Studies On Molecular Effects Of Quinoline Derivative In Human Colon Cancer

Nowadays,Cancer becomes one of the major issues that threaten human health Among them,colon cancer has a high mortality rate and poor prognosis.China is a high-risk area of colon cancer.The treatment of colon cancer mainly includes surgical resection,radiation therapy,and chemical drug treatment.At present,the clinical drugs used for the treatment of colon cancer are very limited,and it is of great significance to find out novel anti-colon cancer drugs.In recent years,anticancer drugs based on quinoline and its derivatives have many applications in the treatment of lung cancer,liver cancer,and colon cancer and so on.The reason why quinoline is favored by more and more researchers is mainly because it is a kind of pharmaceutical intermediate with multiple excellent biological activities.However,the anticancer activity of quinoline drugs still needs to be further improved,and its toxic effects also need to be better controlled.Therefore,based on quinoline,we have made some modifications to its chemical structure,hoping to develop new quinoline derivatives,which can not only further improve the anti-tumor activity of the new drugs,but also reduce the toxicity in vivo.After in vitro,the cell viabilities were determined by CCK-8 counting kit in different cancer cells,the quinoline derivative RQ-43 had the most significant effect to inhibit the cell viabilities.Therefore,we used it as a candidate compound for antitumor drugs and conducted a preliminary study on the molecular mechanism of its inhibition of tumor growth.The aim of this study was to investigate the effect of RQ-43 on colonic cancer cell activity in vitro and in vivo and its mechanism.Programmed cell death is an important mechanism for effective killing of tumor cells by chemotherapy drugs.It mainly includes apoptosis and autophagy.The results of this study show that RQ-43 can induce apoptosis and autophagy in colon cancer cells.On the one hand,western blot analysis of apoptosis marker protein and Annexin-V FITC/PI double staining assay showed that RQ-43 could induce colon cancer cell death.However,pretreatment of cells with the caspase inhibitor Z-VAD-fmk failed to block RQ-43-induced apoptosis in colon cancer cells.Therefore,it can be concluded that the cell death induced by RQ-43 does not depend on Caspase pathway.When we pretreated HCT116 with JNK inhibitor SP600125,Annexin-V FITC/PI double staining assay was able to block the cell apoptosis in some extent by RQ-43 and increased the drug sensitivity of HCT116.It can be inferred that the apoptosis induced by RQ-43 is dependent on the activation of JNK signaling pathway.On the other hand,when RQ-43 stimulates colon cancer cells,it is found that it can induce autophagy.At the same time,the fluorescence spot aggregation of mCherry-EGFP-LC3B and chloroquine demonstrated that RQ-43 could induce autophagy flow in HCT116.When we pretreated HCT116 with SP600125,we found no significant changes in LC3B-II protein levels compared to the untreated group,thus we inferred that RQ-43-induced HCT116 autophagy does not depend on the activation of JNK.When we treated the HCT116 ATG5-/-cells with RQ-43,we found that ATG5 DKO cells were more sensitive to drugs than wild-type cells,thus we inferred that ATG5 is a key factor for RQ-43 to induce autophagy.All the experimental results preliminarily demonstrated that RQ-43 can effectively induce colon cancer cell apoptosis and autophagy in vitro.In addition to in vitro studies,we also established a CT26-CL25 colon cancer cell BALB/c mouse xenograft tumor model to explore the activity of RQ-43 in vivo against colon cancer cells.By comparing the tumor growth curve,animal survival rate,and tumor weight,we found that RQ-43 also has a good tumor suppressor effect in vivo.Therefore,this study shows that RQ-43 can be used as an inducer of apoptosis and autophagy,and it has potential application prospects in the chemotherapy of colon cancer.