Analysis Of T-cadherin Expression In Colon Cancer And The Effect Of 5-Aza-CdR On T-cadherin Expression And Malignant Phenotype Of Colon Cancer Cells

Objective: To investigate the expression of tumor suppressor gene T-cadherin in colon cancer and its relationship with clinicopathological features,and to analyze the effect of5-Aza-Cd R(5-Aza-2-deoxycytidine)on the expression of T-cadherin and the proliferation,invasion and apoptosis of colon cancer cells.Methods: 40 fresh samples of colon cancer and paracancerous tissues were collected,and total RNA and total protein were extracted respectively.The m RNA expression level of T-cadherin was detected by RT-qPCR(real-time fluorescence quantitative reverse transcription polymerase chain reaction),and the protein expression level of T-cadherin was detected by western blot.The relationship between the m RNA expression level of T-cadherin and sex,age,tumor size,depth of tumor invasion,lymph node metastasis and differentiation of patients with colon cancer was analyzed.The survival curve was ploted by kaplan-meier method to analyze the effect of T-cadherin m RNA expression on the survival and prognosis of patients with colon cancer.Furthermore,the colon cancer cell line HT-29 was treated with methylation inhibitor5-Aza-Cd R.RT-qPCR and western blot methods were used to analyze the expression of T-cadherin,CCK-8(cell counting kit-8)assay was used to analyze the proliferation ability,Transwell assay was used to analyze the invasive ability,and flow cytometry was used to analyze apoptosis.Results: The results of RT-qPCR showed that the m RNA expression level of T-cadherin in colon cancer tissues(1.94±0.53)was significantly lower than that in adjacent tissues(4.04±0.77)and the difference was statistically significant(t=12.61,P<0.0001).The results of western blot showed that the protein expression of T-cadherin in colon cancer tissues was also significantly lower than that in adjacent tissues(t=4.602,P<0.05).The analysis of T-cadherin m RNA expression level and clinicopathological features of patients with colon cancer showed that the expression level of T-cadherin was correlated with lymph node metastasis(F=5.316,P=0.0093)and differentiation(F=5.807,P=0.0064),but not with other pathological variables including sex,age,tumor size and depth of tumor invasion(P>0.05).The results of kaplan-meier survival analysis showed that the survival time of T-cadherin high expression group was significantly longer than that of low expression group(χ2=3.888,P<0.05).After treatment with methylation inhibitor 5-Aza-Cd R,the m RNA and protein expression of T-cadherin in HT-29 cells were significantly up-regulated.The results of cell function assay showed that compared with the untreated group,5-Aza-Cd R treatment inhibited the proliferation and invasion of HT-29 cells,and promoted apoptosis.Conclusion: T-cadherin acts as tumor suppressor gene in colon cancer and may be a target for colon cancer patients treated with DNA methylation inhibitors.