Defining phenotypic and functional heterogeneity of glioblastoma stem cells by mass cytometry

Abstract

Most patients with glioblastoma (GBM) die within 2 years. A major therapeutic goal is to target GBM stem cells (GSCs), a subpopulation of cells that contribute to treatment resistance and recurrence. Since their discovery in 2003, GSCs have been isolated using single-surface markers, such as CD15, CD44, CD133, and α 6 integrin. It remains unknown how these single-surface marker–defined GSC populations compare with each other in terms of signaling and function and whether expression of different combinations of these markers is associated with different functional capacity. Using mass cytometry and fresh operating room specimens, we found 15 distinct GSC subpopulations in patients, and they differed in their MEK/ERK, WNT, and AKT pathway activation status. Once in culture, some subpopulations were lost and previously undetectable ones materialized. GSCs that highly expressed all 4 surface markers had the greatest self-renewal capacity, WNT inhibitor sensitivity, and in vivo tumorigenicity. This work highlights the potential signaling and phenotypic diversity of GSCs. Larger patient sample sizes and antibody panels are required to confirm these findings.

UBA1 inhibition contributes radiosensitization of glioblastoma cells via blocking DNA damage repair

“…GSC subpopulations has been considered as one of the factors contributing to the radiotherapy resistance in GBM patients after treatment ( Galdieri et al, 2021 ). Inhibiting GSC survival is an effective treatment strategy to improve radiotherapy sensitivity ( Chen et al, 2022 ).…”

Oncolytic herpes simplex viruses for the treatment of glioma and targeting glioblastoma stem-like cells

“…For example, GSC sensitivity to TMZ correlated with O 6 -methylguanine-DNA methyltransferase (MGMT) methylation ( Beier et al., 2012 ; Wakimoto et al., 2012 ), poly(ADP-ribose) polymerase (PARP) inhibitor with MYC expression ( Ning et al., 2019 ), and epidermal growth factor receptor (EGFR) inhibitor with EGFR amplification ( Tanaka et al., 2019 ). While a number of cell surface markers are enriched in GSCs (CD133, CD44, SSEA1/CD15, α6-integrin/CD49f, L1CAM, and A2B5) there are no definitive markers that can be used to identify GSCs in patient specimens, creating some controversy about their classification ( Bhaduri et al., 2020 ; Prager et al., 2020 ; Suvà and Tirosh, 2020 ; Galdieri et al., 2021 ), so that GSCs described in different studies may actually reflect different cell populations.…”

“…Proliferative marker expression overlapped the stem cell signature, identifying cycling cells as GSCs ( Suvà and Tirosh, 2020 ). The scRNA-seq data suggests 4 cellular states: neural progenitor cell (NPC)-like, oligodendrocyte progenitor cell (OPC)-like, astrocyte (AC)-like, and mesenchymal (MES)-like, with multiple states present in a single tumor ( Neftel et al., 2019 ; Galdieri et al., 2021 ). All cellular states can efficiently propagate tumors in mice, with AC-like GSCs less effective ( Suvà and Tirosh, 2020 ), and implantation of a single cell state propagates tumors with a mix of cell states, further illustrating the cellular plasticity and tumor heterogeneity in GBM ( Neftel et al., 2019 ).…”

A developmental atlas of the mouse brain by single-cell mass cytometry

“…The antibody-based measurements from mass cytometry can directly read out functional biomolecules, unlike mRNA transcripts that do not necessarily correlate with protein abundancea disconnect most pronounced during dynamic cell transitions 28,29 like those occurring in early brain development. Mass cytometry was previously employed to investigate glioma [30][31][32][33][34][35][36][37] , microglia [38][39][40][41][42][43][44][45] , and dorsal root ganglia 46 , but this approach has not yet been applied to study neural cell types in the brain, except for one limited analysis with seven neural-specific markers in a study of obesity-inhibited adult neurogenesis 47 .…”