Glioblastoma, responsible for 3,500 annual deaths in France, is an extremely aggressive brain tumor that is resistant to current treatments. Clinical trials in immunotherapy have shown only transient effects, underscoring the importance of understanding resistance mechanisms and developing more targeted therapeutic strategies.

We have developed an innovative model of glioma stem cell invasion in immunocompetent and vascularized brain organoids derived from induced pluripotent stem cells (iPSCs) (Raguin et al., submitted). This model faithfully reproduces the glioblastoma tumor niche, including vascular co-option, reprogramming of microglia into tumor-associated macrophages, and tumor recurrence following radiotherapy.

The aim of this PhD project is to derive a universal brain organoid model for the transfer of glioma cells from patients and lymphocytes to optimize the immunotherapy approach (CAR-T cells).

The project involves creating a universal model of human brain organoids that are immunologically "silent" by suppressing the expression of the HLA class I/II system in iPSCs (CRISPR/CAS9 for the ß2M and CIITA genes). Additionally, it aims to elucidate the mechanisms of immunosuppression induced by irradiation, such as the reprogramming of microglial/macrophage cells and the involvement of senescence. Various approaches to make the tumor microenvironment more conducive to immunotherapy will be explored, including activating the type I interferon pathway through genetic modification or with cGAS/STING pathway agonists. Subsequently, the use of CAR-T cells targeting an antigen overexpressed by glioblastoma cells (CD276/B7-H3) will be studied. This model could be used in personalized medicine by co-cultivating patients' tumor cells, monocytes, and CAR-T cells.

This project offers innovative perspectives for the personalized treatment of glioblastoma via immunotherapy and could represent a major advancement in this therapeutic approach.