Tumor cell–derived spermidine promotes a protumorigenic immune microenvironment in glioblastoma via CD8+ T cell inhibition
Kristen E. Kay, … , Defne Bayik, Justin D. Lathia
Kristen E. Kay, … , Defne Bayik, Justin D. Lathia
Published November 19, 2024
Citation Information: J Clin Invest. 2025;135(2):e177824. https://doi.org/10.1172/JCI177824.
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Research Article Immunology Oncology

Tumor cell–derived spermidine promotes a protumorigenic immune microenvironment in glioblastoma via CD8+ T cell inhibition

Abstract

The glioblastoma (GBM) microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can directly affect the immune system, but the mechanisms driving these interactions are not completely clear. Here, we demonstrate that the polyamine metabolite spermidine (SPD) was elevated in the GBM tumor microenvironment. Exogenous administration of SPD drove tumor aggressiveness in an immune-dependent manner in preclinical mouse models via reduction of CD8+ T cell frequency and reduced cytotoxic function. Knockdown of ornithine decarboxylase, the rate-limiting enzyme in SPD synthesis, did not affect cancer cell growth in vitro but did result in extended survival. Furthermore, patients with GBM with a more favorable outcome had a significant reduction in SPD compared with patients with a poor prognosis. Our results demonstrate that SPD functions as a cancer cell–derived metabolite that drives tumor progression by reducing CD8+ T cell numbers and function.

Authors

Kristen E. Kay, Juyeun Lee, Ellen S. Hong, Julia Beilis, Sahil Dayal, Emily R. Wesley, Sofia Mitchell, Sabrina Z. Wang, Daniel J. Silver, Josephine Volovetz, Sadie Johnson, Mary McGraw, Matthew M. Grabowski, Tianyao Lu, Lutz Freytag, Vinod Narayana, Saskia Freytag, Sarah A. Best, James R. Whittle, Zeneng Wang, Ofer Reizes, Jennifer S. Yu, Stanley L. Hazen, J. Mark Brown, Defne Bayik, Justin D. Lathia

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Figure 6

CD8+ T cells have reduced viability and functionality in the presence of SPD.

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CD8+ T cells have reduced viability and functionality in the presence of...
(A–C) Splenocyte-derived CD8+ T cells were treated with 5 μM SPD in vitro. (A) Apoptotic cells and cell death were measured via annexin V and DRAQ7 staining, respectively, and analyzed via flow cytometry; data are representative of 3 independent experiments. (B and C) Visual representation of gain in double-positive cells under SPD treatment. (D) ROS levels in CD8+ T cells treated with varying concentrations of SPD measured via CellROX flow cytometry assay; data are representative of 3 independent experiments. (E and F) T cell markers in CD8+ population treated with PBS or 5 μM SPD. (G and H) IFN-γ+TNF-α+ (G) and IFN-γ–TNF-α– (H) subsets in the CD8+CD44+ T cell population. (I) Granzyme B (GzB) levels measured via ELISA in conditioned medium from CD8+ T cells treated in vitro with varying concentrations of SPD; data are representative of 3 independent experiments. (J and K) Intracellular flow cytometry measurement of GzB (J) and perforin (PRF) (K) in CD8+ T cells treated with conditioned medium from non-target or ODC1-KD cells; data are representative of 3 independent experiments. (L) Viability of tumor cells after Transwell coculture with SPD-treated CD8+ T cells via cell killing assay; data combined from 3 experiments. Statistical significance in A was determined by 2-way ANOVA (**P < 0.01). Statistical significance in D, I, and L was determined by 1-way ANOVA (*P < 0.05, ***P < 0.001, ****P < 0.0001). Statistical significance in E–H, J, and K was determined by unpaired, 2-tailed t test (*P < 0.05, **P < 0.01). Bracketed numbers indicate the mean.