Modeling Glioma Stem Cell-Mediated Tumorigenesis Using Zebrafish Patient-Derived Xenograft Systems.

Glioblastoma (GBM) is an aggressive brain tumor associated with high post-therapy recurrence and very poor survival rates. One of the factors contributing to the aggressive nature of this disease is the level of heterogeneity seen at the phenotypic and genetic level. Glioma stem cells (GSCs) are stem-like cells within the tumor with the ability to self-renew and give rise to different types of cells within the tumor, hence giving rise to the heterogeneity found in GBM. GSCs are often implicated in the resistance of glioma to standard of care radiation and chemotherapy. The physical niche within a tumor mass supports stemness and aggressive characteristics of GSCs, hence, experimental systems providing a relevant tumor microenvironment (TME) are critical for adequate assessment of molecular mechanisms regulating GSC populations. Although mouse models continue to be an integral part of an in vivo experimental design, they are neither time- nor cost-efficient. Danio rerio (zebrafish) patient-derived xenografts (PDXs) overcome several of the obstacles of the mammalian systems. Zebrafish constitute a robust, easily reproducible experimental model allowing for relevant investigation of GSC populations with TME. This chapter describes methods required for generation of zebrafish PDXs to study aspects of GSC-mediated tumorigenesis and interactions with the TME.