Cisplatin Induces p53-Dependent FLICE-Like Inhibitory Protein Ubiquitination in Ovarian Cancer Cells

Understanding the mechanism of cisplatin (CDDP) action may improve therapeutic strategy for ovarian cancer. Although p53 and FLICE-like inhibitory protein (FLIP) are determinants of CDDP sensitivity in ovarian cancer, the interaction between p53 and FLIP remains poorly understood. Here, using two chemosensitive ovarian cancer cell lines and various molecular and cellular approaches, we show that CDDP induces p53-dependent FLIP ubiquitination and degradation, and apoptosis in vitro . Moreover, we showed that Itch (an E3 ligase) forms a complex with FLIP and p53 upon CDDP treatment. These results suggest that p53 facilitates FLIP down-regulation by CDDP-induced FLIP ubiquitination and proteasomal degradation. [Cancer Res 2008;68(12):4511–7]