RIG-I Promotes Cell Proliferation in Esophageal Squamous Cell Carcinoma by Facilitating p21 Degradation

Abstract Background Retinoic acid-inducible gene-I (RIG-I) is considered a key sensor for host recognition of RNA virus infections. Recent studies have shown that RIG-I also regulates carcinogenesis. However, the role of RIG-I in esophageal squamous cell carcinoma (ESCC) remains unclear. Method We investigated the RIG-I expression in ESCC cells using a public database, immunohistochemistry, and Western blotting. We evaluated the proliferative activity of ESCC cells using CCK-8, colony formation, and EdU staining assays. Further, we determined the ESCC cell cycle changes using flow cytometry and the ubiquitination of p21 in the cells using cycloheximide chase and ubiquitination assays. Finally, we verified the in vivo effects of RIG-I on ESCC cells by constructing xenograft models. Results RIG-I was highly expressed in ESCC cells and significantly promoted their proliferation and cell cycle. Moreover, RIG-I knockdown inhibited xenograft growth in nude mice. Furthermore, RIG-I accelerated the cell cycle by promoting the ubiquitination and degradation of p21. Conclusion Overall, this study revealed that the increased expression of RIG-I due to ESCC accelerated the progression of esophageal cancer by promoting the ubiquitination and degradation of p21, which is related to the prognosis of ESCC. Thus, RIG-I may be a novel therapeutic target for ESCC treatment.