LncRNA NEAT1 Contributes to the Acquisition of a Tumor Like-phenotype Induced by PM 2.5 in Lung Bronchial Epithelial Cells Via HIF-1α Activation

The hazards of particulate matter (PM2.5) on human respiratory health have been previously reported. However, the molecular mechanisms underlying PM2.5-induced lung carcinogenesis have rarely been studied. In the present study, we explored the effects of PM2.5 on the epithelial-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like properties in lung bronchial epithelial cells. We found that exposure of PM2.5 enhanced lung bronchial epithelial cell proliferation and EMT. In addition, the expression level of CSC-like biomarkers, CD133 and CD44, was significantly elevated by PM2.5 in vitro. Nuclear paraspeckle assembly transcript 1 (NEAT1) has been reported to participate in lung cancer. Loss of NEAT1 represses the malignant transformation of BEAS-2B and HBE cells induced by PM2.5. NEAT1 interacts with microRNA (miR)-582-5p, and miR-582-5p reverses the pro-tumor effects of NEAT1 overexpression. Hypoxia-inducible factor (HIF)-1α is an important transcription factor in the pathological responses to hypoxia. HIF-1α was a predicted target for miR-582-5p, and a direct correlation between them was identified. Inhibitors of miR-582-5p rescued HIF-1α expression, which was attenuated by a lack of NEAT1. In conclusion, PM2.5 increased NEAT1 expression, which, by binding with miR-582-5p, released HIF-1α and promoted EMT and the acquisition of CSC-like characteristics.