Suppression of Long Noncoding RNA SNHG1 Inhibits the Development of Hypopharyngeal Squamous Cell Carcinoma via Increasing PARP6 Expression

Purpose. This study aimed to explore the function and molecular mechanism of long noncoding RNA Small Nucleolar RNA Host Gene 1 (SNHG1) in the development of hypopharyngeal squamous cell carcinoma (HSCC). Methods. Human HSCC cell line FaDu was used in this study. Cell viability and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. Cell migration and invasion were measured by Transwell assay. The expression of PARP6, XRCC6, β-catenin, and EMT-related proteins (E-cadherin and N-cadherin) were determined using western blotting. Moreover, the regulatory relationship between SNHG1 and PARP6 was investigated. Furthermore, the effects of the SNHG1/PARP6 axis on tumorigenicity were explored in vivo. Results. Suppression of SNHG1 suppressed the viability, migration, and invasion but promoted apoptosis of FaDu cells in vitro ( $P<0.01$ ). PARP6 is a target of SNHG1, which was upregulated by SNHG1 knockdown in FaDu cells ( $P<0.01$ ). SNHG1 suppression and RARP6 overexpression inhibited FaDu cell proliferation, migration, and invasion ( $P<0.05$ ). SNHG1 suppression and RARP6 overexpression also inhibited tumorigenicity of HSCC in vivo. Furthermore, the protein expression of E-cadherin was significantly increased and that of N-cadherin, β-catenin, and XRCC6 was dramatically decreased in HSCC after SNHG1 suppression or/and RARP6 overexpression both in vitro and in vivo ( $P<0.01$ ). Conclusions. SNHG1 silencing inhibits HSCC malignant progression via upregulating PARP6. XRCC6/β-catenin/EMT axis may be a possible downstream mechanism of the SNHG1/PARP6 axis in HSCC. SNHG1/PARP6 can be used as a promising target for the treatment of HSCC.