Inhibition of Hec1 expression enhances the sensitivity of human ovarian cancer cells to paclitaxel
Abstract
Qing-qing MO#, Ping-bo CHEN#, Xin JIN, Qian CHEN, Lan TANG, Bei-bei WANG, Ke-zhen LI, Peng WU, Yong FANG, Shi-xuan WANG, Jian-feng ZHOU, Ding MA, Gang CHEN*
Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
Aim: Hec1, a member of the Ndc80 kinetochore complex, is highly expressed in cancers. The aim of this study was to explore the role and mechanism of action of Hec1 with respect to the cytotoxicity of paclitaxel in ovarian cancer.
Methods: Thirty ovarian cancer samples and 6 normal ovarian samples were collected. Hec1 expression in these samples was determined with immunohistochemistry. Ovarian cancer cell lines A2780, OV2008, C13K, SKOV3, and CAOV3 and A2780/Taxol were examined. Cell apoptosis and cell cycle analysis were detected with flow cytometric technique. siRNA was used to delete Hec1 in the cells. The expression of related mRNAs and proteins was measured using RT-PCR and Western blot analysis, respectively.
Results: Hec1 expression was significantly higher in ovarian cancer samples than in normal ovarian samples, and was associated with paclitaxel-resistance and poor prognosis. Among the 6 ovarian cancer cell lines examined, Hec1 expression was highest in paclitaxel-resistant A2780/Taxol cells, and lowest in A2780 cells. Depleting Hec1 in A2780/Taxol cells with siRNA decreased the IC50 value of paclitaxel by more than 10-fold (from 590±26.7 to 45.6±19.4 nmol/L). Depleting Hec1 in A2780 cells had no significant effect on the paclitaxel sensitivity. In paclitaxel-treated A2780/Taxol cells, depleting Hec1 significantly increased the cleaved PARP and Bax protein levels, and decreased the Bcl-xL protein level.
Conclusion: Hec1 overexpression is associated with the progression and poor prognosis of ovarian cancer. Inhibition of Hec1 expression can sensitize ovarian cancer cells to paclitaxel.
Keywords: Hec1; ovarian cancer; paclitaxel; siRNA; mitotic checkpoint; apoptosis; cell cycle
This project was supported by National Natural Science Foundation of China (81272859; 81230038; 81101962; 81025011; 81101962; 81071663); Nature and Science Foundation of Hubei Province (2011CBD542) and Grants from the Fundamental Research Funds for the HUST(2012TS058).
#These authors contributed equally to this paper.
* To whom correspondence should be addressed.
E-mail gumpc@126.com
Received 2012-08-06 Accepted 2012-12-20
Keywords:
Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
Aim: Hec1, a member of the Ndc80 kinetochore complex, is highly expressed in cancers. The aim of this study was to explore the role and mechanism of action of Hec1 with respect to the cytotoxicity of paclitaxel in ovarian cancer.
Methods: Thirty ovarian cancer samples and 6 normal ovarian samples were collected. Hec1 expression in these samples was determined with immunohistochemistry. Ovarian cancer cell lines A2780, OV2008, C13K, SKOV3, and CAOV3 and A2780/Taxol were examined. Cell apoptosis and cell cycle analysis were detected with flow cytometric technique. siRNA was used to delete Hec1 in the cells. The expression of related mRNAs and proteins was measured using RT-PCR and Western blot analysis, respectively.
Results: Hec1 expression was significantly higher in ovarian cancer samples than in normal ovarian samples, and was associated with paclitaxel-resistance and poor prognosis. Among the 6 ovarian cancer cell lines examined, Hec1 expression was highest in paclitaxel-resistant A2780/Taxol cells, and lowest in A2780 cells. Depleting Hec1 in A2780/Taxol cells with siRNA decreased the IC50 value of paclitaxel by more than 10-fold (from 590±26.7 to 45.6±19.4 nmol/L). Depleting Hec1 in A2780 cells had no significant effect on the paclitaxel sensitivity. In paclitaxel-treated A2780/Taxol cells, depleting Hec1 significantly increased the cleaved PARP and Bax protein levels, and decreased the Bcl-xL protein level.
Conclusion: Hec1 overexpression is associated with the progression and poor prognosis of ovarian cancer. Inhibition of Hec1 expression can sensitize ovarian cancer cells to paclitaxel.
Keywords: Hec1; ovarian cancer; paclitaxel; siRNA; mitotic checkpoint; apoptosis; cell cycle
This project was supported by National Natural Science Foundation of China (81272859; 81230038; 81101962; 81025011; 81101962; 81071663); Nature and Science Foundation of Hubei Province (2011CBD542) and Grants from the Fundamental Research Funds for the HUST(2012TS058).
#These authors contributed equally to this paper.
* To whom correspondence should be addressed.
E-mail gumpc@126.com
Received 2012-08-06 Accepted 2012-12-20