Modeling Glioma Progression in Neural Organoids

High-grade gliomas (HGG) are the most aggressive and heterogeneous brain tumors, with poor prognosis and limited therapeutic options. A major barrier to progress in HGG research is the lack of preclinical models that accurately capture tumor complexity and its interactions with the brain microenvironment. In this thesis, we explored neural organoid-based approaches to model gliomagenesis and tumor progression. We first optimized the generation of mouse neural organoids (mNO), which displayed organized neural rosettes, neurons, and astrocytes, recapitulating essential features of brain tissue. Using mNO, we tested two complementary strategies: (1) a cell-based approach, where primary murine glioma cells were introduced into organoids, and (2) a genetic-based approach, where PDGF-B was overexpressed using the PiggyBac transposon system to induce malignant transformation. While mNO provided a supportive microenvironment for mouse high-grade glioma cells (mHGG), sustaining their proliferation and stem-like properties, mouse low-grade glioma cells (mLGG) failed to engraft. Direct transplantation of tumor cells, tested on mHGG and confirming high engrafting, could be a promising strategy to model less invasive gliomas. In parallel, Platelet-Derived Growth Factor B (PDGF-B) overexpression generated proliferative tumor-like cells that express markers consistent with the ones expressed by gliomas in vivo. Finally, we started the transition to human neural organoids (hNO) to increase translational relevance. Transplanted mHGG cells successfully engrafted in hNO, forming heterogeneous tumor masses and interacting with microglia, which exhibited activation around tumor cells. Overall, this work demonstrates that neural organoids represent a versatile and physiologically relevant platform to study glioma biology, providing insights into tumor-microenvironment interactions and potential ways for therapeutic testing.