Abstract 4145: Frizzled-4 expression enhances hepatocellular carcinoma progression, sorafenib resistance and suppresses anti-tumor CD8 T cell immunity

Abstract Background: Hepatocellular carcinoma (HCC) is one of the most common and deadliest cancers. Sorafenib remains the globally accepted systemic first-line treatment for advanced HCC although acquired drug-resistance is becoming increasingly common. Hopefully, immune-checkpoint inhibitor therapy has recently revolutionized the treatment for advanced HCC that have poor response to sorafenib, but the durable response rate remains low in most patients for unknown reasons. This fuels a wave of research into the molecular mechanisms of tumor-intrinsic resistance to both chemotherapy and immune checkpoint blockade (ICB), which may provide potential systemic treatment options for advanced HCC patients. Methods and Results: RNA sequencing of sorafenib-resistant HCC cell lines was performed to identify Frizzled-4 (FZD4) as a critical gene for drug resistance that was further validated in animal models. Clinical implication of FZD4 overexpression was studied in HCC patients. Using genetic and pharmacological approaches, we found that FZD4 was sufficient to increase clonogenicity, migration and invasion, and prevent sorafenib-induced apoptosis. In addition, FZD4 could reduce secretion of tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), as well as intracellular levels of cytotoxic granzyme A and perforin in CD8+ T cells, indicating significant suppression of CD8+ T cell-mediated antitumor immunity in HCC tumors. In vivo studies also revealed that FZD4 expression promoted tumorigenesis and accelerated HCC cell metastatic lung colonization. Combination therapy of FZD4 inhibitor FzM1 with sorafenib in HCC of MYC/sgp53-induced model showed a tendency to significantly impede tumor growth and improve mice survival. Moreover, gene set enrichment analysis (GSEA) identified the cholesterol homeostasis and fatty acid metabolism signaling signatures as the top activated pathways in FZD4-high HCC cells. This evidence suggests a crucial role of FZD4-involved lipid metabolism linked to the development of therapeutic resistance. Conclusion: Our study demonstrates that FZD4 expression plays a pivotal role in HCC progression and holds the potential for expanding the scope of targeted/ICB therapies to tumors that are currently unresponsive, especially in advanced HCC. The resistance mechanisms will be addressed in further work. Citation Format: Jie Luo, Lanqi Gong, Yuma Yang, Qin Liu, Jiao Huang, Xiaona Fang, Xin-Yuan Guan. Frizzled-4 expression enhances hepatocellular carcinoma progression, sorafenib resistance and suppresses anti-tumor CD8 T cell immunity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4145.