Intervening in p53-Induced Death Domain Protein 1 to Decrease Regulatory T Cell Recruitment Boosts the Effectiveness...

The efficacy of radiofrequency ablation is constrained by incomplete tumor ablation, particularly in cases of excessive tumor volume, leading to elevated recurrence rates. Elucidating the genetic and microenvironmental alterations following incomplete ablation is essential for improving therapeutic outcomes. We aimed to identify the tumor-intrinsic molecular link between residual tumor cells and the immunosuppressive microenvironment that drives recurrence after radiofrequency ablation.

We retrospectively compared recurrence in hepatocellular carcinoma patients treated with radiofrequency ablation or liver resection and established complete and incomplete radiofrequency ablation mouse models. Transcriptomic dataset analysis (differentially expressed genes and weighted gene coexpression network analysis) combined with single-cell RNA sequencing was used to identify candidate genes linking incomplete ablation to regulatory T cell recruitment. Mechanistic roles were validated by Western blotting, reverse transcription quantitative polymerase chain reaction, flow cytometry, enzyme-linked immunosorbent assay, immunohistochemistry/immunofluorescence, and T-cell coculture assays, and the effect of p53-induced death domain protein 1 knockdown combined with anti-programmed cell death protein-1 therapy was assessed in vivo.

Analysis of tumor recurrence post radiofrequency ablation revealed a significantly higher local recurrence rate in primary tumors exceeding 2 cm in size, indicating that incomplete ablation is a critical driver of local tumor regrowth. In preclinical animal models, incomplete radiofrequency ablation was associated with increased infiltration of regulatory T cells. Gene expression profiling identified marked upregulation of p53-induced death domain protein 1, which strongly correlated with regulatory T cell infiltration and unfavorable prognosis. Mechanistic studies demonstrated that p53-induced death domain protein 1 enhanced p53 expression via the caspase-2/murine double minute 2 axis, promoted transforming growth factor-β1 secretion, and drove T-cell differentiation into regulatory T cells. Silencing p53-induced death domain protein 1 in hepatocellular carcinoma cells reduced regulatory T cell infiltration and heightened sensitivity to immunotherapy. Strikingly, combining radiofrequency ablation with immunotherapy following p53-induced death domain protein 1 knockdown significantly enhanced treatment efficacy.

These findings provide a robust theoretical and practical basis for integrating radiofrequency ablation with anti-programmed cell death protein-1-targeted therapy to mitigate recurrence and optimize clinical outcomes.