Abstract
Aerobic glycolysis supports tumor growth, but how tumor cells sense glucose to coordinate biosynthesis remains largely unclear. Here we show that in hepatocellular carcinoma cells, glucose-activated PKCε phosphorylates the purine synthesis enzyme ADSL, triggering its translocation to the endoplasmic reticulum. ADSL then promotes succination of INSIG1/2, which disrupts the interaction between INSIG proteins and SCAP, leading to the translocation of the SCAP-SREBP complex to the Golgi, the activation of SREBP-1 and the transcription of downstream lipogenesis-related genes, proliferation of tumor cells, and tumorigenesis in mice. Through virtual screening, we identify Elsulfavirine, an approved HIV drug, which blocks ADSL-INSIG interaction and suppresses SREBP-1 activation induced by glucose. Combining Elsulfavirine with Lenvatinib synergistically inhibits tumor growth. Clinically, ADSL phosphorylation and INSIG succination correlate with SREBP-1 activation and poor prognosis in human HCC. In summary, these findings reveal a repurposing mechanism by which tumor cells coordinate glucose metabolism and lipogenesis via a moonlighting function of ADSL and underscore a repurposing strategy for liver cancer therapy.