Spatiotemporal heterogeneity of glioblastoma is dictated by microenvironmental interference

Abstract

Glioblastomas are highly malignant tumors of the central nervous system. Evidence suggests that these tumors display large intra- and inter-patient heterogeneity hallmarked by subclonal diversity and dynamic adaptation amid developmental hierarchies. However, the source for dynamic reorganization of cellular states within their spatial context remains elusive. Here, we in-depth characterized glioblastomas by spatially resolved transcriptomics, metabolomics and proteomics. By deciphering exclusive and shared transcriptional programs across patients, we inferred that glioblastomas develop along defined neural lineages and adapt to inflammatory or metabolic stimuli reminiscent of reactive transformation in mature astrocytes. Metabolic profiling and imaging mass cytometry supported the assumption that tumor heterogeneity is dictated by microenvironmental alterations. Analysis of copy number variation (CNV) revealed a spatially cohesive organization of subclones associated with reactive transcriptional programs, confirming that environmental stress gives rise to selection pressure. Deconvolution of age-dependent transcriptional programs in malignant and non-malignant specimens identified the aging environment as the major driver of inflammatory transformation in GBM, suggesting that tumor cells adopt transcriptional programs similar to inflammatory transformation in astrocytes. Glioblastoma stem cells implanted into human neocortical slices of varying age levels, independently confirmed that the ageing environment dynamically shapes the intratumoral heterogeneity towards reactive transcriptional programs. Our findings provide insights into the spatial architecture of glioblastoma, suggesting that both locally inherent tumor as well as global alterations of the tumor microenvironment shape its transcriptional heterogeneity. Global age-related inflammation in the human brain is driving distinct transcriptional transformation in glioblastomas, which requires an adjustment of the currently prevailing glioma models.

T-cell dysfunction in the glioblastoma microenvironment is mediated by myeloid cells releasing interleukin-10

“…4a. We observed a median of eight cells per spot (range: 4 to 22 cells per spot), which allows for spatial mapping of gene expression, but not at single-cell resolution 30 . Although this could be considered a limitation, when expression profiles based on the latest glioblastoma subtype classification 29 were spatially mapped, the results confirmed the hypothesized juxta-positioning of the mesenchymal subset to the tumorassociated myeloid compartment 5,21 .…”

Harmonized single-cell landscape, intercellular crosstalk and tumor architecture of glioblastoma

“…However, they were either limited to small sample size or did not provide a holistic overview of the GB cellular composition to construct the tumor interactome. Additionally, despite current technological advances, transcriptomic profiling in a spatially resolved manner has only lately been used to explore GB (Ravi et al, 2021; Ravi et al, 2022).…”

Inhibition of Metabotropic Glutamate Receptor III facilitates sensitization to alkylating chemotherapeutics in Glioblastoma

“…4f-h. Recent reports have pointed to the presence of multiple cell states within the GBM, with the lineage state representing the cells that actively proliferate and migrate to ensure GBM survival (29,34). We show that GBM cells treated with LY341495 show a downregulation of pathways associated with the neural-like, oligodendrocyte-like and astrocyte-like genes, Supp.…”

“…Due to the fact that in vitro models are limited in recapitulating the complexity of glioblastoma within their neural environment, we made use of our recently established human organotypic section-based GBM model, (11,12,29,35). We inoculated GBM cells into cultured human cortical organotypic sections.…”