Abstract 909: A new chemokine identified as a key player of tumor immune microenvironment remodeling in β-catenin mutated hepatocellular carcinoma

Abstract The emergence of immunotherapy has revolutionized the treatment landscape for advanced hepatocellular carcinoma (HCC), significantly enhancing patient survival. However, accumulating evidence indicates that two-thirds of HCC harboring oncogenic mutations in the β-catenin coding gene (CTNNB1) exhibit resistance to immunotherapy. These tumors are largely devoid of immune infiltrates, highlighting a critical mechanism of immune escape. To investigate this phenomenon, we developed two 3D liver cancer spheroid models using a β-catenin-wild-type cell line (Huh7) and a β-catenin-mutated cell line (HepG2) co-cultured with PBMC (Peripheral Blood Mononuclear Cells). Flow cytometry analyses revealed that β-catenin mutation significantly impairs immune cell infiltration, particularly by Natural Killer (NK) cells. Our global transcriptomic analysis conducted in HepG2 cell line identified a specific chemokine, referred to here as CXX*, which is downregulated by mutated-β-catenin. In 2D and 3D cultured models, depletion of the mutated β-catenin in HepG2 cells led to an increase in CXX expression and secretion while β-catenin pathway overactivation in Huh7 cells induced its decrease. As CXX is known to recruit NK cells, we investigated the impact of its depletion or overexpression on immune cell infiltration in Huh7 and HepG2 spheroids. Our results demonstrated that CXX indeed plays a key role in the recruitment of NK cells in both models. In silico transcriptomic analysis of HCC patient cohorts corroborated these findings, revealing reduced CXX expression and diminished NK cell markers in tumors harboring β-catenin mutations, with these two results being positively correlated. Additionally, we report both a decrease in CXX expression and a reduced infiltration of NK cells in tumor sections from HCC patients with β-catenin mutation. Preliminary data obtained from supernatants of HCC patient Precision-Cut Liver Slices (PCLS) also revealed a reduction of CXX secretion by PCLS obtained from patients bearing the β-catenin mutation. In conclusion, our results identify CXX as a novel negative target of oncogenic β-catenin and provide new insights into how β-catenin mutations reshape the tumor microenvironment of HCC, enabling immune evasion. *A patent is in progress. Citation Format: Justine Vaché, Camille Dantzer, Isabelle Mahouche, Ramazan Akyol, Adel Hammoutene, Paulette Bouliac-Sage, Valérie Paradis, Violaine Moreau, Clotilde Billottet. A new chemokine identified as a key player of tumor immune microenvironment remodeling in β-catenin mutated hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 909.