Human plasma-like medium facilitates metabolic tracing and enables upregulation of immune signaling pathways in glioblastoma explants

Mohamad El Shami; Milan R Savani; Lauren C Gattie; Bailey Smith; William H Hicks; Jeremy N Rich; Timothy E Richardson; Samuel K McBrayer; Kalil G Abdullah

doi:10.1101/2023.05.29.542774

Human plasma-like medium facilitates metabolic tracing and enables upregulation of immune signaling pathways in glioblastoma explants

bioRxiv [Preprint]. 2023 May 31:2023.05.29.542774. doi: 10.1101/2023.05.29.542774.

Authors

Mohamad El Shami^{1

2}, Milan R Savani³, Lauren C Gattie^{1

2}, Bailey Smith³, William H Hicks^{1

2}, Jeremy N Rich², Timothy E Richardson⁴, Samuel K McBrayer^{3

5}, Kalil G Abdullah^{1

2}

Affiliations

¹ Department of Neurosurgery, University of Pittsburgh School of Medicine, 200 Lothrop St, Pittsburgh, PA, 15213, USA.
² Hillman Comprehensive Cancer Center, University of Pittsburgh Medical Center, 5115 Centre Ave, Pittsburgh, PA, 15232, USA.
³ Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX, 75235, USA.
⁴ Department of Pathology, Molecular, and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
⁵ Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.

Abstract

Purpose: Metabolism within the tumor microenvironment (TME) represents an increasing area of interest to understand glioma initiation and progression. Stable isotope tracing is a technique critical to the study of tumor metabolism. Cell culture models of this disease are not routinely cultured under physiologically relevant nutrient conditions and do not retain cellular heterogeneity present in the parental TME. Moreover, in vivo, stable isotope tracing in intracranial glioma xenografts, the gold standard for metabolic investigation, is time consuming and technically challenging. To provide insights into glioma metabolism in the presence of an intact TME, we performed stable isotope tracing analysis of patient-derived, heterocellular Surgically eXplanted Organoid (SXO) glioma models in human plasma-like medium (HPLM).

Methods: Glioma SXOs were established and cultured in conventional media or transitioned to HPLM. We evaluated SXO cytoarchitecture and histology, then performed spatial transcriptomic profiling to identify cellular populations and differential gene expression patterns. We performed stable isotope tracing with ¹⁵N₂-glutamine to evaluate intracellular metabolite labeling patterns.

Results: Glioma SXOs cultured in HPLM retain cytoarchitecture and cellular constituents. Immune cells in HPLM-cultured SXOs demonstrated increased transcription of immune-related signatures, including innate immune, adaptive immune, and cytokine signaling programs. ¹⁵N isotope enrichment from glutamine was observed in metabolites from diverse pathways, and labeling patterns were stable over time.

Conclusion: To enable ex vivo, tractable investigations of whole tumor metabolism, we developed an approach to conduct stable isotope tracing in glioma SXOs cultured under physiologically relevant nutrient conditions. Under these conditions, SXOs maintained viability, composition, and metabolic activity while exhibiting increased immune-related transcriptional programs.

Keywords: Glioma; metabolism; organoid; stable isotope tracing.

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Preprint

Abstract

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