Endothelial cells promote 3D invasion of GBM by IL-8-dependent induction of cancer stem cell properties

Michael G Mccoy,Julian Palacios Goerger,Carol K Hung,Nozomi Nishimura,Dennis Nyanyo,Claudia Fischbach,Warren R Zipfel,Rebecca M Williams

doi:10.1038/s41598-019-45535-y

Michael G Mccoy, Julian Palacios Goerger + Show 6 more

Open Access

https://doi.org/10.1038/s41598-019-45535-y

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Journal: Scientific Reports	Publication Date: Jun 21, 2019
Citations: 76	License type: open-access

Affiliation: Cornell University

Abstract

Rapid growth and perivascular invasion are hallmarks of glioblastoma (GBM) that have been attributed to the presence of cancer stem-like cells (CSCs) and their association with the perivascular niche. However, the mechanisms by which the perivascular niche regulates GBM invasion and CSCs remain poorly understood due in part to a lack of relevant model systems. To simulate perivascular niche conditions and analyze consequential changes of GBM growth and invasion, patient-derived GBM spheroids were co-cultured with brain endothelial cells (ECs) in microfabricated collagen gels. Integrating these systems with 3D imaging and biochemical assays revealed that ECs increase GBM invasiveness and growth through interleukin-8 (IL-8)-mediated enrichment of CSCs. Blockade of IL-8 inhibited these effects in GBM-EC co-cultures, while IL-8 supplementation increased CSC-mediated growth and invasion in GBM-monocultures. Experiments in mice confirmed that ECs and IL-8 stimulate intracranial tumor growth and invasion in vivo. Collectively, perivascular niche conditions promote GBM growth and invasion by increasing CSC frequency, and IL-8 may be explored clinically to inhibit these interactions.

Highlights

Glioblastoma (GBM) is defined as a high grade astrocytoma and represents the most common primary malignant brain tumor in adults with a median survival time of 15 months[1]
Blood vessels are critical to GBM growth and invasion by supplying oxygen and nutrients, and because endothelial cells are key to cancer stem-like cells (CSCs) self-renewal, proliferation, and migration[33]
We utilized a collagen-based 3D culture model of GBM spheroids interacting with brain endothelial cells in combination with in vivo studies to analyze how interactions between both cell types modulate GBM invasion in the perivascular niche

Summary

Introduction

Glioblastoma (GBM) is defined as a high grade astrocytoma and represents the most common primary malignant brain tumor in adults with a median survival time of 15 months[1]. As GBM tumor cells and CSCs invade into the brain parenchyma, they engage with physical migration paths along white matter tracts and blood vessels[6]. The molecular and cellular mechanisms that regulate GBM invasion as a function of CSC-perivascular niche interactions remain poorly understood due in part to a lack of model systems that allow studying 3D cellular invasion of patient-derived GBM tumor cells in the presence of human brain endothelial cells. In turn, can regulate tumor cell invasion by directing cell migration via structural and mechanical cues[13,14], a process that is exploited by CSCs15 and is likely accentuated by endothelial cell-secreted factors[16]. Studying GBM invasion in a collagen type I-based model that mimics multicellular interactions between GBM tumor cells, CSCs, and endothelial cells may help reveal mechanisms contributing to GBM invasion within the perivascular space. Studying the role of IL-8-dependent changes of tumor cell invasion in vitro, is subject to significant limitations and requires relevant 3D models as (i) cellular IL-8 expression/secretion is significantly reduced in monolayer culture relative to in vivo scenarios[24] and (ii) tumor cells respond to IL-8 with increased migration/invasion in 3D, but not in 2D cultures[25]

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