Carbohydrate-Responsive Element-Binding Protein-Associated Metabolic Changes in Chemically Induced...

The Carbohydrate-Responsive Element-Binding Protein (ChREBP) is a glucose-sensitive transcription factor that regulates the carbohydrate and lipid metabolism. We investigated its cell-type-specific role in hepatocarcinogenesis using a chemically induced mouse model. Additionally, we examined the functions of its isoforms, ChREBPα and ChREBPβ. After the diethylnitrosamine (DEN) administration, we analyzed hepatocellular adenomas and carcinomas in systemic ChREBP-knockout (KO), hepatocyte-specific ChREBP-KO (L-KO), and wildtype (WT) mice at 4, 12, and 36 weeks using histology, morphometry, proliferation measurements, immunohistochemistry, a Western blot, and a quantitative PCR. Tumors developed 36 weeks after the DEN administration in 27% of WT mice but less frequently in KO (18%) and L-KO (9%) mice. However, preneoplastic foci were less common in KO mice but not in L-KO mice (39% vs. 9%; p < 0.05). L-KO hepatocytes exhibited lower proliferation, while KO tumors showed the downregulation of AKT/mTOR signaling, glycolysis, and lipogenesis compared to WT tumors. Our results showed that the liver-specific loss of ChREBPα, while ChREBPβ remained active, significantly reduced the tumor progression, suggesting an oncogenic role for ChREBPα. In contrast, the systemic knockout of both ChREBPα and ChREBPβ reduced the tumor initiation but did slightly prevent tumor progression, indicating that ChREBPβ may exert tumor-suppressive functions.