Asthma medication may have psychiatric side effects

In a Pharmacology Research & Perspectives study, the asthma medication montelukast (trade name Singulair) was linked with neuropsychiatric reactions such as depression and aggression, with nightmares being especially frequent in children.

For the study, investigators examined all adverse drug reactions on montelukast in children and adults reported to the Netherlands Pharmacovigilance Center Lareb and the WHO Global database, VigiBase®, until 2016.

“Because of the high incidence of neuropsychiatric symptoms–especially nightmares–after using montelukast in both children and adults, the clinician should discuss the possibility of these adverse events with the patient and parents,” said Meindina Haarman, lead author of the study.

Re-Interventions Are Common in Long-Term Survivors of Childhood Heart Operations

Among patients who undergo childhood heart surgery for the severe birth defect single-ventricle disease, two-thirds of survivors require a surgical or catheter-based procedure within 20 years. Pediatric cardiology researchers note that doctors should counsel families about the likelihood of re-interventions.

“Unfortunately, for many patients, the Fontan is not the final intervention,” said study leader Andrew Glatz, MD MSCE, referring to the Fontan operation, the third in a series of reconstructive operations performed on children with a severely underdeveloped ventricle, one of the heart’s two pumping chambers. Glatz is a pediatric interventional cardiologist in the Cardiac Center at Children’s Hospital of Philadelphia (CHOP).

Glatz and colleagues published their study on September 1, 2017 in Circulation: Cardiovascular Interventions. Other key members of the study team include Tacy Downing, MD and Kiona Allen, MD (both were pediatric cardiology fellows at CHOP during the work); and David Goldberg, MD and William Gaynor, MD (current faculty members in the Cardiac Center at CHOP).

The study team performed a retrospective review of 773 patients who underwent the Fontan operation at CHOP between 1992 and 2009.

Although the Fontan procedure offers high survival rates for a condition that previously was universally fatal during infancy, it cannot provide normal blood circulation, and carries long-term risks of complications that continue to be analyzed. Clinicians and researchers were aware of the need for re-interventions in long-term Fontan survivors, but there was little detailed knowledge of re-intervention rates until now.

In the current study, the researchers found that 65 percent of Fontan survivors underwent a re-intervention by 20 years after their operation, with a median time to first re-intervention slightly less than 10 years. The re-interventions were either operations or catheterizations, with catheterizations being more common—often to close unwanted openings or to widen narrowed blood vessels. Among operations, the most common were to place or revise a pacemaker.

“The important message from this work is that, for many patients, the Fontan operation is not the ‘final’ procedure, as it is sometimes referred to. Instead, many patients require further interventions after the Fontan to continue to try to optimize the circulation as best as possible. It’s important for families and doctors to understand this, so expectations are clear. This also highlights the need for close and careful ongoing follow-up after the Fontan operation by pediatric cardiologists familiar with potential complications that could befall a Fontan patient,” said Glatz.

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.”

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.

Liver Cancer Patients Can Start with Lower Dose of Chemotherapy and Live Just as Long

Penn study shows patients can benefit from fewer side effects and lower treatment costs

Patients with the most common type of liver cancer who are taking the chemotherapy drug sorafenib can begin their treatment with a lower dose than is currently considered standard, and it will not affect how long they live when compared to patients who start on the full dose. That finding comes from a new study from the Abramson Cancer Center of the University of Pennsylvania, published this week in the Journal of Clinical Oncology, and it opens the door for patients with hepatocellular carcinoma to begin with a reduced dose of sorafenib, which helps to minimize the drug’s side effects while also saving money for patients, providers, and insurers.

Hepatocellular carcinoma (HCC) is the most common form of liver cancer among adults and is the second leading cause of cancer-related deaths worldwide. Currently, sorafenib is the only first-line treatment approved for HCC by the U.S. Food and Drug Administration, but its side effects can be particularly difficult on patients. A recent study found 85 percent of HCC patients taking the drug experienced adverse events. In 31 percent of patients on that study, the effects were severe enough to stop treatment. The standard dose sorafenib is 400mg, twice per day.

“Previous studies have started patients with half that dose, escalating only after the patients show they can handle it, but those studies have all been on a smaller scale,” said the study’s lead author Kim A. Reiss, MD, an assistant professor of Hematology Oncology in the Perelman School of Medicine at the University of Pennsylvania. “We wanted to see if we could reproduce those results using a much larger cohort of patients.”

Reiss and her team used a Veterans Health Administration database and identified almost 5,000 HCC patients who were treated with sorafenib between 2006 and 2015, but they couldn’t do a side-by-side analysis of those who received a reduced dose versus those who received the full amount.

“One of the challenges that we faced was that the sickest patients tended to get the reduced dose because of concerns over how much they could tolerate, so any attempt to evaluate these groups based on how long they lived was skewed,” Reiss said.

To solve that problem, researchers looked at patient information to match people from each group based on disease stage, overall health, and other factors. That left them with two groups, each with 1,675 patients.

“Essentially, we used a computer model to simulate putting these patients into a randomized, controlled clinical trial,” said senior author David E. Kaplan, MD, MSc, an assistant professor of Gastroenterology and an associate professor of Medicine at the Corporal Michael J. Crescenz VA Medical Center in Philadelphia.

The controlled data showed the reduced dose had no effect on overall survival. Patients starting at a lower dose had a median survival of 198 days, compared to 195 days for patients starting at the full dose.

In addition, about 40 percent of patients receiving the reduced dose escalated the drug amount within the first two months, while almost 12 percent of standard dose patients had to reduce their level within the same time period.

“It’s important to remember that the reduced dose patients will ramp up as they show they can handle it, while the full dose patients may have to ramp down because of these toxicities, so the dosage levels will converge in the middle,” Reiss said. “All of the patients get the treatment they need, but the reduced dose approach helps keep cost and toxicities down.”

The cost saving was significant. The study found the reduced dose patients took an average of about 100 fewer pills over the course of their treatment. That translated to an average savings of about $3,000 per patient. Reiss noted those numbers are based on VA prices, which tend to be lower than other centers, meaning the real savings for many patients could be even larger.

The researchers note that some doctors are already making use of this practice, which is why they were able to identify so many reduced dose patients for this study, but the majority of physicians are still starting with the full dose.

“Our data suggest starting at a reduced dose is a safe strategy that can be used more commonly,” Reiss said.

This study was supported by research funds from Bayer Healthcare Pharmaceuticals and the VA HIV, Hepatitis, and Related Conditions Programs in the Office of Specialty Care Services.

Vaccine to Prevent Most Cervical Cancers Shows Long-Term Effectiveness

More than 14,000 women around the world were followed up to six years.

A vaccine that can literally eradicate the majority of cervical cancer cases shows long-term effectiveness in a study published today in The Lancet. This study of 14,215 women in 18 countries extends and solidifies the initial phase 3 efficacy and safety trial of the nine-valent human papilloma virus vaccine, Gardasil 9, that was published in February 2015 in The New England Journal of Medicine.

These new results strengthen the promise that vaccination with Gardasil 9 can reduce 90 percent of cervical cancers.

“There is no question that the vaccine works,” said primary author Warner Huh, M.D., professor and director of the University of Alabama at Birmingham Division of Gynecologic Oncology and a senior scientist at the UAB Comprehensive Cancer Center. “We’re on the verge of a dramatic change that will positively affect all individuals, particularly women, in the United States. The challenge is to get the new vaccine into widespread use among young women.”

The UAB Comprehensive Cancer Center and a coalition of Alabama health groups last year launched a formal call for action, urging Alabama parents and health care providers to get children — girls and boys — vaccinated against the sexually transmitted human papillomavirus, or HPV. The vaccine is unique in its ability to prevent certain cancers.

HPV infections cause global disease, including an estimated 266,000 deaths from cervical cancer worldwide in 2012, according to the World Health Organization. Routine screening by Pap smears or tests for HPV infection has reduced death rates in developed countries compared to less developed regions of the globe. Still, an estimated 12,200 U.S. women a year are diagnosed with cervical cancer.

Gardasil 9, marketed by Merck & Co., was approved by the U.S. Food and Drug Administration in December 2014. The vaccine immunizes against nine genotypes of HPV known to cause cervical cancer, as well as vulvar, vaginal and anal cancers and genital warts caused by HPV. It is an advance over the four-valent HPV vaccine, Gardasil, which was approved by the FDA in 2006.

Huh helped develop and test Gardasil, which targets the two HPV genotypes known to cause about 70 percent of cervical cancer and two other genotypes that cause genital warts. Gardasil 9 targets those four genotypes and five additional ones as well. Both vaccines are prophylactic, meant to be given before females or males become exposed to possible HPV infection through intimate contact.

“Nationwide, 40 percent of girls and boys do not receive the HPV vaccine, and in the state of Alabama, almost half of girls and boys do not receive the HPV vaccine,” Huh said. “With this new vaccine, there is a very legitimate opportunity to wipe out cancers that are caused by HPV, particularly cervical cancer in women.

“Seventy-five years ago, cervical cancer was a very common cause of mortality in the United States. Looking forward, with widespread vaccination, it is highly likely that cervical cancer will evolve into historical interest only, and screening, like Pap smears, might go away altogether. HPV vaccines are one of the most scrutinized vaccines ever, but multiple studies have demonstrated the vaccine to be safe and well-tolerated.”

In the Lancet study, women were followed for efficacy at preventing disease for up to six years after the first vaccine shots, and they were followed for production of infection-halting antibodies against the nine genotypes of HPV for more than five years. The randomized double-blind efficacy, immunogenicity and safety study involved 105 sites in Austria, Denmark, Germany, Norway and Sweden; Brazil, Chile, Colombia and Peru; Canada, Mexico and the United States; and Hong Kong, Japan, New Zealand, South Korea, Taiwan and Thailand.

Half the women were vaccinated with the four-valent Gardasil and half with the nine-valent Gardasil 9. They were followed via gynecological exams for evidence of infections or disease, and their blood sera were tested for antibody levels against HPV.

Gardasil 9 showed 97.4 percent efficacy to prevent infections and disease caused by the five additional HPV genotypes not included in the four-valent Gardasil vaccine. Gardasil 9 vaccination produced similar antibody protection against the four HPV genotypes in Gardasil. The two vaccines also had similar safety profiles.

The nine-valent HPV vaccine has now been licensed in more than 60 countries for prevention of HPV-related anogenital cancers and precancers, and genital warts. Results of the Lancet study support the public health value of — and the need for — comprehensive vaccination programs.

The study was sponsored and funded by Merck & Co. Huh and 27 co-authors represent 21 universities in Europe, Canada, South America, Australia and the United States, as well as Merck & Co.

At UAB, Huh holds the Margaret Cameron Spain Chair in Obstetrics and Gynecology.

Penn’s Glowing Cancer Tool Illuminates Benign, but Dangerous, Brain Tumors during Pituitary Surgery

Fluorescent, targeted dye illuminates molecular signature of tumor tissue in personalized surgery.

An experimental imaging tool that uses a targeted fluorescent dye successfully lit up the benign brain tumors of patients during removal surgery, allowing surgeons to identify tumor tissue, a new study from researchers at the Perelman School of Medicine at the University of Pennsylvania shows. The tumors, known as pituitary adenomas, are the third most common brain tumor, and very rarely turn cancerous, but can cause blindness, hormonal disorders, and in some cases, gigantism.

Findings from the pilot study of 15 patients, published this week in the Journal of Neurosurgery, build upon previous clinical studies showing intraoperative molecular imaging developed by researchers at Penn’s Center for Precision Surgery can improve tumor surgeries. According to first author John Y.K. Lee, MD, MSCE, an associate professor of Neurosurgery in the Perelman School of Medicine at the University of Pennsylvania and co-director of the Center for Precision Surgery, this study describes the first targeted, near infrared dye to be employed in brain tumor surgery. Other dyes are limited either by their fluorescent range being in the busy visible spectrum or by lack of specificity.

“This study heralds a new era in personalized tumor surgery. Surgeons are now able to see molecular characteristics of patient’s tumors; not just light absorption or reflectance,” Lee said. “In real time in the operating room, we are seeing the unique cell surface properties of the tumor and not just color. This is the start of a revolution.”

Non-specific dyes have been used to visualize and precisely cut out brain tumors during resection surgery, but this dye is believed to be the first targeted, near infrared dye to be used in neurosurgery. The fluorescent dye, known as OTL38, consists of two parts: vitamin B9 (a necessary ingredient for cell growth), and a near infrared glowing dye. As tumors try to grow and proliferate, they overexpress folate receptors. Pituitary tumors can overexpress folate receptors more than 20 times above the level of the normal pituitary gland in some cases. This dye binds to these receptors and thus allows us to identify tumors.

“Pituitary adenomas are rarely cancerous, but they can cause other serious problems for patients by pushing up against parts of their brain, which can lead to Cushing’s disease, gigantism, blindness and death,” Lee explained. “The study shows that this novel, targeted, near infrared fluorescent dye technique is a safe, and we believe this technique will improve surgery.”

Lee says larger studies are warranted to further demonstrate its clinical effectiveness, especially in nonfunctioning pituitary adenomas.

A big challenge with this type of brain surgery is ensuring the entire tumor is removed. Parts of the tumor issue are often missed by conventional endoscopy approaches during removal, leading to a recurrence in 20 percent of patients. The researchers showed that the technique was safe and effective at illuminating the molecular features of the tumors in the subset of patients with nonfunctioning pituitary adenomas.

The technique uses near-infrared, or NIR, imaging and OTL38 fluoresces brightly when excited by NIR light. The VisionSense IridiumTM 4mm endoscope is a unique camera system which can be employed in the narrow confines of the nasal cavity to illuminate the pituitary adenoma. Both the dye and the camera system are needed in order to perform the surgery successfully.

The rate of gross-total resection (GTR) for the 15 patients, based on postoperative MRI, was 73 percent. The GTR with conventional approaches ranges from 50 to 70 percent. Residual tumor was identified on MRI only in patients with more severe tumors, including cavernous sinus invasion or a significant extrasellar tumor.

In addition, for the three patients with the highest overexpression of folate, the technique predicted post-operative MRI results with perfect concordance.

Some centers have resorted to implementing MRI in the operating room to maximize the extent of resection. However, bringing a massive MRI into the operating room theater remains expensive and has been shown to produce a high number of false-positives in pituitary adenoma surgery. The fluorescent dye imaging tool, Lee said, may serve as a replacement for MRIs in the operating room.

Co-authors on the study include M. Sean Grady, MD, chair of Neurosurgery at Penn, and Sunil Singhal, MD, an associate professor of Surgery, and co-director the Center for Precision Surgery.

Over the past four years, Singhal, Lee, and their colleagues have performed more than 400 surgeries using both nonspecific and targeted near infrared dyes. The breadth of tumor types include lung, brain, bladder and breast.

Most recently, in July, Penn researchers reported results from a lung cancer trial using the OTL38 dye. Surgeons were able to identify and remove a greater number of cancerous nodules from lung cancer patients with the dye using preoperative positron emission tomography, or PET, scans. Penn’s imaging tool identified 60 of the 66 previously known lung nodules, or 91 percent. In addition, doctors used the tool to identify nine additional nodules that were undetected by the PET scan or by traditional intraoperative monitoring.

Researchers at Penn are also exploring the effectiveness of additional contrast agents, some of which they expect to be available in the clinic within a few months.

“This is the beginning of a whole wave of new dyes coming out that may improve surgeries using the fluorescent dye technique,” Lee said. “And we’re leading the charge here at Penn.”

Exploring Immunotherapy for Carcinoid and Pancreatic Neuroendocrine Tumors

A clinical trial testing the immunotherapy drug pembrolizumab shows the drug to be well tolerated among patients who have carcinoid or pancreatic neuroendocrine tumors.  Janice M. Mehnert, MD, director of the Phase 1 and Developmental Therapeutics Program at Rutgers Cancer Institute of New Jersey, is the lead author of research that is part of an oral presentation at the European Society for Medical Oncology 2017 Congress taking place this week in Madrid, Spain. Dr. Mehnert, who is also a medical oncologist in the Melanoma and Soft Tissue Oncology Program at Rutgers Cancer Institute, shares more about the work, conducted by a collective of international investigators.

Q: Why explore immunotherapy in these particular patient populations?

A: Immunotherapy drugs put the body’s natural defenses back to work by targeting the PD-L1 protein and PD-1 receptor and blocking their ability to prevent T cells from destroying cancer cells. Pembrolizumab has shown anti-tumor activity in advanced malignancies including melanoma and non-small cell lung cancer. With treatment options being limited for patients with carcinoid and pancreatic neuroendocrine tumors, it is imperative to explore new therapy options for these populations.

Q:  How was the study structured?

A: At the time our abstract was submitted, 25 participants who presented with advanced carcinoid tumors and 16 patients with pancreatic neuroendocrine tumors were accrued from multiple international sites.  Participants received 10 mg of pembrolizumab for up to 24 months or until confirmed progression or intolerable toxicity.  Safety, tolerability and response were assessed every eight weeks for the first six months and every 12 weeks thereafter.

Q:  What did you find?

A: At the time our results were reported we discovered findings similar to other trials of immunotherapy agents, with the majority of patients actually not responding to therapy. 12 percent of patients with carcinoid tumors and six percent of patients with pancreatic neuroendocrine tumors experienced a response to therapy. However, patients who achieved response were likely to have durable control of their disease, with all responses greater than or equal to six months in duration. Therapy was overall well tolerated and safe, with some side effects related to autoimmune processes caused by the medication.

Q: What is the implication of these findings?

A: These findings are interesting but need further validation in larger studies of patients with carcinoid and pancreatic neuroendocrine tumors. As well, investigative work focusing on identifying valuable biomarkers that could help predict which patients would respond to treatment with these agents is critical. Discoveries in this realm would improve the selection of patients for this particular therapeutic approach.

Using DNA to predict schizophrenia and autism

Huntington’s disease, cystic fibrosis, and muscular dystrophy are all diseases that can be traced to a single mutation. Diagnosis in asymptomatic patient for these diseases is relatively easy – You have the mutation? Then you are at risk. Complex diseases, on the other hand, do not have a clear mutational footprint. A new multi-institutional study by Japanese researchers shows a potential rare gene mutation that could act as a predictor for two neurodevelopmental disorders, schizophrenia and autism.

“Aberrant synapse formation is important in the pathogenesis of schizophrenia and autism,” says Osaka University Professor Toshihide Yamashita, one of the authors of the study. “Microglia contribute to the structure and function of synapse connectivities.”

Microglia are the only cells in the brain that express the receptor CX3CR1. Mutations in this receptor are known to affect synapse connectivity and cause abnormal social behavior in mice. They have also been associated with neuroinflammatory diseases such as multiple sclerosis, but no study has shown a role in neurodevelopment disorders.

Working with this hypothesis, the researchers conducted a statistical analysis of the CX3CR1 gene in over 7000 schizophrenia and autism patients and healthy subjects, finding one mutant candidate, a single amino acid switch from alanine to threonine, as a candidate marker for prediction.

“Rare variants alter gene function but occur at low frequency in a population. They are of high interest for the study of complex diseases that have no clear mutational cause,” said Yamashita, who added the alanine threonine substitution was a rare variant.

The structure of CX3CR1 includes a domain known as Helix 8, which is important for initiating a signaling cascade. Computer models showed that one amino acid change is enough to compromise the signaling.

“The variant changes the region from hydrophobic to hydrophilic and destabilize Helix 8. We overexpressed the mutation in cells and found Akt signaling was disrupted,” explains Yamashita.

According to Yamashita, the findings are the first to connect a genetic variation in microglia with neurodevelopment disorders. Moreover, he hopes that the discovery could become a basis for predictive diagnostics.

“There is no reliable way to diagnose schizophrenia or autism in asymptomatic patients. Deeper understanding of the genetic risk factors will help us develop preventative measures.”

Compounds in cocoa may help delay onset of type 2 diabetes

What if eating chocolate helped prevent and treat diabetes? It’s crazy enough to laugh off.

But here’s the thing: BYU researchers have discovered certain compounds found in cocoa can actually help your body release more insulin and respond to increased blood glucose better. Insulin is the hormone that manages glucose, the blood sugar that reaches unhealthy levels in diabetes.

Of course, there’s a catch.

“You probably have to eat a lot of cocoa, and you probably don’t want it to have a lot of sugar in it,” said study author Jeffery Tessem, assistant professor of nutrition, dietetics and food science at BYU. “It’s the compound in cocoa you’re after.”

When a person has diabetes, their body either doesn’t produce enough insulin or doesn’t process blood sugar properly. At the root of that is the failure of beta cells, whose job it is to produce insulin. The new study, published in the Journal of Nutritional Biochemistry, finds beta cells work better and remain stronger with an increased presence of epicatechin monomers, compounds found naturally in cocoa.

To discover this, collaborators at Virginia Tech first fed the cocoa compound to animals on a high-fat diet. They found that by adding it to the high-fat diet, the compound would decrease the level of obesity in the animals and would increase their ability to deal with increased blood glucose levels.

The BYU team, comprised of graduate and undergraduate students in Tessem’s lab and the labs of Ben Bikman and Jason Hansen (BYU professors of physiology and developmental biology), then dove in and dissected what was happening on the cellular level — specifically, the beta cell level. That’s when they learned cocoa compounds named epicatechin monomers enhanced beta cells’ ability to secrete insulin.

“What happens is it’s protecting the cells, it’s increasing their ability to deal with oxidative stress,” Tessem said. “The epicatechin monomers are making the mitochondria in the beta cells stronger, which produces more ATP (a cell’s energy source), which then results in more insulin being released.”

While there has been a lot of research on similar compounds over the past decade, no one has been able to pinpoint which ones are the most beneficial or how exactly they bring about any benefit — until now. This research shows the epicatechin monomers, the smallest of the compounds, are the most effective.

“These results will help us get closer to using these compounds more effectively in foods or supplements to maintain normal blood glucose control and potentially even delay or prevent the onset of type-2 diabetes,” said study co-author Andrew Neilson, assistant professor of food science at Virginia Tech.

But rather than stocking up on the sugar-rich chocolate bars at the checkout line, researchers believe the starting point is to look for ways to take the compound out of cocoa, make more of it and then use it as a potential treatment for current diabetes patients. This research was funded, in part, thanks to grants from the Diabetes Action Research and Education Foundation and the American Diabetes Association.

Scientists Discover Common Obesity and Diabetes Drug Reduces Rise in Brain Pressure

Research led by the University of Birmingham, published today in Science Translational Medicine, has discovered that a drug commonly used to treat patients with either obesity or Type II diabetes could be used as a novel new way to lower brain pressure.

Raised brain pressure is common in emergency situations such as traumatic brain injury, hydrocephalus and stroke, and is also the cardinal feature of Idiopathic Intracranial Hypertension (IIH). IHH causes disabling daily headaches and severely raised pressure around the nerves in the eye. It also causes permanent vision loss in 25% of untreated people.

Over a three-year period, researchers at the University of Birmingham examined whether GLP-1 agonist drugs – existing drugs used in the treatment of diabetes and obesity – could reduce intracranial pressure in an animal model of raised brain pressure.

Corresponding author Dr Alexandra Sinclair, of the University of Birmingham’s Institute of Metabolism and Systems Research, said: “Treatments to lower brain pressure are lacking and new treatments are desperately needed.

“The current primary treatment in IIH is acetazolamide and this does not work well for many patients, while also having such severe side effects that our previous trials have shown that 48 per cent of patients stop taking it.

“We have shown that the GLP-1 agonist extendin-4 significantly reduces brain pressure rapidly and dramatically, by around 44 per cent with significant effects from just 10minutes of dosing – the biggest reduction we have seen in anything we have previously tested. What’s more, we found that the effects last at least 24 hours.

“These findings are rapidly translatable into a new novel treatment strategy for IIH as GLP-1 agonists are safe and widely-used drugs used to treat diabetes and obesity. They are also potentially game-changing for other conditions featuring raised brain pressure, including stroke, hydrocephalus and traumatic brain injury.

“We are very excited that this novel treatment strategy could make a landmark change for future patient care.”

The findings are due to be presented on September 8th and 9th in Vancouver at the International Headache Society Meeting, followed by the British Endocrine Society meeting in the UK from November 6th to 8th.

The research was carried out in collaboration with Birmingham Health Partners, the University of Copenhagen, and the Department of Neurology at University Hospitals Birmingham NHS Foundation Trust.

The University of Birmingham is now due to begin a clinical trial to test GLP-1 agonist drug in patients with raised brain pressure.

  • The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 5,000 international students from over 150 countries.
  • Botfield et al (2017). ‘Glucagon-like peptide-1 receptor agonists as a therapeutic to reduce intracranial pressure’. Science Translational Medicine.
  • The research was funded by a variety of supporters including the National Institute for Health Research, Medical Research Council, the West Midlands Neuroscience Teaching and Research Fund and the University of Birmingham Research Development Fund.
  • The cause of IIH is unknown and it mainly affects obese women in their 20s and 30s, and has been associated with hormone problems. IIH is becoming an increasingly frequent problem and now affects 20 per 100,000 of obese women.

CRI Scientists Discover Vitamin C Regulates Stem Cell Function and Suppresses Leukemia Development

Not much is known about stem cell metabolism, but a new study from the Children’s Medical Center Research Institute at UT Southwestern (CRI) has found that stem cells take up unusually high levels of vitamin C, which then regulates their function and suppresses the development of leukemia.

“We have known for a while that people with lower levels of ascorbate (vitamin C) are at increased cancer risk, but we haven’t fully understood why. Our research provides part of the explanation, at least for the blood-forming system,” said Dr. Sean Morrison, the Director of CRI.

The metabolism of stem cells has historically been difficult to study because a large number of cells are required for metabolic analysis, while stem cells in each tissue of the body are rare. Techniques developed during the study, which was published in Nature, have allowed researchers to routinely measure metabolite levels in rare cell populations such as stem cells.

The techniques led researchers to discover that every type of blood-forming cell in the bone marrow had distinct metabolic signatures – taking up and using nutrients in their own individual way. One of the main metabolic features of stem cells is that they soak up unusually high levels of ascorbate. To determine if ascorbate is important for stem cell function, researchers used mice that lacked gulonolactone oxidase (Gulo) – a key enzyme that most mammals, including mice but not humans, use to synthesize their own ascorbate.

Loss of the enzyme requires Gulo-deficient mice to obtain ascorbate exclusively through their diet like humans do. This gave CRI scientists strict control over ascorbate intake by the mice and allowed them to mimic ascorbate levels seen in approximately 5 percent of healthy humans. At these levels, researchers expected depletion of ascorbate might lead to loss of stem cell function but were surprised to find the opposite was true – stem cells actually gained function. However, this gain came at the cost of increased instances of leukemia.

“Stem cells use ascorbate to regulate the abundance of certain chemical modifications on DNA, which are part of the epigenome,” said Dr. Michalis Agathocleous, lead author of the study, an Assistant Instructor at CRI, and a Royal Commission for the Exhibition of 1851 Research Fellow. “The epigenome is a set of mechanisms inside a cell that regulates which genes turn on and turn off.  So when stem cells don’t receive enough vitamin C, the epigenome can become damaged in a way that increases stem cell function but also increases the risk of leukemia.”

This increased risk is partly tied to how ascorbate affects an enzyme known as Tet2, the study showed. Mutations that inactivate Tet2 are an early step in the formation of leukemia. CRI scientists showed that ascorbate depletion can limit Tet2 function in tissues in a way that increases the risk of leukemia.

These findings have implications for older patients with a common precancerous condition known as clonal hematopoiesis. This condition puts patients at a higher risk of developing leukemia and other diseases, but it is not well understood why certain patients with the condition develop leukemia and others do not. The findings in this study might offer an explanation.

“One of the most common mutations in patients with clonal hematopoiesis is a loss of one copy of Tet2. Our results suggest patients with clonal hematopoiesis and a Tet2 mutation should be particularly careful to get 100 percent of their daily vitamin C requirement,” Dr. Morrison said. “Because these patients only have one good copy of Tet2 left, they need to maximize the residual Tet2 tumor-suppressor activity to protect themselves from cancer.”

Researchers in the Hamon Laboratory for Stem Cell and Cancer Biology, in which Dr. Morrison is also appointed, intend to use the techniques developed as part of this study to find other metabolic pathways that control stem cell function and cancer development. They also plan to further explore the role of vitamin C in stem cell function and tissue regeneration.

Dr. Morrison is a Professor of Pediatrics at UT Southwestern, a Cancer Prevention and Research Institute of Texas (CPRIT) Scholar in Cancer Research, and a Howard Hughes Medical Institute (HHMI) Investigator. He also holds the Mary McDermott Cook Chair in Pediatric Genetics at UT Southwestern and the Kathryne and Gene Bishop Distinguished Chair in Pediatric Research at Children’s Research Institute at UT Southwestern.

CRI and UTSW co-authors include Dr. Zhiyu Zhao, Assistant Professor at CRI and of Pediatrics at UT Southwestern; Dr. Weina Chen, Associate Professor of Pathology at UT Southwestern; Dr. Corbin Meacham, Dr. Rebecca Burgess, and Dr. Malea Murphy, postdoctoral researchers; and Dr. Ralph DeBerardinis, Associate Professor at CRI, of Pediatrics, and in the Eugene McDermott Center for Human Growth & Development. Dr. DeBerardinis, who holds the Joel B. Steinberg, M.D. Chair in Pediatrics and is a Sowell Family Scholar in Medical Research at UTSW, also is the Director of CRI’s Genetic and Metabolic Disease Program and Chief of the Division of Pediatric Genetics and Metabolism at UTSW.

The National Institutes of Health, HHMI, CPRIT, and donors to the Children’s Medical Center Foundation supported this work.

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.

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.

Research opens possibility of reducing risk of gut bacterial infections with next-generation probiotic

A team of researchers is exploring the possibility that next-generation probiotics – live bacteria that are good for your health – would reduce the risk of infection with the bacterium Clostridium difficile. In laboratory-grown bacterial communities, the researchers determined that, when supplied with glycerol, the probiotic Lactobacillus reuteri produced reuterin, an antibacterial compound that selectively killed C. difficile. The study appears in Infection and Immunity.

C. difficile causes thousands of deaths and billions of dollars in healthcare expenses in the U.S. each year. Although most patients respond to antibiotic treatment, up to 35 percent will relapse and require extended antibiotic treatments,” said first and corresponding author Dr. Jennifer K. Spinler, instructor of pathology & immunology at Baylor College of Medicine, who oversees microbial genetics and genomics efforts at the Texas Children’s Microbiome Center at Texas Children’s Hospital.

C. difficile infections are the most common cause of diarrhea associated with the use of antibiotics. If these bacteria attempt to invade the human gut, the ‘good bacteria,’ which outnumber C. difficile, usually prevent them from growing. However, when a person takes antibiotics, for example to treat pneumonia, the antibiotic also can kill the good bacteria in the gut, opening an opportunity for C. difficile to thrive into a potentially life-threatening infection.

“When repeated antibiotic treatments fail to eliminate C. difficile infections, some patients are resorting to fecal microbiome transplant – the transfer of fecal matter from a healthy donor – which treats the disease but also could have negative side effects,” Spinler said. “We wanted to find an alternative treatment, a prophylactic strategy based on probiotics that could help prevent C. difficile from thriving in the first place.”

“Probiotics are commonly used to treat a range of human diseases, yet clinical studies are generally fraught by variable clinical outcomes and protective mechanisms are poorly understood in patients. This study provides important clues on why clinical efficacy may be seen in some patients treated with one probiotic bacterium but not with others,” said senior author Dr. Tor Savidge, associate professor of pathology & immunology and of pediatrics at Baylor and the Texas Children’s Microbiome Center.

Working in the Texas Children’s Microbiome Center, Spinler and her colleagues tested the possibility that probiotic L. reuteri, which is known to produce antibacterial compounds, could help prevent C. difficile from establishing a microbial community in lab cultures.

An unexpected result with major implications for a preventative strategy

Spinler and Savidge established a collaboration with co-author Dr. Robert A. Britton, professor of molecular virology and microbiology at Baylor and member of the Dan L Duncan Comprehensive Cancer Center.

The Britton lab uses mini-bioreactor arrays – multiple small culture chambers – that provide a platform in which researchers could recreate the invasion of an antibiotic-treated human intestinal community by C. difficile.

“Using the mini-bioreactors model we showed that L. reuteri reduced the burden of C. difficile infection in a complex gut community,” Britton said. “To achieve its beneficial effect, L. reuteri requires glycerol and converts it into the antimicrobial reuterin.”

The literature reports reuterin as a broad-spectrum antibiotic; it affects the growth of a wide variety of bacteria when they are tested individually in the lab. What was intriguing in this study is that reuterin didn’t have a broad-spectrum effect in the mini-bioreactor bacterial community setting.

“I expected reuterin to have an antibacterial effect on several different types of bacteria in the community, but it only affected C. difficile and not the good bacteria, which was exciting because it has major implications for a preventative strategy,” Spinler said.

“Although these results are too preliminary to be translated directly into human therapy, they provide a foundation upon which to further develop treatments based on co-administration of L. reuteri and glycerol to prevent C. difficile infection,” said co-author Dr. Jennifer Auchtung, director of the Cultivation Core at Baylor’s Alkek Center for Metagenomics and Microbiome Research and assistant professor of molecular virology and microbiology at Baylor.

In the future, this potential treatment could be administered prophylactically to patients before they take antibiotics known to disrupt normal gut microbes. The L. reuteri/glycerol formulation would help maintain the healthy gut microbial community and also help prevent the growth of C. difficile, which would result in decreased hospital stay and costs and reduced long-term health consequences of C. difficile recurrent infections.

Prostate Cancer Cells Become ‘Shapeshifters’ to Spread to Distant Organs

Johns Hopkins Kimmel Cancer Center scientists report they have discovered a biochemical process that gives prostate cancer cells the almost unnatural ability to change their shape, squeeze into other organs and take root in other parts of the body. The scientists say their cell culture and mouse studies of the process, which involves a cancer-related protein called AIM1, suggest potential ways to intercept or reverse the ability of cancers to metastasize, or spread.

Results of the research are described in the July 26 issue of Nature Communications.

For the study, the Johns Hopkins scientists mined publically available research data on the genetics and chemistry of hundreds of primary and metastatic cancers included in five studies of men with prostate cancer. They found that a gene called AIM1 (aka “absent in melanoma 1”), which makes proteins also called AIM1, is deleted in approximately 20 – 30 percent of prostate cancers confined to the gland and about 40 percent of metastatic prostate cancers. In addition, the scientists found, on average, two- to fourfold less amounts of AIM1 expression in metastatic prostate cancers compared with normal prostate cells or those from men with prostate cancers confined to the prostate, suggesting that reduction of AIM1 proteins is somehow linked to tumor spread.

Aside from its link to the development of melanoma, a deadly skin cancer, scientists knew little about the function of AIM1.

“Our experiments show that loss of AIM1 proteins gives prostate cancer cells the ability to change shape, migrate and invade. These abilities could allow prostate cancer cells to spread to different tissues in an animal and presumably a person,” says Michael Haffner, M.D., Ph.D., a pathology resident and former postdoctoral fellow at the Johns Hopkins Kimmel Cancer Center who is involved in the research. “It’s not the whole story of what is going on in the spread of prostate cancer, but it appears to be a significant part of it in some cases.”

Looking more closely at the AIM1 gene and its protein levels in prostate cancer tissues, the Johns Hopkins scientists found that many times, even when the gene isn’t completely deleted and its protein production is reduced, its location in the prostate cancer cell is highly abnormal compared with normal prostate cells. This occurs even in primary prostate cancer cells, which have invaded the local structures to form invasive cancer within the prostate gland, say the scientists.

The research team used dyes to track the location of AIM1 proteins in human cells grown in the lab and followed where they appear in normal and cancerous prostate tissues. In normal prostate cells, AIM1 was located along the outside border of each cell and paired up with a protein called beta-actin that helps form the cell’s cytoskeleton, or scaffolding. However, in prostate cancer cells, the protein spread away from the outer border of the cells and no longer paired up with beta-actin.

The scientists found this pattern among a set of human prostate tissue samples including 81 normal prostates, 87 localized prostate cancers and 52 prostate cancers that had spread to the lymph nodes.

“It appears that when AIM1 protein levels drop, or when it’s abnormally spread throughout the cell instead of confined to the outer border, the prostate cancer cells’ scaffolding becomes more malleable and capable of invading other tissues,” says Vasan Yegnasubramanian, M.D., Ph.D., associate professor at the Kimmel Cancer Center and a member of the research team. With AIM1, the scaffold, Yegnasubramanian says, keeps normal cells in a rigid, orderly structure. Without AIM1, cells become more malleable, shapeshifting nomads that can migrate to other parts of the body, he says.

To track how these shapeshifting cancer cells move, the Johns Hopkins scientists, with Steven An, Ph.D., an expert in cellular mechanics and an associate professor at the Johns Hopkins Bloomberg School of Public Health, took a close-up look at AIM1-lacking prostate cancer cells, using sophisticated and quantitative single-cell analyses designed to probe the material and physical properties of the living cell and its cytoskeleton.

They found that cells lacking AIM1 remodeled their scaffolding more than twice as much as cells that had normal levels of AIM1, and that they exert three- to fourfold more force on their surroundings than cells with normal levels of the protein. Such cellular properties are reminiscent of cells with high potential to invade and migrate, An notes.

In addition, the scientists found that AIM1-lacking prostate cells were capable of migrating to unoccupied spaces on a culture dish or invading through connective tissue-like materials at rates fourfold higher than cells with normal levels of AIM1.

Next, the scientific team implanted human prostate cancer cells engineered without AIM1 in five mice and found that the cells spread to other tissues at levels 10 to 100 times more than cells with normal levels of AIM1 that were implanted in five similar mice. However, the AIM1-lacking cells were not able to establish full colonies and tumors at those other tissues, suggesting that AIM1 depletion is not the whole story in the spread and growth of metastatic prostate cancer.

“AIM1 may help prostate cancer cells disseminate throughout the body, but something else may be helping them form full-blown metastatic tumors when they get there,” says Yegnasubramanian.

The Johns Hopkins scientists plan to further study what happens to the AIM1 protein to cause its abnormal location in prostate cancers and identify other proteins and genes that work with AIM1 to cause metastasis. Such studies could help scientists find new drug targets aimed at preventing or reversing prostate metastasis.

First Long-Term Study on Medical Marijuana’s Impact on Opioid Use for Pain

The National Institutes of Health (NIH) has awarded researchers at Albert Einstein College of Medicine and Montefiore Health System a five-year, $3.8 million grant for the first long-term study to test whether medical marijuana reduces opioid use among adults with chronic pain, including those with HIV.

Millions of Americans experience chronic, severe pain as a result of their health conditions.  Many take prescribed opioids, including Oxycodone, to help relieve their symptoms. But given the dangers of opioid use and misuse, both doctors and patients are seeking safe and effective alternatives to manage pain.

“There is a lack of information about the impact of medical marijuana on opioid use in those with chronic pain,” says Chinazo Cunningham, M.D., M.S., associate chief of general internal medicine at Einstein and Montefiore and principal investigator on the grant. “We hope this study will fill in the gaps and provide doctors and patients with some much needed guidance.”

Compared to the general population, chronic pain and opioid use is even more common in people with HIV. Between 25 and 90 percent of adults with HIV suffer from chronic pain. Previous studies have reported that despite the high risk for misuse of opioid pain relievers, adults with HIV are likely to receive opioids to help manage their pain. In recent years, medical marijuana has gained recognition as a treatment option. Twenty-nine states, plus the District of Columbia, have legalized its use; in those states, chronic pain and/or HIV/AIDS are qualifying conditions for medical marijuana use.

Researchers have never studied—in any population—if the use of medical marijuana over time reduces the use of opioids. Additionally, there are no studies on how the specific chemical compounds of marijuana, tetrahydrocannabinol (THC) and cannabidiol (CBD), affect health outcomes, like pain, function, and quality of life. Most studies that have reported negative effects of long-term marijuana use have focused on illicit, rather than medical, marijuana.

“As state and federal governments grapple with the complex issues surrounding opioids and medical marijuana, we hope to provide evidence-based recommendations that will help shape responsible and effective healthcare practices and public policies,” notes Dr. Cunningham.

Dr. Cunningham will enroll 250 HIV-positive and HIV-negative adults with chronic pain who use opioids and who have received certification from their physicians to use medical marijuana, which is provided through approved dispensaries in New York State. Over 18 months, the study subjects will complete web-based questionnaires every two weeks, which will focus on pain levels and the medical and illicit use of marijuana and opioids. They’ll also provide urine and blood samples at in-person research visits every three months. In addition, in-depth interviews with a select group of these participants will explore their perceptions of how medical marijuana use affects the use of opioids.