Abstract 754: Development of death receptor agonists for breast cancer therapy

Abstract TRAIL and death receptor (TRAIL-R1 and TRAIL-R2) agonistic antibodies have been shown to induce apoptosis in cancer cells and their clinical trials have produced positive results. However, there are no small organic molecular weight compounds that bind to TRAIL-death receptors and induce apoptosis specifically in cancer cells. The purpose of this study was to identify and characterize death receptor agonists (DRAs)/ small molecular weight organic compounds that induce apoptosis in breast cancer cells. The pharmacokinetics of the DRA with a single oral dose was characterized in nude mice. Blood was collected over 72 hour period after drug administration, and analyzed by HPLC-MS/MS for plasma drug concentration. The Cmax, tmax, and AUC of DRA was measured. DRAs inhibited cell viability and colony formation, and induced apoptosis in estrogen-dependent (MCF-7) and independent (MDA-MB-231 and MDA-MB-468) human breast cancer cell lines, but had no effect on human normal mammary epithelial cells and hepatocytes. The ability of DRAs to induce apoptosis was further enhanced in the presence of TRAIL. DRAs formed active TRAIL-DISC (death-inducing signaling complex) similar to that of TRAIL. DRAs inhibited the growth of orthotopically implanted MDA-MB-231 and MDA-MB-468 tumors in nude mice. Histological examination of tumor tissues derived from DRAs-treated nude mice revealed massive caspase-3 activation and apoptosis. Pharmacokinetic data demonstrate that DRA possesses a long terminal half-life, which is acceptable for further clinical development. In conclusion, we have identified, for the first time, DRAs that can be used in the clinic for the treatment of human breast cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 754.