miR-195 induces apoptosis and modulates expression of some invasion and angiogenesis genes in human colon cancer

Downregulation of miR-195 has been reported in colon cancer tissues. Furthermore, it has been shown that miR-195 can serve as a tumor suppressor by targeting cell cycle and anti-apoptotic genes in some cancers. Therefore we aimed to investigate the possible impact of miR-195 overexpression on multiple features of two human colon cancer cell lines including apoptotic rate and expression of some invasion, angiogenesis and apoptosis genes. Caco2 and SW480 human colon cancer cells were cultured in DMEM+10% FBS and transfected with a synthetic miR-195 mimic using HiPerFect transfection reagent (Qiagen). Transfection was repeated after 3 days and at the end of the 7th day the cells were collected and assessed for apoptosis by flow cytometry using Annexin-V/FITC. Expression of some invasion and angiogenesis markers was evaluated by quantitative real-time PCR. In miR-195 transfected Caco2 cells, DLL4, SNAI1, VIM and ZEB2 and in miR-195 transfected SW480 cells, DLL4, SNAI1, SNAI2, and ZEB1 were downregulated. Investigation of the angiogenesis profile showed that VEGFA, HIF1A and HIF1B in Caco2 cells, and VEGFA and HIF1A in SW480 cells were downregulated after transfection by miR-195 mimic. Exogenous induction of miR-195 also induced apoptosis in both cell lines as assessed by Annexin-V/FITC staining and flow cytometry. Our results are indicating a tumor suppressor role for miR-195 in colorectal cancer. This may have important implications for treatment of colorectal malignancies. However further mechanistic and in vivo experiments would be required in order to provide enough evidence for this purpose.