Adipocyte-derived FABP4 promotes metabolism-associated steatotic liver-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation.

Metabolic dysfunction-associated steatotic liver disease-induced (MASLD-induced) hepatocellular carcinoma (HCC) is an emerging malignancy linked to excessive accumulation of adipose tissue and hepatic fat. Understanding the role of adipocytes in the development of MASLD-induced HCC is crucial. In an in vitro coculture system, differentiated adipocytes were found to enhance cancer stemness and drug resistance in HCC through paracrine signaling. Fatty acid-binding protein 4 (FABP4) was preferentially secreted by adipocytes, and recombinant FABP4 further augmented the cancer stem cell (CSC) properties of HCC cells. Notably, Fabp4-/- mice exhibited a marked delay in the progression of MASLD-HCC, which correlated with the increased HCC risk observed in MASLD patients with elevated FABP4 expression. Mass spectrometry analysis identified integrin β 1 (ITGB1) as a binding partner of FABP4. These data, together with a substantial downregulation of the Wnt/β-catenin pathway in Fabp4-/- mouse tumors, revealed that FABP4 augmented liver CSC functions by activating PI3K/AKT/β-catenin signaling via ITGB1. We developed an anti-FABP4 neutralizing antibody that successfully inhibited FABP4-driven CSC functions and suppressed MASLD-induced HCC. In conclusion, our findings indicate that adipocyte-derived FABP4 plays a critical role in the development of MASLD-induced HCC and targeting the ITGB1/PI3K/AKT/β-catenin signaling cascade may offer a promising approach to combat this aggressive disease.