Rui Zhang1,2, Rui Liu3, Chang Liu1,2, Yahan Niu1,2, Jianguo Zhang4, Baoliang Guo4, Chen-Yu Zhang1,2, Jing Li1,2, Jie Yang2, Xi Chen1,2. 1. State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, China. 2. State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China. 3. Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tiyuanbei, China. 4. The Second Affiliated Hospital of Harbin Medical University, Harbin, China.
Abstract
BACKGROUND/AIMS: MicroRNAs (miRNAs) have been consistently demonstrated to be involved in colorectal cancer as either tumour oncogenes or tumour suppressors. However, the detailed role of miR-520a-3p in colorectal cancer remains poorly understood. METHODS: Quantitative RT-PCR and western blotting assays were used to measure miR-520a-3p and EGFR expression levels in colorectal cancer tissues, respectively. Luciferase reporter assay was employed to validate the direct targeting of EGFR by miR-520a-3p. Cell migration, apoptosis and cell cycle assays were performed to analyse the biological functions of miR-520a-3p and EGFR in colorectal cancer cells. In vivo experiment was performed to analyse the effects of miR-520a-3p and EGFR on the growth of colorectal cancer xenografts in mice. RESULTS: In this study, we found that miR-520a-3p was most likely to target the EGFR 3'-UTR, which was experimentally validated. In addition, we investigated the biological effects of EGFR inhibition by miR-520a-3p both in vitro and In vivo and found that miR-520a-3p could suppress cell migration, promote apoptosis, lead to colorectal cancer cell cycle arrest at the G0/G1 phase, and decelerate tumour growth in xenograft mice, potentially by targeting EGFR. CONCLUSIONS: This study highlights a tumour suppressor role for miR-520a-3p in colorectal cancer via the regulation of EGFR expression. Thus, miR-520a-3p may be a novel molecular therapeutic target for colorectal cancer.
BACKGROUND/AIMS: MicroRNAs (miRNAs) have been consistently demonstrated to be involved in colorectal cancer as either tumour oncogenes or tumour suppressors. However, the detailed role of miR-520a-3p in colorectal cancer remains poorly understood. METHODS: Quantitative RT-PCR and western blotting assays were used to measure miR-520a-3p and EGFR expression levels in colorectal cancer tissues, respectively. Luciferase reporter assay was employed to validate the direct targeting of EGFR by miR-520a-3p. Cell migration, apoptosis and cell cycle assays were performed to analyse the biological functions of miR-520a-3p and EGFR in colorectal cancer cells. In vivo experiment was performed to analyse the effects of miR-520a-3p and EGFR on the growth of colorectal cancer xenografts in mice. RESULTS: In this study, we found that miR-520a-3p was most likely to target the EGFR 3'-UTR, which was experimentally validated. In addition, we investigated the biological effects of EGFR inhibition by miR-520a-3p both in vitro and In vivo and found that miR-520a-3p could suppress cell migration, promote apoptosis, lead to colorectal cancer cell cycle arrest at the G0/G1 phase, and decelerate tumour growth in xenograft mice, potentially by targeting EGFR. CONCLUSIONS: This study highlights a tumour suppressor role for miR-520a-3p in colorectal cancer via the regulation of EGFR expression. Thus, miR-520a-3p may be a novel molecular therapeutic target for colorectal cancer.