Tumor Expression of CD83 Reduces Glioma Progression and Is Associated with Reduced Immunosuppression

Abstract

Abstract: Malignant glioma, the most lethal form of brain cancer, presents with an immunosuppressive microenvironment that obstructs tumor cell clearance and hampers immunotherapeutic interventions. Despite advancements in characterizing cellular and extracellular profiles in cancer, the immunosuppressive mechanisms specific to glioma remain poorly understood. We conducted single-cell RNA sequencing of glioma samples, which revealed a select subset of human and mouse glioma cells that express CD83, a marker associated with mature antigen-presenting cells. To investigate the impact of tumor cell CD83 expression on glioma outcomes, we used an immunocompetent mouse model of glioma, bioinformatic analyses of human samples, and in vitro assays. Our findings revealed that CD83+ tumor cells contribute to tumor growth suppression and are associated with enhanced cytotoxic T-cell profiles and activated CD8+ T cells. Increased proinflammatory cytokines were identified in CD83-overexpressing tumor conditions, which were also correlated with long-term CD8+ antitumor responses. Importantly, tumor-derived CD83 could mediate communication with T cells, altering the immune microenvironment to potentially enhance immune-related tumor clearance. Collectively, our data suggest that tumor cell expression of CD83 supports the endogenous antitumor T-cell constituency in malignant glioma. Future research endeavors may aim to further investigate whether CD83 expression can enhance immunotherapeutic approaches and improve patient outcomes.

Significance: Immunosuppression in malignant glioma remains a barrier to therapeutic development. CD83 overexpression in human and mouse glioma increases survival. CD83+ tumor cells promote signatures related to cytotoxic T cells, enhanced activation of CD8+ T cells, and increased proinflammatory cytokines. These findings suggest that tumor-expressed CD83 could mediate tumor-immune communications.

Figure 1

Antigen presenting–like tumor cells express Cd83 in human and mouse glioma. Expression of GO:0002291: T-cell activation via T-cell receptor contact with antigen bound to MHC molecule on APC and GO:0002468: dendritic cell antigen processing and presentation in human IDH^WT and IDH^mut glioma tumor cells that were differentially expressed (A). scRNA-seq from five IDH^mut and seven IDH^WT gliomas demonstrate a rare population of CD83⁺ tumor cells (B and C). Percentage of IDH^mut and IDH^WT tumor cells from scRNA-seq that expressed different combinations of CD45 and CD83 (D). Immunofluorescence imaging for IDH1^R132H tumor cells that express CD83 (E). scRNA-seq from pB-IUE glioma isolates similar murine tumor cells (F). Percentage of murine tumor cells from scRNA-seq that expressed different combinations of CD45 and CD83 (G). Multispectral flow cytometry isolates a distinct population of GFP⁺CD83⁺ tumor cells (H). (Created with Biorender.com.)

Figure 2

CD83 influences tumor growth in the pB-IUE system. Kaplan–Meier survival curve of pB-IUE tumors control (n = 17, Med OS = 102 days), CD83^KO (n = 20, Med OS = 94 days), and CD83^OE (n = 16, Med OS = 116 days; log-rank, all three curves, P value = 0.018; A). Age-matched P60 brains demonstrating decreased growth of CD83^OE tumors compared with control and CD83^KO tumors (B). Hematoxylin and eosin stain of pB-IUE control, CD83^OE, and CD83^KO tumors (C and D). IHC for Ki67 of pB-IUE control, CD83^OE, and CD83^KO tumors (one-way ANOVA P value = 0.0133. Tukey MCT: CD83^KO vs. CD83^OEP value = 0.0158, CD83^KO vs. control P value = 0.8075, and CD83^OE vs. control P value = 0.0454; E and F). EdU staining of in vitro cultured control, CD83^OE, and CD83^KO tumors (one-way ANOVA P value < 0.0001. Tukey MCT: CD83^KO vs. CD83^OEP value = 0.0193, CD83^KO vs. control P value < 0.0001, and CD83^OE vs. control P value < 0.0001; G and H). *, P value < 0.05; ****, P value < 0.0001. (Created with Biorender.com.)

Figure 3

CD83 gene signature related to tumor survival, reduced immunosuppressive response signatures, and enhanced antitumor response gene signatures. Expression of CD83 in scRNA-seq from pB-IUE CD83OE compared with control pB-IUE tumors (A). EnrichR analysis of the identified DEGs enriched in CD83⁺ tumor cells (B). Kaplan–Meier survival of TCGA IDH^WT GBM of tumors with high CD83 gene scoring compared with low CD83 gene scoring (median = 19.9 months vs. 12.9 months, P value = 0.027; C). Kaplan–Meier survival of IDH^mut low-grade gliomas with high CD83 gene scoring compared with low CD83 gene scoring (median OS = 202.8 months vs. 84.7 months, P value = 0.0022; D). Heatmap of CD83 gene scoring and immune expression gene profiles (E). Immunosuppressive gene sets vs. CD83 gene score showing an inverse relationship between CD83 signature and regulatory T cell (R = −0.65; P = 0.0034), TAM (R = −0.79; P = 0.00011), and PD-1–PD-L1 (R = −0.73; P = 0.00053) gene signatures in our 12 human glioma single-cell samples (F). Antitumor response gene sets vs. CD83 gene score showing a direct relationship between CD83 signature and CD8 T cell (R = 0.58; P = 0.012), central memory T cell (R = 0.57; P = 0.013), and Th cell (R = 0.45; P = 0.064) gene signatures in our 12 human glioma single-cell samples (G). *, P value < 0.05; **, P value < 0.01. (Created with Biorender.com.)

Figure 4

Tumoral CD83 influences expression of T-cell exhaustion markers. Immunofluorescence for CD8 and CD3 in pB-IUE control, CD83^OE, and Cd83^KO tumors (A). Increased number of CD3 and Cd8 T cells in CD83^KO compared with CD83^OE (two-way RM ANOVA P value < 0.0001, tumor type P value = 0.0183. Tukey MCT CD3: CD83^KO vs. CD83^OEP value = 0.0094, CD83^KO vs. control P value = 0.0897, and OE CD83^OE vs. control P value = 0.6658. Tukey MCT CD8: CD83^KO vs. CD83^OEP value = 0.0270, CD83^KO vs. control P value = 0.1466, and CD83^OE vs. control P value = 0.7514; B). Expression of T-cell exhaustion markers in subset T-cells from scRNA-seq in pB-IUE IUE control, CD83^OE, and CD83^KO tumors (C). Immunofluorescence for PD-1 and TIM3 in pB-IUE control, CD83^OE, and CD83^KO tumors (D and F). Increased number of PD-1–positive cells in CD83^KO compared with control and CD83^OE tumors and in control compared with CD83^OE OE (one-way ANOVA P value < 0.0001. Tukey MCT: CD83^KO vs. CD83^OEP value < 0.0001, CD83^KO vs. control P value = 0.0120, and CD83^OE vs. control P value = 0.0003; E). Increased number of TIM3-positive cells in CD83^KO compared with control and control compared with CD83^OE tumors and in control compared with CD83^OE (one-way ANOVA P value < 0.0001. Tukey MCT: CD83^KO vs. CD83^OEP value < 0.0001, CD83^KO vs. control P value = 0.9737, and CD83^OE vs. control P value < 0.0001; G). *, P value < 0.05; **, P value < 0.01; ***, P value < 0.001; ****, P value < 0.0001. CTLA4, cytotoxic T lymphocyte–associated antigen 4. (Created with Biorender.com.)

Figure 5

ALTs are sufficient to activate CD8⁺ T cells and act via cytokine release. In vitro tumor cells cocultured with isolated naïve CD8⁺ T cells (A). Multispectral imaging and flow cytometry for cocultured naïve CD8⁺ T cells demonstrating higher expression of mature CD3⁺CD8⁺ markers (B–E). ELISA for IFNγ showing increased in CD83^OE cocultured T cells compared with control (two-way ANOVA: tumor type P value = 0.7105, treatment P value = 0.0021, interaction P value = 0.6425, Šidák MCT: tumor vs. treated tumor control P value = 0.1160, tumor vs. treated tumor control P value = 0.00236; F). ELISA for IL-2 in control and CD83^OE tumors and cocultured T cells (two-way ANOVA: tumor type P value = 0.1314, treatment P value = 0.0232, interaction P value = 0.8087, Šidák MCT: tumor vs. treated tumor control P value = 0.2739, tumor vs. treated tumor control P value = 0.1437; G). ELISA for TNFα in control and CD83^OE tumors and cocultured T cells (two-way ANOVA: tumor type P value = 0.8411, treatment P value = 0.9121, interaction P value = 0.3234; H). Increased expression of TNFα and IL-2 by CD83^OE tumors compared with CD83^KO and control tumors in scRNA-seq from pB-IUE tumors (I). *, P value < 0.05. (Created with Biorender.com.)

Figure 6

ALTs alter the myeloid compartment of the tumor immune microenvironment. Immunofluorescence for Cd11b in pB-IUE control, CD83^OE, and Cd83^KO tumors (A and B; one-way ANOVA P value < 0.0001, Tukey MCT: Cd83^KO vs. CD83^OEP value < 0.0001, Cd83^KO vs. control P value = 0.588, CD83^OE vs. control P value < 0.0001). Cd11b score in macrophages vs. CD83 gene scoring showing a positive relationship between CD83 signature and Cd11b score (C). Immunofluorescence for Iba1 in control, CD83^OE, and Cd83^KO tumors (D and E; one-way ANOVA P value = 0.0961). CellChat comparison between CD83^OE and control tumor displaying number of signaling interactions (F), strength of the interactions (G), and overrepresented signaling pathways (H). The relative difference in number and strength of interactions within Cd45⁺ immune cells, tumor cells, and T cells between CD83^OE and control mouse tumor (I). CellChat comparison between high and low CD83 gene scoring displaying the number of signaling interactions (J), the strength of the interactions (K), and overrepresented signaling pathways (L). The relative difference in number and strength of interactions within Cd45⁺ immune cells, tumor cells, and T cells between high and low CD83 gene scoring human tumors (M). (Created with Biorender.com.)