MicroRNA-187 inhibits PTEN expression and promotes cell proliferation in non-small-cell lung cancer

The recent discovery of microRNAs (miRNAs) has provided a novel mechanism for the tumorigenesis. In the present study, we explored the expression and function of miR-187 in non-small-cell lung cancer (NSCLC). Quantitative real-time PCR analysis showed that miR-187 was up-regulated in NSCLC specimens and cultured cancer cells. In vitro studies demonstrated that overexpression of miR-187 mimics enhanced cell proliferation and invasion. Mechanistically, the targets of miR-187 were predicted by bioinformatics tools. Luciferase reporter assays and western blot further revealed that the phosphatase and tensin homolog (PTEN) gene, a tumor suppressor, was suppressed by miR-187. As a result, overexpression of miR-187 mimics led to an enhanced activation of AKT signaling. In agreement, restoration of PTEN expression or inhibition of AKT activity by its antagonist in lung cancer cells largely attenuated the oncogenic roles of miR-187. Therefore, our results suggest that miR-187 promotes NSCLC progression by directly targeting PTEN and may serve as a potential therapeutic target for cancer therapy.