Abstract: Objective　To explore the mechanism of regulatory effects of miR-138 overexpression through inhibiting TCF-4 expression on the proliferation, apoptosis and movement of thyroid carcinoma cell line CAL-62.　Methods　miR-138 mimic was transfected into CAL-62 cells, and detected by RT-PCR. After overexpression of pcDNA vector, TCF-4 was transfected into CAL-62 cells, and Western blot was used to detect the expression levels of TCF-4, proliferating nuclear antigen 67 (Ki67), proliferating cell nuclear antigen (PCNA), caspase-3, caspase-9, E-cadherin, Vimentin and target genes cycD and c-Myc. EDU staining was used to detect the cell proliferation. Hoechst staining was used to detect the cell apoptosis, and transwell was used to detect the cell invasion ability.　Results　Compared with the control group, the protein expression levels of caspase-3, caspase-9 and Vimentin in miR-138 transfection+TCF-4 group were significantly decreased (P<0.01). The protein expression levels of Ki67, PCNA, E-cadherin, cycD and c-Myc were significantly increased (P<0.01). And the apoptosis of thyroid tumor cells was significantly inhibited (P<0.01), and the proliferation and invasion were significantly promoted (P<0.01). Compared with TCF-4 group, the protein expression levels of caspase-3, caspase-9 and Vimentin in miR-138 transfection+TCF-4 group were significantly increased (P<0.01). The protein levels of Ki67, PCNA, E-cadherin, cycD and c-Myc were significantly decreased (P<0.01). Proliferation and invasion of thyroid tumor cells were significantly inhibited (P<0.01), as well apoptosis was significantly promoted (P<0.01).　Conclusions　miR-138 overexpression can significantly inhibit the proliferation and invasion and significantly promote the apoptosis of thyroid cancer cell line CAL-62, by inhibiting TCF-4 expression.

Key words:  , miR-138, 　TCF-4, 　CAL-62, 　Proliferation, 　Apoptosis