Influences of combination of chemotherapy and autophagy inhibitor on the calreticulin expression in colon cancer cells

Objective 　To investigate the influence of chemotherapy combined with autophagy inhibitor on apoptosis and calreticulin (CRT) expression on colonic cancer cells. Methods 　The colon cancer cells HCT116 were taken as the target in the present study. The inhibition rates (IC50) of chemotherapeutics oxaliplatin, 5-Fu and SN-38 were assessed by MTT assay. The changes in CRT expression on the membrane of HCT116 and apoptosis were determined with flow cytometry before and after treatment with chemotherapeutics. CRT location in HCT116 was detected by fluorescent immunoassay before and after treatment with chemotherapeutic agents. The influence on HCT116 autophagy was determined by Western blotting after treatment with these chemotherapeutic agents. The changes in CRT expression on HCT116 membrane and apoptosis were determined with flow cytometry before and after treatment with the chemotherapeutics combined with autophagy inhibitor chloroquine (CQ). Results 　The ratio of apoptosis and membrane expression of CRT were elevated 12 hours after treatment with Oxaliplatin, 5-Fu and SN38, but without statistical significance. Fluorescent immunoassay showed a transposition of CRT from cytoplasm to the membrane after oxaliplatin treatment. Western blotting revealed that oxaliplatin, 5Fu and SN38 induced autophagy of HCT116 cells, and the autophagy was inhibited by the addition of CQ. Flow cytometric analysis indicated that the percentages of annexin V+ cells and membrane expression of CRT were higher after treatment with the chemotherapy agents combined with CQ. The upregulation of CRT expression on membrane was obviously higher after treatment with oxaliplatin combined with CQ than that before the treatment with these agents (P=0.027). Conclusion 　Oxaliplatin combined with CQ may increase the apoptosis rate of HCT116 cells and upregulate CRT expression in the membrane. DOI: 10.11855/j.issn.0577-7402.2016.04.03