LncRNA TSIX acts as a ceRNA of miR-342-3p to Promote the Progression of Nasopharyngeal Carcinoma by Regulating AGR2

Abstract Background: LncRNA TSIX has been observed to be abnormally expressed in many human cancers. However, its roles in nasopharyngeal carcinoma (NPC) remains unclear, and this study aims to explore the functions of TSIX in NPC. Methods: The expression of TSIX and miR-342-3p in NPC tissues and corresponding cell lines was detected by qRT-PCR. Bioinformatics analysis and luciferase activity assay and RIP assay were applied to determine the interaction between TSIX, miR-342-3p, and AGR2. The roles of TSIX, miR-342-3p and AGR2 in the proliferation, apoptosis, migration and invasion of NPC cells were explored both in vitro and in vivo . In addition, the rescue experiments were used to confirm the functions of TSIX, miR-342-3p, and AGR2 in NPC progression. Results: Our study firstly found that TSIX was significantly upregulated in NPC tissues and corresponding cell lines. Moreover, upregulation of TSIX obviously exacerbated the NPC progression including the proliferation, apoptosis, migration and invasion, while downregulation of TSIX efficiently attenuated the development of NPC. Further, our results demonstrated that TSIX could increase the expression of AGR2, which was directly targeted by miR-342-3p, and then lead to the facilitated development of NPC cells. Conclusion: In summary, our study revealed that lncRNA TSIX promoted the progression of NPC through targeting miR-342-3p/AGR2 axis, suggested that it might be a potential therapeutic target for NPC.