Abstract: Objective To investigate the expression and biological function of miRNA-449a in lung cancer. Methods A case-control study was conducted in 58 patients diagnosed with lung cancer(carcinoma and adenocarcinoma) and normal tissue closely adjacent to tumor. MiRNA-449a simulation was designed and synthesized, was dissolved into two different concentrations as 10 and 20 mg/mL. The expression of miRNA-449a in lung cancer tissues and matched normal tissues were detected by Real time PCR. The expression of luciferase gene was detected by chemiluminescence technique. MiRNA-449a mimics on cell apoptosis was evaluated by MTT assay. Results The mean tissues expression levels of miRNA-449a in squamous carcinoma group and adenocarcinoma group were 1.48±1.63 and 1.52±1.54 respectively, and were significantly lower than in control group(2.74±1.55)(P<0.01). The average intensity of fluorescent protein in 10 mg/mL group and 20 mg/mL group were 2115±168 and 1352±159 respectively, and were significantly lower than that in control group(4975±115)(P<0.01). Conclusion MiRNA-449a was down-regulated expression in lung cancer and induced apoptosis.

Key words: lung neoplasms, miRNA-449a, tumor biomarker, polymerase chain reaction, fluorogenic quantitative