PINK1 dysfunction in hepatocellular carcinoma fosters immune evasion and disease progression by promoting neutrophil infiltration.

backgroundDespite breakthroughs in immune checkpoint blockade (ICB) for advanced hepatocellular carcinoma (HCC), tumor immune evasion remains a major limitation to immunotherapy efficacy. PTEN-induced putative kinase 1 (PINK1) has highlighted roles in immune system regulation and tumor progression, but its specific role in HCC and impact on ICB response remains unclear. This study aimed to elucidate how PINK1 dysfunction enables HCC adaptation to ICB-induced immune attacks and identify potential therapeutic targets.

methodsOnline patient dataset analyses were performed to evaluate the impact of reduced PINK1 expression on clinical prognosis in HCC. An orthotopic HCC tumor cell mouse model was established. Single-cell RNA sequencing and flow cytometry were employed to explore the immune characteristics and remodeling of the tumor microenvironment in PINK1-deficient HCC. Neutrophils and T cells were isolated, stimulated, and/or cultured for ex vivo functional assays. Gene Expression Omnibus database analyses were performed to identify key genes involved in HCC resistance to ICB.

resultsWe identified PINK1 as a key mediator of ICB resistance in HCC. We found that PINK1 expression was significantly reduced in ICB-resistant HCC and a reduced PINK1 signature was associated with poorer clinical outcomes in patients with HCC. Importantly, PINK1 deficiency serves as a predictive biomarker for diminished responsiveness to immunotherapy. Function experiments have revealed that PINK1 regulates HCC progression and infiltration and activation of neutrophils and T cells. Mechanistically, the tumor cell-intrinsic downregulation of PINK1 activated the production of chemokines involved in neutrophil recruitment, and tumor-infiltrating neutrophils inhibited T cell activity. Additionally, a neutrophil-depleting antibody resensitized tumors to antiprogrammed death-ligand 1 therapy in orthotopic HCC models, further demonstrating that neutrophils are the primary population responsible for the adaptation of cancer cells with reduced PINK1 to ICB-induced immune attacks.

conclusionsOur study uncovered PINK1 as both a predictor of the ICB response and a key mediator of immune evasion by promoting neutrophil infiltration. These results highlight that the therapeutic targeting of neutrophils may represent a viable strategy to overcome ICB resistance in HCC.