LncRNA BC200 promotes the development of EBV-associated nasopharyngeal carcinoma by competitively binding to miR-6834-5p to upregulate TYMS expression

Nasopharyngeal carcinoma (NPC) is closely related to Epstein–Barr virus (EBV) infection. Long noncoding RNAs (lncRNAs) play important roles in cancers. However, the molecular mechanism underlying the roles of lncRNAs in EBV-associated NPC remains largely unclear. In this study, we confirmed that the expression of the lncRNA brain cytoplasmic 200 (BC200) was significantly increased in EBV-infected NPC cells and tissues. BC200 facilitated the growth and migration of NPC cells, suggesting that it participated in NPC progression by functioning as an oncogene. Mechanistically, BC200 was found to act as a ceRNA by sponging and inhibiting miR-6834-5p. Thymidylate synthetase (TYMS), whose high expression was reported to be an independent indicator of poor prognosis in NPC via an unknown mechanism, was identified as a target gene of miR-6834-5p in the present study. BC200 upregulated TYMS expression in a manner that depends on miR-6834-5p. TYMS was abnormally upregulated in EBV-positive NPC cells and tissues, and its ectopic expression contributed to the proliferation and migration of NPC cells. This study highlights the role of lncRNA BC200, which is upregulated by EBV, in promoting the development of NPC, suggesting that BC200-mediated ceRNA network may be valuable biomarkers for the diagnosis and treatment of EBV-associated NPC.