Significance Of CD44 Expression In Colon Cancer Chemotherapy And Intervention Research

Background:Recently,the prevalence and mortality of colon cancer in China have increased every year.The incidence rank of colon cancer is among the top five of cancer dieases.The formation of drug resistance of tumor cells caused by postoperative chemotherapy of colon cancer and the subsequent recurrence and metastasis are the main reasons for the failure of treatment of colon cancer.At present,studies have shown that cancer stem cells(CSC)may be one of the reasons for the formation of drug resistance of tumors.It has been found that the expression of CD44 molecules in colon cancer tissues is increased.And some researchers believe that CD44 can be used as a surface molecular marker of colon cancer stem cells.Increased expression of CD44 molecules may lead to increased drug resistance in tumor cells.The mechanism of the increased expression of CD44 in colon cancer drug resistance is currently unknown.Objective:Preliminary study on the role of CD44 in the formation of drug resistance in colon cancer cells and evaluate the inhibitory effect of curcumin against CD44~+colon cancer cells.Methods:1.Using bioinformatics method to analyze the relationship between the expression level of CD44 in colon cancer tissue and the occurrence of colon cancer.2.After treatment against colon cancer cells with low-dose of chemotherapy drugs(5-FU),Western Blotting,RT-PCR,and tumor sphere formation experiments were used to detect the expression level of CD44molecule and the change of CSC characteristics of colon cancer cells.3.Using RNA-Seq to sequence and detect the transcriptome profile changes of colon cancer cells treated with chemotherapy drugs.4.Western Blotting and RT-PCR were used to detect the expression of CD44 in colon cancer cells after the transfection with ELF3 si RNA and the treatment of 5-FU.5.Western Blotting,MTT,and clone formation experiments were used to verify the inhibitory effect of curcumin against CD44~+colon cancer cells.Results:The results of bioinformatics analysis showed that the expression level of CD44 molecules in colon cancer tissues was significantly higher than that in normal adjacent tissues.After a period of low-dose chemotherapy drugs treatment,the expression levels of CD44 in colon cancer cells were up-regulated,and the stemness of cancer cells were also observed to be enhanced.The results of RNA-Seq indicated that the treatment with chemotherapy drugs could specifically increase the expression level of ELF3,one of the members of ETS transcription factor family in colon cancer cells.The subsequent RT-PCR and Western blotting experiments also confirmed the above results.After the transfection of ELF3 si RNA and the treatment of low-dose chemotherapeutic drugs such as 5-FU,it was observed that the CD44 expression was down-regulated in colon cancer cells.In addition,this study found that curcumin can inhibit the proliferation of colon cancer cells,and also inhibit chemo-resistant colon cancer cells.Curcumin can inhibit the colony formation and migration ability of colon cancer cells and inhibit the appearance of stemness characteristics in colon cancer cells.Curcumin can reduce the expression level of CD44 molecules on the surface of colon cancer cells and has a specific inhibitory effect against CD44~+colon cancer cells.Conclusion:1.Treatment with low-dose chemotherapeutic drugs can increase the expression of CD44 molecules in colon cancer cells.2.Low-dose chemotherapeutic drugs treatment can specifically up-regulate ELF3transcription factor,a member of the ETS family,which is correlated with the increase of CD44 expression in colon cancer cells.3.Curcumin has an inhibitory effect on colon cancer cells,especially against CD44~+ colon cancer cells.