BCAT1-dependent HIF-1α stabilization is a targetable metabolic vulnerability in hepatocellular carcinoma

Hypoxia is a common characteristic of solid tumors, especially in hepatocellular carcinoma (HCC). Hypoxia-inducible factors (HIFs), particularly HIF-1α, mediate metabolic adaptation, which is crucial for survival of hypoxic cells. Branched-chain amino transferase 1 (BCAT1) catalyzes the reversible transamination reaction between branched-chain amino acids (BCAAs) and branched-chain keto acids (BCKAs), involving the inter-conversion of α-ketoglutarate (α-KG) and glutamate. We investigate and delineate the mechanisms by which BCAT1 consumes α-KG and stabilizes HIF-1α, suppressing α-KG-dependent oxygen dehydrogenase, prolyl hydroxylase-domain protein (PHD), inducing HIF-1α-mediated metabolic reprogramming and promoting hypoxic survival of HCC. We evaluate the potency of a BCAT1 inhibitor, ERG245, as a single or combination treatment with tyrosine kinase inhibitor (TKI) in vivo. We further validate the over-expression and correlation of BCAT1 and HIF-1α downstream metabolic genes in HCC clinical samples. Our results indicate that BCAT1 benefits HCC growth through HIF-1α-induced metabolic reprogramming. Targeting BCAT1 will provide an effective therapeutic strategy for HCC patients.