(631c) Development of Heterogeneous Tumor Tissue-Mimicking Glioblastoma Organoids

Glioblastoma multiforme (GBM) is the most aggressive type of brain tumor that originates from glioblastoma stem cells (GSCs). In the brain, GSCs are supported by a tumor microenvironment (TME) residing in the perivascular niche and the hypoxic niche. The GBM TME is highly heterogenous and exhibits complex cell-to-cell interactions. However, most in vitro models do not adequately capture such heterogeneity. Here, we describe the development of a simple, matrix-free, and tissue-like GBM organoids (GBOs) using patient-derived xenograft GBM lines in small-scale bioreactors. Shear stress was optimized to produce highly reproducible millimeter-scale GBOs within 4-5 weeks. Our GBOs exhibited high stemness and strong cell-to-cell interactions compared to conventional tumorsphere cultures. They displayed spatial gradients of HIF-1α positive hypoxic cores where CD133-positive GSCs resided, as well as spatially heterogeneous expression of Notch signaling. We also observed a self-established, hierarchically organized, and heterogeneous TME with GBM transdifferentiation into endothelial cells, pericytes, and astrocytes. Collectively, we demonstrate the ability to biomanufacture uniformly sized GBOs that recapitulate in vivo GBM TME features.