[Study on RNA interference silencing hMSH2 induces the reversal chemo-resistance of ovarian carcinoma cell line OC3/TAX300].

OBJECTIVE To investigate the reversal effect of hMSH2 small interference RNA(siRNA) on chemo-resistance of ovarian carcinoma cell line OC3/TAX300, explore the clinical significance. METHODS The specific hMSH2 siRNA (experimental group) and non-specific hMSH2 siRNA (negative control group) was designed, synthesized and transfected into ovarian carcinoma cell line OC3/TAX300. The expression mRNA and protein levels of hMSH2 were detected by real-time reverse transcription (RT)-PCR and western blot. The cell proliferation was detected by methyl thiazolyl tetrazolium(MTT) method after 12, 24, 48, 72 hours of 2 µg/ml taxol, the apoptosis rate after 24, 48 hours of 2 µg/ml taxol was analyzed by flow cytometry. Morphological changes and ultramicrostructure of cells after 48 hours of 2 µg/ml taxol were observed with transmission electron microscope. RESULTS (1) The mRNA levels of hMSH2 were 0.004 ± 0.000, 0.053 ± 0.006 and 0.057 ± 0.012 in experimental group, negative control group and non-infected group, respectively. The protein levels of hMSH2 were 0.19 ± 0.04, 1.00 ± 0.07 and 0.95 ± 0.03 in experimental group, negative control group and non-infected group, respectively. (2) Compared with the non-infected group and the negative control group. The cell proliferation was effectively inhibited after 12, 24, 48, 72 hours of 2 µg/ml taxol (P < 0.05). The cell cycle was arrested at G2/M phase, the apoptotic rate was significantly increased after 24, 48 hours of 2 µg/ml taxol (P < 0.05). The experimental group after 48 hours of 2 µg/ml taxol was found to have more visible cell shrinkage, more serious chromatin margination, nucleus condensation, fragmentation and apoptotic body formation, nucleolus disappeared, markedly swollen mitochondria, mitochondrial cristae disappeared and other signs of apoptosis. While the nucleus was located in the cells of the central and nucleolus is clear, only mild chromatin pyknosis and marginalized, mild swelling of mitochondria in the control group and blank group. CONCLUSION siRNA targeting hMSH2 may reverse the chemo-resistance of ovarian carcinoma cell line OC3/TAX300 and may become a treatment or a new direction in the adjuvant therapy of ovarian cancer.