Abstract 5927: ACBP/DBI inhibition suppresses NASH-induced hepatocarcinogenesis

Abstract Background: Non-alcoholic fatty liver disease (NAFLD) or its severe form non-alcoholic steatohepatitis (NASH) is becoming an ever more prevalent risk factor of hepatocellular carcinoma (HCC). Currently, there are no approved drugs for the treatment of NASH. Extracellular ACBP/DBI (Acyl coenzyme A binding protein, also called diazepam-binding inhibitor) acts as an autophagy checkpoint and neutralization of ACBP/DBI prevents NASH. Therefore, we investigated the functional roles, mechanisms, and clinical relevance of ACBP/DBI in HCC. Methods: ACBP/DBI was blocked by four strategies: an inducible Acbp/Dbi knockout (Acbp-/-, control: Acbp+/+), a constitutive Gabrg2F77I mutation that prevents binding of ACBP/DBI to the receptor (control: WT), induction of ACBP/DBI-specific autoantibodies (induced by KLH-DBI, control: KLH), and monoclonal anti-DBI antibody (control: isotype). Three different types of HCC mouse models, including toxins/diet-based NASH-induced models (western diet plus CCl4), hydrodynamic transfection of oncogenes (Myc+Ctnnb1), and orthotopic transplantation (Hep55.1C) were used in combination with the aforementioned ACBP/DBI inhibition strategies to determine the association of ACBP/DBI and HCC. Results: ACBP/DBI inhibition attenuates tumorigenesis in mice with NASH, blunts oncogene induced HCC, and reduces the growth of orthotopically transplanted cancers. Mechanistically, ACBP/DBI inhibition retards cell cycle, suppresses cell proliferation, and favors ferroptosis, as determined by RNA-seq data and mass spectrometric metabolomics. CCK-8 proliferation, colony formation, and cell cycle assays performed on Huh-7, HepG2 and Hep55.1C cells demonstrated that ACBP/DBI knockdown reduced cell proliferation and induced G0/G1 arrest. IHC detection of Ki67 and PCNA in liver sections revealed antiproliferative effects of ACBP/DBI inhibition. qRT-PCR demonstrated the ACBP/DBI inhibition-induced upregulation of cell cycle inhibitor genes and downregulation of genes invoded in G0/G1 phase in liver tissues. qRT-PCR and immunoblot confirmed the upregulation of pro-ferroptotic and the downregulation of anti-ferroptotic genes and proteins in liver tissues upon ACBP/DBI inhibition. Primary HCC cell lines from Acbp+/+ and Acbp-/- mice further confirmed the pro-ferroptotic effects of ACBP/DBI inhibition obtained in liver tissues. Acbp-/- cell lines were more sensitivity to RSL3-induced ferroptosis. Conclusion: ACBP/DBI inhibition constitutes a potential strategy for treating NASH and NASH-induced HCC. Citation Format: Sijing Li, Omar Motiño, Flavia Lambertucci, Maria Chiara Maiuri, Isabelle Martins, Guido Kroemer. ACBP/DBI inhibition suppresses NASH-induced hepatocarcinogenesis [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(6_Suppl):Abstract nr 5927.