LncRNA NNT-AS1 is a major mediator of cisplatin chemoresistance in non-small cell lung cancer through MAPK/Slug pathway.

Abstract

To investigate the role of long non-coding ribonucleic acid (lncRNA) nicotinamide nucleotide transhydrogenase-antisense RNA1 (NNT-AS1) in cisplatin (DDP) resistance in non-small cell lung cancer (NSCLC) and its molecular mechanism. Fluorescence quantitative Real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of lncRNA NNT-AS1 in NSCLC cell lines (A549 and SPCA-1) and DDP-resistant cell lines (A549/DDP and SPCA-1/DDP). Corresponding plasmids of si-NTT-AS1 and si-NC were conducted. Then, methyl thiazolyl tetrazolium (MTT) assay was applied to detect the changes in half inhibition concentration (IC50) values of DDP in A549/DDP and SPCA-1/DDP cells after interference in lncRNA NNT-AS1 expression. Clone formation assay and flow cytometry were employed to detect the changes in proliferation, cycle and apoptosis of A549/DDP and SPCA-1/DDP cells caused by si-NNT-AS1. Protein expressions of molecular markers in mitogen-activated protein kinase (MAPK)/Slug signaling pathway after interference in lncRNA NNT-AS1 expression was detected by Western blotting. The differential expressions of lncRNA NNT-AS1 in 10 pairs of drug-resistant and non-resistant tissues were detected by qRT-PCR. QRT-PCR results showed that the expression of lncRNA NNT-AS1 in drug-resistant cells was higher than that in parental cells. The IC50 value of DDP in drug-resistant cells was increased by interfering with the expression of lncRNA NNT-AS1. Clone formation assay and flow cytometry revealed that interfering in the expression of lncRNA NNT-AS1 could inhibit the proliferation, promote the apoptosis and cell cycle arrest of drug-resistant cells. Western blotting assay found that after interfering the expression of lncRNA NNT-AS1, the expressions of molecular markers in MAPK/Slug signaling pathway were downregulated. qRT-PCR assay indicated that there were 9 pairs of drug-resistant tissues with up-regulated lncRNA NNT-AS1 expression in a total of 10 pairs of drug-resistant tissues. LncRNA NNT-AS1 is highly expressed in drug-resistant NSCLC tissues and cells, promoting the DDP resistance of NSCLC cells through the MAPK/Slug signaling pathway.