Multicellular tumor-stromal interactions recapitulate aspects of therapeutic response and human oncogenic signaling in a 3D disease model for H3K27M-altered DIPG

It has become evident from decades of clinical trials that multimodal therapeutic approaches with focus on cell intrinsic and microenvironmental cues are needed to improve understanding and treat the rare, inoperable, and ultimately fatal diffuse intrinsic pontine glioma (DIPG), now categorized as a diffuse midline glioma. In this study we report the development and characterization of an in vitro system utilizing 3D Tumor Tissue Analogs (TTA), designed to replicate the intricate DIPG microenvironment. The innate ability of fluorescently labeled human brain endothelial cells, microglia, and patient-derived DIPG cell lines to self-assemble has been exploited to generate multicellular 3D TTAs that mimic tissue-like microstructures, enabling an in- depth exploration of the spatio-temporal dynamics between neoplastic and stromal cells. The 3D-TTA model recapitulates clinical patterns of DIPG growth, evidenced by resistance to chemotherapy, HDAC and proteasome inhibitors, as well as sensitization to the antibody-activated innate immune microenvironment including complement proteins and surrounding microglia. Multimodal fluorescence imaging platforms integrated with high-throughput omics revealed that alterations in tumor cell motility and growth in the 3D-TTA model compared to tumor cell only spheroids correlated with specific transcriptomic and proteomic changes. STAT3, ITGA5, LGALS1, SOD2, MVP, and CLIC1, associated with microenvironment signaling, DNA replication, and immune regulation, were identified as potential novel targets in the 3D model. The results indicate that the 3D TTA platform developed here represents a powerful tool for preclinical studies, paving the way for identification/validation of tissue specific biomarkers and novel drug targets, thus advancing disease management strategies for DIPG in children.