Abstract:

Abstract:Objective  To research the relationship between miR-21 and radiation sensitivity of cervical cancer HeLa cells,and to elucidate the possible action mechanism of miR-21 in apoptosis and autophagy of cells.Methods The HeLa cells were divided into mock groups (transfected with miR-21 NC,mimics, inhibitor NC or inhibitor) and 4 Gy irradiation groups(transfected with miR-21 NC,mimics, inhibitor NC or inhibitor with irradiation).The miR-21 expression was detected by real-time PCR;colony-forming assay was used to detect the changes of radiation sensitivity;the apoptosis and autophagy were analyzed by FACS assay;the target gene of miR-21 was predicted by bioinformatics methods;Dual-luciferase Reporter Assay was used to demonstrate the binding of miR-21 and targets;the expression of beclin1 protein was measured by Western blotting method.Results After 4 Gy radiation,compared with mock group,the expression of miR-21 was increased remarkably (P<0.05). Colony-forming assay showed that there were no changes of radiation sensitivity of HeLa cells after overexpressing or inhibiting miR-21  compared with miR-21 NC or miR-21 inhibitor NC groups(P>0.05). Compared with miR-21 NC＋4 Gy group,the apoptotic rate of HeLa cells in　miR-21 mimics+4 Gy　group was  increased (P<0.05).After transfection with  miR-21 inhibitor,compared with miR-21 inhibitor NC  group,the apoptotic rate of HeLa cells in duced by radiation was  decreased (P<0.05).Compared with miR-21 NC  group,the autophagy rate was increased after transfection with miR-21 mimics (P<0.05).After transfection with miR-21 mimics and radiation,the expression level of beclin1 protein was increased(P<0.05) compared with miR-21 NC+4 Gy group.Conclusion Beclin1 is the target gene of miR-21 in HeLa cells.Overexpression of miR-21 can increase the radiation-induced apoptosis and autophagy,but has on influence in radiation sensitivity of HeLa cells.

Key words: miR-21, cervical neoplasms, HeLa cells, radiation sensitivity, apoptosis, autophagy