Biomarkers Pinpoint the Effects of Thirdhand Smoke on Liver and Lung Found to Worsen Over Time

Researchers at the University of California, Riverside have found that thirdhand-smoke (THS) exposure has a significant effect on health as early as one month after initiation of exposure – an effect that worsens with time.

THS results when exhaled smoke and smoke emanating from the tip of burning cigarettes gets on surfaces such as clothing, hair, homes, and cars. THS has been shown, in mice, to cause type 2 diabetes, hyperactivity, liver and lung damage, and wound-healing complications.

Using a system in which the exposure of mice to THS mimics that of human exposure in the homes of smokers, the researchers investigated the effects of THS exposure on biological molecular markers – or “biomarkers” – found in serum, and in liver and brain tissues. The liver plays a major role in metabolism and detoxification; the brain plays significant roles in behavior.

Thirdhand smoke results when exhaled smoke and smoke emanating from the tip of burning cigarettes gets on surfaces such as clothing, hair, homes, and cars.Photo credit: UCR University Communications.

Our goal was to determine the minimum amount of time required to cause physiological changes in mice when they are exposed to THS, using an exposure system that mimics human exposure,” said Manuela Martins-Green, professor and chair of the Department of Molecular, Cell and Systems Biology, who led the research. “We found that THS exposure as early as one month resulted in liver damage. THS exposure for two months resulted in further molecular damage, and at four to six months caused even more such damage. We also found that the mice showed insulin resistance after long-term THS exposure.”

Damage to the liver can hinder its capability to detoxify the body, leading to more damage by THS toxins. Martins-Green and her team examined the brains of THS-exposed mice and found that stress hormones, such as epinephrine, increased in one month of exposure. Additional stress hormones are seen at two months, four months, and six months, eventually causing immune fatigue in the mice.

Study results appear in Clinical Science, a Portland Press journal.

“THS is a stealth toxin, a silent killer,” Martins-Green said. “Contaminants can be absorbed through the skin and through breathing. Although our research was not done on humans, people should be aware that hotel rooms, cars, and homes that were occupied by smokers are very likely to be contaminated with THS.”

Most people are either unaware they are being exposed to THS, or don’t believe in the damage THS can do, according to Martins-Green. THS toxins, which are invisible but can be smelled, remain on surfaces for many years, and are resistant to even strong cleaning agents. Further, they accumulate and age by reacting with the ambient air, and change into carcinogenic chemicals.

Because THS is absorbed through skin, children are especially vulnerable given their close contact with household surfaces. Children frequently ingest these toxins by putting their hands in their mouths. They also absorb them through the skin. Children living in the homes where smoking has occurred have been known to show tobacco metabolites in their urine as well as tobacco-derived carcinogens called tobacco specific nitrosamines.

“Exposure to tobacco smoke deposited on surfaces in homes and in house dust is an entirely newly recognized form of toxicity: THS,” said Stephen T. Holgate, the Medical Research Council Clinical Professor of Immunopharmacology and Honorary Consultant Physician within Medicine at the University of Southampton, England, who was not involved in the research. “The fact that noxious chemicals in tobacco smoke once deposited change in chemistry to become even more toxic and carcinogenic is of considerable importance to the health of all of us, but our children in particular. The studies of this Californian research team puts further pressure on those who continue to smoke in homes to realize what they are doing to the health of others, as well as mandating a search for methods to remove such products from furnishings and materials used in homes. This study adds to the increasing concerns of chemical exposures in the home and the serious adverse effects this may cause.”

Martins-Green and her team exposed mice to THS for up to six months, collecting brain, liver, and serum samples after one, two, four, and six months of exposure to test for hormonal alterations, insulin resistance, metabolic syndrome, and damage to the liver and brain. To produce THS, the researchers exposed common household fabrics such as curtain material, upholstery, and carpet to secondhand smoke (smoke that is exhaled and that leaves a burning cigarette) that was generated in the lab by a smoking machine devised to mimic the behavior of human smokers. These materials were then placed in cages housing the mice, which were never exposed to secondhand smoke). The researchers then tested 15 biomarkers of damage and disease associated with THS exposure in serum and nine biomarkers in liver and brain tissue of the mice in a time-dependent manner.

“We found a positive time-dependent significant correlation with increased time of THS exposure and the effects it had on all the variables we measured,” Martins-Green said. “These biomarkers, once validated in humans, can be used as critical indicators of exposure to THS, and how long this exposure has occurred.”

In other preliminary experiments, Martins-Green and her team found that mice exposed to THS are less social than unexposed mice. Insulin problems arising because of THS are seen to worsen with the Western diet. Further, the researchers found that over time the mice get addicted to THS.

“Clearly, THS is affecting the behavior of mice,” said Martins-Green, who plans to write a review paper on the health impacts of THS. “It’s not hard to imagine what the impact is on children who, unlike most adults, cannot remove themselves from these harmful environments. Although our work was done on mice, we are confident our results will apply to humans.”

New research on probiotics in the prevention and treatment of colon cancer

In an innovative approach to colorectal cancer (CRC) prevention and treatment, scientists are studying ways to replace missing metabolites in patients prone to gut inflammation and CRC. A new study in The American Journal of Pathology describes how administration of histamine-producing gut microbes to mice lacking the enzyme histidine decarboxylase (HDC) reduced inflammation and tumor formation. These results suggest that alteration of the gut microbiome with probiotics may become a new preventative or therapeutic strategy for patients at risk for inflammatory bowel disease (IBD)-associated CRC.

“We are on the cusp of harnessing advances in microbiome science to facilitate diagnosis and treatment of human disease,” explained James Versalovic, MD, PhD, pathologist-in-chief at Texas Children’s Hospital, and Milton J. Finegold Professor of pathology & immunology at Baylor College of Medicine (Houston). “By simply introducing microbes that provide missing life substances, we can reduce the risk of cancer and supplement diet-based cancer prevention strategies.”

Researchers conducted a series of experiments using mice that were deficient in HDC, the enzyme required to convert histidine to histamine. Experimental mice were orally administered the probiotic Lactobacillus reuteri 6475, which is known to possess the histidine decarboxylase gene (hdc+) and is able to convert histidine to histamine; control animals received a placebo. The probiotic was administered both before and after the mice received a single dose of a colonic carcinogen (azoxymethane) plus an inflammation-inducing chemical (DSS) to induce tumor formation. Fifteen weeks later, the mice were sacrificed and the tissues removed for study.

The probiotic increased expression of bacterial HDC and amounts of histamine in the colons of the mice. Using positron emission tomography (PET) to visualize the tumors, control-treated mice showed evidence of tumors and increased glucose uptake in colon walls. In contrast, mice administered the probiotic had fewer and smaller tumors and significantly diminished areas of glucose uptake.

Inactive L. reuteri strains (those deficient in HDC activity) did not provide protective effects. These mice showed increased numbers of “hot spots” indicative of tumor formation and increased abdominal glucose uptake.

The active probiotic also reduced inflammation induced by the carcinogen plus DSS, as indicated by suppressed pro-inflammatory cytokine gene expression (i.e., those encoding KC, interleukin (IL)-22, IL-6, tumor necrosis factor (TNF), and IL-1α) and reduced cytokine concentrations in plasma (i.e., KC, IL-22, and IL-6). The active probiotic also counteracted an increase in immature myeloid cells induced by the carcinogen. According to Dr. Versalovic, “These observations are consistent with the conclusion that histamine-generating probiotic L. reuteri may attenuate AOM+DSS-induced colon carcinogenesis, at least in part, via enhanced maturation of circulating myeloid cells and concomitant reduction of pro-inflammatory cytokines.”

The role of histamine in human cancer is still unclear. However, when investigators analyzed data obtained from 2,113 CRC patient samples taken from 15 datasets, results showed better survival in patients with elevated patterns of HDC and histamine receptor gene expression. These findings indicate that histamine-generating probiotics, in the presence of sufficient protein (L-histidine) intake, may improve outcomes for patients with sporadic and IBD-associated CRC.

“Our results suggest a significant role for histamine in the suppression of chronic intestinal inflammation and colorectal tumorigenesis. We have also shown that cells, both microbial and mammalian, can share metabolites or chemical compounds that together promote human health and prevent disease,” said Dr. Versalovic.

Immunotherapy treatment option for selected breast cancer patients, genetic study suggests

Immunotherapy drugs could help some breast cancer patients based on the genetic changes in their tumours, researchers at the Wellcome Trust Sanger Institute and their collaborators find. Published today (13 September) in Cancer Research, scientists identify particular genetic changes in a DNA repair mechanism in breast cancer.

The results open up the possibility to another therapy option for around 1,000 breast cancer patients in the UK, who could benefit from existing drugs.

Breast cancer is the most common cancer in the UK, affecting nearly 55,000 women a year. Globally it accounts for nearly 1.7 million cancer cases.

In the study, scientists found that a particular group of breast cancer patients have genetic changes, or mutations, that occur because of an abnormality of a DNA repair mechanism known as mismatch repair*. These mutations are found in other cancers, such as colorectal cancer, but are rarely looked for in breast cancer.

Colorectal cancers with deficient mismatch repair have recently been treated with immunotherapies called checkpoint inhibitors in the US**, including the drug pembrolizumab. Immunotherapies exploit the fact that, under the influence of check point inhibitors, highly mutated tumour cells can be recognised as ‘foreign’ by the patient’s immune system.

The results of this new study suggest that these immunotherapies could also be effective for some breast cancer patients based on the same mutation patterns seen in their tumours. Therefore clinical trials are required to determine if immunotherapies could help selected breast cancer patients.

In the study, the team analysed the whole genome sequences of 640 breast cancer tumours. They looked for patterns in the mutations, known as mutational signatures, which indicated abnormalities in the mismatch repair mechanism. From the mutational signatures, the team identified 11 tumours that had the mismatch repair defects causing the breast cancer.

Dr Serena Nik-Zainal, lead author from the Wellcome Trust Sanger Institute, said: “We’ve unequivocally found mismatch repair deficient breast cancers. As these tumours have the same mutational signatures as those of other cancers, like colorectal cancer, they should in theory respond to the same immunotherapy drugs. Our results suggest expanding the cohort of cancer patients that could possibly be treated with checkpoint inhibitors to include these mismatch repair deficient breast cancer patients.”

Dr Helen Davies, first author from the Wellcome Trust Sanger Institute, said: “Using whole genome sequencing we can start to stratify breast cancer patients into different categories based on their mutational signatures. Current clinical criteria means these tumours would not have been detected as being deficient in the mismatch repair pathway. We have shown that there is in fact another category of breast cancers – those with defective mismatch repair.”

Professor Karen Vousden, Cancer Research UK’s chief scientist, said: “Immunotherapies have shown promise for some cancer patients, but the challenge for doctors has been predicting which patients they are likely to help. This study, using a technique called whole genome sequencing, reveals more about the genetic patterns that could show which women with breast cancer are more likely to respond to immunotherapy treatments. The next step will be to test this approach in clinical trials to find out if identifying these patterns and using them to tailor breast cancer treatments helps to improve survival.”

Modulating T-Cell Metabolism Uncovers New Technology for Enhancing Immunotherapy

T lymphocytes found in tumors and implicated in killing tumor cells cope with the shortage of oxygen and nutrients in the tumor microenvironment by using fat as the main source of energy. Promoting a switch from glucose to fatty acid to generate energy enhances T cell antitumor activity. These findings from a study conducted at The Wistar Institute were published in the journal Cancer Cell.

The presence of tumor infiltrating T lymphocytes (TILs) in solid tumors is often associated with better clinical outcomes and better patient responses to some immunotherapeutic treatments. These cells can be isolated from a cancer patient, manipulated ex vivo, and infused into the same patient to treat her/his own cancer. However, the effectiveness of TILs antitumor responses is limited by their progressive loss of functions. Metabolic stress plays a central role in the exhaustion of T cells as they compete with tumor cells for oxygen and nutrients in the tumor microenvironment. In these unfavorable conditions, the function of TILs is impaired, reducing their potency against the tumor and the efficacy of T cell-based immunotherapy.

“The mechanisms behind TILs exhaustion are poorly understood,” said lead author of the study Hildegund C.J. Ertl, M.D., Caspar Wistar Professor in Vaccine Research and member of Wistar’s Vaccine & Immunotherapy Center. “Considering the central importance of TILs for cancer immunotherapy, we believe that our findings may have critical implications to boost the efficacy of T cell-based therapies.”

This study by Ertl and colleagues shows that low oxygen levels combined with low glucose availability cause TILs to adapt their metabolism and change their source for energy production from glucose to fatty acids, the building blocks of fat. Further inducing this metabolic shift instructs the T cells to increase their use of fatty acids for energy production, thus improving TILs’ effector functions and their ability to delay tumor progression.

The Ertl lab studied the effectiveness of metabolic manipulations to improve TIL functions in two melanoma mouse models and in the context of two different immunotherapy approaches. Ertl and colleagues confirmed the clinical relevance of these observations by showing that T cells isolated from metastases of melanoma patients have increased fatty acid metabolism compared with circulating lymphocytes from healthy donors. Furthermore, using fibrates, a class of FDA approved drugs used to lower cholesterol levels, they promoted the breakdown of fatty acids and observed that this enforced metabolic switch is associated with improved T cell functions within tumors. Importantly, these drugs can also synergize with immune checkpoint blockade therapy, improving the efficacy of this melanoma immunotherapy.

“Pharmacological interventions aimed at promoting the metabolic adaptation of TILs towards fatty acid metabolism may have a broad implication for T cell-based immunotherapy for different cancer types,” added Ertl.

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.

KEYNOTE-040 evaluates pembrolizumab in head and neck cancer

Immunotherapy with the checkpoint inhibitor pembrolizumab may be a better option than standard treatments for patients whose head and neck cancer has spread, or recurred after an initial round of chemotherapy, according to results of the Keynote-040 trial presented at the ESMO 2017 Congress in Madrid. (1)

Although the 19% improvement in overall survival among patients treated with pembrolizumab did not meet the prespecified difference for statistical significance, it was nevertheless a clinically meaningful difference for this population who only lived seven to eight months, on average, after initiating treatment, said lead investigator Dr. Ezra Cohen, from the University of California, San Diego Moores Cancer Center, in La Jolla, California.

“Even though the study did not meet its primary endpoint, I still think it is a positive trial,” he said. “It reinforces that pembrolizumab should continue to be offered as an important option for all patients with this devastating disease.”

The KEYNOTE-040 trial was a global, open-label, phase 3 study which included patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) after a platinum-based chemotherapy.

Patients were randomised to receive either pembrolizumab (n=247) or standard of care (SOC) treatment (n=248), which was the investigator’s choice of either methotrexate, docetaxel, or cetuximab.

Median overall survival (OS) was only marginally higher in the pembrolizumab compared to standard treatment arm (8.4 versus 7.1 months, hazard ratio [HR] 0.81 95% CI 0.66-0.99, P= .0204), however for a subset of patients who had PD-L1-expressing tumours, pembrolizumab was associated with dramatic and significantly improved outcomes.

Specifically, among patients with combined tumour and immune cell PD-L1-expression (CPS) of at least 1%, median OS was 8.7 months with pembrolizumab versus 7.1 months with standard treatments (HR 0.75; 95% CI 0.59-0.95, P=.0078), and among patients with PD-L1-expression in more than 50% of their cancer cells, median OS was 11.6 versus 7.9 months respectively (HR 0.54; 95% CI 0.35-0.82, P=.0017).

Compared to the other treatments, pembrolizumab measured up well in terms of side-effects.

“In almost every category it had a better side-effect profile, meaning a lower incidence of toxicity, versus standard treatments,” said Cohen. “The exception is hypothrodism, which occurred in 13% of those treated with pembro versus only 1% of those given other treatments.”

Overall, Cohen said the KEYNOTE-040 trial reinforces what is already known about anti-PD therapy in head and neck cancer. “From a clinician’s perspective I would feel the same in any country. This is a meaningful therapy that improves survival.”

Asked to comment for ESMO, Dr. Amanda Psyrri, from the University of Athens Medical School, and Attikon University Hospital in Athens said: “Keynote-040 did not reach its primary endpoint of overall survival; however, pembrolizumab was superior to investigator’s choice in terms of toxicity, an important consideration in treatment decisions for these poor-prognosis patients with recurrent/metastatic platinum-refractory HNSCC. As the authors point out, subsequent immunotherapy in the SOC arm may have confounded OS analysis. The magnitude of treatment effect was greater in patients with PD-L1 combined positive score (CPS) ? 1%, especially those with CPS ?50%,suggesting that pembrolizumab may represent the preferable treatment option for this subset of patients.”

Cancer Immunotherapy May Get a Boost by Disabling Specific T Cells

Cancer immunotherapy drugs only work for a minority of patients, but a generic drug now used to increase blood flow may be able to improve those odds, a study by Columbia University Medical Center (CUMC) researchers suggests.

In mice with melanoma, the researchers found that the drug – called pentoxifylline – boosts the effectiveness of immune-checkpoint inhibitors, a type of immunotherapy now commonly used in the treatment of melanoma and other cancers.

The study was published today in the online edition of Cell.

Checkpoint-blockade immunotherapy drugs – the first drugs were approved in 2011 – target proteins on tumor cells or cells of the immune system that prevent “killer” T cells from attacking cancer. These drugs have revolutionized cancer care, but do not work for all patients. “In advanced melanoma, for example, the cure rate is only about 20 percent. That’s a remarkable improvement over previous therapies,” says study leader Sankar Ghosh, PhD, Chair and Silverstein and Hutt Family Professor of Microbiology & Immunology. “But why doesn’t it work for the other 80 percent? There must be another mechanism that contributes to the suppression of the immune response.”

Dr. Ghosh and other cancer biologists suspected that a different type of T cell, known as regulatory T cells, or Tregs, may also suppress the immune system’s attack on cancer. Large numbers of these cells are found within several types of tumors. “One possible therapy would be to get rid of Tregs,” he said. “But Tregs are also needed to keep the immune system in check, and shutting down Tregs completely would unleash an attack against the body’s healthy cells and organs.”

This point is underscored by a related study, published today in Immunity, in which Dr. Ghosh and colleagues found that removing NF-kB from Tregs caused widespread and lethal autoimmunity in mice. However, a partial inhibition of NF-kB, achieved by removing only one, specific, NF-kB protein, called c-Rel, changed Treg function without causing widespread autoimmunity.  In the Cell study Ghosh and colleagues showed that these c-Rel deficient Tregs were specifically crippled in their ability to protect cancer cells. As a result, when c-Rel is blocked, killer T cells mounted a more robust attack on cancer cells without causing autoimmunity.

Pentoxifylline is a drug that is used in patients to increase blood flow in the hands and feet of people with poor circulation, but it’s also known to inhibit the c-Rel protein. In the Cell study, the researchers demonstrated that pentoxifylline blocked Treg function and boosted the effectiveness of standard checkpoint-blockade immunotherapies.  As a result, mice treated with both drugs showed significantly reduced melanoma tumor burden, compared to animals that received the standard therapy alone.

“The next step is to test this drug combination in human clinical trials,” Dr. Ghosh says. “If trials are successful, the use of c-Rel inhibitors could become a standard addition to immune checkpoint therapy for many types of cancer.”

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Drug May Curb Female Infertility From Cancer Treatments

An existing drug may one day protect premenopausal women from life-altering infertility that commonly follows cancer treatments, according to a new study.

Women who are treated for cancer with radiation or certain chemotherapy drugs are commonly rendered sterile. According to a 2006 study from Weill Cornell Medicine, nearly 40 percent of all female breast cancer survivors experience premature ovarian failure, in which they lose normal function of their ovaries and often become infertile.

Women are born with a lifetime reserve of oocytes, or immature eggs, but those oocytes are among the most sensitive cells in the body and may be wiped out by such cancer treatments.

The current study, published in the journal Genetics, was led by John Schimenti, Cornell University professor in the Departments of Biomedical Sciences and Molecular Biology and Genetics. The study builds on his 2014 research that identified a so-called checkpoint protein (CHK2) that becomes activated when oocytes are damaged by radiation.

CHK2 functions in a pathway that eliminates oocytes with DNA damage, a natural function to protect against giving birth to offspring bearing new mutations. When the researchers irradiated mice lacking the CHK2 gene, the oocytes survived, eventually repaired the DNA damage, and the mice gave birth to healthy pups.

The new study explored whether the checkpoint 2 pathway could be chemically inhibited.

“It turns out there were pre-existing CHK2 inhibitor drugs that were developed, ironically enough, for cancer treatment, but they turned out not to be very useful for treating cancer,” said Schimenti, the paper’s senior author. Vera Rinaldi, a graduate student in Schimenti’s lab, is the paper’s first author. “By giving mice the inhibitor drug, a small molecule, it essentially mimicked the knockout of the checkpoint gene,” Rinaldi said.

By inhibiting the checkpoint pathway, the oocytes were not killed by radiation and remained fertile, enabling birth of normal pups.

“The one major concern,” Schimenti said, “is that even though these irradiated oocytes led to the birth of healthy mouse pups, it’s conceivable that they harbor mutations that will become manifested in a generation or two, because we are circumventing an evolutionarily important mechanism of genetic quality control. This needs to be investigated by genome sequencing.”

When doctors recognize the need for oocyte-damaging cancer treatments, women may have their oocytes or even ovarian tissue removed and frozen, but this practice delays treatment. Also, when women run out of oocytes, women’s bodies naturally undergo menopause, as their hormonal systems shift.

“That is a serious dilemma and emotional issue,” Schimenti said, “when you layer a cancer diagnosis on top of the prospect of having permanent life-altering effects as a result of chemotherapy, and must face the urgent decision of delaying treatment to freeze oocytes at the risk of one’s own life.”

The study sets a precedent for co-administering this or related drugs and starting cancer therapy simultaneously, though such interventions would first require lengthy human trials.

“While humans and mice have different physiologies, and there is much work to be done to determine safe and effective dosages for people, it is clear that we have the proof of principle for this approach,” Schimenti said.

The study was funded by the National Institutes of Health.

Study Suggests that Zika Virus Could Be Used to Treat Brain Cancer Patients

Recent outbreaks of Zika virus have revealed that the virus causes brain defects in unborn children. But in a study to be published September 5 in The Journal of Experimental Medicine, researchers from Washington University School of Medicine in St. Louis and the University of California, San Diego report that the virus could eventually be used to target and kill cancer cells in the brain.

Glioblastoma is the most common form of brain cancer and is frequently lethal; most patients die within two years of diagnosis. Just like normal, healthy tissues, the growth and development of glioblastomas is driven by stem cells that proliferate and give rise to other tumor cells. Glioblastoma stem cells are hard to kill because they can avoid the body’s immune system and are resistant to chemotherapy and radiation. But killing these cells is vital to prevent new tumors from recurring after the original tumor has been surgically removed.

“It is so frustrating to treat a patient as aggressively as we know how, only to see his or her tumor recur a few months later. We wondered whether nature could provide a weapon to target the cells most likely responsible for this return,” says Milan Chheda from Washington University School of Medicine in St. Louis.

One approach to killing cancer stem cells involves using viruses that specifically target tumor cells. Zika virus appears to disrupt fetal brain development by preferentially targeting neural stem and progenitor cells. The virus’ effects on adult brains—which contain fewer active stem cells that developing fetal brains—are generally much less severe.

“We hypothesized that the preference of Zika virus for neural precursor cells could be leveraged against glioblastoma stem cells,” says Michael Diamond, also from Washington University School of Medicine in St. Louis, who co-directed the study with Milan Chheda and with Jeremy Rich, from the University of California, San Diego and the Cleveland Clinic Lerner Research Institute.

The researchers found that Zika virus preferentially infected and killed patient-derived glioblastoma stem cells compared with other glioblastoma cell types or normal neural cells. When mice with aggressive glioma were injected with a mouse-adapted strain of Zika virus, the virus slowed tumor growth and significantly extended the animals’ lifespan.

The researchers then tested a mutant strain of Zika that is less virulent than naturally occurring strains of the virus. This “attenuated” strain, which is more sensitive to the body’s immune response, was still able to specifically target and kill glioblastoma stem cells and was even more effective when combined with a chemotherapy drug, temozolomide, that usually has little effect on these cells. “This effort represents the creative synthesis of three research groups with complementary expertise to attack a deadly cancer by harnessing the cause of another disease,” says Jeremy Rich. “Adults with Zika may suffer less damage from their infection, suggesting that this approach could be used with acceptable toxicity.”

“Our study is a first step towards the development of safe and effective strains of Zika virus that could become important tools in neuro-oncology and the treatment of glioblastoma,” says Diamond. “However, public health concerns will need to be addressed through pre-clinical testing and evaluations of the strains’ ability to disseminate or revert to more virulent forms.”

Novartis garners first ever FDA approval for a CAR-T cell therapy, Kymriah(TM), for children and young adults with B-cell ALL that is refractory or has relapsed at least twice

Novartis announced today that the US Food and Drug Administration (FDA) has approved Kymriah(TM)(tisagenlecleucel) suspension for intravenous infusion, formerly CTL019, the first chimeric antigen receptor T cell (CAR-T) therapy, for the treatment of patients up to 25 years of age with B-cell precursor acute lymphoblastic leukemia (ALL) that is refractory or in second or later relapse. Kymriah is a novel immunocellular therapy and a one-time treatment that uses a patient’s own T cells to fight cancer. Kymriah is the first therapy based on gene transfer approved by the FDA.

“At Novartis, we have a long history of being at the forefront of transformative cancer treatment,” said Joseph Jimenez, CEO of Novartis. “Five years ago, we began collaborating with the University of Pennsylvania and invested in further developing and bringing what we believed would be a paradigm-changing immunocellular therapy to cancer patients in dire need. With the approval of Kymriah, we are once again delivering on our commitment to change the course of cancer care.”

The FDA has approved a Risk Evaluation and Mitigation Strategy (REMS) for Kymriah. The REMS program serves to inform and educate healthcare professionals about the risks that may be associated with Kymriah treatment. To support safe patient access, Novartis is establishing a network of certified treatment centers throughout the country which will be fully trained on the use of Kymriah and appropriate patient care.

There has been an urgent need for novel treatment options that improve outcomes for patients with relapsed or refractory (r/r) B-cell precursor ALL, whose prognosis is poor. Patients often undergo multiple treatments including chemotherapy, radiation, targeted therapy or stem cell transplant, yet less than 10% of patients survive five years [2], [3].

Kymriah is an innovative immunocellular therapy that is a one-time treatment. Kymriah uses the 4-1BB costimulatory domain in its chimeric antigen receptor to enhance cellular expansion and persistence. In 2012, Novartis and the University of Pennsylvania (Penn) entered into a global collaboration to further research, develop and commercialize CAR-T cell therapies, including Kymriah, for the investigational treatment of cancers.

“This therapy is a significant step forward in individualized cancer treatment that may have a tremendous impact on patients’ lives,” said Carl June, MD, the Richard W. Vague Professor of Immunotherapy, Director of the Center for Cellular Immunotherapies in Penn’s Perelman School of Medicine, who is a pioneer of this new treatment. “Through our collaboration with Novartis, we are creating the next wave of immunocellular cancer treatments, and are eager to progress CAR-T therapy in a host of hematologic and other cancer types.”

In close collaboration with Novartis and Penn, Children’s Hospital of Philadelphia (CHOP) was the first institution to investigate Kymriah in the treatment of pediatric patients leading the single site trial.

“Tisagenlecleucel is the first CAR-T therapy to demonstrate early, deep and durable remission in children and young adults with relapsed or refractory B-cell ALL,” said Stephan Grupp, MD, PhD, the Yetta Deitch Novotny Professor of Pediatrics at the Perelman School of Medicine at Penn, and Director of the Cancer Immunotherapy Frontier Program at Children’s Hospital of Philadelphia (CHOP). “We’ve never seen anything like this before and I believe this therapy may become the new standard of care for this patient population.”

Novartis is committed to ensuring eligible patients have access to Kymriah, and is working to ensure payers understand the value of Kymriah and provide coverage for patients. To address the unique aspects of the therapy, Novartis has also developed various patient access programs to support safe and timely access for patients. Novartis is also providing traditional support to patients by helping them navigate insurance coverage and providing financial assistance for those who are uninsured or underinsured.

Novartis plans additional filings for Kymriah in the US and EU later this year, including applications with the FDA and European Medicines Agency (EMA), for the treatment of adult patients with r/r diffuse large B-cell lymphoma (DLBCL). Additional filings beyond the US and EU are anticipated in 2018.

Gilead to buy Kite Pharma in $11.9 billion deal

Reuters — Gilead Sciences agreed to buy Kite Pharma in a $11.9 billion deal on Monday, as it looks to fuel growth with an emerging class of cancer immunotherapies that are expected to generate billions.

Gilead will pay $180 per share in an all-cash deal, representing a 29.4 percent premium over Kite’s Friday close. Kite’s shares were trading up at $178.15 before the bell.

Santa Monica, California-based Kite is developing a CAR-T, or chimeric antigen receptor T-cell therapy, which harnesses the body’s own immune cells to recognize and attack malignant cells.

Gilead’s growth has been fueled by its pricey but revolutionary hepatitis C drugs but with fewer eligible patients and rising competition, sales have begun to fall.

Second-quarter sales of its hepatitis C drugs — Sovaldi, Harvoni and Epclusa — totaled $2.9 billion, down from $4 billion a year earlier.

Wall Street and Gilead shareholders have long been expecting Gilead to use its cash pile for a big-ticket acquisition.

The deal for Kite, which has been approved by the boards of both companies, is expected to close in the fourth quarter.

Kite is one of the leading players in the emerging field of CAR-T, and is competing with rivals Novartis, Juno Therapeutics, and Bluebird bio in a race to get the first approved therapy.

If approved, these drugs are expected to cost up to $500,000 and generate billions of dollars. Success would also help advance a cancer-fighting technique that scientists have been trying to perfect for decades.

The U.S. Food and Drug Administration (FDA) is expected to decide by Nov. 29 whether to approve Kite’s CAR-T, axi-cel, for treatment of adults with advanced lymphoma.

Gilead has a market value of $96.36 billion, according to Thomson Reuters data. The company was once the world’s largest maker of HIV drugs, and in 2011 agreed to acquire hep C drug developer Pharmasset for $11 billion.

Last year, Gilead generated total sales of $30.39 billion, of which $14.8 billion came from hep C treatments.

Bank of America/Merrill Lynch and Lazard are acting as financial advisers to Gilead, while Centerview Partners is Kite’s exclusive financial adviser.

Skadden, Arps, Slate, Meagher & Flom is the legal counsel to Gilead and Sullivan & Cromwell and Cooley for Kite.

The Wall Street Journal reported first reported the deal.

Gilead’s shares were little changed in premarket trading, while Juno’s shares rose nearly 14 percent and Bluebird’s 2.6 percent.

Combination of Traditional Chemotherapy, New Drug Kills Rare Cancer Cells in Mice

An experimental drug combined with the traditional chemotherapy drug cisplatin, when used in mice, destroyed a rare form of salivary gland tumor and prevented a recurrence within 300 days, a University of Michigan study found.

Called adenoid cystic carcinoma, or ACC, this rare cancer affects 3,000-4,000 people annually, and typically arises in the salivary glands. It’s usually diagnosed at an advanced stage, is very resistant to therapy, and there’s no cure. People may have read about ACC in the news lately, because elite professional runner Gabe Grunewald is currently undergoing her fourth round of treatment since her 2009 ACC diagnosis.

Typically, oncologists treat ACC tumors with surgery and radiation. They rarely use chemotherapy because ACC is extremely slow-growing, and chemotherapy works best on cancers where cells divide rapidly and tumors grow quickly, said Jacques Nör, a U-M professor of dentistry, otolaryngology and biomedical engineering, and principal investigator on the study.

The Nör lab treated ACC tumors with a novel drug called MI-773, and then combined MI-773 with traditional chemotherapy cisplatin. MI-773 prevents a molecular interaction that causes tumor cells to thrive by disarming the critical cancer fighting protein, p53.

Study co-author Shaomeng Wang, U-M professor of medicine, pharmacology and medicinal chemistry, discovered MI-773, which is currently licensed to Sanofi.

Researchers believe that blocking that interaction sensitized ACC cancer cells to cisplatin––a drug that under normal conditions, wouldn’t work. When administered to the mice with ACC tumors, the cisplatin targeted and killed the bulk cells that form the tumor mass, while MI-773 killed the more resistant cancer stem cells that cause tumor recurrence and metastasis.

“This drug MI-773 prevents that interaction, so p53 can induce cell death,” Nör said.  “In this study, when researchers activated p53 in mice with salivary gland cancer, the cancer stem cells died.”

The key is that in many other types of cancer, p53 is mutated so it can’t kill cancer cells, and this mutation renders the MI-773 largely ineffective. However, in most ACC tumors p53 is normal, and Nör said researchers believe this makes these tumors good candidates for this combined therapy.

Researchers performed two different types of experiments to test ACC tumor reduction and recurrence. First, they treated tumors in mice with a combination of MI-773 and cisplatin, and tumors shrank from about the size of an acorn to nearly zero.

In the second experiment, the acorn-sized tumors were surgically removed, and for one month the mice were treated with MI-773 only, with the hope of eliminating the cancer stem cells that fuel recurrence and metastasis.

“We did not observe any recurrence in the mice that were treated with this drug after 300 days (about half of mouse life expectancy), and we observed about 62 percent recurrence in the control group that had only the surgery,” Nör said. “It’s our belief that by combining conventional chemotherapy with MI-773, a drug that kills more cancer stem cells, we can have a more effective surgery or ablation.”

One limitation of the study is that it’s known that about half of all ACC tumors recur only after about 10 years, and this observational period was only 300 days.

In a typical metastasis, the cancer cells spread through the blood to other parts of the body. But ACC cancer cells like to move by “crawling” along nerves, and it’s common for ACC tumor cells to follow the prominent facial nerves to the brain––picture a mountain climber ascending a rope––where it’s often fatal.

Research is still too early-stage to know how humans will respond, and the drug will work primarily in tumors where p53 is normal. If p53 is mutated, which is fairly common in other tumor types, this drug won’t work as well, Nör said.

The work was funded by the Adenoid Cystic Carcinoma Research Foundation, U-M and the National Institutes of Health.

The study, “Therapeutic Inhibition of the MDM2-p53 interaction prevents recurrence of adenoid cystic carcinomas,” appeared earlier this year in the journal Clinical Cancer Research.

Spaser can detect, kill circulating tumor cells to prevent cancer metastases, study finds

A nanolaser known as the spaser can serve as a super-bright, water-soluble, biocompatible probe capable of finding metastasized cancer cells in the blood stream and then killing these cells, according to a new research study.

The study found the spaser can be used as an optical probe and when released into the body (possibly through an injection or drinking a solution), it can find and go after circulating tumor cells (CTCs), stick to them and destroy these cells by breaking them apart to prevent cancer metastases. The spaser absorbs laser light, heats up, causes shock waves in the cell and destroys the cell membrane. The findings are published in the journal Nature Communications.

The spaser, which stands for surface plasmon amplification by stimulated emission of radiation, is a nanoparticle, about 20 nanometers in size or hundreds times smaller than human cells. It has folic acid attached to its surface, which allows selective molecular targeting of cancer cells. The folate receptor is commonly overexpressed on the surface of most human cancer cells and is weakly expressed in normal cells.

The discovery was made by researchers at Georgia State University, the University of Arkansas for Medical Sciences, the University of Arkansas at Little Rock and the Siberian Branch of the Russian Academy of Science.

“There is no other method to reliably detect and destroy CTCs,” said Dr. Mark Stockman, director of the Center for Nano-Optics and professor of physics at Georgia State. “This is the first. This biocompatible spaser can go after these cells and destroy them without killing or damaging healthy cells. Any other chemistry would damage and likely kill healthy cells. Our findings could play a pivotal role in providing a better, life-saving treatment option for cancer patients.”

Metastatic cancer occurs when cancer spreads to distant parts of the body, often to the bone, liver, lungs and brain, through a process called metastasis. Many types of cancers refer to this as stage IV cancer. Once cancer spreads, it can be difficult to control, and most metastatic cancer can’t be cured with current treatments, according to the National Institute of Health’s National Cancer Institute. One of the most dangerous ways metastasizing occurs is through the CTCs, which this study aims to detect and destroy using spasers.

The spasers used in this study measure just 22 nanometers, setting the record for the smallest nanolasers. A nanometer is one-billionth of a meter. Most results were obtained with a gold, spherical nanoparticle surrounded by a silica shell and covered with a uranine dye, which is widely used for tracing and biomedical diagnostics.

The researchers studied the spaser’s capabilities in vitro in human breast cancer cells with high folate receptor expression and endothelial cells with low folate receptor expression, as well as in mouse cells in vivo.

They found cells with spasers demonstrated high image contrasts with one or many individual “hot spots” at different laser energies above the spasing threshold. The presence of spasers was confirmed with several optical and electron microscopy techniques, which revealed an initial accumulation of individual spasers on the cell membrane followed by their entrance into the cell cytoplasm.

The study also found low toxicity of the spasers for human cells. At the same time, the spasers subjected to laser irradiation selectively killed the tumor cells without damaging the healthy ones.

Based on the study’s results, spaser-based therapeutic applications with high-contrast imaging is a promising field. The data suggest spasers have high potential as therapeutic and diagnostic agents that integrate optical diagnosis and photothermal-based cell killing, using just a few laser pulses to kill cancer cells.

Wistar scientists develop novel immunotherapy technology for prostate cancer

A study led by scientists at The Wistar Institute describes a novel immunotherapeutic strategy for the treatment of cancer based on the use of synthetic DNA to directly encode protective antibodies against a cancer specific protein. This is the first application of the new technology, called DNA-encoded monoclonal antibody (DMAb), for cancer immunotherapy. The study was published online in Cancer Immunology, Immunotherapy.

Prostate cancer is the second most common cancer in men worldwide. Traditional treatments are invasive and can impair the quality of life of patients, underscoring the need for alternative therapeutic strategies, including immunotherapy. One of the immunotherapeutic approaches that has been explored thus far relies on the use of monoclonal antibodies that specifically target a protein present on the surface of prostate cancer cells called prostate specific membrane antigen (PSMA) to elicit an anti-tumor immune response and control the cancer. Although promising, this strategy is limited by the production cost required to make these therapeutic antibodies. Additionally, multiple infusions are often required to achieve efficacy.

Wistar researchers devised a novel DNA-based approach in which an engineered DNA plasmid is constructed and used to deliver the instructions to make the desired anti-PSMA antibody so that the therapy can be generated in the patient’s body in a sustained manner. This research has important implications for the use of DNA-encoded monoclonal antibody technology as a platform for delivering the next generation of immunotherapies for cancer and many human diseases.

“This is an important demonstration of the possibilities opened up for immunotherapy by DMAb technology to direct in vivo production of antibodies of major relevance to human cancer,” said David B. Weiner, Ph.D., executive vice president of The Wistar Institute, director of The Wistar Institute Vaccine & Immunotherapy Center, W.W. Smith Charitable Trust Professor in Cancer Research, and senior author of the study. “There is a great need for such new approaches for prostate disease as well as many other cancers. As recent data suggest, PSMA is an important cancer antigen expressed on many human prostate, bladder, renal as well as ovarian cancers, so additional study of the possible benefits of this therapy are important.”

The new technology was tested in mice for the ability to generate antibodies in their blood stream that would target human PSMA as well as target PSMA-positive tumors. Results showed that antibodies were able to bind to the cancer cells and recruited specific immune cells called natural killer cells, resulting in shrinkage of the tumor, significantly improving survival.

“Our data provide proof of concept that DMAb engineered DNA plasmids can be successfully used to target important cancers,” said Kar Muthumani, M.Sc., Ph.D., assistant professor in the Translational Tumor Immunology Program at Wistar, member of the Vaccine & Immunotherapy Center and lead author of the study. “The unique features of our synthetic DNA-based system make it a promising novel approach for cancer therapy, alone or in combination with other treatments.”

Skewing the aim of targeted cancer therapies

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

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

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

RNA concept incomplete

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

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

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

RNA skews drug cues

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

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

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

Hiding drug targets

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

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

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

RNA muted or magnified

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

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

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

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

Micro RNA managing

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

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

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

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

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

No one at fault

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

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

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

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

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

Spider peptides battle superbugs and cancer

As antibiotic resistance rises and fears over superbugs grow, scientists are looking for new treatment options. One area of focus is antimicrobial peptides (AMPs), which could someday be an alternative to currently prescribed antibiotics, many of which are becoming increasingly useless against some bacteria. Now, a team reports in ACS Chemical Biology that they have improved the antimicrobial — and anticancer — properties of an AMP from a spider.

According to the U.S. Centers for Disease Control and Prevention, 2 million people become infected with antibiotic-resistant bacteria in the U.S. each year. Because no known antibiotics work against these bacteria, patients simply have to hope that their natural defenses eventually overcome the infection. But some patients experience severe symptoms, landing them in a hospital, and in extreme cases, they could die. Researchers are trying to find alternatives to traditional antibiotics, and one such possibility is a group of peptides called AMPs. These peptides are found in all plants and animals as a type of immune response and have been shown to be potent antibiotics in the laboratory. Gomesin, an AMP from the Brazilian spider Acanthoscurria gomesiana can function as an antibiotic, but it also has anticancer activity. When gomesin was synthesized as a circle instead of as a linear structure, these characteristics were enhanced. Sónia Troeira Henriques and colleagues wanted to further boost the peptide’s traits.

The team made several variations of the cyclic gomesin peptide and found that some of these were 10 times better at killing most bacteria than the previously reported cyclic form. In other experiments, the new AMPs specifically killed melanoma and leukemia cells, but not breast, gastric, cervical or epithelial cancer cells. The researchers determined that the modified peptides killed bacteria and cancer cells in a similar way — by disrupting the cells’ membranes. The group also notes that the modified AMPs were non-toxic to healthy blood cells.

Study identifies molecules that could help to prevent the development of brain tumors

Researchers from the University of Portsmouth’s Brain Tumour Research Centre of Excellence have identified molecules which are responsible for metastatic lung cancer cells binding to blood vessels in the brain.

In order for a cancer cell to enter the brain, it must first bind to the cells which line the structure separating the blood from the brain which is called the blood-brain barrier (BBB). Such information about the factors associated with this process may provide a way of preventing the cancer cells binding to the BBB and crossing over into the brain.

Twenty to 40 percent of patients with non-small cell lung cancer (NSCLC) develop brain metastasis.

The study, funded by the charity Brain Tumour Research and conducted by researchers at their UK Centre of Excellence at the University of Portsmouth, examined the factors present on the surface of NSCLC cells. These cells have different factors on their surfaces which determines how “sticky” the cells are and whether they are responsible for mediating the cancer cells binding to the blood vessel walls.

One of these factors is a molecule called CD15s. While it is present on a number of different types of cells in the body, it is expressed at higher levels on metastatic tumour cells, including those which have spread from the lung. It is only present at low levels in lung cancer cells which are not metastatic and remain within the lung.

The scientists examined what CD15s binds to on the blood vessel wall and identified another factor called CD62E. The researchers then used a specific tool to block the CD15s on the surface of the tumour cells, and this prevented the NSCLC cells from attaching to the blood vessels. They also used a model which simulated the cancer cells flowing through the blood vessels, and got the same result. So, blocking the adhesive properties of CD15s may provide a tool to prevent the establishment of secondary cancers.

Professor Geoff Pilkington, study co-author and Head of the Brain Tumour Research Centre, said: “Although this work is still at an early stage, we have demonstrated key elements that are associated with tumour cell binding to blood vessels and this may provide a target for future drug development to prevent the development of secondary tumours in the brain. Increasing our understanding of the adhesive properties of tumours may also help to develop new treatments to halt the development and spread of primary brain tumours.”

The adhesive properties of cancer cells play a key role in the formation and development of a tumour. While cells in a low-grade tumour bind very tightly together, the cells become less adhesive as the tumour becomes malignant. This is very important for the tumour cells which then spread into the surrounding nervous tissue.

Understanding more about the factors which mediate cell adhesion is key for the potential identification of new therapies.

Dr Kieran Breen, Director of Research at Brain Tumour Research, said: “Brain tumours kill more children and adults under the age of 40 than any other cancer, yet just 1 per cent of the national spend on cancer research has been allocated to this devastating disease. We are funding vital research in the UK to address this situation and are encouraged by Professor Pilkington’s findings.”

In addition to primary tumours which start in the brain, the secondary or ‘metastatic’ tumours which originate elsewhere and which migrate to the brain have been the focus of this new study. Secondary brain tumours are most likely to originate in the breast, lung or skin (melanoma). When they enter the brain, they generally form multiple tumours and can be extremely difficult to treat. Usually, treatment would require whole-brain radiation which is extremely toxic and the average survival time is just 3-6 months from diagnosis, with fewer than 20 per cent of patients surviving more than one year. If the people whose tumours are more likely to spread to the brain could be identified, researchers may be able to prevent this from happening.

A new HER2 mutation, a clinical trial and a promising diagnostic tool for metastatic breast cancer

There is a group of metastatic breast cancers that has the HER2 gene amplified – the cells have many copies of it – which leads to enhanced activity of the product enzyme, a tyrosine kinase. HER2 has been established as a therapeutic target in breast cancer, and breast cancers in which the HER2 gene is not amplified do not, in general, respond to HER2-directed therapeutic approaches.

A few years ago, when the research teams of Dr. Matthew Ellis and others carried out a molecular characterization of breast cancer tumors, they found a new mutation in HER2 that was different from gene amplification but also resulted in tyrosine kinase being constantly activated.

“In this particular activation mechanism, the cells develop a subtle mutation within the functional part of the HER2 gene that activates the enzyme,” said Ellis, professor and director of the Lester and Sue Smith Breast Center, part of the National Cancer Institute-designated Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine. “The mutation locks the enzyme into an ‘on’ position.”

Ellis and his colleagues developed a preclinical model to study this new HER2 mutation and discovered that the enhanced enzymatic activity could trigger tumor formation. Furthermore, these tumor cells were sensitive to an experimental drug, neratinib. With this information in hand, the researchers took the next step.

“We launched a phase II clinical trial of neratinib in patients with metastatic breast cancer carrying a HER2 mutation,” Ellis said. “Finding patients that are positive for a HER2 mutation required a national collaboration because we had to screen hundreds of patients to identify the 2 to 3 percent that have a tumor driven by a HER2 mutation. The results of the clinical trial were encouraging in that about 30 percent of the 16 patients treated with neratinib had a meaningful clinical response showing significant disease stabilization or regression. Neratinib was well tolerated by most patients.”

“This is the first time we had a reasonable number of patients treated for HER2 mutations in whom we could estimate the response rate.”

The number of patients who could potentially benefit from this new treatment approach is estimated to be in the thousands. The researchers estimate that as many as 200,000 patients are likely to be living with metastatic breast cancer today in the United States. Based on the estimate that the new mutation is present in 2 to 3 percent of cases, the researchers calculated that approximately 4,000 to 6,000 patients with metastatic breast cancer carry a HER2 mutation and are therefore potential candidates for neratinib treatment.

Circulating tumor DNA analysis, a promising diagnostic tool

To identify the patients in this study who carried the new HER2 mutation, the researchers required tissue from the tumor, a biopsy, from which they could extract and sequence the genetic material to determine the presence of the HER2 mutation. This task turned out to be a major challenge because for 20 to 30 percent of the patients the researchers did not have sufficient material to make the diagnosis.

“To assist in our ability to identify patients with HER2 mutation-positive tumors, we conducted circulating tumor DNA analysis,” Ellis said. “The tumor’s DNA is released into the human bloodstream, and we were able to determine the presence of the mutation in blood samples from the patients. Importantly the circulating tumor DNA results were highly concordant with the tumor sequencing results, and they were much easier to determine. Notably, the blood test was sensitive enough that we could use it as a tool to determine eligibility for the clinical trial.”

In addition to bringing to the table a novel treatment for metastatic breast cancer carrying a HER2 mutation, the researchers have tested the value of the circulating tumor DNA as a disease-monitoring marker.

“A circulating tumor DNA-based blood test also could therefore be potentially used to monitor tumor progression and to determine whether patients are responding or not to treatment after just one month of therapy,” Ellis said.

Ellis also is a McNair Scholar at Baylor.

Read all the details of this study, the full list of contributors and their financial support in Clinical Cancer Research.