eIF3a mediates HIF1α-dependent glycolytic metabolism in hepatocellular carcinoma cells through translational regulation.

eIF3a is the largest subunit of eIF3 complex and is a key player in translational control. Recently eIF3a is recognized as a proto-oncogene, which is overexpressed and connected to tumorigenesis of many cancers. However, the mechanistic roles of eIF3a during the tumorigenesis remain largely elusive. Here, we report that depletion of eIF3a significantly reduced HIF1α protein level and cellular glycolysis ability. Mechanistically, we found that eIF3a regulates HIF1α protein synthesis through internal ribosomal entry site (IRES)-dependent translation. Importantly, through analyses of our own sample collection, we found that eIF3a is overexpressed in hepatocellular carcinoma (HCC) tissues, and a high level of eIF3a predicts poor prognosis of HCC patients. TCGA analyses further confirmed that eIF3a is coincident with an elevated activity of HIF1α pathway genes. Collectively, we identify eIF3a as a regulator for glycolysis through HIF1α IRES-dependent translational regulation, which may be a potential therapeutic target for HCC.