Abstract 574: Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation

Abstract Nonalcoholic fatty liver disease (NAFLD) -induced hepatocellular carcinoma (HCC) is an emerging malignancy in the developed countries. However, the mechanisms contributing to its formation remain largely unknown. Given the role of cancer stem cells (CSCs) in tumor initiation and therapeutic resistance, we hypothesize that adipocytes, one of the key cellular factors within the tumor microenvironment of NAFLD-induced HCC, may play a critical role in HCC development and drug resistance by regulating liver CSCs. Using a co-culture system in which differentiated adipocytes were grown with HCC cells, we found that adipocytes enhanced the self-renewal ability of HCC cells through indirect paracrine secretion. HCC cells pre-incubated with conditioned medium from adipocytes showed enhanced liver CSC properties including self-renewal, tumorgenicity, invasiveness and chemo-resistance to doxorubicin and sorafenib. Secretome profiles showed that FABP4 was preferentially secreted by adipocytes and its level was further augmented when co-cultured with HCC cells. Concurrently, recombinant FABP4 enhanced CSC properties of HCC cells. Drastic delay in the onset of tumor development in FABP4−/- mice upon DEN-injected and high fat diet-induced mouse models of NAFLD-HCC. Mass spectrometry analysis revealed ITGB1 as a direct binding partner of FABP4 for the first time. This data, together with the observation of significant downregulation of the Wnt/β-catenin pathway in tumors of FABP4−/− mice, revealed the role of adipocyte-derived FABP4 promotes liver CSC function by activating the PI3K/Akt/β-catenin signaling pathway via ITGB1. Overexpression of ITGB1 led to poorer survival of HCC patients with NAFLD as a risk factor. The development of a monoclonal neutralizing antibody against FABP4 successfully blocked FABP4-driven CSC functions, implicating the targetability of FABP4 for the treatment of NAFLD-induced HCC. Citation Format: Carmen Oi Ning Leung, Shilpa Gurung, Katherine Po Sin Chung, Sze Man Chan, Terence Kin Wah Lee. Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD) -induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 574.