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.