[Growth inhibitory effect of microRNA-519b-3p on larynx squamous Hep-2 cells]

To investigate the effects of microRNA-519b-3p (miR-519b-3p) on laryngeal carcinoma Hep-2 cell growth, and to analyze the underlying molecular mechanisms.

The effects of miR-519b-3p on the growth and cell cycle of Hep-2 cells transfected with miR-519b-3p mimic were tested by MTT assay and flow cytometry, respectively. The mRNA and protein expressions of the related genes were tested by reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. The expressions of miR-519b-3p were tested by real-time RT-PCR in 48 pairs of laryngeal carcinoma and adjacent tissue samples.

The expression of miR-519b-3p in laryngeal carcinoma tissues was significant lower than that in adjacent non-cancerous tissues (S(ΔCt) = 2.989, t = 2.693, P < 0.01) . Increasing the level of miR-519b-3p inhibited significantly Hep-2 cell proliferation, arrested the cell cycle in the G2/M phase (10.29% ± 4.63%, t = 4.395, P < 0.05) , and decreased significantly the percentage of cells in the S phase (7.56% ± 2.05%, t = 3.555, P < 0.05) , with the increase in the expression of cyclin dependent kinase (CDK) 1 and the decrease in the expressions of CDK 2 and Cyclin A. RT-PCR and Western blot showed that miR-519b-3p down-regulated the protein but not mRNA expressions of HuR and cyclooxygenase-2(COX-2) genes.

The expression of MiR-519b-3p as carcinoma suppressor gene is low in laryngeal carcinoma. The cell cycle of Hep-2 cells was arrested in the G2/M phase by MiR-519b-3p.