An immunosuppressed microenvironment distinguishes lateral ventricle–contacting glioblastomas
Todd Bartkowiak, Sierra M. Lima, Madeline J. Hayes, Akshitkumar M. Mistry, Asa A. Brockman, Justine Sinnaeve, Nalin Leelatian, Caroline E. Roe, Bret C. Mobley, Silky Chotai, Kyle D. Weaver, Reid C. Thompson, Lola B. Chambless, Rebecca A. Ihrie, Jonathan M. Irish
Todd Bartkowiak, Sierra M. Lima, Madeline J. Hayes, Akshitkumar M. Mistry, Asa A. Brockman, Justine Sinnaeve, Nalin Leelatian, Caroline E. Roe, Bret C. Mobley, Silky Chotai, Kyle D. Weaver, Reid C. Thompson, Lola B. Chambless, Rebecca A. Ihrie, Jonathan M. Irish
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Research Article Immunology Oncology

An immunosuppressed microenvironment distinguishes lateral ventricle–contacting glioblastomas

Abstract

Radiographic contact of glioblastoma (GBM) tumors with the lateral ventricle and adjacent stem cell niche correlates with poor patient prognosis, but the cellular basis of this difference is unclear. Here, we reveal and functionally characterize distinct immune microenvironments that predominate in subtypes of GBM distinguished by proximity to the lateral ventricle. Mass cytometry analysis of isocitrate dehydrogenase wild-type human tumors identified elevated T cell checkpoint receptor expression and greater abundance of a specific CD32+CD44+HLA-DRhi macrophage population in ventricle-contacting GBM. Multiple computational analysis approaches, phospho-specific cytometry, and focal resection of GBMs validated and extended these findings. Phospho-flow quantified cytokine-induced immune cell signaling in ventricle-contacting GBM, revealing differential signaling between GBM subtypes. Subregion analysis within a given tumor supported initial findings and revealed intratumor compartmentalization of T cell memory and exhaustion phenotypes within GBM subtypes. Collectively, these results characterize immunotherapeutically targetable features of macrophages and suppressed lymphocytes in GBMs defined by MRI-detectable lateral ventricle contact.

Authors

Todd Bartkowiak, Sierra M. Lima, Madeline J. Hayes, Akshitkumar M. Mistry, Asa A. Brockman, Justine Sinnaeve, Nalin Leelatian, Caroline E. Roe, Bret C. Mobley, Silky Chotai, Kyle D. Weaver, Reid C. Thompson, Lola B. Chambless, Rebecca A. Ihrie, Jonathan M. Irish

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Figure 6

Immune cells infiltrating GBM tumors are functional and responsive to cytokine stimulation.

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Immune cells infiltrating GBM tumors are functional and responsive to cy...
(A) Schema of cytokine stimulation and phospho-protein readouts. (B) Heatmaps indicating the arcsinh fold-transformed median intensity values of each indicated phospho-protein within each manually gated immune subset in healthy donor PBMCs (gray, n = 1), C-GBM tumors (red, n = 5), or NC-GBM tumors (blue, n = 5). Graphs below the heatmaps indicate the median ± IQR for each indicated immune population and phospho-protein readout. (C) Representative t-SNE plot indicating the density of CD45+ leukocytes (left), enumerated FlowSOM clusters (middle), and overlay of expert-gated immune populations onto the clustered t-SNE axes (right) pooled from n = 10 patients. Representative heatmaps on the t-SNE axes indicate the cluster-specific median arcsinh fold-change of the indicated phospho-protein under IL-2 stimulation conditions compared with basal phosphorylation. (D) Box-and-whisker plots indicating the proportion of clusters in C-GBM or NC-GBM immune infiltrates surpassing the phospho-signaling threshold (>0.2 arcsinh fold-change) in response to IL-2 stimulation. Box-and-whisker plots indicate the median ± IQR.