The effect and mechanism of action of metformin on in vitro FaDu cell proliferation

OBJECTIVE: To investigate the effect and mechanism of action of metformin on proliferation of a human hypopharyngeal carcinoma cell line (FaDu). METHODS: FaDu cells were treated with metformin (25–125 mmol/l). Cell proliferation was evaluated via CCK-8 assay. Real-time quantitative reverse transcription–polymerase chain reaction was used to evaluate microRNA (miR)-21-5p and PDCD4 (programmed cell death 4) expression. PDCD4 protein was quantified by Western blot. RESULTS: Metformin significantly inhibited FaDu cell proliferation in a dose- (25–100 mmol/l) and time-dependent manner (12 h–36 h), significantly downregulated miR-21-5p, and upregulated PDCD4 mRNA and protein expression. CONCLUSIONS: Metformin significantly inhibited FaDu cell proliferation, possibly via downregulation of miR-21-5p and upregulation of PDCD4.