摘要
Background MicroRNAs （miRNAs） contribute to tumorigenesis by acting as either oncogenes or tumor suppressor genes. In this study, we investigated the role of miR-145 in the pathogenesis of uveal melanoma. Methods Expression profiles of miRNAs in uveal melanoma were performed using Agilent miRNA array. Quantitative real-time polymerase chain reaction was used to screen the expression levels of miR-145 in normal uveal tissue, uveal melanoma tissue, and uveal melanoma cell lines. Lenti-virus expression system was used to construct MUM-2B and OCM-1 cell lines with stable overexpression of miR-145. Cell proliferation, cell cycle, and cell apoptosis of these miR-145 overexpression cell lines were examined by MTT assay and flow cytometry respectively. The target genes of miR-145 were predicted by bioinformatics and confirmed using a luciferase reporter assay. The expression of insulin-like growth factor-1 receptor （IGF-1R）, insulin receptor substrate-1 （IRS-1） proteins was determined by Western blotting analysis. IRS- 1 was knocked down in OCM-1 cells. TUNEL, BrdU, and flow cytometry assay were performed in IRS-1 knocked down OCM-1 cell lines to analyze its function. Results Forty-seven miRNAs were up regulated in uveal melanoma and 61 were down regulated, miR-145 expression was significantly lower in uveal melanoma sample and the cell lines were compared with normal uveal sample. Overexpression of miR-145 suppressed cell proliferation by blocking the G1 phase entering S phase in uveal melanoma cells, and promoted uveal melanoma cell apoptosis. IRS-1 was identified as a potential target of miR-145 by dual luciferase reporter assay. Knocking down of IRS-1 had similar effect as overexpression of miR-145. Conclusion miR-145 might act as a tumor suppressor in uveal melanoma, and downregulation of the target IRS-1 might be a potential mechanism.
Background MicroRNAs （miRNAs） contribute to tumorigenesis by acting as either oncogenes or tumor suppressor genes. In this study, we investigated the role of miR-145 in the pathogenesis of uveal melanoma. Methods Expression profiles of miRNAs in uveal melanoma were performed using Agilent miRNA array. Quantitative real-time polymerase chain reaction was used to screen the expression levels of miR-145 in normal uveal tissue, uveal melanoma tissue, and uveal melanoma cell lines. Lenti-virus expression system was used to construct MUM-2B and OCM-1 cell lines with stable overexpression of miR-145. Cell proliferation, cell cycle, and cell apoptosis of these miR-145 overexpression cell lines were examined by MTT assay and flow cytometry respectively. The target genes of miR-145 were predicted by bioinformatics and confirmed using a luciferase reporter assay. The expression of insulin-like growth factor-1 receptor （IGF-1R）, insulin receptor substrate-1 （IRS-1） proteins was determined by Western blotting analysis. IRS- 1 was knocked down in OCM-1 cells. TUNEL, BrdU, and flow cytometry assay were performed in IRS-1 knocked down OCM-1 cell lines to analyze its function. Results Forty-seven miRNAs were up regulated in uveal melanoma and 61 were down regulated, miR-145 expression was significantly lower in uveal melanoma sample and the cell lines were compared with normal uveal sample. Overexpression of miR-145 suppressed cell proliferation by blocking the G1 phase entering S phase in uveal melanoma cells, and promoted uveal melanoma cell apoptosis. IRS-1 was identified as a potential target of miR-145 by dual luciferase reporter assay. Knocking down of IRS-1 had similar effect as overexpression of miR-145. Conclusion miR-145 might act as a tumor suppressor in uveal melanoma, and downregulation of the target IRS-1 might be a potential mechanism.
基金
This study was supported by grants from the National Natural Science Foundation of China （No. 81272981） and Natural Sciences Fundation of Beijing, China （No. 7112031）.
