Abstract: Objective：To investigate the expression of β-catenin in several human ovarian cancer cell lines and its effect on cisplatin resistance. Methods：The protein level of β-catenin in two cisplatin-resistant cell lines（C13K，SKOV-3），two cisplatin-sensitive cell lines（OV2008，A2780），A2780，A2780-cis，COC10 and COC1-cis was examined by real-time PCR and western blotting analysis. Expression of β-catenin in ovarian cancer cells was knockdown by siRNA transfection. The effect of β-catenin silencing on cisplatin resistance was examined by trypan blue staining and flowcytometry. The change of apoptosis-related proteins were examined by western blotting analysis. Results：The expression of β-catenin was upregulated in cisplatin-resistant cell lines（C13K，SKOV-3）compared with cisplatin-sensitive cell lines. The expression of β-catenin in cisplatin-resistant A2780 and COC1 was also higher than that in paretnal A2780 and COC1 cells. siRNA targeting β-catenin effectively knockdown expression of β-catenin in ovarian cancer cells. Silencing of β-catenin enhanced the sensitivity of cisplatin-resistant cells（C13K，SKOV-3）to cisplatin. β-catenin siRNA also resulted in more apoptosis compared with control siRNA. Cisplatin treatment in β-catenin silencing cells induced the expression of apoptosis-related protein p53 and caspase-3. Conclusions：These finding suggested that β-catenin was upregulated in cisplatin-resistant cells. Gene silencing of β-catenin enhanced sensitivity to cisplatin in cisplatin-resistant cells by inducing more cisplatin-mediated apoptosis.

Key words: Ovarian neoplasms, Cell line, tumor, Beta catenin, Cisplatin, Drug resistance