Antioxidants May Enhance Efficacy of Chemotherapy on Glioblastoma

MedicalResearch.com Interview with:

Dr. Scott Litofsky, MD  Division of Neurological Surgery University of Missouri-Columbia School of Medicine Columbia, MO 65212 

Dr. Litofsky

Dr. Scott Litofsky, MD
Division of Neurological Surgery
University of Missouri-Columbia School of Medicine
Columbia, MO 65212 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Many patients take over-the-counter medications to held their cancers. Some of these remedies may be helpful; others are potentially harmful. Anti-oxidant medications are frequently selected by patients as they are inexpensive and available.

We were approached by a high school student, Macy Williams (one of the authors) to do some research in our laboratory when she won a research scholarship (the 2016 Emperor Science Award) from Stand Up to Cancer. She worked with us several times per week doing experiments during her senior year of high school. When she graduated, we continued the work that she started.

We studied effects of Vitamin D3, Melatonin, and alpha-Lipoic Acid on glioblastoma cells, a highly malignant brain tumor. We included experiments of these agents alone and in combination with Temozolomide, a chemotherapy agent used as standard of care in glioblastoma. The work was done in cultured cells, measuring growth and survival of cells. We used concentrations that could be achieved by oral intake of the drugs.

We found that antioxidant medications, particularly alpha Lipoic Acid, had synergistic effects with Temozolomide – that is Temozolomide impair glioblastoma cell growth and survival better when combined with an antioxidant. The mechanism of action may be through reactive oxygen species.  Continue reading

Targeting CD44s May Make Glioblastoma More Sensitive To Clinical Treatment

MedicalResearch.com Interview with:

Chonghui Cheng, M.D., Ph.D. Associate Professor Department of Molecular & Human Genetics Lester & Sue Smith Breast Center Baylor College of Medicine Houston, TX77030

Dr. Cheng

Chonghui Cheng, M.D., Ph.D.
Associate Professor
Department of Molecular & Human Genetics
Lester & Sue Smith Breast Center
Baylor College of Medicine
Houston, TX77030

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Understanding the mechanisms that give cancer cells the ability to survive and grow opens the possibility of developing improved treatments to control or cure disease. In the case of glioblastoma multiforme, the deadliest type of brain cancer, abnormal EGFR signaling is frequently observed.

Treatment with the EGFR inhibitor erlotinib attempts to kill cancer cells. However, the clinical benefit of treatment with this and other EGFR inhibitors has been limited by the development of drug resistance.

Scientists at Baylor College of Medicine discovered that the molecule CD44s seems to give cancer cells a survival advantage. Eliminating this advantage by reducing the amount of CD44s resulted in cancer cells being more sensitive to the deadly effects of the drug erlotinib.

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Mibefradil Dihydrochoride with Hypofractionated Radiation for Recurrent Glioblastoma

MedicalResearch.com Interview with:

Nataniel Lester-Coll, MD Chief Resident in Radiation Oncology at Yale New Haven, Connecticut

Dr. Nataniel Lester-Coll

Nataniel Lester-Coll, MD
Chief Resident in Radiation Oncology at Yale
New Haven, Connecticut 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Recurrent Glioblastoma Multiforme (GBM) has limited treatment options and the prognosis is poor. Mibefradil diydrochloride was identified using a high-throughput compound screen for DNA double stranded break repair inhibitors. Mibefradil was found to radiosensitize GBM tumor cells in vitro and in vivo. Based on these findings, we sought to determine the maximum tolerated dose of mibefradil and radiation therapy in a Phase I recurrent GBM study. Eligible patients with recurrent  Glioblastoma Multiforme received Mibefradil over a 17 day period, with hypofractionated radiation (600 cGy x 5 fractions). There are 18 patients currently enrolled who have completed treatment. Thus far, there is no clear evidence of radionecrosis. A final dose level of 200 mg/day was reached as the maximum tolerated dose. The drug was very well tolerated at this dose. We saw intriguing evidence of enhanced local control in selected cases. Patients enrolled in a translational substudy who received Mibefradil prior to surgery were found to have adequate levels of Mibefradil in resected brain tumor tissue.

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Recurrent Glioblastoma: Treatment with Cytomegalovirus Immunotherapy

MedicalResearch.com Interview with:
Dr Andrea Schuessler
QIMR Berghofer Medical Research Institute
Herston, Queensland 4006

MedicalResearch.com: What are the main findings of the study?

Dr . Schuessler: Recurrent glioblastoma is a very aggressive brain cancer and most patients do not survive much longer than 6 months. Our study has assessed a novel immunotherapy and treated 10 patients with late stage cancer. The treatment did not have any serious side effects and most of the patients have survived much longer than the expected 6 months. Importantly, four of the 10 patients have not shown signs of disease progression during the study period with one of them still being cancer free four years after the treatment.
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Scientists map genetic mutations in the second-most common form of brain cancer, oligodendroglioma

Johns Hopkins Kimmel Cancer Center scientists have completed a comprehensive map of genetic mutations occurring in the second-most common form of brain cancer, oligodendroglioma. The findings, reported in the Aug. 4 issue of Science, also appear to reveal the biological cause of the tumors, they say.

To create the map, the scientists sequenced protein-coding genes in seven oligodendroglioma tissue samples, and focused attention on recurring mutations in two genes not previously associated with these tumors – CIC and FUBP1. The investigators say that CIC and FUBP1 are known to regulate cell-signaling processes, and CIC mutations have been rarely linked to sarcoma, breast and prostate cancers.

More mutations in the two genes were found in an additional 27 oligodendroglioma samples. In all, two-thirds of the samples studied had CIC and FUBP1 mutations.

“Whenever we find genes mutated in a majority of tumors, it is likely that the pathway regulated by that gene is critical for the development and biology of the tumor,” says Nickolas Papadopoulos, Ph.D., associate professor of oncology at the Johns Hopkins Kimmel Cancer Center.

In brain cancer, the Hopkins investigators say CIC and FUBP1 mutations may be the “missing link” in what scientists describe as a “two-hit” theory of cancer development. The theory is based on the fact that each cell in the human body has two copies of 23 chromosomes containing thousands of protein-producing genes. If a gene on one chromosome is damaged or deleted, the other copy makes up for the loss of protein. But if the second copy fails as well, the cell cannot make the proper protein and may become cancerous.

In oligodendrogliomas, the “first hit” has long been known to occur in regions of chromosome 1 and 19, which fuse together resulting in a loss of many genes on both chromosomes. Up to 70 percent of oligodendroglioma patients have these DNA fusions, and most of them respond better to chemotherapy and radiation than those who lack the deletions in the chromosomes. For more than a decade, researchers have been looking for evidence of a “second hit” in specific mutated genes that allow oligodendrogliomas to develop.

In the current study, the Johns Hopkins investigators found mutations in the remaining copies of the CIC and FUBP1 genes on chromosomes 1 and 19, suggesting that these mutations represent the second hit needed to create cancer.

“Thanks to the Human Genome Project and advances in cancer genome sequencing, a single study can now resolve decade-old questions and reveal the genetics of this brain cancer,” says Kenneth Kinzler, Ph.D., professor and co-director of the Ludwig Center at Johns Hopkins. “Knowing the genetic roadmap of a cancer is the key to attacking it.”

Oligodendrogliomas account for up to 20 percent of brain cancers and more commonly occur in younger people aged 30 to 45. The cancer forms most often in the frontal lobe of the brain in cells that coat neurons. Median survival of 10 years is considered far better than other brain cancers. Oligodendrogliomas are treated initially with surgery, followed by chemotherapy and radiation.

The research team says its next step will be to test whether patients with CIC and FUBP1 mutations have the same favorable prognosis as those who have the chromosome 1 and 19 fusion, says Chetan Bettegowda, M.D., Ph.D., chief resident in the Department of Neurosurgery at Johns Hopkins.

“We can focus now on when these mutations develop during tumor formation, whether they can guide prognosis, and how they might form targets for therapy,” says Bettegowda.

Bettegowda says the gene map uncovered mutations in other genes, such as PIK3CA, which have been well-studied in cancer. It is possible, he says, that oligodendroglioma patients with mutations in PIK3CA or other genes could be enrolled in current clinical trials using experimental therapies that target these mutations.

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Funding for the research was provided by the Virginia and D.K. Ludwig Fund for Cancer Research, the Pediatric Brain Tumor Foundation, the Duke Comprehensive Cancer Center Core, the Burroughs Wellcome Fund, the James S. McDonnell Foundation, state funding from Sao Paulo (FAPESP), the National Cancer Institute and National Institutes of Health.

Contributors to the research include Nishant Agrawal, Yuchen Jiao, Mark Sausen, Laura D. Wood, Ralph H. Hruban, Fausto J. Rodriguez, Daniel P. Cahill, Gregory Riggins, Victor Velculescu and Bert Vogelstein of Johns Hopkins; Roger McLendon, Darell Bigner and Hai Yan of Duke University; and Sueli Mieko Oba-Shinjo and Suely Kazue Nagahashi Marie of the University of Sao Paulo, Brazil.