| Background:Colon cancer is a serious diease to people’s health,and is the third leading cause of cancer-related mortality.Although the 5 year survival rate of early colorectal cancer is about 90%,the survival rate in metastatic colorectal cancer has decreased to about 15%.Invasion and metastasis is the most common cause of death.Colon cancer is a genetic disease involving multiple steps,multiple stages and multiple genes.micro RNA(miRNA)is a single-stranded RNA that is commonly found in plants and animals.The endogenous non-coding small molecule RNA consisting of 21-24 nucleotides can influence the expression of the gene of interest and inhibit the synthesis of a protein,thereby exerting its biological function.micro RNA-490(miR-490),a member of the miRNAs family,is a kind of miRNA,which has been studied in recent years.It is located on chromosome7.Many literatures have reported that miR-490-3P can inhibit the development of many tumors.miR-490-3p can inhibit the occurrence and development of ovarian cancer research shows that,the low expression of miR-490-3p in gastric carcinoma can be made to enhance the carcinogenic effects of Helicobacter pylori by modification of chromatin,miR-490-3p can inhibit the proliferation of lung cancer cells,miR-490-3p can also regulate cell the epithelial mesenchymal transition,which enhance the ability of transfer.It was reported that low expression of miR-490-3p in colon cancer.That the relationship between the low expression of miR-490-3p and the prognosis of patients and the effect of miR-490-3p on the biological behavior of colon cancer cells is still not very clear.In this study,miR-490-3p was studied in colon cancer.Objective:1 To study the expression of miR-490-3p in colon cancer and its relationship with clinical pathological parameters and prognosis;2 To explore the effect of miR-490-3p on the biological behavior of colon cancer cell line SW480.Materials and methods:1 material1.1 tissue samples: from July 2010 to December 2010,a total of 40 pairs of frozen tissue specimens of colorectal cancer were collected;1.2 cell lines: SW480 cell line;1.3 miR-490-3p mimetic and its control were purchased.2 methods2.1 q RT-PCR method was used to detect the expression of miR-490-3p in tissues,and to analyze the relationship between the expression and clinicopathological parameters and prognosis;2.2 Transwell invasion assay was used to evaluate the invasive ability of the cells2.3 cell cycle test(PI staining)was used to detect the cell cycle2.4 the ability of cell clone formation was evaluated by plate clone formation assay;2.5 Western Blot assay expression of EMT related proteins,after overexpression of miR-490-3p2.6 statistical methods: analysis of the relationship between miR-490-3p expression and clinicopathological parameters of the chi square test,survival analysis was performed by Kaplan-Meier method,comparison of two used non paired t test,P< 0.05 was considered statistically significantResults:1 Expression of miR-490-3p in colonic tissue and its clinicopathological features Compared with the corresponding normal colonic mucosa,miR-490-3p was significantly lower in 40 colon cancer tissues(0.87±0.17 vs.1.97±0.39,P=0.01).Analysis of clinical and pathological features of 40 cases,the results showed that the expression of miR-490-3p was correlated with TNM stage and distant metastasis(TNM staging: P = 0.025;Distant metastasis: P = 0.048).Survival analysis showed that the mean survival time of patients with low expression of micro RNA-490-3p(23 cases)was significantly lower than that in high expression group(17 cases).The difference was statistically significant(c2=5.55,P=0.018);2 The expression of miR-490-3p in two transfected groups RT-PCR results showed that the level of miRNA-490-3p in cells of m490 group was higher than that in group m NC after transfection,the difference was statistically significant(m490 group vs.m NC group: 1.04±0.17 vs.58.97±3.04,P <0.001);3 Effects of overexpression of miR-490-3p on the biological behavior of colon SW480 cells3.1 Effects of overexpression of miR-490-3p on invasion ability of colon SW480 cells Compared with the control group transfected with miR-490-3p mimics Negative Control(m NC group),the invasion and metastasis ability of colon cancer cell line SW480 was significantly decreased after transfection with miR-490-3p mimics(m490 group),the difference was statistically significant(m490 group vs.m NC group: 134.80±23.76 vs.214.55±9.55,P =0.048).3.2 Effects of overexpression of miR-490-3p on the expression of EMT-related proteins in colon SW480 cells To further verify the above results,several EMT-related proteins were tested.The expression of neural cadherin(N-cadherin),matrix metalloproteinase(MMP2)and vimentin in the colon cancer cell SW480 with up regulation of miR-490-3p expression was significantly decreased,and epithelial cadherin(E-cadherin)is increased,the difference was statistically significant(m490 group vs.m NC group: N-cad: 0.93 ±0.05 vs.1.07± 0.05,P=0.01,E-cad: 1.20±0.09 vs.0.89±0.09,P<0.001,MMP2: 0.91±0.075 vs.1.10±0.09,P<0.001,vinmentin: 0.84±0.10 vs.1.16±0.10,P<0.001).The results of EMT related proteins were consistent with the transwell cell invasion assay;3.3 Effects of overexpression of miR-490-3p on colon SW480 cells colony-forming ability Compared with control group transfected miR-490-3p mimics Negative Control(m NC group),the colony-forming ability of colonic cancer cell SW480 was significantly decreased after transfection with miR-490-3p mimics(m490 group),the difference was statistically significant(m490 group vs.m NC group: 117±9.17 vs.145.3±13.80,P=0.04).3.4 Effects of overexpression of miR-490-3p on cell cycle of colon SW480 cells It was found that G2-M phase arrest of SW480 cells after transfection with miR-490-3p mimics increased significantly,the difference was statistically significant(m490 group vs.m NC group:5.72±0.62 vs.2.97±1.84,P=0.034)Conclusions:1 The expression of miR-490-3p was significantly lower in colon cancer tissues,and correlated with TNM stage and distant metastasis of tumor.The prognosis of patients with low expression of miR-490-3p was poor.2 Over expression of miR-490-3p can inhibit the invasion of colon cancer cells,weaken the ability of clone formation,and lead to G2-M phase arrest of cancer cells.miR-490-3p may be a new target for colon cancer... |
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