Disrupting KAT8 Liquid-Liquid Phase Separation with Hybrid Vesicle-Liposome Platform for Enhanced PD-L1 Blockade
Xinyao Hu1,2, Hua Zhu3, Qian-Fang Meng2
1Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China.
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.
Insights
A novel therapy combines PD-1 blockade with KAT8 inhibition to disrupt immune-evading condensates. This approach enhances cancer immunotherapy by reducing PD-L1 expression and boosting anti-tumor immunity.
Area of Science:
- Biomedical Engineering
- Cancer Research
- Immunology
Background:
- Programmed cell death protein 1/its ligand 1 (PD-1/PD-L1) blockade is a cornerstone of cancer immunotherapy but faces limitations due to incomplete checkpoint inhibition and sustained PD-L1 transcription.
- Lysine acetyltransferase 8 (KAT8) has been identified as a key factor in promoting immune resistance by nucleating liquid-liquid phase separation (LLPS)-mediated condensates that sustain PD-L1 transcription.
Purpose of the Study:
- To develop a novel therapeutic platform that integrates PD-1 blockade with disruption of LLPS-dependent transcription for enhanced cancer immunotherapy.
- To investigate the efficacy of a PD-1-functionalized hybrid vesicle-liposome platform delivering siRNA targeting KAT8 (PD-1-HVL-siKAT8) in modulating LLPS and overcoming immune resistance.
Main Methods:
- Development of a PD-1-functionalized hybrid vesicle-liposome platform (PD-1-HVL-siKAT8) for co-delivery of PD-1 blockade and KAT8-targeting siRNA.
- Utilizing the platform to achieve tumor-specific accumulation, PD-L1 blockade, efficient siRNA delivery, KAT8 silencing, and LLPS condensate dissolution.
- Assessing the impact on the tumor immune microenvironment, including type I interferon signaling, dendritic cell maturation, cytotoxic T-cell activation, and macrophage polarization.
Main Results:
- The PD-1-HVL-siKAT8 platform effectively suppressed PD-L1 expression and remodeled the tumor immune microenvironment.
- Significant augmentation of type I interferon signaling, dendritic cell maturation, cytotoxic T-cell activation, and M1-like macrophage polarization was observed.
- In hepatocellular carcinoma models, PD-1-HVL-siKAT8 demonstrated significant tumor growth inhibition, prevention of recurrence, and extended survival with minimal toxicity.
Conclusions:
- The developed LLPS modulator platform effectively integrates PD-1 blockade with disruption of LLPS-dependent transcription, leading to durable immunotherapy.
- This novel approach offers a promising strategy to overcome limitations in current cancer immunotherapy by targeting persistent PD-L1 expression and enhancing anti-tumor immune responses.
