A human 3D culture-organ-on-chip platform for investigating the tumor microenvironment response to ionizing radiation

Studying complex human responses, such as radiation-induced effects in the tumor microenvironment (TME), requires advanced <i>in vitro</i> systems. Here, we present the Apparatus to Simulate Tumor and Reproduce Organs in an Interactive and Dynamic System (ASTEROIDS), which integrates three-dimensional cell culture with organ-on-chip technology. To characterize the ASTEROIDS, a lung TME was reproduced by co-culturing cancer spheroids with endothelial and fibroblast cells mimicking vascular and stromal compartments. The ASTEROIDS maintained cell viability, endothelial barrier formation, and spheroid zonal structure for seven days. Transcriptomic profiling revealed endothelial-tumor crosstalk, while perfused immune cells exhibited recruitment and immunoregulatory activation. Upon single fraction stereotactic irradiation, ASTEROIDS showed dose-dependent DNA damage, nuclear hypertrophy, endothelial barrier disruption, spheroid growth inhibition, and metabolomic alterations. Together, these results demonstrate that ASTEROIDS faithfully reproduces TME-level organization and responses, establishing its feasibility as a pre-clinical human model for studying radiation effects and tumor-immune interactions.