Individual effects of metformin and PEITC on ovarian cancer lines in vitro. A. Metformin growth inhibition of multiple human ovarian cancer cell lines after 48 hour treatment with control (H2O vehicle) 8 mM metformin. B. PEITC growth inhibition of multiple human ovarian cancer cell lines after 24 hour treatment with control (DMSO vehicle) or 5 μM PEITC. Both metformin and PEITC induce a significant decrease in cell proliferation across all tested cell lines. Cell proliferation and growth inhibition was measured using hemacytometry with Trypan blue exclusion. C. Anchorage dependant colony formation assay on cisplatin resistant SKOV3 line shows significantly fewer colonies in metformin [5 mM] compared to cisplatin [5uM] treatment. D. In CAOV3, metformin is just as effective as cisplatin in reducing colony formation. * p < 0.01; # p < 0.05; n.s. = not significant.