Abstract Epithelial-to-mesenchymal transition (EMT) is a key biological process that facilitates cancer metastasis to distant organs. Most preclinical studies investigating EMT are conducted using traditional two-dimensional (2D) culture models, which fail to recapitulate the in vivo tumor microenvironment, limiting the translational relevance of their findings to clinical settings. Consequently, three-dimensional (3D) culture systems have emerged as a superior approach for modeling metastatic processes and evaluating therapeutic candidates. However, these models typically rely on animal-derived extracellular matrices like Matrigel, which are poorly defined, exhibit batch-to-batch variability, and lack mechanical and biochemical stability, thereby compromising experimental reproducibility and clinical translation. In this study, we developed tumoroids from two cancer types known to undergo EMT such as glioblastoma multiforme (GBM) and breast cancer using VitroGel® hydrogel, a fully synthetic and biocompatible hydrogel system. The VitroGel® hydrogel is tunable in both mechanical and biofunctional properties, making it a powerful tool for generating advanced tumoroid models that might require distinct microenvironments. The tumoroids were generated from a single spheroid formed in ultra-low attachment, u-shaped, 96-well plates, which were then embedded in VitroGel® hydrogel diluted in our xeno-free supplement. Within the first three days after adding the hydrogel, the cells began migrating from the spheroid into the matrix, developing a tube-like structure with rapidly proliferating cells. By day seven, the tumoroids exhibited an outer layer enriched with EMT marker-positive cells expressing vimentin and N-cadherin, while the spheroid core and tube-like structure were mostly composed of cells expressing the cancer stem cell–associated markers Oct4 and Sox2. The tumoroids were susceptible to standard chemotherapies, including temozolomide and 5-fluororacil, indicating that these structures developed in the xeno-free hydrogel are a suitable system for drug screening studies.Additionally, to enhance the physiological relevance of the tumoroid model, we aimed to mimic tumor-vasculature interactions by performing co-cultures of tumoroids with endothelial cells. The endothelial cells penetrated the matrix and migrated towards the tumoroids, enhancing their long-term survival. Altogether, these findings demonstrate that the xeno-free hydrogel system supports the development of robust 3D cancer models, providing a platform for the evaluation of therapeutic drug candidates. Citation Format: Alejandra I. Ferrer Díaz, John Huang. Developing advanced tumoroid models driven by epithelial-to-mesenchymal transition with a novelxeno-free andbiofunctionalhydrogel system abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4832.
Díaz et al. (Fri,) studied this question.