Development and characterization of a novel human 3D model of bone metastasis from breast carcinoma in vitro cultured and retaining the in vivo tumor microenvironment and cell heterogeneity

Breast cancer frequently metastasizes to the skeleton causing significant morbidity. None of the therapeutic strategies used to manage breast cancer bone metastases are really curative, also because of the limits associated to the existing preclinical models. Here, we set-up a novel and advanced model by using fresh tissue from human vertebral bone metastasis from breast carcinoma patients, which able to retain the tumor microenvironment and tumor cell heterogeneity. The tissue model is based on an ex-vivo culture for up to 40 days and on a constant monitoring of tissue viability, gene expression profile (IL10, IL1b, MMP1, MMP7, PTH1R, PTH2R, TNF, ACP5, SPI1, VEGFA, CTSK, TGF-β) and histological and immunohistochemical analyses (CDH1/E-cadherin, CDH2/N-cadherin, KRT8/Cytokeratin 8, KRT18/Cytokeratin 18, Ki67, CASP3/Caspase 3, ESR1/Estrogen Receptor Alpha, CD68 and CD8). Results confirmed the development of a reliable, reproducible and cost-effective advanced model of breast cancer bone metastasis able to preserve and maintain long-term tissue viability, as well as molecular markers, tissue histomorphology, tissue micro-architecture and antigen expression. The study provides for the first time the feasibility and rationale for the use of a human-derived advanced alternative model for cancer research and testing of drugs and innovative strategies, taking into account patient individual characteristics and specific tumor subtypes so predicting patient specific responses.