Basement Membrane-Rich Organoids with Functional Human Blood Vessels Are Permissive Niches for Human Breast Cancer Metastasis

Abstract

Metastasic breast cancer is the leading cause of death by malignancy in women worldwide. Tumor metastasis is a multistep process encompassing local invasion of cancer cells at primary tumor site, intravasation into the blood vessel, survival in systemic circulation, and extravasation across the endothelium to metastasize at a secondary site. However, only a small percentage of circulating cancer cells initiate metastatic colonies. This fact, together with the inaccessibility and structural complexity of target tissues has hampered the study of the later steps in cancer metastasis. In addition, most data are derived from in vivo models where critical steps such as intravasation/extravasation of human cancer cells are mediated by murine endothelial cells. Here, we developed a new mouse model to study the molecular and cellular mechanisms underlying late steps of the metastatic cascade. We have shown that a network of functional human blood vessels can be formed by co-implantation of human endothelial cells and mesenchymal cells, embedded within a reconstituted basement membrane-like matrix and inoculated subcutaneously into immunodeficient mice. The ability of circulating cancer cells to colonize these human vascularized organoids was next assessed in an orthotopic model of human breast cancer by bioluminescent imaging, molecular techniques and immunohistological analysis. We demonstrate that disseminated human breast cancer cells efficiently colonize organoids containing a functional microvessel network composed of human endothelial cells, connected to the mouse circulatory system. Human breast cancer cells could be clearly detected at different stages of the metastatic process: initial arrest in the human microvasculature, extravasation, and growth into avascular micrometastases. This new mouse model may help us to map the extravasation process with unprecedented detail, opening the way for the identification of relevant targets for therapeutic intervention.

Exosomes enriched in stemness/metastatic-related mRNAS promote oncogenic potential in breast cancer

“…One week post-transfection, CXCR4 and RFP-mock expressing cells were selected by sorter and expanded in RPMI supplemented with 20% FBS. MDA-MB-231 FLuc cells [ 24 ] were kindly provided by Dr. L. Vallina (University Hospital Puerta de Hierro Research Institute, Madrid, Spain).…”

Matrigel: From discovery and ECM mimicry to assays and models for cancer research

“…An additional use of the plug is as a vascularized organoid to study tumor extravasation. The model involves coimplanting human endothelial cells and mesenchymal cells in BME/ Matrigel supplemented with angiogenic factors to obtain a network of functional vessels [147]. After 48 h, metastatic breast cancer cells, MDA-MB-231, are implanted in the mammary fat pad, and after several weeks, metastatic tumor cells can be found colonizing the vascularized organoids.…”

Circulatory shear stress induces molecular changes and side population enrichment in primary tumor-derived lung cancer cells with higher metastatic potential

“…Data acquisition and analysis were performed using the Living Image Software. Regions of interest were drawn, and the light emitted was recorded as the total flux (number of photons per second) 25 . To determine the number of metastases, region of interest (ROI) were traced on bioluminescence images, metastases were identified as ROIs were the total flux [p/s] was two times greater than the background.…”