Inhibitory effects of anti-miRNA oligonucleotides (AMOs) on A549 cell growth.

MicroRNAs (miRNAs) are a new class of non-protein-coding, endogenous small RNA molecules of 18-24 nt in size. miRNAs can specifically down-regulate gene expression involved in proliferation, apoptosis, and differentiation in cancer cells. Our purpose was to identify several functional miRNAs as potential drug targets by using specific antisense-microRNA oligonucleotides (AMOs), and to study the inhibitory effects of these AMOs on A549 cell growth. miR-16, miR-21, miR-214, and miR-181a were selected as target candidates, based on which specific AMOs were designed, synthesized, and transfected into A549 cells. The viable cells were counted by using trypan blue dye exclusion assay. Apoptosis of A549 cells were determined flowcytometrically, and miR-21 expression levels in A549 cells were determined by real-time PCR. The results showed that AMO-miR-21, AMO-miR-16, and AMO-miR-181a inhibited A549 cell growth by inducing apoptosis and S-phase arrest. These inhibitory effects increased with dose and time. It was found that AMO-miR-21 down-regulated miR-21 expression in A549 cells. We conclude that miR-21, miR-16, and miR-181a are potential targets for lung cancer therapy, and specific AMOs can be a powerful technique for miRNA inhibition.