Fig. 3: TREM2⁺TAM drives HCC progression and immunotherapy resistance via SPP1-mediated dual action on CD8⁺T cells and cancer cells.

A UMAP of the Scissor-selected cells (left). Barplot shows the distribution of Scissor⁺ cells across different myeloid populations and conditions (right). B Forestplot shows the hazard ratios and 95% confidence intervals for different myeloid cluster signatures and clinical information according to a multivariable Cox model in the TCGA-LIHC cohort (n = 353 patients). Squares represent the hazard ratios, and the horizontal bars extend from the lower limits to the upper limits of the 95% confidence intervals of the estimates of the hazard ratios. C Dotplot displays the DEGs between Scissor⁺ cells and all other cells. D Dotplot displays the expression correlation of SPP1 with other genes in myeloid cells (left). Heatmap shows the expression correlation of indicated genes with SPP1 in myeloid cells from adjacent non-tumor (ANT) and tumor samples (right). E Representative images and quantification of TREM2, SPP1, and CD68 immunofluorescence staining on human HCC sections. Representative cells that denote the co-upregulation of TREM2 and SPP1 in CD68⁺ TAMs are circled by a dotted line. Scale bar, 50 μm. F Kaplan–Meier survival analysis of HCC patients from the TCGA-LIHC cohort categorized into groups based on normalized TREM2 and SPP1 expression. The cutpoints for patient grouping were calculated by the surv_cutpoint function from the survminer R package. G Barplot shows the mean expression of SPP1 across different myeloid cell populations (upper) and in TAMs from ICB-R and ICB-NR HCC samples (lower). H Dotplot shows the expression of SPP1 ligands in CD8⁺T cells (above) or cancer cells (below) from pre-ICB, ICB-NR, and ICB-R HCC scRNA-seq samples. I Schematic of the interaction between TREM2⁺TAMs and CD8⁺T cells or cancer cells in immunotherapy-resistant HCC. J Heatmap shows the relative expression of indicated genes in isolated TREM2⁺/TREM2⁻ TAMs. K Flow cytometry of IFNγ expression in CD8⁺T cells co-cultured with human HCC-isolated TREM2^-TAMs or TREM2⁺TAMs ± SPP1 antibody (1 μg/mL). CD8⁺T cells were isolated from human PBMC and then activated with anti-CD3/CD28 + IL-2 (50 U/mL) before co-culture assays. L Violin plots display the expression of IFNG and TNF in CD8⁺T cells from ICB-NR or ICB-R scRNA-seq samples, with two-tailed Wilcoxon-test statistics. M Dotplot shows the relative expression of IFNG and TNF in CD8⁺T cell clusters. N Tissue preference of CD8⁺T cell clusters, revealed by odds ratio (OR) value. O Relative cell viability (mean of n = 3 biological replicates) for Hep3B cells treated with a half-log dilution series of TNF (2.5–250 ng/mL) and IFNγ (1–100 ng/mL), cocultured with human HCC-isolated TREM2^-TAMs or TREM2⁺TAMs ± SPP1 antibody (1 μg/mL). P Relative cell viability of Hep3B cells treated with mock, SPP1 (50 ng/mL), integrin inhibitor TFA (100 μM), TNF (250 ng/mL) plus IFNγ (100 ng/mL) (TNF/IFNγ), TNF/IFNγ plus SPP1, or TNF/IFNγ plus SPP1 plus TFA (100 μM) for 24 h. Q Relative cell viability for patient-derived HCC organoid with indicated treatment. Data represent the mean ± SD, n = 5 biological replicates in (P), n = 6 biological replicates in (K, Q). Statistical significance was determined by two-tailed Wald test (B), two-tailed unpaired t test (K, P, Q), two-tailed Wilcoxon signed rank test (L), and log rank test (F). Schematic in I was created in BioRender. Chu, T. (2025) https://BioRender.com/r2v4jgs. Source data are provided as a Source Data file.