Fishing for contact: Modeling perivascular glioma invasion in the zebrafish brain

Abstract

Glioblastoma multiforme (GBM) is a highly invasive, central nervous system (CNS) cancer for which there is no a cure. Invading tumor cells evade treatment, limiting the efficacy of current standard of care treatments. Understanding the underlying invasive behaviors that support tumor growth may allow for generation of novel GBM therapies. Zebrafish (Danio rerio) are attractive for genetics, live imaging, and in recent years, have emerged as a model system suitable for cancer biology research. While other groups have studied CNS tumors using zebrafish, few have concentrated on the invasive behaviors supporting the development of these diseases. Previous studies demonstrated that one of the main mechanisms of GBM invasion is perivascular invasion, i.e. single tumor cell migration along blood vessels. Here, we characterize phenotypes, methodology, and potential therapeutic avenues for utilizing zebrafish to model perivascular GBM invasion. Using patient derived xenolines or an adherent cell line, we demonstrate tumor expansion within the zebrafish brain. Within 24 hours post-intracranial injection, D54-MG-tdTomato glioma cells produce finger-like projections along the zebrafish brain vasculature. As few as 25-50 GBM cells were sufficient to promote single cell vessel co-option. Of note, these tumor-vessel interactions are CNS specific, and do not occur on pre-existing blood vessels when injected into the animal's peripheral tissue. Tumor-vessel interactions increase over time and can be pharmacologically disrupted through inhibition of Wnt signaling. Therefore, zebrafish serve as a favorable model system to study perivascular glioma invasion, one of the deadly characteristics that make GBM so difficult to treat.

Residual Disease in Glioma Recurrence: A Dangerous Liaison with Senescence

“…Distinctive paracrine signals can direct perivascular invasion. Wnt stimulates single-cell invasion onto blood vessels in a zebrafish glioma model [ 110 ]. Additionally, Wnt7 promotes single-cell perivascular invasion into brain slices of Olig2 + GBM cells, whereas Olig2-cells migrate over blood vessels as clusters of cells [ 83 ].…”

Cellular and Molecular Mechanisms Underlying Glioblastoma and Zebrafish Models for the Discovery of New Treatments

“…The mechanisms of glioma-vessel interactions, angiogenesis and tumor invasion have also been studied in zebrafish models. Umans et al intracranially injected an adult glioma cell line and a pediatric patient derived xenoline into Tg( fli1a :eGFP) casper embryos at 3 dpf and observed the attachment of cells to the brain vasculature within 24 hpi, as well as their expansion and migration along the vascular network by 7 dpf [ 161 ]. The same cells injected into the trunk failed to interact with the vasculature and moved rostrally towards the brain, highlighting the importance of the microenvironment.…”