MiR-34c induces apoptosis and inhibits the viability of M4e cells by targeting BCL2

The present study aimed to investigate microRNA (miR/miRNA)-34c expression and the association of miR-34c with B cell lymphoma 2 (BCL2) in M4e laryngeal carcinoma cell line. M4e laryngeal carcinoma cells were cultured and transfected with lenti-miR-34c or scramble miRNA for 72 h. Cell viability and the percentage of cells undergoing apoptosis of transfected cells were detected using MTT and Annexin V/allophycocyanin and propidium iodide assays, respectively. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were performed to determine BCL2 mRNA and protein expression in transfected M4e cells. In addition, luciferase reporter assay was performed to identify whether BCL2 is a direct target of miR-34c. Transfection of lenti-miR-34c was able to significantly inhibit cell viability (P<0.01), increase the percentage of cells undergoing apoptosis (P<0.001) and downregulate BCL2 protein expression (P<0.01) in M4e cells. RT-qPCR data revealed that lenti-miR-34c transfection did not affect BCL2 mRNA expression. However, data from the luciferase reporter assay revealed that transfection with miR-34c negative control decreased luciferase activity in M4e cells co-transfected with pGL3-BCL2-MUT plasmid, compared with miR-34c inhibitor (P<0.01). Collectively, the results from the present study provided evidence that miR-34c may be involved in the pathogenesis of laryngeal cancer, and BCL2 may be negatively regulated by miR-34c in M4e cells.