Background and Aim: Some studies have confirmed that miRNA-140  exhibits a suppressive role in gastric cancer, Wilms’ tumor. However, the function of miRNA-140  in colorectal cancer has not been completely elucidated. The present study aims to verify TRAF6  as the targeted gene by miRNA-140  which was investigated in colorectal cancer tissues and cells, and its effects on the biological characteristics of colorectal cancer cells were determined, in order to provide an experimental and theoretical basis for the application of TRAF6  in the treatment of colorectal cancer.
Methods: qPCR analyzed miRNA-140  expression levels in colorectal cancer tissues, normal colorectal cancer tissues and colorectal cells including SW480 and HCT116 cancer cells and FHC normal colorectal epithetical cells. A serial biological experiment analyzed miRNA-140  effects on cell proliferation, migration and invasion capacities in SW480 and HCT116 cells. miRNA targeting gene prediction and a dual luciferase assay were used to analyze miRNA-140- targeted TRAF6 . qPCR and Western blot analyzed miRNA-140  effects on the mRNA and protein expression of TRAF6 . Western blot analyzed miRNA-140  effects on NF-κB/c-jun signaling pathways. Animal studies were performed to investigate the effects of miRNA-140  on colorectal cancer implantation tumor growth. Immunohistochemistry analyzed TRAF6  expression in animal experimentation tumors.
Results: miRNA-140  expression is lower in colorectal cancer tissues and colorectal cancer cells. Over-expression of miRNA-140  inhibited the proliferation, migration and invasion capacities of colorectal cancer cells. miRNA-140  targeted the TRAF6  mRNA 3ʹUTR area and decreased TRAF6  protein expression. miRNA-140  suppressed p-NF-κB/p-c-jun proteins expression. miRNA-140  inhibited colorectal cancer implantation tumor growth in the mice model.
Conclusion: miRNA-140  targeting TRAF6  affects the progression and growth of colorectal cancer, the mechanism could be miRNA-140  decreasing the TRAF6  expression effects on the NF-κB/c-jun signaling pathways.
Keywords: TRAF6 , miRNA-140 , NF-kB/c-jun signaling pathways, progression, colorectal cancer