophage colony-stimulating factor (GM-CSF), a substance that activates the immune system by allowing the body to recognize and eliminate cancerous cells by inducing tumor-directed T cell and potentially antibody responses.

The results of two previous proof-of-concept clinical trials (one with the precursor cell line not genetically engineered to produce GM-CSF and one with Bria-IMT™) produced encouraging results in patients with advanced breast cancer. Most notably, one patient with metastatic breast cancer responded to Bria-IMT™ with substantial reduction in tumor burden including breast, lung, soft tissue and brain metastases. The company is currently conducting a Phase I/IIa clinical trial for Bria-IMT™ in patients with advanced breast cancer.  This trial is listed in ClinicalTrials.gov as NCT03066947.  The trial is being conducted along with the co-development of BriaDX™, the Company’s companion diagnostic test. The interim data for the first 10 patients is expected by the first quarter of 2018. Additionally, the FDA recently approved the roll-over combination study of Bria-IMT™ with pembrolizumab [Keytruda; manufactured by Merck & Co., Inc.] or ipilimumab [Yervoy; manufactured by Bristol-Myers Squibb Company] for patients previously treated with Bria-IMT™ in the Company’s ongoing Phase I/IIa clinical trial in advanced breast cancer. The roll-over trial is listed in ClinicalTrials.gov as NCT03328026.

BriaCell is also developing Bria-OTS™, an off-the-shelf personalized Immunotherapy.  Bria-OTS™ consists of 14 individually pre-manufactured genetic alleles. BriaCell’s BriaDX™ companion diagnostic reveals a patient’s specific HLA-types and the 2 best matching alleles are administered to the patient. BriaCell’s 14 alleles (8 Class I and 6 Class II) cover approximately 90% of the Breast Cancer population while eliminating the complex manufacturing logistics required for other personalized immunotherapies. Bria-OTS™ is a personalized therapy without the need for personalized manufacturing.

BriaCell is also developing novel, selective protein kinase C delta (PKCδ) inhibitors. PKCδ inhibitors have shown activity in a number of pre-clinical models of RAS genes’ transformed cancers including breast, pancreatic, non-small cell lung cancer and neuroendocrine tumors (such as carcinoid tumors).

For additional information on BriaCell, please visit our website: http://briacell.com.

Researchers Detect a Loophole in Chronic Lymphocytic Leukemia Treatment

A team of researchers in Italy and Austria has determined that a drug approved to treat chronic lymphocytic leukemia (CLL) may be less effective in a particular subset of patients. The study, which will be published January 4 in the Journal of Experimental Medicine, reveals that ibrutinib has a diminished capacity to delocalize and kill tumor cells expressing an adhesive protein called CD49d, but combining ibrutinib treatment with drugs that block CD49d activation could prevent the tumor cells from sheltering in lymphoid organs.

CLL is the most common leukemia in adults, and it is characterized by the presence of cancerous B cells that accumulate in the lymph nodes, spleen, and liver. Ibrutinib reallocates CLL cells from lymph nodes into the blood by inhibiting Bruton’s tyrosine kinase (BTK), a key enzyme in the B cell receptor (BCR) signaling pathway.

BCR signaling promotes the survival and differentiation of normal, healthy B cells in several ways, including by activating the adhesion receptor VLA-4, which attaches B cells to other, supportive cells within lymph nodes. One of the subunits of VLA-4, CD49d, is highly expressed in about 40% of CLL patients. These patients tend to have poorer outcomes than patients that do not express CD49d, but the role of VLA-4 in CLL is unclear.

A team of researchers led by Antonella Zucchetto and Valter Gattei of the CRO Aviano National Cancer Institute in Italy and Tanja Nicole Hartmann of the Paracelsus Medical University in Salzburg, Austria, found that BCR signaling can activate VLA-4 in CD49d-expressing CLL cells, thereby enhancing the cells’ adhesiveness. Even though ibrutinib treatment impaired BCR signaling in these cells, it was unable to fully hinder the pathway from activating VLA-4 and enhancing cell adhesion.

The researchers analyzed three different cohorts of CLL patients from Italy and the United States. In all three groups, patients expressing higher levels of CD49d showed reduced responses to ibrutinib treatment: the drug appeared to be less able to displace tumor cells from lymph nodes into the blood, resulting in decreased lymph node shrinkage and shorter progression-free survival times.

“Our results suggest that VLA-4–expressing CLL cells residing in the secondary lymphoid organs can receive BCR-mediated stimuli that can activate VLA-4 even in the presence of ibrutinib,” says Zucchetto. “This activation leads to enhanced retention of VLA-4–positive CLL cells in tissue sites, thereby affecting patient outcome.”

In addition to the ibrutinib target BTK, BCR signaling can proceed through an alternative enzyme called phosphatidylinositide 3-kinase. The researchers found that simultaneously inhibiting both BTK and phosphatidylinositide 3-kinase completely blocked VLA-4 activation in CLL cells.

“Our data suggest that evaluation of CD49d expression in patients initiating ibrutinib therapy may identify those cases that would benefit from combination therapy approaches designed to completely block VLA-4 activation and VLA-4–mediated retention of leukemic cells in protective tissue compartments,” says Gattei.

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.”

How Defeating THOR Could Bring a Hammer Down on Cancer

It turns out Thor, the Norse god of thunder and the Marvel superhero, has special powers when it comes to cancer too.

Researchers at the University of Michigan Comprehensive Cancer Center uncovered a novel gene they named THOR while investigating previously unexplored regions of the human genome – the dark matter of the human genome.

They characterized a long non-coding RNA (lncRNA) that is expressed in humans, mice and zebrafish. It’s unusual for this type of RNA to be conserved throughout species like this. The team’s thinking was that if the RNA plays a role in other animals and species besides humans, it must be important.

“Genes that are evolutionarily conserved are likely important for biological processes. The fact that we found THOR to be a highly conserved lncRNA was exciting. We chose to focus on it with the thought that it has been selected by evolution for having important functions,” says Arul Chinnaiyan, M.D., Ph.D., director of the Michigan Center for Translational Pathology and S.P. Hicks Professor of Pathology at Michigan Medicine.

In fact, the researchers found this particular lncRNA plays a role in cancer development. And that knocking it out can halt the growth of tumors.

This is the first group to identify and characterize THOR, which stands for Testis-associated Highly-conserved Oncogenic long non-coding RNA. They published their results in Cell.

It’s an early example of how this previously unexplored portion of the genome could lead to a potential new way of attacking cancer.

In 2015, Chinnaiyan’s team published a paper analyzing the global landscape of lncRNAs, which had been considered dark matter because so little was known about it. They identified thousands of potential lncRNAs that might warrant future study.

THOR rose to the top of the list because it was evolutionarily highly conserved. It was also highly expressed, specifically in testes cells. It had little to no expression in other types of adult normal tissue.

Because THOR is highly conserved, researchers were able to study it in mice and zebrafish, as well as in human cells.

“That is one of the challenges of studying lncRNAs that are not conserved. If they’re not conserved in model systems, they are difficult to characterize. Here, because THOR is so highly conserved, we were able to look at its expression and function in zebrafish models,” Chinnaiyan says.

In addition to finding THOR expression in normal testis tissue, the researchers found it was highly expressed in some subsets of cancers, particularly lung cancer and melanoma. As they investigated THOR, they found its expression had a direct impact on cancer development. If they knocked down THOR in cell lines expressing it, tumor growth slowed. If they overexpressed THOR, cells grew faster. And when they eliminated THOR from normal cells, the cells continued to develop normally, suggesting it only impacts cancer cells.

“We’ve gone through a lot of lncRNAs to get to that. Most of the ones we test don’t have a clear function like this,” Chinnaiyan says.

Researchers also found that THOR impacted proteins called IGFBPs, which are thought to be involved in stabilizing RNAs. Knocking down THOR inhibited IGFBP activity.

“If we perturb THOR function, we disturb the ability to stabilize RNA. This inhibits cell proliferation,” Chinnaiyan says. Conversely, when researchers overexpressed THOR, cells grew faster.

Chinnaiyan suggests THOR could be a good target for drug development because blocking it does not impact normal cells. That would likely mean fewer toxic side effects. In future studies, the researchers will look at how to create a compound that binds with THOR in a complimentary sequence designed to knock it down. This approach, known as antisense oligonucleotides, has been used successfully in other contexts.

UK Study Finds Biomarker Targets to Make Drugs More Effective in Fighting Cancer

A new study published in Nature Communications and led by University of Kentucky Markey Cancer Center researcher Qing-Bai She identifies biomarker targets that may make existing drugs more effective in fighting certain cancers.

The mTOR protein is a central regulator of cell growth and division. Abnormal activation of mTOR protein results in limitless cell division in many human cancers. Though mTOR-targeted drugs exist, their effectiveness has so far been limited, possibly due to the loss of the mTOR downstream effector 4E-BP1, a key repressor of protein production.

The study identifies Snail, a nuclear transcription regulator known to promote cancer progression, as a strong repressor of 4E-BP1 expression. She’s team found an inverse correlation between Snail and 4E-BP1 levels in colorectal cancer, the second leading cause of cancer-related mortality in the United States. This study shows promise that the Snail level may serve as a predictive marker to tailor personalized treatments using mTOR-targeted drugs. Physicians may be able to prescribe treatment for cancers that have high Snail/low 4E-BP1 activities, using cancer drugs that are already in clinical development.

“This finding has significant clinical ramification, because incorporating the analysis of Snail and 4E-BP1 expression in cancers may help to prospectively identify resistance to mTOR-targeted drugs in the clinic,” said She, associate professor in the UK Department of Pharmacology & Nutritional Sciences.

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.

Combination Strategy Could Hold Promise for Ovarian Cancer

 Johns Hopkins Kimmel Cancer Center researchers demonstrated that mice with ovarian cancer that received drugs to reactivate dormant genes along with other drugs that activate the immune system had a greater reduction of tumor burden and significantly longer survival than those that received any of the drugs alone.

The study already spurred a clinical trial in ovarian cancer patients. The investigators, led by graduate student Meredith Stone, Ph.D.; postdoctoral fellow Kate Chiappinelli, Ph.D.; and senior author Cynthia Zahnow, Ph.D., believe it could lead to a new way to attack ovarian cancer by strengthening the body’s natural immune response against these tumors. It was published in the Dec. 4, 2017, issue of the Proceedings of the National Academy of Sciences.

Ovarian cancer is currently the leading cause of death from gynecological malignancies in the U.S. “We’ve taken two types of therapies that aren’t very effective in ovarian cancer and put them together to make them better at revving up the immune system and attacking the tumor,” says Zahnow, associate professor of oncology at the Johns Hopkins Kimmel Cancer Center.

Zahnow says that a class of immunotherapy drugs known as checkpoint inhibitors, currently being studied at the Bloomberg~Kimmel Institute for Cancer Immunotherapy, helps the immune system recognize cancers and fight them off. The drugs have shown success in treating melanoma, nonsmall cell lung cancer and renal cell cancers, but they have had only modest effects on ovarian cancer.

Similarly, another class of drugs known as epigenetic therapies has been used to treat some types of cancer by turning on genes that have been silenced— either by the presence of chemical tags, known as methyl groups, or by being wound too tightly around protein spools, known as histones—but these drugs haven’t been effective against ovarian cancer either.

Zahnow and her colleagues became inspired to investigate a new way to treat ovarian cancer by two recent publications from their group that showed epigenetic drugs turn on immune signaling in ovarian, breast and colon cancer cells (Li et al., Oncotarget 2014). These immune genes are activated when epigenetic therapy turns on segments of ancient retroviruses that activate type 1 interferon signaling in the cells (Chiappinelli et al., Cell 2015).  Stone, Chiappinelli and Zahnow wanted to know if this increase in immune signaling could lead to the recruitment of tumor killing immune cells to the cancer.

Zahnow and her colleagues worked with a mouse model of the disease in which mouse ovarian cancer cells are injected into the animals’ abdomens to mimic human disease. These cells eventually develop into hundreds of small tumors, which cause fluid to collect within the abdomen, a condition known as ascites. Floating in this fluid is a milieu of both cancer and immune cells, offering a convenient way to keep tabs on both the tumor and the animals’ immune response.

The researchers started by pretreating the ovarian cancer cells outside of the animal in a culture dish with a DNA methyltransferase inhibitor (a drug that knocks methyl groups from DNA) called 5-azacytidine (AZA). After injecting these cells into mice, the researchers found that animals receiving the pretreated cells had significantly decreased ascites or tumor burden and significantly more cancer-fighting immune cells in the ascites fluid compared to those injected with untreated cells. These cells also had increased activity in a variety of genes related to immune response. Pretreating these cells with histone deacetylase inhibitors (HDACis), which help DNA uncoil from histones, didn’t affect the animals’ ascites or boost their immune response.

These early findings suggested that changes in gene activity induced by AZA cause the tumor cells themselves to summon immune cells to their location. In addition, when the researchers transplanted untreated cells into mice and treated the animals with both AZA and an HDACi, significantly more immune cells were in the ascites fluid, suggesting that the HDACi was acting on the animals’ immune systems. These mice also had decreased ascites, lower tumor burden and longer survival than mice that received just AZA.

When the researchers treated the mice with both AZA and an HDACi, along with an immune checkpoint inhibitor, they got the greatest response—the highest decreases in ascites and tumor burden, and the longest survival. Further experiments using immunocompromised mice showed that the immune system is pivotal to the action of these drugs, rather than the drugs themselves acting directly to kill tumor cells.

“We think that AZA and the HDACis are bringing the soldiers, or immune cells, to the battle. But the checkpoint inhibitor is giving them the weapons to fight,” says Zahnow, who also collaborated with epigenetics scientist Stephen Baylin, M.D., on this project.

The preclinical data generated through this study is already being used to help patients with ovarian cancer through an ongoing clinical trial to test the effectiveness of combining AZA and a checkpoint inhibitor. Future trials may add an HDACi to determine if it affects outcomes.

“Combining epigenetic therapy and a checkpoint blocker leads to the greatest reduction in tumor burden and increase in survival in our mouse model and may hold the greatest promise for our patients,” says Zahnow.

Researchers show stress suppresses response to cancer treatments

New research shows that chronic stress suppresses the immune system’s response to cancer, reducing the effectiveness of immunotherapy treatments.

University of Queensland scientists say they are investigating dual therapies for patients to reduce stress signalling and improve their response to treatments.

UQ Diamantina Institute researcher Dr Stephen Mattarollo said lymphoma progressed more rapidly in mouse models when stress pathways were induced to reflect chronic psychological stress.

“When we used immunotherapies on these mice they were not able to respond as effectively as those which had not been stressed,” Dr Mattarollo said.

“This is because the stress led to poor function against the cancer by T-cells, which are very important in the immune system’s control and surveillance of tumours and are a major target in many immunotherapy treatments.”

Dr Mattarollo said increased anxiety was natural with a cancer diagnosis, and it should be managed to ensure the best possible outcome for patients.

“Absolutely there is now pre-clinical evidence to suggest that treatments and lifestyle interventions to manage or reduce stress levels will improve the chances of these patients responding to therapies,” he said.

“This applies particularly to immunotherapies, but many conventional therapies such as chemotherapy also rely on components of the immune system for their effectiveness.

“It is quite possible that by increasing the immune function in patients they will also respond better to some other therapies.”

PhD candidate Michael Nissen said as immunotherapies became more widely available, it was important to build on the knowledge of factors which influence their effectiveness.

“The more we know, the better chance we have of designing them effectively and efficiently to work in cancer patients,” Mr Nissen said.

Dr Mattarollo said the lab was hoping to combine immunotherapy treatments with commonly used blood pressure drugs that block the effects of stress hormones.

“We hope this will reduce the stress-induced neural signalling and improve immune function,” Dr Mattarollo said.

“We are about to test this combination in animal models.”

Dr Mattarollo said psychoneuroimmunology – or the interaction between the mind, the nervous system and the immune system – is a rapidly growing discipline and is becoming an increasing focus of the lab’s cancer research.

The research is published in Cancer Immunology Research.

Dr Mattarollo’s lab is located at the Translational Research Institute.

New strategy for multiple myeloma immunotherapy

In recent decades monoclonal antibody-based treatment of cancer has been established as one of the most successful therapeutic strategies for both solid tumors and blood cancers. Monoclonal antibodies (mAb), as the name implies, are antibodies that are made by clonal cells derived from a single parent cells and therefore share the identical amino acid sequences.

One of the leading technologies to emerge in mAb-based treatment is CAR-T, where CAR stands for “chimeric antigen receptor”, and T represents T cells, a type of white blood cells that have pivotal roles in immune defenses. CARs are produced by combining together the gene for an antibody that recognizes a tumor antigen with the gene for a receptor that resides on the surface of the T cells; insert this new gene into a T cell and it will be precisely targeted at the tumor.

Theoretically, new antigens – molecules capable of inducing an immune response to produce an antibody – that arise from cancer-specific mutations of cell-surface proteins are excellent targets. However, mAb therapy targeting such antigens is impractical because of these proteins’ vast diversity within and between individual tumors, which renders identifying new cancer-specific target antigens difficult.

However, such challenges have driven researchers centered at Japan’s Osaka University to think outside of the box; cancer-specific antigen formed by the modification of proteins during or after synthesis, such as glycosylation (attachment of sugar moieties to protein) or conformational changes, might have been missed in previous analyses. The team believed new antigen epitopes, which is the part of an antigen recognized by the immune cells, could be discovered by thoroughly searching for cancer-specific mAbs and characterizing the antigens they recognize.

“We applied this strategy to identify novel therapeutic targets for multiple myeloma (MM), a cancer that forms in a type of white blood cell called a plasma cell,” explains Naoki Hosen, lead author of the study, which was recently published in Nature Medicine. “Despite advances in MM treatment, relapse remains common. As such, there is an ongoing need for new therapeutic approaches, including mAb-based therapies.”

The team screened more than 10,000 anti-MM mAb clones and identified MMG49 as an MM-specific mAb specifically recognizing a subset of integrin β7, a cell-surface receptors that facilitate cell-extracellular matrix adhesion. MMG49 reacted to MM cells, but not other bone marrow cell types in MM patient samples. This prompted the researchers to design a CAR that incorporates a fragment derived from MMG49. The resulting MMG49 CAR T was found to have anti-MM effects without damaging normal blood cells.

“Our results also demonstrate that the active conformer of integrin β7 can serve as an immunotherapeutic target against MM, even though the expression of the protein itself is not specific to MM,” study coauthor Yukiko Matsunaga says. “Therefore it’s highly plausible that there are other cancer immunotherapeutic targets that have yet to be identified in many cell-surface proteins that undergo conformational changes, even if the expression of the proteins themselves is not cancer-specific.”