Endoplasmic Reticulum Stress Apoptotic Signaling Pathways Are Involved In Colon Cancer Death Induced By MEK Inhibitors

Background Colon cancer is one of the most common malignancies of the digestive tract worldwide and is the third leading cause of cancer-related deaths worldwide.Colorectal cancer,which has the fifth highest mortality rate of all cancers in our country,has posed a serious threat to the health of the population and placed a heavy burden on society and the family economy.Endoplasmic reticulum stress（ER）is a protective mechanism produced by cells in response to various kinds of stress（such as accumulation of acidic wastes,hypoxia and nutrient deficiency）.It can promote cell survival and independently induce cell apoptosis.At the same time,ER stress is closely related to tumor development,aggressiveness and response to cancer treatment.Binimetinib is an effective inhibitor of MEK1/2,and Binimetinib is a non-competitive ATP inhibitor of MEK1 and MEK2.Whether Binimetinib is involved in endoplasmic reticulum stress and induces apoptosis is unclear.Objectives To clarify the effect of Binimetinib on the biological behavior of colon cancer cells,to study the role and mechanism of Binimetinib in the death of colorectal cancer cells caused by endoplasmic reticulum stress,so as to provide a new target for clinical treatment of colon cancer,and to provide a theoretical basis for clinical combination of drugs.Methods1.The effect of Binimetinib on the survival of colon cancer cells（RKO,CaCo₂,SW480 and Lo Vo）was detected by CCK8 experiment.2.Flow cytometry was used to detect the apoptosis of colon cancer cells treated with different concentrations of Binimetinib（RKO,CaCo₂）.3.According to the experimental results of CCK8,the protein was extracted from colon cancer cells treated with different concentrations of Binimetinib（RKO,CaCo₂）for a certain period of time,and the expression of apoptose-related proteins in colorectal cancer cells was detected by WB.4.Colon cancer cells（RKO,CaCo₂）were treated with different concentrations of Binimetinib for a certain period of time and the protein was extracted,and the expression of er stress-related proteins in colorectal cancer cells was detected by WB.5.Binimetinib combined with endoplasmic reticulum stress inducer was used to treat 2types of colorectal cancer cells（RKO,CaCo₂）,and the effect of the combined drug on the survival of colon cancer cells was detected by CCK8 experiment.6.Binimetinib combined with endoplasmic reticulum stress inducer induced colorectal cancer cells（RKO,CaCo₂）,and flow cytometry was used to detect the effect of the combined drug on the apoptosis of colon cancer cells.7.Binimetinib combined with endoplasmic reticulum stress inducers（RKO,CaCo₂）were used to extract total proteins,and the effects of the combined drug on apoptotic proteins of colon cancer cells were detected by WB.Results1.CCK8 results showed that Binimetinib at different concentrations had significant inhibitory effects on the survival rate of CaCo₂,SW480 and Lo Vo in colorectal cancer cells.The difference was statistically significant.（P < 0.05）2.Flow cytometry results showed that,compared with the untreated group,different concentrations of Binimetinib could increase the apoptosis rate of colon cancer RKO and CaCo₂ cells.3.WB results showed that,compared with the untreated group,different concentrations of Binimetinib affected the expression of apoptosis-related protein Cleaved caspase-3,and apoptosis-related protein also increased with the increase of drug concentration.The difference was statistically significant（P<0.05）.4.WB results showed that,compared with the untreated group,the expressions of er stress-related proteins P-EIF-2,ATF4,and CHOP were enhanced after treatment with different concentrations of Binimetinib in colorectal cancer cells,and the differences were statistically significant（P<0.05）.5.CCK8 results showed that Binimetinib combined with endoplasmic reticulum stress agonists（toxocortin and ytomycin）had a significant inhibitory effect on the survival rate of COLORECTAL cancer cells RKO and CaCo₂,and the difference was statistically significant.（P < 0.05）6.Flow cytometry results showed that Binimetinib combined with endoplasmic reticulum stress agonisters（toxocarotin and ytomycin）could further improve the apoptosis rate of Binimetinib in colorectal cancer cells compared with the untreated group.7.WB results showed that,compared with the untreated group,Binimetinib combined with er stress agoner affected the expression of apoptotic protein Cleaved caspase-3,and apoptotic protein was significantly increased in the combined treatment group.The difference was statistically significant（P<0.05）.Conclusions1.Binimetinib can reduce the survival rate of colon cancer RKO,CaCo₂,Lo Vo and SW480 cells,and induce the apoptosis of colon cancer RKO and CaCo₂ cells.2.Binimetinib induced apoptosis of RKO and CaCo₂ in colorectal cancer cells through endoplasmic reticulum stress pathway.3.Enhanced ER stress can further increase the damage of Binimetinib to colon cancer RKO and CaCo₂ cells,and further enhance the apoptosis induced by Binimetinib.