Long non-coding RNA CCAT2 drives the growth of laryngeal squamous cell carcinoma via regulating YAP activity

Emerging evidence suggests that long non-coding RNA (lncRNA) is closely associated with numerous human diseases, including cancer. However, the functional relevance of lncRNA in human laryngeal squamous cell carcinoma (LSCC) is largely unknown. In the current study, we described CCAT2, a previously unappreciated oncogenic lncRNA in LSCC. CCAT2 was significantly upregulated in human LSCC tissue and serum samples, associated with larger tumor volume, higher clinical stage, and poorer differentiation status. Lentivirus-mediated CCAT2 knockdown notably repressed the cell viability, colony formation, and DNA synthesis rate of LSCC. Screening of transcription factors revealed that YAP/TEAD activity was affected by CCAT2 in LSCC cells. Further, CCAT2 directly binds to YAP protein and blocks the phosphorylation of YAP induced by LATS1, resulting in the nuclear translocation of YAP and the activation of YAP oncogenic targets, such as CTGF, CYR61 and AMOTL2. Importantly, we also confirmed the regulation of CCAT2 on YAP activity in vivo based on nude mice model. Altogether, we identified a novel lncRNA that controls YAP nucleocytoplasmic shuttling and promotes LSCC cell proliferation. Given the importance of YAP in tumorigenesis and progression, our results provide insights to intervene LSCC by targeting the CCAT2/YAP axis.