Single-Cell and Bulk Transcriptomics Uncover the Cellular Ecosystem of Vascular Invasion in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive liver malignancy with a rising global incidence and limited therapeutic options. Vascular invasion (VI) is a hallmark of advanced disease, correlating with early recurrence and dismal prognosis, yet its tumor microenvironment (TME) drivers remain elusive. We analyzed single-cell RNA sequencing (scRNA-seq) data from 25 ICC samples to systematically characterize the cellular composition and molecular features related to VI. By integrating bulk RNA-seq data, spatial transcriptomics, and multiplex immunofluorescence, we identified a distinct subset of tumor-like cancer-associated fibroblasts (CAFs), termed tCAFs, enriched in VI-positive tumors. Functional enrichment analyses revealed that tCAFs were prominently associated with hypoxia and angiogenesis pathways, findings corroborated by the significant upregulation of tCAF markers (MME and NT5E) in ICC-derived CAFs under hypoxic conditions in vitro. Cell–cell communication analysis and spatial mapping uncovered that tCAFs might promote VI primarily through VEGF signaling interactions with endothelial cells. Integrative bioinformatics and RT-qPCR validation identified three key functional genes in tCAFs: SLC2A1, PTGS2, and PLOD2. In endothelial sprouting assays, pharmacological inhibition of SLC2A1 exerted a pronounced suppressive effect. Consistently, sprouting assays using ICC-derived CAFs with SLC2A1 knockdown confirmed that its downregulation significantly reduced endothelial sprouting capacity. Importantly, administration of the SLC2A1 inhibitor BAY-876 effectively suppressed tumor progression and intrahepatic metastasis in the orthotopic ICC mouse model. Our findings define a VI-associated cellular ecosystem and molecular landscape in ICC, unveiling a novel hypoxia–tCAFs–endothelial cells axis. Furthermore, we identify SLC2A1 as a clinically relevant therapeutic target, offering new insights into tumor VI.