Disrupting KAT8 Liquid–Liquid Phase Separation with Hybrid Vesicle–Liposome Platform for Enhanced PD‐L1 Blockade Treatment

Abstract

ABSTRACT Programmed cell death protein 1/its ligand 1 (PD‐1/PD‐L1) blockade has revolutionized cancer immunotherapy, yet its efficacy is limited by incomplete checkpoint inhibition and persistent PD‐L1 transcription. In this work, lysine acetyltransferase 8 (KAT8) is identified as a nucleator of liquid–liquid phase separation (LLPS)‐mediated condensates that concentrate transcription factors to drive sustained PD‐L1 transcription and promote immune resistance. Leveraging this mechanism, a PD‐1‐functionalized hybrid vesicle–liposome platform (PD‐1‐HVL–siKAT8) is developed to deliver small interfering RNA (siRNA) targeting KAT8 for LLPS modulation and enhanced cancer immunotherapy. In this platform, the PD‐1‐presenting vesicles enable tumor accumulation and PD‐L1 blockade, while the fused liposomes provide efficient siRNA encapsulation and cytosolic release, leading to potent KAT8 silencing and condensate dissolution. This LLPS modulator platform markedly suppresses PD‐L1 expression and reshapes the tumor immune microenvironment, augmenting type I interferon signaling, dendritic cell maturation, cytotoxic T‐cell activation, and M1‐like macrophage polarization. In subcutaneous and recurrent hepatocellular carcinoma models, PD‐1‐HVL–siKAT8 significantly inhibits tumor growth, prevents recurrence, and extends survival with negligible toxicity. Collectively, this approach integrates PD‐L1 blockade with disruption of LLPS‐dependent transcription for durable immunotherapy.