EIF3H stabilizes CCND1 to promotes intrahepatic cholangiocarcinoma progression via Wnt/β-catenin signaling.

Abstract

Cholangiocarcinoma (CCA) is a group of tumors that arise along the human biliary duct tree, ranking second in primary hepatic malignancies. Intrahepatic CCA (iCCA) represents about 10%-20% of CCAs. There is an increasing body of evidence suggesting that iCCAs' incidence and mortality have been increasing globally over the past few decades. In this study, we found that the EIF3H expression level in iCCA tissues was significantly increased compared to the adjacent non-cancerous tissues by immunohistochemistry analysis (IHC). A similar tendency of EIF3H mRNA and protein level was confirmed in iCCA cell lines using RT-qPCR and Western blot. EIF3H has been identified as a critical molecule that plays a pro-neoplasmic role in iCCA both in vivo and in vitro, such as proliferation, migration, and anti-apoptosis. Mechanistically, we found that EIF3H knockdown can promote the degradation of CCND1 and the proteolysis of CCND1 is mediated by ubiquitin-proteasome system (UPS). Thus, we come to the conclusion that EIF3H promotes proliferation and migration of iCCAs, inhibiting apoptosis of iCCA cells at the same time by stabilizing the CCND1 protein structure. Our findings provide insights into the mechanism of tumorigenesis role of EIF3H in iCCAs and a potential therapeutic target for iCCA treatment.