Abstract: Objective: To explore the effect of silencing REV3 and MMS2 gene in reversing oxaliplatin (L-OHP) resistance of human colon carcinoma THC8307/L-OHP cell line. Methods: The real - time fluorescent quantitative PCR ( qRT -PCR) was used to detect MMS2 expression in L-OHP-resistant THC8307/L-OHP cells and THC8307/L-OHP cells transfected with MMS2/REV3-RNAi plasmid vecto or empty plasmid vector. The difference in MMS2 and REV3 expression was compared among the groups. MTT assay, Rhodamine 123 assay and Flow – cytometric analysis were sequentially used to detect transfection of THC8307/L-OHP cells to L-OHP drug sensitivity, apoptosis on treatment with L-OHP．The protein expression of MMS2 and REV3 in THC8307/L-OHP cells was detected by immunofluorescence . Results: Compared to the control group, the half inhibition concentration ( IC50) and resistance index(RI) of L-OHP in experimental group cells lower (P < 0.05), apoptosis on treatment with L-OHP increased ( P < 0.05).Furthermore,the protein expression of MMS2 and REV3 was downregulated in experimental group cells than that in the control group (P<0.05) .Conclusion: Silencing REV3 and MMS2 gene from Oxaliplatin-resistant human colon cancer cells enhances the drug-sensitivity to L-OHP and induces apoptosis.

Key words: RNA interference, MMS2, REV3, THC8307/L-OHP cell , cell apoptosis.