Study of the interaction between cancer and stromal cells in a silk-based 3D breast cancer model.

Cancer is a complex disease regulated by a cross-talk among epithelial cells, cancer associated fibroblasts, endothelial and immune system cells interacting with soluble and insoluble components of the extracellular matrix (ECM). Flat cell cultures and xenograft animal are the tools exploited by researchers to investigate this pathology. In the last decades, relevant scientific results highlighted the reliability of 3D bioengineered tissue culture to recapitulate cell-cell and cell-ECM interaction. In particular, 3D tumor models have gained attention since they better recapitulate the dynamic mechanisms driving cancer progression, invasion and metastasis. However a golden standard model that faithfully mimic solid cancer disease is not available yet, also due to the complexity of the disease. In this work, a 3D breast cancer model based on freeze-dried silk fibroin scaffold (SF) has been initiated. SF from mulberry silkworm Bombyx mori is used due to its good biocompatibility, elasticity, toughness, suitable mechanical properties and biodegradability with tunable degradation rates. SF scaffold have been characterized to investigate the physico-chemical properties. Two type of breast cancer cell lines, as MCF-7 and MDAMB-231, have been used to mimic non-invasive and metastatic phenotype of the solid tumor. Breast cancer cells and normal mammary fibroblast (HMF) are seeded on silk derived biomaterial matrix to better mimic the tumor microenvironment and the crosstalk between cancer cells and stroma. Proliferation of the cells has been evaluated in the monoculture and co-culture systems by mean of Alamar blue assay and DNA quantification. 3D breast cancer model morphology has been investigated by mean of scansion electron microscopy and confocal microscopy by mean staining. The different expressions of some ECM markers are investigated to characterize the tumor microenvironment. The 3D bioengineered breast cancer model may help to make drug development safer and more efficient and reduce research and development expenses. Additionally, it represents a promising model for individualized oncologic therapy by revealing new insights into mechanisms of organogenesis and expression of malignancy.