OncoTargets and Therapy (Oct 2016)
miR-497 suppresses epithelial–mesenchymal transition and metastasis in colorectal cancer cells by targeting fos-related antigen-1
Abstract
Nan Zhang,1 Quan Shen,2 Pingping Zhang3 1Department of General Surgery, First Affiliated Hospital of Henan University of Chinese Medicine, 2Department of Hepatobiliary Surgery, Henan Provincial People’s Hospital, Zhengzhou, 3Department of Integrated Chinese and Western Medicine, Tianjin First Central Hospital, Tianjin, People’s Republic of China Objective: MicroRNAs have key roles in tumor metastasis. The acquisition of metastatic capability by cancer cells is associated with epithelial–mesenchymal transition (EMT). Here, we describe the role and molecular mechanism of miR-497 in colorectal cancer (CRC) cell EMT, migration, and invasion.Methods: Quantitative real-time polymerase chain reaction and Western blot assays were performed to detect the expression levels of miR-497 and Fos-related antigen-1 (Fra-1) in the CRC cells. HCT116 and SW480 cells with miR-497 overexpression or Fra-1 low expression were constructed by lipofection. Target prediction and luciferase reporter assays were performed to investigate whether Fra-1 is one of the targets of miR-497. Western blot and Transwell assays were performed to detect the effects of miR-497 and Fra-1 on CRC cell EMT, migration and invasion.Results: We searched the miRanda, TargetScan, and PicTar databases and found that Fra-1, a key driver of CRC metastasis, is a potential target of miR-497. Quantitative real-time polymerase chain reaction and Western blot analysis verified downregulation of miR-497 and upregulation of Fra-1 in CRC cells. Western blot and Transwell assays showed that overexpression of miR-497 suppresses CRC cell EMT, migration, and invasion. Luciferase gene reporter assay revealed that Fra-1 is a downstream target of miR-497 as miR-497 bound directly to the 3' untranslated region of Fra-1 messenger RNA. An inverse correlation was also found between miR-497 and Fra-1 in HCT116 and SW480 cells. Furthermore, knockdown of Fra-1 recuperated the effects of miR-497 overexpression.Conclusion: miR-497 suppresses CRC cell EMT, migration, and invasion partly by targeting Fra-1. Keywords: colorectal cancer, miR-497, Fos-related antigen-1, epithelial–mesenchymal transition, metastasis
