Transforming acidic coiled-coil-containing protein 3-mediated lipid metabolism reprogramming impairs CD8+ T-cell cytotoxicity in hepatocellular carcinoma

Abstract

Recent evidence has highlighted immune checkpoint inhibitors as among the most promising immunotherapies for various malignancies. However, a significant proportion of HCC patients exhibit poor responses. Lipid metabolic heterogeneity is considered a key driver of cancer progression. However, the role of lipid metabolic reprogramming in HCC immunotherapy resistance remains poorly understood. Herein, we aimed to illuminate the potential relationship between lipid metabolic reprogramming and ICI resistance and provide novel strategies to increase the HCC immunotherapy response. Patients who received PD-1/PD-L1 inhibitors were enrolled. The effect of TACC3 on the tumor microenvironment was validated via single-cell RNA sequencing in HCC-bearing mouse models. Targeted metabolomics was performed to analyze the regulatory role of TACC3 in HCC metabolism. To address HCC immunotherapy resistance, we developed a targeted nucleic acid therapeutic utilizing N-acetylgalactosamine (GalNAc) to conjugate siTACC3. Through clinical cohort analysis, we found that TACC3 was overexpressed in HCC patients with poor response to immunotherapy. Furthermore, we demonstrated that silencing tumor-derived TACC3 optimizes the cytotoxicity of infiltrating CD8⁺ T lymphocytes. Both in vitro and in vivo assays suggested that TACC3 maintains ACSL4-mediated polyunsaturated fatty acid (PUFA) metabolism in HCC cells. Additionally, TACC3 accelerates ACSL4 expression by interacting with LARP1 and PABPC1, which stabilize ACSL4 mRNA. The results of preclinical models demonstrated the satisfactory efficacy of GalNAc-conjugated siTACC3 combined with PD-1 inhibitor therapy for HCC. In summary, tumor-derived TACC3 impairs the tumor-killing activity of CD8⁺ T lymphocytes through PUFA metabolism-associated crosstalk. Targeting TACC3 represents a novel and practicable strategy to augment ICI efficacy against HCC.