Mimicking physiologically relevant environments in patient-derived tumor-immune models to target immunologically cold high-grade serous tumors

High-grade serous tumors are immunologically cold, characterized by limited immune cell infiltration and reduced clinical outcome, primarily due to hypoxia and extensive extracellular matrix remodeling that disrupt tumor-stromal-immune interactions. However, current experimental models fail to fully capture oxygen and matrix microenvironmental features, limiting progress in understanding tumor-immune dynamics and developing effective treatments. Here, we demonstrate that patient-derived tumor-immune models, mimicking physiologically relevant oxygen levels and extracellular matrix remodeling, recapitulate the hypoxia-induced stromal/matrix dysregulation, which associates with impaired immune infiltration, and enable dissecting targeted opportunities via TGF-β signaling. The models incorporate cancer cells co-cultured with cancer-associated fibroblasts within 3D matrices bioengineered using human plasma or grown on decellularized human ovarian extracellular matrices. Immune cells were either included within the 3D constructs as a multiculture to study tumor-immune interactions or challenged to infiltrate the matrices. By bioengineering physiologically relevant oxygen levels, we uncovered that intratumoral hypoxia acts as a friend and a foe, causing hypoxia-induced stromal-driven impaired immune infiltration but enhancing the activation and cytotoxicity of CD8+ T cells. We also showed that targeting TGF-β signaling reversed the hypoxia-induced stromal-driven impaired immune infiltration. These female patient-relevant models may aid the development of targeted therapies to turn immunologically cold tumors into hot ones.