MicroRNA­187 is an independent prognostic factor in lung cancer and promotes lung cancer cell invasion via targeting of PTRF.

MicroRNAs (miRNAs) are involved in the progression of different types of cancers giving new hope for cancer treatment. The role and regulatory mechanism of microRNA­187 (miR­187) are largely unknown. In the present study, 74 patients with non­small cell lung cancer (NSCLC) were selected. Tumor tissues and matched normal tissues were collected for determining the expression level of miR­187. Cell research was performed to detect the function of miR­187. The expression level was measured and miR­187 was found to be overexpressed in the NSCLC cell lines and tissues. Overexpression of miR­187 promoted cell proliferation in the A549 and H1650 cell lines. Moreover, overexpression of miR­187 also promoted cell migration and invasion. Polymerase I and transcript release factor (PTRF) was identified as a target of miR­187. Overexpression of miR­187 suppressed the expression of PTRF. Knockdown of PTRF promoted lung cancer cell invasion, and overexpression of PTRF had a negative effect on lung cancer cell invasion. The PTRF messenger RNA (mRNA) levels in cancer tissues were significantly lower than those in their adjacent normal lung tissues as determined by real­time PCR (RT­PCR). The expression of the PTRF protein was significantly weaker than that in the adjacent normal lung tissues using immunohistochemical staining. The findings revealed that miR­187 promotes cell growth and invasion by targeting PTRF and miR­187 may be a new prognostic factor for NSCLC.