MicroRNAs (miRNAs) play crucial roles in tumor initiation and development. The aim of the study was to explore the clinicopathological role and functional effects of miR-504 in non small cell lung cancer (NSCLC).

Quantitative reverse transcription polymerase chain reaction (QRT-PCR) was applied to detect the expression of miR-504 in 55 cases of NSCLC tissues and matched adjacent normal tissues in NSCLC patients. MTT, colony formation and transwell invasion assays were performed to evaluate the effects of miR-504 on cell proliferation and invasion, respectively. Dual luciferase reporter assay was used to verify that LOXL2 was a direct target of miR-504. QRT-PCR and western blot analysis were performed to analyze mRNA and protein expression.

In the study, we demonstrated that miR-504 was notably downregulated in NSCLC tissues compared with adjacent normal tissues. Lower miR-504 expression positively correlated with lymph node metastasis and advanced TNM stage in patients. Furthermore, upregulation of miR-504 significantly inhibited cell proliferation, cell invasion and EMT process of NSCLC. QRT-PCR, western blot and luciferase reporter assays confirmed that miR-504 could bind to LOXL2 3′UTR region and regulate its expression. Moreover, ectopic expression of LOXL2 could rescue the inhibiting effects on cell proliferation and invasion induced by miR-504 in NSCLC cells.

Our results indicated that miR-504 functioned as a tumor suppressor in NSCLC and may serve as a target of NSCLC treatment.