Upregulated miR-155 in Papillary Thyroid Carcinoma Promotes Tumor Growth by Targeting APC and Activating Wnt/β-Catenin Signaling

Context: MicroRNAs (miRNAs) are strongly implicated in many cancers, including papillary thyroid carcinoma (PTC), which is the most common malignancy in thyroid tissue. Recently, miRNA-155 (miR-155) has been proved to play a substantial role in liposarcoma and breast cancer, but its functions in the context of PTC remain unknown. Objectives: The objective was to investigate the potential involvement of miR-155 in PTC. Design: Expression levels of miR-155 were assessed via quantitative real-time PCR in 20 pairs of human PTC and adjacent normal tissues and in 4 human PTC cell lines. Lentiviral miR-155 overexpression models were performed in TPC-1 and CGTH-W3 cells, and the effects on cell growth were evaluated. We have searched for miR-155 targets and identified the hypothesis that miR-155 could promote tumor growth of PTC by targeted regulation of adenomatous polyposis coli (APC) expression and activating the Wnt/β-catenin signaling. Results: MiR-155 levels were markedly increased in PTC specimens and PTC ...