Abstract: Objective To investigated the effect of FLIP-siRNA-mediated gene silencing on sensitivity of ovarian cancer cells to TRAIL. Methods Design and chemically synthesize three siRNAs based on the sequence of FLIP mRNA. They were transfected into ovarian cancer cell line A2780 with LipofectamineTM2000. The FLIP mRNA and protein level were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The FLIP-siRNA which has the most powerful inhibition was selected. Cell growth inhibition and apoptosis induced by TRAIL were observed with MTT assay and flow cytometry, respectively. Results Short siRNAs targeting FLIP down-regulated the mRNA and the protein level of FLIP oncogene in a time-dependent manner（P<0.01）. Cell growth inhibition and apoptosis efficiency induced by TRAIL was obviously enhanced after FLIP-siRNA transfection（P<0.05）. Conclusion FLIP-siRNAs can effectively inhibit FLIP expression in transcriptional and translational level, and greatly enhance TRAIL sensitivity in ovarian cancer cells.

Key words: RNA interference, Double-stranded RNA, FLIP gene, TRAIL, Ovarian Neoplasms