TMOD-20. RAPID PROCESSING AND BIOBANKING OF RESECTED BRAIN TUMOR TISSUE TO GENERATE PATIENT-DERIVED BRAIN TUMOR EXPLANT ORGANOIDS (GBOS) FOR PRECLINICAL STUDIES

Abstract Improved preclinical tools are urgently needed to translate new brain cancer treatments. Patient-derived brain tumor explant organoids (GBOs) offer promise for studying tumor cells in a relevant human tumor microenvironment and predicting patient responses to therapy. However, generating GBOs is time-consuming, costly, and technically challenging, hindering the creation of comprehensive biobanks covering the spectrum of brain tumor heterogeneity. This work presents a semi-automated method for producing GBOs, involving tumor tissue processing, size selection, and same-day cryopreservation, reducing generation time to less than 1 hour. We established a biobank of 24 GBOs from 33 samples (11 males and 13 females) with primary (n=13, GBO Yield (GY)>90%) and recurrent (n=5, GY>90%) glioblastomas, high-grade gliomas (HGG, n=2, GY≤50%), and low-grade gliomas (LGG, n=2 with GY>90%, n=2 with GY≤50%). Using GBO size and propidium iodide as readouts, we used this biobank to compare anticancer activities of novel idronoxil-conjugated benzopyran compounds (NX786, NX904/904E1) against Bortezomib (100% cell death reference). NX786 and NX904/904E1 reduced GBO growth (≥50%) in all primary glioblastoma and one (of two) recurrent glioblastoma GBOs with milder effects in LGG GBOs. Two (of four) primary glioblastoma, one (of two) recurrent glioblastoma, and one LGG GBOs exhibited significant cell death (>60%) in response to NX904/904E1. In contrast, NX786 induced cell death in one (of three) primary glioblastoma (34% cell death) and one (of two) recurrent glioblastoma (71% cell death) GBOs but not in LGG GBOs, together showcasing varied responses across different brain tumors. Highly-passaged GBOs lacking the non-malignant tumor microenvironment were more susceptible to these treatments, underlining the tumor microenvironment’s critical role in responses to anticancer agents. We provide a new method for efficient processing and cryopreserving GBOs, enabling the establishment of large biobanks for patient-specific preclinical drug testing across brain tumor subgroups in a clinically relevant human 3D model.