The mechanism of microRNA-451 targeting macrophage migration inhibitory factor on proliferation and apoptosis of thyroid cancer cells

Objective To investigate the effect and mechanism of microRNA (miR)-451 targeting macrophage migration inhibitory factor on proliferation and apoptosis of thyroid cancer cells. Methods MiR-451 mRNA expression in thyroid carcinoma and follicular papillary (PTC-133), (K1) and undifferentiated (8505C) thyroid cancer cell lines were detected by reverse transcription-polymerase chain reaction (RT-PCR); miR-NC, miR-451 mimics (Analog), miR-451 inhibitor (inhibitor) were transfected with thyroid cancer K1 cells, and macrophage migration inhibitory (MIF) protein expression were detected by Western blotting, the three Co transfection group miR-NC+ miR-451 mimics, Wt-MIF+ miR-451 mimics, Mut-MIF+ miR-200b mimics was transfected into K1 thyroid cancer cells, luciferase activity was detected to confirm whether MIF is the target gene of miR-451; the follow-up experiment was divided into miR-NC, miR-451 mimics, miR-451 mimics+ pcDNA3.1-MIF and miR-NC+ pcDNA3.1-MIF, each group cell were cultured for 48 h, cell proliferation was detected by cell counting kit (CCK-8) test; apoptosis was detected by flow cytometry; the expression of Cleaved Caspase-3, phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt), phosphorylated protein kinase B (p-Akt) protein was detected by Western blotting. Results The expression of miR-451 mRNA (0.889±0.367) in thyroid carcinoma was significantly lower than adjacent tissues (6.214±0.884), (t=28.883, P=0.004), the lowest expression of K1 cells in thyroid cancer cells, selected as a follow-up study; compared with miR-NC group [PI3K (0.562±0.051) p-Akt (0.134±0.022) Cleaved Caspase-3 (0.052±0.014) cell apoptosis rate (5.16±0.77)%, PI3K (0.133±0.021, 0.223±0.026), p-Akt (0.034±0.011, 0.062±0.013) protein expression in miR-451 mimics and miR-451 mimics+ pcDNA3.1-MIF group was significantly decreased miR-451 mimics group: tPI3K=30.157, P=0.003; tp-Akt=46.626, P=0.001. Conclusion MIF is the target gene of miR-451, miR-451 targeting MIF can inhibit the proliferation of K1 thyroid cancer cell and promote cell apoptosis by inhibiting the PI3K/Akt signaling pathway. Key words: MicroRNA-451; Macrophage migration inhibitory; Thyroid carcinoma; Proliferation; Apoptosis; Phosphatidylinositol 3 kinase/protein kinase B signaling pathway