RRP9 Promotes Esophageal Squamous Cell Carcinoma Progression through E2F1 Transcriptional Regulation of CDK1

Esophageal cancer is a major disease that seriously threatens human health. Ribosomal RNA biogenesis is implicated in tumorigenesis, while the small nucleolar RNAs (snoRNAs) are responsible for post-transcriptional modifications of ribosomal RNAs during biogenesis, which are identified as potential markers of various cancers. The clinical significance, biological behavior, and potential molecular mechanism of the nucleolar small nuclear ribonucleoprotein RRP9 in esophageal squamous cell carcinoma (ESCC), which is a major pathological type of esophageal cancer, are investigated in this study. It is found that RRP9 is abnormally highly expressed in ESCC tissues and is closely associated with poor prognosis. Furthermore, it is found that RRP9 could regulate the cell cycle protein-dependent kinase CDK1 to promote ESCC progression in vitro and in vivo. Mechanistically, RRP9 promotes ESCC progression through enhancing the E2F1-mediated transcriptional regulation of CDK1. Collectively, the results defined RRP9 as an important tumor driver in ESCC that acted by activating oncogenic signaling by the E2F1-CDK1 pathway, and suggested RRP9 as a candidate therapeutic target for ESCC.