LncRNA-CASC15 knockdown inhibits the progression of esophageal squamous cell carcinoma through targeting miR-33a-5p/PTGS2 axis.

LncRNA CASC15 has been determined as a novel tumor-related lncRNA in many cancers. However, the in-detail role of CASC15 remains elusive in esophageal squamous cell carcinoma (ESCC). CASC15 expression level was detected in 113 ESCC tissues and paired adjacent normal tissues and in human ESCC cell lines. The effects of CASC15 on ESCC proliferation, migration, and invasion were assessed using CCK-8 and transwell assays. In addition, the potential downstream molecules of CASC15 were searched and confirmed by software algorithms, RT-qPCR, western blot, dual-luciferase reporter, and rescue experiments. CASC15 was upregulated in ESCC tissues and cell lines. CASC15 overexpression was associated with poorer prognosis in ESCC patients. Functionally, CASC15 knockdown inhibited cell proliferation, migration, and invasion of ESCC cells. Mechanistically, it was confirmed that CASC15 acts as competing endogenous RNA for miR-33a-5p to regulate PTGS2 expression. In addition, rescue assay showed that miR-33a-5p knockdown or PTGS2 overexpression abolished the cell proliferation, migration, and invasion inhibition role of CASC15 knockdown. In conclusion, this study indicates that CASC15 was upregulated in ESCC and CASC15 knockdown hindered ESCC progression through targeting the miR-33a-5p/PTGS2 axis. CASC15 might serve as a novel biomarker and therapeutic target for ESCC.