Public Release:  Combining cell replication blocker with common cancer drug kills resistant tumor cells

University of Pittsburgh Schools of the Health Sciences

SAN DIEGO, April 4, 2014 - Researchers from the University of Pittsburgh Cancer Institute (UPCI), a partner with UPMC CancerCenter, have found that an agent that inhibits mitochondrial division can overcome tumor cell resistance to a commonly used cancer drug, and that the combination of the two induces rapid and synergistic cell death. Separately, neither had an effect. These findings will be presented Monday at the annual meeting of the American Association for Cancer Research Annual Meeting 2014.

"In our earlier work, we found that blocking production of a protein called Drp1 stopped mitochondria, known as the powerhouses of the cell, from undergoing fission, which is necessary for the cellular division process called mitosis," said Bennett Van Houten, Ph.D., the Richard M. Cyert Professor of Molecular Oncology, Pitt School of Medicine, and leader of UPCI's Molecular and Cell Biology Program. "The loss of this critical mitochondrial protein caused the cells to arrest in mitosis and to develop chromosomal errors, and eventually led the tumor cell into the cell death pathway known as apoptosis."

The researchers blocked Drp1 in breast cancer cell lines with an agent called mitochondrial division inhibitor-1 (mdivi-1) and found that when mdivi-1 and the cancer drug cisplatin were given together, they caused DNA damage, DNA replication stress, and greater than expected apoptosis rates. The synergistic drug combination acted through two independent biochemical pathways that caused the mitochondrial membrane to swell, increasing its permeability and allowing the leak of chemical signals that trigger apoptosis.

"Cisplatin is one of the most widely used cancer drugs today, but some tumors are inherently resistant to it, and many others become resistant, leading to treatment failure," Dr. Van Houten said. "In our studies, this combination overcame cisplatin resistance and caused cancer cell death, which is very encouraging."

The team is testing the regimen's effectiveness in a mouse model of ovarian cancer, a disease that often recurs and no longer responds to cisplatin treatment.

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About UPCI

As the only NCI-designated comprehensive cancer center in western Pennsylvania, UPCI is a recognized leader in providing innovative cancer prevention, detection, diagnosis, and treatment; bio-medical research; compassionate patient care and support; and community-based outreach services. Investigators at UPCI, a partner with UPMC CancerCenter, are world-renowned for their work in clinical and basic cancer research.

About the University of Pittsburgh School of Medicine

As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1998. In rankings recently released by the National Science Foundation, Pitt ranked fifth among all American universities in total federal science and engineering research and development support.

Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see http://www.medschool.pitt.edu.

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Contact: Allison Hydzik
Phone: 412-647-9975
Mobile: 412-559-2431
E-mail: HydzikAM@upmc.edu

Contact: Anita Srikameswaran
Phone: 412-578-9193
E-mail: SrikamAV@upmc.edu

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