摘要Background:MicroRNAs (miRNAs) have been extensively studied over the decades and have been identified as potential molecular targets for cancer therapy.To date,many miRNAs have been found participating in the tumorigenesis of non-small cell lung cancer (NSCLC).The present study was designed to evaluate the functions of miR-125b-l-3p in NSCLC cells.Methods:MiR-125b-l-3p expression was detected in tissue samples from 21 NSCLC patients and in NSCLC cell lines using the real-time polymerase chain reaction.A549 cell lines were transfected with a miR-125b-1-3p mimic or miR-125b-1-3p antisense.Cell counting kit-8,wound healing,Matrigel invasion assays,and flow cytometry were used to assess the effects of these transfections on cell growth,migration,invasion,and apoptosis,respectively.Western blotting was used to detect apoptosis-related proteins,expression ofS 1PR1,and the phosphorylation status of STAT3.Significant differences between groups were estimated using Student's t-test or a one-way analysis of variance.Results:MiR-125b-1-3p was downregulated in NSCLC samples and cell lines.Overexpression of miR-125b-1-3p inhibited NSCLC cell proliferation (37.8 ± 9.1％,t =3.191,P =0.013),migration (42.3 ± 6.7％,t =6.321,P =0.003),and invasion (57.6 ± 11.3％,t =4.112,P =0.001) and simultaneously induced more NSCLC cell apoptosis (2.76 ± 0.78 folds,t =3.772,P =0.001).MiR-125b-1-3p antisense resulted in completely opposite results.S1PR1 was found as the target gene ofmiR-125b-1-3p.Overexpression ofmiR-125b-1-3p inhibited S 1PR1 protein expression (27.4 ± 6.1％ of control,t =4.083,P =0.007).In addition,S1PR1 siRNA decreased STAT3 phosphorylation (16.4 ± 0.14％ of control,t =3.023,P=0.015),as in cells overexpressing miR-125b-1-3p (16.7 ± 0.17％ of control,t =4.162,P=0.026).Conclusion:Our results suggest that miR-125b-1-3p exerts antitumor functions in NSCLC cells by targeting S1PR1.