UM School of Medicine Researchers Identify Mechanism for Treating Cancer Cells

Finding Could Lead Pave Way for Expanded Use of Powerful Cancer Drug

Researchers at the University of Maryland School of Medicine (UMSOM) have identified a surprising new mechanism that may significantly expand use of an important cancer drug, called a PARP inhibitor. These drugs are currently only approved to be used in those with certain mutations in the BRCA1 or BRCA2 genes that are associated with breast and ovarian cancers. The new findings were published online last week in the Proceedings of the National Academy of Science (PNAS) journal in collaboration with a group at Johns Hopkins School of Medicine.

In the new study, the investigators determined a chemotherapy drug called Azacytidine (AZA) can cause certain cancer cells that do not have a BRCA mutation to respond very well to therapies that specifically target cells with these gene mutations. They found the drug activates an inflammation pathway that causes the release of inflammatory proteins called cytokines in the tumor cells. This inflammatory response in the cancer cells tricks them into acting as if they have been infected with a virus, a process known as “viral mimicry”. The inflammatory-like signal then directly causes the cancer cells to make a change in DNA damage repair genes. This change causes the cells to resemble those with a BRCA mutation, thus making them sensitive to killing with a PARP inhibitor.

In a previous 2019 study also published in the journal PNAS, the group determined that lung cancer cells given AZA respond to a PARP inhibitor as if they have BRCA mutations, but the underlying causes were not known. “We now understand that the inflammation changes described above directly link to inducing ‘BRCA-ness’ in cells that do not have these mutations,” explained Feyruz V. Rassool, PhD, Professor of Radiation Oncology at UMSOM and a researcher in the Experimental Therapeutics Program of the University of Maryland Greenebaum Comprehensive Cancer Center (UMGCCC).

The above new findings provide further evidence to test whether PARP inhibitors can  effectively treat cancer cells without BRCA mutations once they have BRCA-ness induced by AZA. (PARP inhibitors – which block an enzyme that helps repairs damaged DNA in cells --  are currently approved only to treat those cancers with BRCA mutations.)

In fact, the researchers recently helped launched an early phase clinical trial, combining an AZA-like drug and a PARP inhibitor for patients without BRCA mutations who have advanced breast cancer. While the trial is primarily being conducted at Indiana University, the investigator team at UMSOM and Johns Hopkins will evaluate inflammatory processes in tumor biopsies and blood samples from the study patients both before and after treatment.

The new PNAS study was co-authored by Michael Topper, PhD, Instructor of Oncology at Hopkins, UMSOM postdoctoral Fellow Lena Mclaughlin, PhD, and Stephen Baylin, MD, Chief of Cancer Biology at Johns Hopkins University School of Medicine. It was funded by Stand Up to Cancer, a charitable initiative founded in 2008 by nine women in the entertainment industry to accelerate groundbreaking research and bring new treatments to cancer patients as quickly as possible. Funding for the current study was also provided by the National Cancer Institute, NIH and the Adelson Medical Research Foundation as well as the Hodson Trust and the Evelyn Glick Fund.

“Identifying how inflammation is linked to cancer-causing processes is foundational work that has broad implications,” said E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs, UM Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor and Dean, University of Maryland School of Medicine. "This translational research will hopefully lead to exciting new avenues for treatment to improve the lives of cancer patients.”

About the University of Maryland School of Medicine

Now in its third century, the University of Maryland School of Medicine was chartered in 1807 as the first public medical school in the United States. It continues today as one of the fastest growing, top-tier biomedical research enterprises in the world -- with 45 academic departments, centers, institutes, and programs; and a faculty of more than 3,000 physicians, scientists, and allied health professionals, including members of the National Academy of Medicine and the National Academy of Sciences, and a distinguished two-time winner of the Albert E. Lasker Award in Medical Research.  With an operating budget of more than $1.2 billion, the School of Medicine works closely in partnership with the University of Maryland Medical Center and Medical System to provide research-intensive, academic and clinically based care for nearly 2 million patients each year. The School of Medicine has more than $540 million in extramural funding, with most of its academic departments highly ranked among all medical schools in the nation in research funding. As one of the seven professional schools that make up the University of Maryland, Baltimore campus, the School of Medicine has a total population of nearly 9,000 faculty and staff, including 2,500 student trainees, residents, and fellows. The combined School of Medicine and Medical System (“University of Maryland Medicine”) has an annual budget of nearly $6 billion and an economic impact more than $15 billion on the state and local community. The School of Medicine faculty, which ranks as the 8th highest among public medical schools in research productivity, is an innovator in translational medicine, with 600 active patents and 24 start-up companies. The School of Medicine works locally, nationally, and globally, with research and treatment facilities in 36 countries around the world. Visit medschool.umaryland.edu

About the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center

The University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center is a National Cancer Institute-designated comprehensive cancer center in Baltimore. The center is a joint entity of the University of Maryland Medical Center and University of Maryland School of Medicine. It offers a multidisciplinary approach to treating all types of cancer and has an active cancer research program. It is ranked among the top 20 cancer programs in the nation by U.S. News & World Report. www.umgccc.org.