Targeting p21-High Senescent Kupffer Cells Nanotherapeutically Potentiates Antitumor Immunity in Advanced Hepatocellular Carcinoma with Portal Vein Tumor Thrombus.

Hepatocellular carcinoma (HCC) patients with portal vein tumor thrombus (PVTT) are associated with a significantly poor prognosis and limited treatment options. Single-cell RNA sequencing (scRNA-seq) has revealed senescent Kupffer cells (sKCs), which are characterized by high levels of p21 expression and enriched in the tumor microenvironment (TME) of HCC-PVTT. These sKCs exhibit a pronounced senescence-associated secretory phenotype (SASP), promoting the proliferation and invasion of tumors and crosstalk with cancer-associated fibroblasts. To target sKCs, a biomimetic nanodelivery system termed SKEV@AAV has been developed. This system comprises adeno-associated virus (AAV) vectors carrying p21-specific shRNA, encapsulated within sKCs-derived exosomes (SKEV). SKEV@AAV effectively downregulated p21, suppressed SASP signaling, and disrupted pro-tumor interactions between sKCs and cancer-associated fibroblasts. In an orthotopic PVTT model, SKEV@AAV showed single-agent antitumor activity and attenuated SASP-associated inflammatory remodeling. Furthermore, the combination efficacy with anti-PD-1 was evaluated in a murine splenic liver-metastasis model, where SKEV@AAV reduced tumor burden, enhanced CD8+ T-cell infiltration, decreased regulatory T cells, and promoted memory T-cell differentiation. Our findings reveal a pivotal role of sKCs in mediating immune suppression in HCC-PVTT and provide a nanotherapeutic strategy that reverses sKCs' senescence, reprograms the TME, and ultimately enhances antitumor immune activation.