Role of STAT3 decoy oligodeoxynucleotides on cell invasion and chemosensitivity in human epithelial ovarian cancer cells

Recent studies have reported that STAT3 activation is associated with poor prognosis in human epithelial ovarian cancer. STAT3 has been proposed to play an important role in ovarian cancer metastasis and chemoresistance. This mechanism, however, is still not thoroughly understood. In this study, to investigate the role of STAT3 on ovarian cancer cells, we used decoy oligodeoxynucleotide (ODN) technology to regulate STAT3 in SKOV3 and OVCAR3 cells in vitro. Cell invasive power and chemo-sensitivity were assessed in the cells transfected with STAT3 decoy ODN and control ODN. Western blot analysis was used to examine the expression of EMMPRIN, P-gp, and Akt. Results showed that STAT3 decoy ODN inhibited cancer cell invasive power and enhanced sensitivity to paclitaxel for SKOV3 and OVCAR3 cells. The mechanism involved the inhibition of EMMPRIN, P-gp, and pAkt by STAT3 decoy ODN. These three proteins were probably the target proteins of STAT3. These findings suggest that STAT3 is a key factor for ovarian cancer metastasis and chemoresistance. STAT3 decoy ODN may prove to be a beneficial therapeutic agent, especially for invasive or chemoresistant ovarian cancer.