Abstract 1586: Oral administration of HIV-protease inhibitors reduces ovarian tumor growth in vivo

Abstract INTRODUCTION: Ritonavir boosted lopinavir (LPV/r) is an FDA approved HIV-protease inhibitor combination that is a well tolerated and preferred treatment for HIV patients. Ritonavir is a potent irreversible inhibitor of cytochrome P450 isoform 3A (CYP3A) which can substantially increase bioavailability of lopinavir in vivo. This combination of lopinavir and ritonavir has been shown to increase the efficacy of reducing viral load in AIDS patients. HIV patients taking antiretroviral protease inhibitors such as LPV/r have a lower incidence of HIV associated malignancies such as non-Hodgkin's lymphoma, cervical cancer and Kaposi's sarcoma, leading to the hypothesis that these drugs have antineoplastic activity. Given the need for novel treatment approaches in ovarian cancer, we are investigating the antineoplastic effects of LPV/r, in vivo. METHODS: A xenograph model of ovarian cancer is used to assess the antineoplastic effect of LPV/r in vivo. Oral doses of LPV/r dissolved in corn oil are administered to mice over the course of 2-3 weeks. Tumor area and mouse weight are monitored. After 2-3 weeks tumors are harvested and analyzed. RESULTS: Preliminary results indicate that LPV/r administered orally in combination with a high fat diet inhibits tumor growth in vivo without inducing weight loss. In contrast, the dose of intraperitoneal cisplatin required to attain a similar antineoplastic effect resulted in significant weight loss and morbidity. CONCLUSIONS: Because protease inhibitors can induce both apoptotic and non-apoptotic ovarian cancer cell death in vitro and in vivo, these drugs may circumvent chemoresistance due to alterations in apoptotic response. Our data suggests that LPV/r may also have clinical application in the treatment of ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1586. doi:10.1158/1538-7445.AM2011-1586