Abstract:

Objective To determine the inhibitory effect of the synthetic RRM1 siRNA on the expression of RRM1 in human gastric cancer AGS cell lines and investigate the effect of RRM1 siRNA on chemosensitivity of AGS cells to oxaliplatin. Methods Three specific RRM1 interference fragment RRM1 siRNA1， RRM1 siRNA2 and RRM1 siRNA3 were constructed and transfected into gastric cancer AGS cells；meanwhile， blank control group and negative control group were set up. The expression of RRM1 mRNA and protein in the AGS cells were detected by qPCR and Western blotting， and the interfering fragment with best transfection effect was selected. CCK-8 and flow cytometry assay were used to determine cell proliferation and apoptosis of AGS cells treated by different concentrations of oxaliplatin. Results With the transfection of specific RRM1 interference fragment， compared with blank control group， the expression level of RRM1 mRNA for three groups of AGS cells（RRM1 siRNA1， RRM1 siRNA2 and RRM1 siRNA3） were reduced by 28％， 40％ and 82％， respectively. The relative protein expression of AGS cells in RRM1 siRNA3 group was 0.135±0.017， lower than 0.641±0.003 and 0.636±0.056 of blank control group and negative control group（P＜0.05）. siRNA3 interfering fragment was used in the following experiments. With different concentrations of oxaliplatin treated in each group for 24 h， the proliferation inhibited rate in RRM1 siRNA3 group was higher than those of the other two groups. The IC50 of oxaliplatin to RRM1 siRNA3 group， blank control group and negative control group were 3.34， 5.85 and 5.13 μmol／L. Gastric cells in RRM1 siRNA3 group treated by 3 μmol／L oxaliplatin for 24 h， the rate of apoptosis was（35.84±2.0）％， higher than（28.26±1.5）％ and（27.32±2.6）％ of negative control group and blank control group（P＜0.05）. Conclusion Interfering the expression of RRM1 can effectively enhance the sensitivity of gastric cancer cells to oxaliplatin. It provides a theoretical support for efficacy prediction of oxaliplatin-based regimen and individualized regimen design.