Postoperative recurrence remains one of the greatest clinical challenges in hepatocellular carcinoma (HCC), with recurrence rates approaching 70% after surgical resection and 40% following liver transplantation. Although immune checkpoint blockade has transformed cancer therapy, only a minority of HCC patients achieve durable clinical benefit.
Increasing evidence suggests that metabolic reprogramming enables tumor cells to evade immune surveillance and resist immunotherapy; however, the key metabolic pathways underlying immune escape and recurrence have remained poorly understood.
In a study published in Immunity, the research teams led by Prof. WANG Guangchuan and Prof. XU Chenqi from the Center for Excellence in Molecular Cell Science (Shanghai Institute of Biochemistry and Cell Biology) of the Chinese Academy of Sciences, together with Prof. WANG Zhengxin from Huashan Hospital, Fudan University, identified sterol O-acyltransferase 1 (SOAT1) as a critical metabolic driver of immune evasion and postoperative recurrence in HCC. The study demonstrates that cholesterol esterification enables tumor cells to survive CD8⁺ T-cell attack by preserving metabolic and redox resilience. Importantly, genetic or pharmacological inhibition of SOAT1 markedly enhances the efficacy of both anti-PD-1 therapy and CAR-T cell therapy, even in obesity-associated tumors and under post-transplant immunosuppressive conditions, highlighting cholesterol esterification as a promising therapeutic target for preventing HCC recurrence.
To identify metabolic regulators of postoperative recurrence, the researchers integrated quantitative proteomics with five-year clinical follow‑up data from 28 liver transplant recipients with HCC and combined these analyses with an in vitro T-cell cytotoxicity screen. This integrated strategy identified SOAT1, the enzyme responsible for cholesterol esterification, as a key determinant of tumor resistance to T-cell-mediated killing.
Clinical analyses further demonstrated that elevated SOAT1 expression was associated with a significantly higher risk of recurrence, poorer overall survival, and reduced responsiveness to immune checkpoint inhibitors. SOAT1 expression was also markedly increased in tumors from obese patients. In both subcutaneous and orthotopic HCC models, genetic deletion or pharmacological inhibition of SOAT1 significantly suppressed tumor growth and substantially enhanced the therapeutic efficacy of anti-PD-1 treatment in a CD8⁺ T-cell-dependent manner. Notably, SOAT1 inhibition remained highly effective in obesity-associated HCC models induced by a high-fat, high-cholesterol diet, as well as in mouse models mimicking post-transplant immunosuppression using tacrolimus, underscoring its strong translational potential.
Mechanistically, deficiency caused free cholesterol to accumulate within the endoplasmic reticulum, leading to retention of the SCAP–SREBP complex and suppression of SREBP activation.
Consequently, cholesterol and fatty acid biosynthesis were broadly inhibited, triggering profound metabolic reprogramming. This metabolic remodeling produced two major consequences: (1) reduced synthesis of unsaturated fatty acids and phospholipids diminished production of the immunosuppressive lipid mediator prostaglandin E₂ (PGE₂), thereby alleviating suppression of CD8⁺ T-cell function and promoting a more immunostimulatory tumor microenvironment; (2) depletion of cholesterol-derived antioxidant metabolites impaired the ability of tumor cells to maintain redox homeostasis during immune attack. As a result, tumor cells exposed to IFN-γ or CD8⁺ T-cell-mediated cytotoxicity accumulated excessive lipid reactive oxygen species (lipid ROS) and became markedly more susceptible to immune killing.
Restoring SREBP activity largely rescued these defects, demonstrating that SOAT1 promotes immune resistance by maintaining cholesterol homeostasis, metabolic fitness, and redox balance. Consistent with these findings, SOAT1 inhibition significantly enhanced the cytotoxic efficacy of GPC3-specific CAR-T cells against human HCC cells. Furthermore, the researchers developed tacrolimus-resistant CAR-T (TR-CAR-T) cells, providing a potential therapeutic strategy for recurrent HCC in liver transplant recipients receiving immunosuppressive therapy.
Collectively, this study identifies SOAT1 as a key metabolic driver of immune evasion and postoperative recurrence in hepatocellular carcinoma. More importantly, it establishes a conceptual framework in which cholesterol esterification sustains metabolic and redox resilience, thereby enabling tumor cells to withstand CD8⁺ T-cell-mediated immune attack. These findings redefine cholesterol esterification as more than a lipid storage pathway, revealing it as a central metabolic mechanism that links lipid metabolism to antitumor immunity. By identifying SOAT1 as a therapeutically actionable target, the study provides a strong rationale for combining SOAT1 inhibition with immune checkpoint blockade or CAR-T cell therapy to overcome immunotherapy resistance and reduce postoperative recurrence, particularly in obesity-associated HCC and liver transplant recipients.
Reference: https://www.cell.com/immunity/abstract/S1074-7613(26)00253-0
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