• Guangjun Zhang, He Zhou, Huaxu Xiao, Zuoliang Liu, Hongpeng Tian, and Tong Zhou.
• First Department of General Surgery, Institute of Hepatobiliary, Pancreatic and Intestinal Disease, The Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong, 637000, People's Republic of China, zhanggj1977@126.com.
• Dig. Dis. Sci. 2014 Jan 1; 59 (1): 98-107.

BackgroundOur previous studies show that microRNA-92a (miR-92a) is overexpressed in colorectal cancer (CRC) and is thought to be correlated with the development of the cancer. However, its biological role in CRC remains poorly understood.AimsThe aim of the study was to determine the role of miR-92a and to elucidate its regulatory mechanism in CRC.MethodsThe expression levels of miR-92a and phosphatase and tensin homologue (PTEN) were detected by qRT-PCR and western blot. MTT, migration and invasion assays were used to examine the proliferation, migration and invasion of pre-miR-92a transfected SW480 cells, and a mouse model was used to investigate tumorigenesis. In addition, the regulation of PTEN by miR-92a was evaluated by qRT-PCR, western blot and luciferase reporter assays.ResultsThe expression of miR-92a was significantly up-regulated in the tissues of CRC patients with lymph node metastasis. The ectopic expression of miR-92a enhanced CRC cell proliferation, migration and invasion. Similar results were found in xenograft assay performed in nude mice. Up-regulation of miR-92a induced EMT in CRC cells. There was an inverse correlation between the levels of miR-92a and PTEN in CRC tissues. The overexpression of miR-92a in CRC cells decreased PTEN expression at the translational level, and decreased PTEN-driven luciferase-reporter activity.ConclusionsOur results demonstrated that miR-92a induced EMT and regulated cell growth, migration and invasion in the SW480 cells, at least partially, via suppression of PTEN expression. MiR-92a may serve as a novel therapeutic target in colorectal cancer.

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