Spatial multi omic profiling maps hypoxia-driven pro-fibrotic SPP1+ macrophages underpinning immune escape and TACE resistance in hepatocellular carcinoma

BACKGROUND: To elucidate the cellular and molecular mechanisms underlying therapeutic resistance (refractoriness) following transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) by comprehensively characterizing the post-treatment tumor microenvironment (TME). METHODS: We employed an integrative spatial multi-omics strategy, combining bulk and single-cell RNA sequencing, subcellular-resolution spatial transcriptomics, and spatial proteomics on tissues from TACE-treated and treatment-naïve HCC patients. Public datasets were used for prognostic and predictive validation, and key findings were confirmed with multiplex immunofluorescence and in vitro experiments. RESULTS: TACE induced a profoundly hypoxic TME, which drove the selective enrichment of a pro-fibrotic tumor-associated macrophage (TAM) population characterized by high SPP1 expression (SPP1 + TAMs). Spatial mapping demonstrated that these SPP1 + TAMs localize to hypoxic tumor cores, where they remodel the extracellular matrix by producing fibronectin (FN1), establish fibrotic niches, and restrict T-cell activation, thereby orchestrating an immune-excluded microenvironment. The abundance of this macrophage subtype was a robust predictor of TACE resistance. CONCLUSIONS: TACE-induced hypoxia promotes a macrophage-driven fibrotic program that is a key determinant of immune evasion and treatment failure in HCC. Targeting this SPP1 + TAM-mediated fibrotic niche presents a potential therapeutic strategy to overcome TACE resistance and improve clinical outcomes.