Long non‐coding RNA TTN‐AS1 facilitates tumorigenesis of papillary thyroid cancer through modulating the miR‐153‐3p/ZNRF2 axis

BACKGROUND: Long non-coding RNAs (lncRNAs) are crucial modulators in the tumorigenesis of numerous cancers, including papillary thyroid cancer (PTC). However, it is unclear whether lncRNA TTN antisense RNA 1 (TTN-AS1) can regulate PTC progression. The present study aimed to reveal the mechanism and function of TTN-AS1 in PTC. METHODS: TTN-AS1 expression in 92 pairs PTC tissues and four PTC cells was measured via a quantitative reverse transcriptase-polymerase chain reaction assay. The relationship of TTN-AS1 expression and clinical pathological features of PTC patients was analyzed using a chi-squared test. The biofunction of TTN-AS1 in PTC was identified by loss or gain-of-function assays. Based on bioinformatics analysis and mechanism experiments, the molecular mechanism of TTN-AS1 was analyzed and identified. RESULTS: A high level of TTN-AS1 was observed in PTC tissues and cells. The expression level of TTN-AS1 is possibly associated with lymphatic metastasis, TNM stage and the overall survival of PTC patients. Functionally, TTN-AS1 knockdown inhibited cell proliferation, migration, invasion and epithelial-mesenchymal transition in PTC, whereas overexpression of TTN-AS1 led to the opposite results. Mechanistically, TTN-AS1 acted as a competing endogenous RNA by sponging microRNA-153-3p (miR-153-3p) to elevate zinc and ring finger 2 (ZNRF2) expression. Additionally, a high level of TTN-AS1 in PTC was closely correlated with the activity of the phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway. CONCLUSIONS: The findings obtained in the present study indicate that TTN-AS1 facilitated PTC progression by regulating the miR-153-3p/ZNRF2 axis and activating the PI3K/Akt/mTOR pathway.