MicroRNA-34a affects the occurrence of laryngeal squamous cell carcinoma by targeting the antiapoptotic gene survivin.

Survivin has been shown to be an ideal target for cancer gene therapy because of its strong antiapoptotic effect. MicroRNA-34a (miR-34a) can function as a tumor suppressor in some cancers through negative regulation of gene expression. However, the relationship between miR-34a and survivin in larynx squamous cell carcinoma (LSCC) has not been explored. The abundance of survivin mRNA and miR-34a in LSCC tissues were measured using quantitative real-time polymerase chain reaction. Their expression levels were analyzed and correlated with tumor differentiation, lymphatic metastasis, clinical stages, and survival rates. MiR-34a mimic was transfected using liposomes to increase its level in LSCC cancer cell line, Hep-2. The effects of miR-34a on survivin protein expression were tested using western blot analysis. Cell cycle analyses were performed using flow cytometry. The results showed that transfection of miR-34a mimic significantly suppressed cell proliferation with decreased survivin protein expression, but did not affect mRNA expression level. The results from LSCC tissue samples showed that miR-34a was downregulated, while survivin expression was upregulated. The miR-34a levels were negatively correlated with histologic differentiation and were positively correlated with survival rate. MiR-34a significantly suppressed cell proliferation by arresting cells at G0/G1 phase in Hep-2 cells. These results indicated that miR-34a may affect the occurrence of LSCC by targeting survivin.