The Biological Effects Of MiR-138,miR-145 On Colon Cancer Caco-2 Cells

BackgroundColon cancer is the third most frequently occurring cancer and the fourth most common causes of cancer-related death worldwide.Although the treatment methods of surgery,chemotherapy,radiotherapy and targeted therapy have developed rapidly in recent years,the metastasis rate and fatality rate are still high.Therefore,further knowledge about the molecular mechanisms of Colon cancer progression is of great importance.MicroRNAs(miRNAs)are noncoding RNAs of approximate 20~25 nt in length that function as post-transcriptional regulators by base-pairing with the complementary sites in the 3’untranslated region(3’-UTR)of the mRNA.Mi RNAs are involved in a wide array of biological processes,such as proliferation,differentiation and apoptosis,etc.ObjectiveTo investigate the effects of mi R-138,miR-145 on proliferation,motility and cell cycle distribution of human colon cancer cell line Caco-2 cells and the effects of miR-138,mi R-145 on cell proliferation-associated protein c-myc expression.In order to further study the biological function of miR-138,miR-145 on colon cancer,and the specific regulation mechanism,so can we provide experimental evidence for early diagnosis and treatment of colon cancer.MethodsMiR-138,miR-145 and negative control plasmid were constructed and Caco-2 cells were selected and cultured.The miR-138,miR-145 and negative control plasmid were transfected into Caco-2 cells by the liposome transfection method.The experiments were consists of three groups: miR-138 group,miR-145 group and negative control(NC)group.Under the fluorescence microscope observe the cell growth and transfection efficiency at different time points.Wound healing assay was used to detect the impact of miR-138 and mi R-145 on Caco-2 cell motility.The change of proliferation of Caco-2 cells was detected by MTT method.The flow cytometry was used to examine the changes of miR-138 and mi R-145 on Caco-2 cell cycle distribution.The total protein were extracted from miR-138 group,miR-145 group and negative control group to compare the difference in expression of proliferation-associated protein c-myc using Western blot.ResultsAfter Caco-2 cells transfected with miR-138,miR-145 and negative control over expression plasmid,the speed of cell wound healing in miR-138 group and miR-145 group was slower than negative control group(P < 0.05).Compared to the negative control group,the cell proliferation of miR-138 group and miR-145 group were also significantly inhibited.MiR-138 group and miR-145 group were compared with the control cells,the percentage of G1-stage cells was increased(P < 0.05),as well as the proportion of G2-stage and S-stage were no obvious change(P > 0.05).C-myc protein expression levels was significantly decreased after over expressing miR-138 and miR-145 in Caco-2cells.ConclusionMiR-138,miR-145 significantly inhibited Caco-2 cell proliferation and motility,led to the cell cycle arrest at G1 phase and slow down cell cycle progression.MiR-138,mi R-145 might decreased the expression of c-myc protein,thereby inhibiting cell proliferation.