Abstract 5190: Leveraging the International Space Station to study glioblastoma-immune interactions in microgravity-grown organoids

Abstract Glioblastoma (GBM) is the most aggressive primary brain cancer with current treatments achieving an average overall survival of less than 2 years. This is due in part to the highly immunosuppressive tumor microenvironment (TME), a characteristic of many solid tumors that thwarts immunotherapy. However, the complex interactions between cancer cells and immune cells are difficult to recapitulate in culture models. Microgravity offers key advantages for cancer organoid development, including the ability to generate more robust, larger, complex, uniform, and reproducible spheroids that recapitulate cell-cell interactions more accurately than ground-based 3-D models, which are subject to gravitational forces leading to spheroid settling, disassociation, and heterogeneity. We sent individual small-scale, static experiments contained within Space Tango's High Sample Capacity CubeLab to the International Space Station (ISS) in March 2024 aboard the SpX-30 commercial resupply mission. We first developed tumor-myeloid organoids to recreate the 3D spatial interactions in the TME. These combine human GBM cells with monocytes and macrophages and can be treated to polarize the macrophages into pro-inflammatory (M1-like) or anti-inflammatory (M2-like) phenotypes. Spheroids of uniform size and tunable cell content were generated using the hanging drop method. We then optimized spheroid size and media conditions to support long-term spheroid growth in the absence of gas or media exchange to be compatible with the carrier system. We observed intact spheroids with viable cells beyond two months in sealed vials. Over time, the organoids reside in an acidic and hypoxic environment, with live cells at the organoid edges and a necrotic central core. This recapitulates the microenvironment of GBM and other tumors, which is known to be acidic, hypoxic, and necrotic. The launched experiment contained spheroids with GBM cells alone, GBM cells + macrophages, GBM cells + monocytes, and GBM + macrophages with M1-like or M2-like polarizing agents. These were maintained in microgravity aboard the ISS for 40 days and were processed within 24 hours of their return to Earth. We collected RNA for bulk sequencing, media for secreted proteomics, and fixed intact spheroids for spatial sequencing, spatial proteomics, and histology. While analysis is ongoing to determine the impact of microgravity on GBM-immune interactions, this experiment has already laid the groundwork for future flights by revealing successful organoid culture conditions for future experiments. We anticipate that these microgravity immune-tumoroids will provide valuable insight into the role of macrophages in GBM biology that would not be possible to obtain in Earth’s gravity. Upcoming microgravity experiments will include more complex organoids from patient-derived glioma cells and the potential for drug screening. Citation Format: Alice Burchett, Maksym Zarodniuk, Fionn Lay, Ina Satpathy, Wenjun Zhao, Karyme Hernandez Torrens, Haley Marco, Maria Mendez, Julian Najera, Shelby Giza, Jason Rexroat, Paul Kuehl, Twyman Clements, Meenal Datta. Leveraging the International Space Station to study glioblastoma-immune interactions in microgravity-grown organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5190.