The Relationship Between Inhibition Of DNA-PKcs Damage To Telomere And Radiosensitivity Of Liver Cancer Cell

Objective: To study the effect of inhibiting DNA-PKcs on the telomere of liver cancer cells,and the relationship between telomere damage and radiosensitivity of liver cancer cells.It provides a theoretical basis for exploring the mechanism of inhibiting DNA-PKcs to increasing the radiosensitivity of the liver cancer cell,and providing new ideas and theoretical basis for the treatment of liver cancer.Methods: HepG2 cells were selected,and NU7026 inhibited DNA-PKcs.The experiment was divided into a blank group,a control group(0.1%DMSO)and a NU7026 group;A blank group,a control group,a NU7026 pretreatment group,a radiation group and a radiation NU7026 pretreatment group.CCK8 assay was used to detect the cell survival rate;Growth curve assay,clone formation assay,and cell scratch assay detected cell proliferation and migration capabilities;The cell apoptosis and cell cycle were detected by flow cytometry;Micronucleus assay detected cell DNA damage;Chromosome analysis assay and chromosome bridge assay detected telomere damage;Western blot was used to detect PCNA,Caspase3,Caspase9 and ATR protein.Result:1.10μM NU7026 treated HepG2 cells for 24,48 and 72 hours,compared with the control group,the survival rate detached was reduced(P<0.05);15μM and 20μM NU7026 treated on HepG2 cells,the cell survival rate was significantly decreased than the blank group and the control group(P<0.05).2.On the third day of DNA-PKcs inhibition,the number of cells in the NU7026 group was lower than the control group(P<0.05).The number of clones in the NU7026 group was less than the control group,and the survival fraction was 93.04%(P<0.05).Inhibition of DNA-PKcs for 48 and 72 hours,PCNA protein decreased in the NU7026group(P<0.05).3.After 72 hours of inhibiting DNA-PKcs,the scratch healing rate was 52.41%,and the scratch healing rate was lower than the control group(P<0.05).4.Inhibiting DNA-PKcs for 24,48 and 72 hours,the apoptosis rate increased in NU7026 group(P<0.05).Inhibiting DNA-PKcs for 12 hours resulted in a slight G2/M phase block.5.Inhibiting DNA-PKcs for 24,48 and 72 hours,the rate of cell micronucleus increased(P<0.05),the number of chromosome fusion and chromosome bridges increased.Inhibiting DNA-PKcs for 24 and 48 hours,compared with the control group,ATR protein increased(P<0.05).6.With the increase of radiation dose and culture time after radiation,the survival rate of HepG2 cells gradually decreased.After 48 hours of radiation,the number of chromosome fusion and chromosome bridges in the NU7026 pretreatment group increased(P<0.05).ATR protein in the NU7026 pretreatment group was more than the control group(P<0.05).7.Inhibiting DNA-PKcs by NU7026 for 24,48,and 72 hours induced varying degrees of telomere damage,and the survival rate of HepG2 cells gradually decreases 24 hours after radiation(P<0.05);After48 hours of radiation,the survival rate of HepG2 cells in NU7026 pretreatment group was significantly reduced(P<0.05).24 hours after radiation,in the growth curve assay,the number of cells in the NU7026 pretreatment group was less than the control group(P<0.05).After radiation,the number of clones in the NU7026 pretreatment group was less than the control group(P<0.05),the cell survival fraction was35.79%.8.48 hours and 72 hours after radiation,the scratch area of HepG2 cells in the NU7026 pretreatment group was larger than that in the control group,and the scratch healing rate was significantly reduced(P<0.05).9.48 hours after radiation,the number of micronucleus in the NU7026 pretreatment group increased(P<0.05).The apoptosis rate of the NU7026 pretreatment group was more than the control group(P<0.05),and Caspase3 and Caspase9 protein in the NU7026 pretreatment group increased(P<0.05).After 4 hours of radiated HepG2 cells,cells in the G2/M phase began to increase;After radiation for 24 hours,the NU7026 pretreatment hours group still blocked the G2/M phase.Conclusion:1.Inhibiting DNA-PKcs can damage telomeres,inhibit HepG2 cell proliferation and cell migration,and promote cell apoptosis.2.Telomere damage HepG2 cells increase telomere damage after radiation.3.After radiation of telomere damaged HepG2 cells,the cell proliferation and migration ability decrease,promote cell apoptosis,block G2/M phase,increase the radiosensitivity of HepG2 cells.