miR-21 Influence on Radiation Sensitivity of Cervical Cancer HeLa Cells

Abstract

Objective: This study discussed the relation of miR-21 and radiation sensitivity of cervical cancer HeLa cells, clarify the possible action mechanism of miR-21 on cell apoptosis and autophagy change. Method Cevical cancer HeLa cells were divided into sham-irradiated group and 4Gy radiotherapy group, respectively transfected miR-21 NC (negative control), miR-21 mimics, miR-21 inhibitor NC and miR-21 inhibitor. Real-time fluorescent quantitative PCR detection were performed to check the miR-21 expression level before and after the irradiation. Colony forming experiment was to observe the effect of miR-21 on radiation sensitivity of HeLa cells. Flow cytometry was to detect cell apoptosis and autophagy cell percentage. Bioinformatics method was adopted to predict the target genes of miR-21. The combination of miR-21 and target gene 3’UTR were verified by luciferase reporter gene analysis. Expression level of related protein beclin1 were detected by Western Blotting method. Results: compared to shamirradiated group, the miR-21 expression level increased significantly in 4Gy radiotherapy group (p<0.05). In colony forming experiment, compared to miR-21 NC group, the HeLa cells radiation sensitivity had no obvious changes in miR-21 mimics group (p>0.05). Compared to miR-21 inhibitor NC group, the HeLa cells radiation sensitivity also had no evident changes in miR-21 inhibitor group (p>0.05). Compared to miR-21 NC +4Gy group, HeLa cell apoptosis rate increased significantly in miR-21 mimics + 4Gy group. Compared to miR-21 inhibitor NC group, HeLa cell apoptosis rate decreased apparently in miR-21 inhibitor group. Compared to miR-21 NC group, the autophagy rate of inR-21 mimics group could increase (p<0.05). Compared to miR-21NC+4Gy group, the autophagy rate in miR-21 mimics+4Gy could increase (p<0.05). Compared to miR-21 NC+4Gy group, the protein expression level increased in miR- 21 mimics_4Gy group (p<0.05). Conclusion: the taregt genes beclin1 of miR-21 were detected. Over expression of miR-21 promoted the radiation induced apoptosis and autophagy, but had no direct impact on cervical cancer HeLa cell radiation sensitivity