Int J Biol Sci 2017; 13(1):122-134. doi:10.7150/ijbs.14770 This issue Cite
1. Department of Gastrointestinal Surgery, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China 361004.
2. Institute of Gastrointestinal Oncology, Medical college of Xiamen University, Xiang'an, Xiamen, China 361102.
3. Xiehe Clinical Medical College, Fujian Medical University, Fuzhou, China 350001.
4. State Key Laboratory of Cellular Stress Biology and Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China 361102.
5. State Key Laboratory Breeding Base of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, 184 University Road, Xiamen, China 361005.
6. Department of Basic Medical Sciences of Medical College, Xiamen University, Xiang'an, Xiamen, China 361102.
7. College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27514.
MicroRNAs are a novel class of gene regulators that function as oncogenes or tumor suppressors. In our current study, we investigated the role of miR-15a-3p and miR-16-1-3p in the regulation of Twist1 expression and EMT process. Our bioinformatics analysis suggested that on the 3' UTR of Twist1, there are two conserved miRNA recognition sites for miR-15a-3p and miR-16-1-3p respectively. Interestingly, overexpression of miR-15a-3p and miR-16-1-3p significantly suppressed the activity of luciferase reporter containing Twist1-3' UTR, reduced mRNA and protein level of EMT related genes such as TWIST1, N-cadherin, α-SMA and Fibronectin, and repressed MMP9 and MMP2 activity, as well as cell migration and invasion. Conversely, inhibition of miR-15a-3p and miR-16-1-3p significantly increased TWIST1, N-cadherin, α-SMA and Fibronectin protein expression. In addition, Twist1 co-transfection significantly ameliorated the loss of cell migration and invasion. Moreover, overexpression of miR-15a-3p and miR-16-1-3p dramatically suppressed the ability of BGC823 cells to form colonies in vitro and develop tumors in vivo in nude mice. Finally, qPCR and Western blot analysis showed that miR-15a-3p and miR-16-1-3p were significantly reduced in clinical gastric cancer tissue, whereas Twist1 mRNA and protein were significantly up-regulated, suggesting that this aberrant down-regulation of miR-15a-3p and miR-16-1-3p might be associated with the abnormal regulation of Twist1 and the EMT process in gastric cancer development. Our results help to elucidate a novel and important mechanism for the regulation of Twist1 in the development of cancer.
Keywords: miR-15a-3p, miR-16-1-3p, Twist1, Gastric cancer, cell invasion and metastasis.