Blocking interleukin-1 receptor type 1 (IL-1R1) signaling in hepatocytes slows down diethylnitrosamine-induced liver tumor growth in obese mice.

Background: An increasing number of HCC develops in the context of metabolic dysfunction-associated steatotic liver disease and its inflammatory form, metabolic dysfunction-associated steatohepatitis, even in the absence of cirrhosis. Chronic metabolic inflammation is the driving force of metabolic dysfunction-associated steatotic liver disease progression and a key factor in hepatocarcinogenesis. Given the prominent role of IL-1 signaling in inflammation and metabolic diseases, we investigated the relevance of the hepatocyte-specific IL-1 receptor type 1 knockout in metabolic dysfunction-associated steatohepatitis-related noncirrhotic HCC.

Methods: For HCC induction, Il1r1Hep-/- mice received a single i.p. injection of diethylnitrosamine at 2 weeks and were fed with high-fat plus high-carbohydrate diet, starting from 4 weeks. After 18 weeks of diet intervention, mice were sacrificed, and macroscopic and microscopic tumor loads were assessed.

Results: Knockout of the hepatic IL-1 receptor type 1 pathway significantly reduced liver tumor growth. Il1r1Hep-/- mice were also less susceptible to hepatic steatosis, insulin resistance, and associated hepatic c-Jun N-terminal kinase activation than their wild-type (WT) littermates. Reduced Ki-67 and cyclin D1 levels, as well as decreased phosphorylation of signal transducer and activator of transcription 3, occur in Il1r1Hep-/- livers, lowering cancer cell proliferation and growth. Additionally, in Il1r1Hep-/- livers, the chemokine (C-X-C motif) ligand 1/2-driven accumulation of myeloid-derived suppressor cells and CD8+ T-cell infiltration were reduced compared to the wild type.

Conclusions: Metabolic inflammation mediated by the hepatocytic IL-1 receptor type 1 is a cofactor in mutagenic hepatocarcinogenesis. Targeting IL-1 signaling could be an adjunct strategy to the current immunomodulatory HCC treatments.