Abstract:

Background and purpose: The miR-224 in a variety of malignant tumors is overexpression, however, its expression and function in colon cancer are not clear. The aim of this study was to investigate the expression of miR-301 in colon cancer tissues and demonstrate the regulative effects of miR-301 ASO on the proliferation and apoptosis of colon cancer cell in vitro and in vitro. Methods: The expression of miR-301 in 120 colon cancer tissues and their adjacent tissues was detected by real-time quantitative PCR method. After transfection with miR-301ASO, the biological effects of miR-301 in SW620 cells were measured by MTT assay, the colony formation experiment, flow cytometry and the in vivo experiment. Results: The expression level of miR-301 was found to be overexpressed in 63.33% (76/120) of the colon cancer cases (P<0.05). miR-301 expression in SW620 cells (transfection with miR-301 ASO, 0.09±0.01) was significantly less than control group (0.50±0.07, P=0.00). MTT assay results showed that SW620 cells survived rate at 24, 48 and 96 h decreased greatly after transfection with miR-301ASO (P=0.00). Clone formation assay revealed that miR-301 ASO group colony formation rate (5.33%±0.74%) was significantly lower than the control group (33.33%±8.38%, P=0.00). In vivo study further confirmed that miR-301ASO could inhibit the proliferation of SW620 cells (P<0.05), and miR-301ASO group grew substantially slow compared with the negative control group (P=0.00). Flow cytometry indicated that the apoptotic index in miR-301 ASO group (15.68±1.46) was significantly higher than the control group (3.36±0.88, P=0.02). In addition, the Bcl2 mRNA and protein were significantly decreased after reduce the expression of miR-301 (P=0.00, P=0.00). Conclusion: MiR-301 was overexpressed in human colon cancer. Reduce the expression of miR-301 can effectively inhibit the growth of colon cancer cells and promote apoptosis. MiR-301 may become a new target for the regulation of gene expression in colon cancer.

Key words: MiR-301, Colon cancer, Antisense oligonucleotides