SPINK1-driven cellular heterogeneity and interaction networks in intrahepatic cholangiocarcinoma revealed by integrated multi-omics analysis.

INTRODUCTIONIntrahepatic cholangiocarcinoma (ICC) is a highly heterogeneous and aggressive malignancy with poor prognosis and limited treatment options. The lack of precise molecular classification and incomplete understanding of the tumor microenvironment (TME) impede therapeutic development.

OBJECTIVESThis study aims to dissect the cellular heterogeneity and intercellular interactions in ICC, with a particular focus on SPINK1-overexpressing epithelial subsets. We sought to determine the role of SPINK1 in modulating immune cell recruitment and tumor metabolism, and to evaluate its clinical relevance.

METHODSWe performed single-cell RNA sequencing (scRNA-seq) on human ICC tumors and adjacent normal tissues to construct a transcriptomic atlas. Integrative proteomic analysis, transwell assays, co-culture systems, and functional perturbation experiments (SPINK1 knockdown and ASCT2 inhibition) were conducted to explore epithelial-macrophage interactions and metabolic dynamics.

RESULTSScRNA-seq identified a SPINK1-overexpressing epithelial subcluster enriched in ICC tumors. High SPINK1 expression correlated with significantly shorter patient survival. SPINK1-overexpressing epithelial subcluster secretes CCL20, which recruits lipid-associated macrophages (LAMs). This effect was reversed by CCL20 neutralizing antibodies. In co-culture, LAMs increased intracellular glutamine levels in SPINK1-overexpressing epithelial subcluster, promoting proliferation. Disruption of SPINK1 expression or glutamine transport abolished this metabolic support.

CONCLUSIONOur findings uncover a novel SPINK1-CCL20-LAMs axis that orchestrates immune recruitment and metabolic reprogramming in ICC. SPINK1 facilitates tumor growth by establishing a glutamine-rich microenvironment via LAMs. These insights highlight SPINK1 as a potential therapeutic target and prognostic biomarker in ICC.