[Impacts of LncRNA NORAD on the Proliferation, Apoptosis, and Chemosensitivity of Non-small Cell Lung Cancer Cells by Regulating ZNF217 through MiR-199a-3p].

Background: The treatment and diagnosis of non-small cell lung cancer (NSCLC) is still a difficult problem in the medical community, and exploring the molecular mechanism of the occurrence and development of NSCLC is a hot topic of the current research. Long non-coding RNA (lncRNA) NORAD is highly expressed in a variety of cancer cells. It may be a molecular target that promotes NSCLC. The aim of this study was to investigate the impacts of lncRNA NORAD on the proliferation, apoptosis, and chemosensitivity of NSCLC by regulating zinc finger protein 217 (ZNF217) through miR-199a-3p.

Methods: Real-time quantitative polymerase chain reaction (qRT-PCR) method was applied to detect the expressions of NORAD, miR-199a-3p and ZNF217 genes in normal lung epithelial cells BEAS-2B, lung cancer H460 cells, and Cisplatin (DDP) resistant cell lines H460/DDP. H460/DDP cells were devided into control group, si-NC group, si-NORAD group, miR-NC group, miR-199a-3p mimic group, si-NORAD+inhibitor NC group and si-NORAD+miR-199a-3p inhibitor group. Cell proliferation, apoptosis, the expression of NORAD, miR-199a-3p and ZNF217 genes of cells in each group were detected and the expression levels of Ki-67, caspase-9 and ZNF217 proteins in different cells were also observed. The relationship between miR-199a-3p, NORAD and ZNF217 was vefified.

Results: Compared with BEAS-2B cells, the expressions of NORAD, ZNF217 mRNA were significantly increased in H460 and H460/DDP cells (P<0.05) but the expression of miR-199a-3p was significantly reduced (P<0.05). Compared with H460 cells, the expression of NORAD and ZNF217 mRNA in H460/DDP cells was significantly increased (P<0.05) and the expression of miR-199a-3p was significantly reduced (P<0.05). Compared with the control group and si-NC group, the proliferation rate, NORAD and ZNF217 mRNA expression, Ki-67 and ZNF217 protein expression of H460/DDP cells in the si-NORAD group were significantly reduced (P<0.05), but the apoptosis rate, miR-199a-3p expression and caspase-9 expression were significantly increased (P<0.05). Compared with the miR-NC group, the proliferation rate, NORAD and ZNF217 mRNA expression, Ki-67 and ZNF217 protein expression of H460/DDP cells in the miR-199a-3p mimic group were significantly reduced (P<0.05), but the apoptosis rate, miR-199a-3p expression and caspase-9 expression were significantly increased (P<0.05). Compared with the si-NORAD+inhibitor NC group, the proliferation rate, ZNF217 mRNA expression, Ki-67 and ZNF217 protein expression of H460/DDP cells in the si-NORAD+miR-199a-3p inhibitor group were significantly increased (P<0.05), the apoptosis rate, miR-199a-3p expression and caspase-9 expression were obviously increased reduced (P<0.05).

Conclusions: Down-regulating NORAD expression can enhance miR-199a-3p expression and inhibit ZNF217 expression, thereby inhibiting H460/DDP cell proliferation, promoting apoptosis and enhancing its DDP chemotherapy sensitivity.