Inhibit PARP1 By Marein Enhances The Sensitivity Of HCT116 Cells To Cisplatin Chemotherapy

Objective:To investigate the effect of marein on enhancing the sensitivity of human colon cancer cell line HCT116 to cisplatin chemotherapy by inhibiting PARP1.Methods:1.MTT experiment was used to detect the effect of cisplatin(8 μM)on the proliferation ability of colon cancer cell line HCT116 after 24 h pretreatment with different concentrations of marein(2.5 μM,5 μM,10μM and 20μM)and the effect of cisplatin(4μM,8μM,12 μM and 16μM)on the proliferation ability of HCT116 cells after 24 h pretreatment with marein 10μM.2.Colony cloning experiment detected the effect of 8μM cisplatin on HCT116 colony formation of colon cancer cells after marein 10μM and olaparib10μM pretreatment for 24 h.3.Western Blot detected the effect of 8μM cisplatin on PARP1 and PARP1 catalytic product PAR after marein 10μM and olaparib 10μM pretreatment for 24 h.Western Blot detected the effect of 8μM cisplatin on DNA damage marker-H2 AX and cell apoptosis marker Cleaved PARP after marein 10μM and olaparib 10μM pretreatment for 24 h.4.Immunofluorescence experiment was performed to detect the effect of 8μM cisplatin on γ-H2 AX after pretreatment with 10μM of Marein and 10μM of Olaparib for 24 h.Results:1.The results of MTT showed that different concentrations of Marein(2.5μM,5μM,10μM,20μM)had no significant effect on the proliferation of colon cancer cell HCT116.Compared with the 8μM cisplatin chemotherapy group alone,the proliferation ability of colon cancer cell HCT116 in the different concentrations of Marein(2.5μM,5μM,10μM,20μM)+ cisplatin chemotherapy group was significantly reduced,and it was dependent on the concentration of Marein(all P<0.05).Pretreatment with 10μM Marein for 24 h increased the sensitivity of colon cancer cell HCT116 to different concentrations of cisplatin chemotherapy(4μM,8μM,12μM,16μM)(all P<0.05).2.The results of the clonal colony experiment showed that after pretreatment with 10μM marein and 10μM olaparib for 24 h,the colony forming ability of colon cancer cell HCT116 was significantly reduced under 8μM cisplatin chemotherapy(all P<0.05).3.Western Blot results showed that 10μM marein and 10μM olaparib pretreatment had no effect on PARP1 expression of HCT116 in colon cancer cells,but significantly inhibited the formation of PAR,a PARP1 catalysed product,under 8 cisplatin chemotherapy,and significantly enhanced cleaved PARP1 and γ-H2 AX expression.4.Immunofluorescence results showed that after pretreatment with10μM marein and 10μM olaparib for 24 h,the expression of γ-H2 AX was significantly increased under 8μM cisplatin chemotherapy(all P<0.05).Conclusion: Marein can inhibit the formation of PAR,the catalytic product of PARP1 in HCT116 colorectal cancer cells,thereby enhancing the sensitivity of cisplatin chemotherapy.