Abstract 1618: Tolfenamic Acid Inhibits Ovarian Cancer Cells Growth and Decreases the Expression of c-Met and Survivin Through Suppressing the Transcription Factors Sp1 and Sp3

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC The aberrant expression of hepatocyte growth factor (HGF) and its receptor c-Met are associated with poor prognosis in a variety of human malignancies including ovarian cancer. Survivin, which belongs to inhibitor of apoptosis gene family, plays an important role in ovarian tumor resistance to chemo- and radiotherapy. Specificity protein (Sp) transcription factors regulate the expression of c-Met and survivin. We have previously shown that the non-steroidal anti-inflammatory drug, Tolfenamic acid (TA), induces the degradation of Sp proteins in cancer cells and tumors. Our aim was to explore the anti-ovarian cancer activity of TA in an in vitro model, as preliminary screening to investigate the therapeutic applications of this small molecule. We developed three ovarian cancer cell-lines, (SKOV3-AF1, SKOV3-AF2, and SKOV3-AF3) which express red fluorescent protein (RFP), derived from the original SKOV-3 line. The AF1 and AF2 lines are more resistant to IFNα-2b and are more tumorigenic in nude mice than the parental SKOV-3 cells. The inhibitory effects of TA on ovarian cancer cells were tested using SKOV-3-derived cells. Cells were grown in the presence of DMSO (vehicle) or TA at increasing concentrations (25, 50 and 100 µM) and cell viability assay was performed using the Cell Titr Glo kit (Promega) at 24, 48, and 72 h, post-treatment. Cell lysates were prepared from cells exposed to DMSO or 50 µM TA for 48 h and the expression of Sp proteins (Sp1 and Sp3), c-Met and survivin was analyzed using Western blot analysis. SKOV-3-derived cells showed marked inhibition with TA treatment and this effect was dose and time dependent. At the maximal dose (100 µM), TA treatment showed significant inhibitory response (RFP:67%; AF1:96%;AF2:88%; AF3:92%) at 48 h post-treatment, while the response at 50 µM TA was 30-60% (RFP:34%; AF1:58%; AF2:59%; AF3:60%). TA-induced cell proliferation arrest was associated with the decreased expression of Sp1, Sp3, c-Met and survivin. These data clearly suggest that TA has a profound inhibitory effect on ovarian cancer cell proliferation, presumably through the degradation of Sp proteins. These studies also suggest that targeting c-Met through Sp proteins degradation could be a promising strategy in the therapeutic applications for ovarian cancer. In addition to its tumor suppressant effects, TA can also enhances tumor response to chemo- and/or radiotherapy due to its inhibitory actions on survivin expression. Using small molecules like TA to target key transcription factors associated with ovarian cancer growth and progression can be a promising treatment approach. TA is currently in Phase I clinical trial at M. D. Anderson Cancer Center Orlando to test on upper GI cancer patients. 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 1618.