Repurposed Acarbose Targets Nidogen-1 to Remodel the Tumor Stroma and Suppress Portal Vein Tumor Thrombus in Hepatocellular Carcinoma.

Portal vein tumor thrombus (PVTT) is among the most lethal complications of hepatocellular carcinoma (HCC), yet its molecular mechanisms and immune features remain poorly characterized. To address this gap, we performed a comprehensive multi-omics analysis of 99 specimens from 47 patients, integrating nCounter profiling, single-cell RNA sequencing, digital spatial profiling, and proteomics to construct the first spatial map of the PVTT microenvironment. These analyses revealed marked intratumoral heterogeneity and enrichment of myofibroblast-like cancer-associated fibroblasts (myCAFs) arising through a macrophage-to-myofibroblast transition. Nidogen-1 (NID1) was identified as a stromal driver of immune barriers, highly expressed in PVTT cores and associated with impaired antitumor immunity. Guided by these mechanistic insights, we repurposed acarbose, a Food and Drug Administration-approved drug, to inhibit the NID1 axis. Functional assays demonstrated that acarbose disrupted myCAF-mediated immune barriers, suppressed PVTT progression, and synergized with anti-programmed death-1 (anti-PD-1) therapy in preclinical models. Furthermore, analysis of an independent clinical cohort of 810 HCC patients revealed a substantially lower incidence of PVTT among those receiving acarbose, underscoring its translational potential. Collectively, these findings establish the immune-stromal landscape of PVTT, uncover NID1-driven stromal remodeling as a mechanism of immune evasion, and highlight drug repurposing as an immediately actionable strategy to improve outcomes in HCC with PVTT.