1:Universidad de Granada; 2:Centro de Investigación Biomédica; 3:Biosanitary Research Institute of Granada (ibs.GRANADA); 4:Excellence Research Unit "Modeling Nature" (MNat); 5:GENyO- Centro de Genomica e Investigacion Oncologica: Pfizer / Universidad de Granada / Junta de Andalucia

Mimicking the cancer microenvironment still remains challenging but it is acquiring a vital importance due to its influence on tumor progression and metastasis. 3D bioprinting is an emerging tool that enables the creation of tissue models by combining different cell types and supporting matrices, providing a platform to represent the great tumor heterogeneity. In this work, we have developed two 3D melanoma tumor model based on cancer stem cells (CSCs), employing the extrusion bioprinting method. For that, we embedded cancer stem cells isolated from a MM established cell line or a primary-patient derived cell line, fibroblasts, mesenchymal stem cells, and endothelial cells, within a hydrogel representing the three human skin layers, in order to mimic melanoma and its tumor microenvironment. TME-cells showed high proliferation and metabolic activity, and actively remodeled their niche. MM models displayed similar rheological properties that skin and were able to support an early onset of vascularization. Besides, MM models displayed different response to vemurafenib compared with cell cultures, allowing the detection of chemoresistant tumors. Moreover, MM hydrogels supported tumorigenesis in murine xenotransplant achieving more mimetic in vivo models. To our knowledge, it is the first time that a novel tri-layered bioprinted 3D CSCs- based melanoma model has been developed, with potential alternative to small animal models and use for oncological research and analysis of tumor response to new personalized therapies against melanoma.