Millimeter-scale, high-density three-dimensional constructs recapitulate hot and cold tumor microenvironment

The tumor microenvironment (TME) exerts a pivotal influence on malignant phenotypes, including invasion, metastasis, immune evasion, and therapeutic resistance, thereby dictating clinical outcomes and patient prognosis. Consequently, a comprehensive elucidation of TME dynamics is of paramount importance. To address this, the development of in vitro tumor models capable of faithfully recapitulating its inherent complexity is indispensable. In this study, we engineered millimeter-scale, high-density 3D tumor constructs that recapitulate the intricate architectural and functional hallmarks of the in vivo TME. Within this biomimetic platform, reciprocal crosstalk with cancer cells induced the differentiation of cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs). Furthermore, we successfully modeled divergent immunophenotypes, characterized as "hot" and "cold" tumors, and integrated a hierarchical vascular network comprising venous and capillary-like structures. Collectively, this construct accurately mirrors the in vivo TME, providing a robust platform for modeling complex tumor ecosystems and offering substantial potential to catalyze advancements in cancer research and drug discovery.