Gene Therapy Completely Suppresses Ovarian Cancer Growth In Animal Model

Ovarian cancer is diagnosed in more than 25,000 women in the United States each year, and about 16,000 American women die from the disease annually. Despite aggressive surgery and chemotherapy approaches, the prognosis for ovarian cancer is poor, and most women have a life expectancy of only three to four years after their diagnoses.

In this study, the Pitt investigators inoculated mice with an ovarian cancer cell line. They treated some of the mice immediately with a genetically engineered vaccinia virus containing a gene coding cytosine deaminase, a suicide gene, and delayed treatment of other mice for 30 or 60 days. Control mice were inoculated with ovarian cancer cells but were not given the gene therapy.

The researchers found complete inhibition of tumor growth in the mice that were treated immediately with gene therapy and significant tumor inhibition in the 30- and 60-day delayed treatment mice. In contrast, all non-gene-therapy treated mice either died or were euthanized due to overwhelming buildup of fluid in the peritoneal cavity by 94 days following tumor inoculation.

According to corresponding author David L. Bartlett, M.D., professor of surgery and chief of the division of surgical oncology at the University of Pittsburgh School of Medicine, gene therapy offers an attractive new approach for treating ovarian cancer. "Current treatments for ovarian cancer are fairly harsh. Given their tumor selectivity and cancer killing potential, vaccinia vectors expressing recombinant gene products represents a potent, non-toxic alternative for treating this deadly disease," he said.

Others involved in this research include Xiang Da (Eric) Dong, Mark E. O'Malley, Sri Chalikonda, Zongsheng Guo, Ph.D., and Herbert J. Zeh, M.D., division of surgical oncology, University of Pittsburgh School of Medicine.