Abstract
Histone deacetylase inhibitors (HDACis) - based therapeutic drug tolerance is one of the principal factors of poor prognosis of patients with nasopharyngeal cancer (NPC). Mechanisms of tolerance to HDACis are not well understood. Nowadays, dysregulation of long non-coding RNAs (LncRNAs) and microRNAs (miRNAs) has been reported to provide beneficial or inhibitory effects in drug-tolerance in various cancers. Herein, we established the HDAC inhibitor (SAHA)-tolerant NPC cell sublines, which had decreased apoptosis in response to SAHA treatment. We observed that the expression of miR-129 was significantly reduced in SAHA-tolerant NPC cells. Manipulating the expression of miR-129 overcame SAHA tolerance, and enhanced the SAHA-induced apoptosis. In terms of miR-129 downregulation, we identified that NEAT1 suppresses miR-129 expression. NEAT1 was found to be upregulated in SAHA tolerance cells. The depletion of NEAT1 phenocopied the effect of miR-129 overexpression, which also enhanced SAHA-induced apoptosis. Bcl-2 was the downstream target of miR-129 and contributed to SAHA tolerance in NPC. Our in vivo xenograft experiment confirmed that the administration of miR-129 or inhibition of Bcl-2 overcame the SAHA tolerance in NPC. In conclusion, NEAT1 increases in NPC tissues and manages to facilitate SAHA tolerance by modulating the miR-129/Bcl-2 axis, providing novel therapeutic targets for NPC treatment.