LncRNA TUG1 influences papillary thyroid cancer cell proliferation, migration and EMT formation through targeting miR-145.

LncRNA TUG1, a tumor oncogene associated with various human cancers, has been reported to be involved in regulating various cellular processes, such as proliferation, apoptosis and invasion through targeting multiple genes. However, its biological function in thyroid cancer cells has not been elucidated. The aim of this study is to measure TUG1 expression level and evaluate its function in thyroid cancer cells. LncRNA TUG1 expression levels in thyroid cancer tissues and three thyroid cancer cell lines (the ATC cell lines SW1736 and KAT18 and the FTC cell line FTC133) were assessed by qRT-PCR and compared with that of the human normal breast epithelial cell HGC-27. MTT assay, colony formation assay, transwell assay and western blot analysis were performed to assess the effects of TUG1 on proliferation, metastasis and EMT formation in thyroid cancer cells in vitro. Rescue assay was performed to further confirm that TUG1 contributes to the progression of thyroid cancer cells through regulating miR-145/ZEB1 signal pathway. LncRNA TUG1 was found to be up-regulated in thyroid cancer tissues and thyroid cancer cells compared with that in the human normal breast epithelial cell HGC-27. Increased lncRNA TUG1 expression was found to significantly promote tumor cell proliferation, and facilitate cell invasion, while down-regulated TUG1 could obviously inhibit cell proliferation, migration/invasion and reverse EMT to MET. These results indicated that TUG1 may contribute to the progression of thyroid cancer cells by function as a ceRNA competitive sponging miR-145, and that lncRNA TUG1 is associated with tumor progression in thyroid cancer cells.