OBJECTIVE: To explore the role of miR-593 in regulating the proliferation of colon cancer cells and the molecular mechanism. METHODS: Bioinformatics analysis identified PLK1 as the possible target gene of miR-593. Luciferase assay was employed to verify the binding between miR-593 and PLK1, and qRT-PCR and Western blotting were used to verify that PLK1 was the direct target gene of miR-593. CCK-8 assay was performed to test the hypothesis that miR-593 inhibited the proliferation of colon cancer cells by targeting PLK1. RESULTS: Luciferase assay identified the specific site of miR-593 binding with PLK1. Western blotting showed a significantly decreased expression of PLK1 in the colon cancer cells transfected with miR-593 mimics and an increased PLK1 expression in the cells transfected with the miR-593 inhibitor as compared with the control cells ( < 0.05). The results of qRT-PCR showed no significant differences in the expression levels of PLK1 among the cells with different treatments ( > 0.05). The cell proliferation assay showed opposite effects of miR-593 and PLK1 on the proliferation of colon cancer cells, and the effect of co-transfection with miR-593 mimic and a PLK1-overexpressing plasmid on the cell proliferation was between those in PLK1 over-expressing group and miR-593 mimic group. CONCLUSIONS miR-593 inhibits the proliferation of colon cancer cells by down-regulating PLK1 and plays the role as a tumor suppressor in colon cancer.
Binding Sites ; Cell Cycle Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms ; metabolism ; pathology ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; In Vitro Techniques ; MicroRNAs ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sincalide ; metabolism ; Transfection

To investigate the induction of cell cycle arrest of human breast cancer MDA-MB231 cells by Di-indolyl pyrrolidine(DIPRD), a pyrrolidine-derived spirooxindoles compounds. The cytotoxic effect of DIPRD on MDA-MB231 cells was detected by CCK-8 method. The cell cycle arrest of MDA-MB231 cells was detected by DAPI/EdU double-staining. Phosphorylation levels of AKT, mTOR, apoptosis-related proteins p53, MDM2, and DNA repair enzyme PARP levels were detected by Western blot. DIPRD inhibited the viability of MDA-MB231 cells by downregulating the number of EdU-positive cells, increase G1 phase and reduce cell number in S/G2 phase, down-regulated the p-AKT(Ser473), p-mTOR, p-p53, cyclin D1, CDK4, and the upregulated the p-AKT(Thr308), p-MDM2 and Cleaved-PARP levels were detected in a dose-dependent manner at 12. 5, 25, and 50 mg/mL. DIPRD may play a role in cell cycle arrest through AKT signaling pathway and induce cell apoptosis.