Abstract 4066: Combination metformin and ODC siRNA inhibit human melanoma proliferation and migration

Abstract

Abstract Metformin can exert an antiproliferative effect on human tumor cells through the AMP-activated kinase (AMPK) pathway. Ornithine decarboxylase (ODC) is a key enzyme in polyamine biosynthesis pathway in cancer cell proliferation and tumor progression. We hypothesized that the combination of Metformin and small interfering RNA (siRNA) against ODC could inhibit human melanoma cell growth and migration in vitro. Human melanoma cell line cells (SK-MEL23, MEL1861, MEL938, MEL3910, and MEL888) were evaluated. ODC siRNA and contol siRNA were transfected into the human melanoma cells using lipofectamine per manufacturer's instructions (Santa CruZ. CA). Transfected cell were then treated with 1uM, 2uM, 5uM Metformin and assess for cell proliferation and migration assay at various time points up to 72 hours. Cell proliferation assay was performed in triplicates using Cell Titer Blue Assay system according to manufacturer's protocol (Promega). Migration was assessed by creating an artificial homogenous wound onto a cell culture monolayer with a sterile plastic 10µl micropipette tip. Migration of cells into the wound was observed and photographed up to 48 hours. A total of three areas were selected randomly from each well and the cells in three wells of each group were quantified. All Data were presented as means ± SD for the three separate experiments. For comparison between groups, the student's t test was used and p< 0.05 was considered to be statically significant. Human melanoma cells were infected with ODC siRNA or control siRNA. On quantitative RT-PCR and Western blot analysis, >95% suppression of ODC expression was achieved. The siRNA-ODC significantly inhibited cells growth up to 50% at 72 hour (P<0.01). Inhibition of melanoma cell proliferation was also observed with Metformin in a dose-dependent fashion in all 5 melanoma cell line cells. Combination of ODC siRNA and Metformin significantly inhibited cell growth compared to ODC siRNA or MF alone (P<0.01) in all 5 melanoma cell line cells. The addition of Metformin to siRNA-ODC also significantly inhibited melanoma migration in the wounding assay model. Metformin treatment and inhibition of ODC expression can have anti-proliferative effect on human melanoma cells. The combination also retard melanoma cell migration in a wounding model. The combination of Metformin and ODC inhibition may be a novel treatment strategy for human melanoma. 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 4066. doi:10.1158/1538-7445.AM2011-4066