Identifying conserved molecular targets required for cell migration of glioblastoma cancer stem cells

Abstract

Glioblastoma (GBM) is the most prevalent primary malignant brain tumor and is associated with extensive tumor cell infiltration into the adjacent brain parenchyma. However, there are limited targeted therapies that address this disease hallmark. While the invasive capacity of self-renewing cancer stem cells (CSCs) and their non-CSC progeny has been investigated, the mode(s) of migration used by CSCs during invasion is currently unknown. Here we used time-lapse microscopy to evaluate the migratory behavior of CSCs, with a focus on identifying key regulators of migration. A head-to-head migration assay demonstrated that CSCs are more invasive than non-CSCs. Time-lapse live cell imaging further revealed that GBM patient-derived CSC models either migrate in a collective manner or in a single cell fashion. To uncover conserved molecular regulators responsible for collective cell invasion, we utilized the genetically tractable Drosophila border cell collective migration model. Candidates for functional studies were generated using results from a targeted Drosophila genetic screen followed by gene expression analysis of the human homologs in GBM tumors and associated GBM patient prognosis. This strategy identified the highly conserved small GTPase, Rap1a, as a potential regulator of cell invasion. Alteration of Rap1a activity impaired the forward progress of Drosophila border cells during development.Rap1a expression was elevated in GBM and associated with higher tumor grade. Functionally, the levels of activated Rap1a impacted CSC migration speed out of spheres onto extracellular matrix. The data presented here demonstrate that CSCs are more invasive than non-CSCs, are capable of both collective and single cell migration, and express conserved genes that are required for migration and invasion. Using this integrated approach, we identified a new role for Rap1a in the migration of GBM CSCs. RAP1A

Human glioblastoma cell motility depends on the activity of the cysteine metabolism enzyme 3-Mercaptopyruvate sulfurtransferase

“…However, it remains unknown whether our modeling results pertain to a specific mode of cell motility and/or path of migration. Both individual and collective migrations have been identified in GB (Vollmann-Zwerenz et al 2020) (Volovetz et al 2020). Enrichment of oRG-like gene modules in M HIGH cells suggests that the motile cells we captured move in a solitary fashion like oRGs in the developing cortex.…”

“…Three major migration/invasion routes have been described: the narrow and tortuous extracellular space of the brain parenchyma (Scherer 1938), the perivascular spaces surrounding blood vessels (Scherer 1938) (Montana & Sontheimer 2011) (Watkins et al 2014) (Cuddapah et al 2014) and white matter tracts, notably the corpus callosum, used as a highway for bilateral brain hemisphere invasion (Scherer 1938) (Pedersen et al 1995). Both single cell and collective migration have been reported (Vollmann-Zwerenz et al 2020) (Volovetz et al 2020), the latter appearing to be facilitated by the formation of an interconnected network of tumor microtubes (Osswald et al 2015). So far, an integrated view of the metabolic pathways at play in a motile GB cell is lacking.…”

Effectiveness of porous silicon nanoparticle treatment at inhibiting the migration of a heterogeneous glioma cell population

“…In particular, this 10% difference may be attributed to the presence of a CSC population in WK1 cells, which is less susceptible to treatment with Tf@pSiNPs (Fig. 6) and is established as being more invasive than non-CSCs [45][46][47][48]. For example, Volovetz et al [46] found that glioma stem cells showed 2-5 times greater cell motility when compared to non-CSCs.…”

“…6) and is established as being more invasive than non-CSCs [45][46][47][48]. For example, Volovetz et al [46] found that glioma stem cells showed 2-5 times greater cell motility when compared to non-CSCs. Our observation is further consolidated by previous investigations showing that on average glioma stem cells constitute approximately 10-13% of primary glioma cells [26,49,50].…”