| BackgroundCapecitabine is a new fluorouracil chemotherapeutic agent.It is widely used in adjuvant therapy of colon cancer because of its activation in tumor and oral convenience especially in patients with advanced colon cancer.It was found that capecitabine could induce apoptosis of tumor cells,but its effect on colon cancer cells and the mechanism of inducing apoptosis were unclear.Capecitabine is a new type of fluorouracil chemotherapeutics,which is widely used in adjuvant therapy of colon cancer,especially for advanced patients because of its activation in tumors and convenient oral administration.It has been found that capecitabine can induce apoptosis of human colon cancer cells,but its effect on colon cancer cells and the mechanism of inducing apoptosis are still unclear.Endoplasmic reticulum stress is a protective mechanism for cells to respond to various stress stimuli.It can not only promote cell survival through activating a series of signal transduction pathways,but also independently induce apoptosis.It can also affect the production of resistance by regulating the activity of tumor cells.It is not clear whether endoplasmic reticulum stress is involved in capecitabine-induced colon cancer cell death.ObjectivesTo clarify the effect of capecitabine on the biological behavior of colon cancer cells,and to explore the role of endoplasmic reticulum stress in the induction of colon cancer cell death by capecitabine,so as to provide a new strategy for clinical treatment of colon cancer.Methods1.Human colon cancer RKO,HCT116 cells were cultured in vitro.The survival rate of RKO,HCT116 cells treated with different concentrations of capecitabine was detected by CCK-8 assay,and the effect of capecitabine alone on the survival rate of colon cancer RKO,HCT116 cells was observed.To determine the optimal effective concentration of capecitabine for toxicity damage to colon cancer cells in vitro.2.The expression level of apoptosis-related protein Cleaved caspase-3 in human colon cancer RKO and HCT116 cells after capecitabine treatment with different concentration was detected by Western blotting,and the apoptosis rate of colon cancer RKO cells was detected by flow cytometry.3.The effects of capecitabine at different concentrations on the expression of endoplasmic reticulum stress signaling pathway proteins Bip,eIF-2?,p-eIF-2? and CHOP were detected by Western blotting.4.The effect of capecitabine combined with endoplasmic reticulum stress activator on the survival rate of colon cancer RKO,HCT116 cells was detected by CCK-8 assay.5.The expression of apoptosis-related protein Cleaved caspase-3 in colon cancer RKO,HCT116 cells treated with capecitabine combined with endoplasmic reticulum stress activator was detected by Western blotting.The apoptosis rate of colon cancer RKO cells was detected by flow cytometry.Results1.The results of CCK-8 assay showed that the survival rate of RKO,HCT116 cells in different concentrations of capecitabine intervention group was significantly lower than that in control group,and the effect was enhanced with the increase of capecitabine concentration.The difference was statistically significant(P<0.05).2.Compared with the control group,the expression of apoptosis-related protein Cleaved caspase-3 in the capecitabine intervention group was obviously increased than that in the control group(P<0.05).The results of flow cytometry showed that capecitabine at different concentrations could increase the apoptosis rate of colon cancer RKO cells.3.The results of Western blotting assay showed that the expression of endoplasmic reticulum stress-associated protein Bip,p-eIF-2? and CHOP in capecitabine intervention group was markedly increased than that in control group(P<0.05).4.The results of CCK-8 showed that the survival rate of RKO and HCT116 cells in capecitabine combined with endoplasmic reticulum stress activator group was significantly lower than that in capecitabine alone group(P<0.05).5.The results of Western blotting showed that the expression of Cleaved caspase-3 protein in colon cancer cells of capecitabine combined with endoplasmic reticulum stress activator group was significantly higher than that of capecitabine alone group(P<0.05).The results of flow cytometry showed that capecitabine combined with endoplasmic reticulum stress agonist could further enhance the apoptosis rate induced by capecitabine.Conclusions1.Capecitabine can decrease the survival rate of colon cancer RKO,HCT116 cells and induce apoptosis of colon cancer RKO,HCT116 cells.2.Endoplasmic reticulum stress is involved in capecitabine-induced apoptosis of colon cancer RKO,HCT116 cells.This effect is to activate endoplasmic reticulum transmembrane protein,promote the expression of CHOP protein through eIF-2? phosphorylation pathway,and induce cell apoptosis.3.Enhanced endoplasmic reticulum stress can further increase the damage induced by capecitabine in colon cancer RKO,HCT116 cells and further enhance the apoptosis induced by capecitabine. |
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