[Long non-coding RNA XIST modulates cisplatin resistance by altering PDCD4 and Fas-Lexpressions in human nasopharyngeal carcinoma HNE1 cells in vitro].

Abstract

OBJECTIVE\nTo explore the role of long non-coding RNA (lncRNA) X inactive specific transcript (XIST) in modulating cisplatin (DDP) resistance of human nasopharyngeal carcinoma cells and investigate the possible mechanism.\n\n\nMETHODS\nRealtime PCR was performed to detect the expression of XIST in cisplatin-resistant human nasopharyngeal carcinoma cell line HNE1/DDP. The effects of up-regulation and down-regulation of XIST on DDP resistance, proliferation and apoptosis of HNE1/ DDP cells were assessed using MTT assay, EdU assay and flow cytometry. Western blotting was used to detect the changes in the expressions of programmed cell death 4 (PDCD4) and Fas ligand (Fas-L) proteins in the cells in response to up-regulation or down-regulation of XIST.\n\n\nRESULTS\nThe expression of XIST was significantly up-regulated in HNE1/DDP cells in comparison with HNE1 cells (0.57±0.06 vs 0.1±0.02, P < 0.05). Down-regulation of XIST significantly decreased while up-regulation of XIST obviously increased DDP resistance of HNE1/DDP cells (P < 0.05). Down-regulation of XIST significantly reduced the proliferation (6.17 ± 1.93 vs 16.59 ± 4.86, P < 0.05) and enhanced apoptosis [(18.04 ± 4.72)% vs (4.22 ± 1.65)%, P < 0.05], while upregulating XIST enhanced the proliferation (25.40±7.21 vs 13.16±3.95, P < 0.05) and inhibited apoptosis [(2.82±0.88)% vs (6.46± 1.75)%, P < 0.05] in HNE1/DDP cells. Down-regulation of XIST significantly increased the protein expressions of PDCD4 and Fas-L (P < 0.05) in HNE1/DDP cells, and up-regulation of XIST resulted in reverse changes in PDCD4 and Fas-L expressions (P < 0.05).\n\n\nCONCLUSIONS\nXIST is up-regulated in HNE1/DDP cells, and down-regulation and up-regulation of XIST expression reduce and increase DDP resistance of the cells, respectively, possibly as a result of changes in the expressions of PDCD4 and Fas-L.