Long non-coding RNA PITPNA-AS1 regulates UNC5B expression in papillary thyroid cancer via sponging miR-129-5p

Background: Long non-coding RNA (lncRNA) PITPNA antisense RNA 1 (PITPNA-AS1) expression characteristics, function, and mechanism in papillary thyroid cancer are unclear. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was applied for detecting PITPNA-AS1, UNC-5 netrin receptor B (UNC5B) mRNA, and miR-129-5p expressions in papillary thyroid cancer tissues and cell lines. EdU assay, cell counting kit-8 (CCK-8) assay, wound healing assay, and flow cytometry analysis were performed to investigate the biological functions of PITPNA-AS1 in papillary thyroid cancer. Dual-luciferase reporter assay was utilized for determining whether PITPNA-AS1 and miR-129-5p, as well as UNC5B and miR-129-5p could directly bind to each other. Western blot assay was employed for measuring UNC5B protein expression level in papillary thyroid cancer cell lines. Results: PITPNA-AS1 and UNC5B expressions were markedly increased in papillary thyroid cancer tissues and cell lines while miR-129-5p expression was down-regulated. Knockdown of PITPNA-AS1 could significantly inhibit papillary thyroid cancer cell growth and migration and promote cell apoptosis while UNC5B overexpression plasmids or miR-129-5p inhibitors counteracted the knockdown effect of PITPNA-AS1 on papillary thyroid cancer cells. PITPNA-AS1 targeted miR-129-5p to repress its expression and miR-129-5p targeted UNC5B to repress its expression. Silencing PITPNA-AS1 reduced the expression of UNC5B via regulating miR-129-5p expression. Conclusions: PITPNA-AS1 facilitated papillary thyroid cancer cell proliferation and migration, and suppressed apoptosis through miR-129-5p/UNC5B axis.