Selection of a Relevant In Vitro Blood-Brain Barrier Model to Investigate Pro-Metastatic Features of Human Breast Cancer Cell Lines

Abstract

Around 7–17% of metastatic breast cancer patients will develop brain metastases, associated with a poor prognosis. To reach the brain parenchyma, cancer cells need to cross the highly restrictive endothelium of the Blood-Brain Barrier (BBB). As treatments for brain metastases are mostly inefficient, preventing cancer cells to reach the brain could provide a relevant and important strategy. For that purpose an in vitro approach is required to identify cellular and molecular interaction mechanisms between breast cancer cells and BBB endothelium, notably at the early steps of the interaction. However, while numerous studies are performed with in vitro models, the heterogeneity and the quality of BBB models used is a limitation to the extrapolation of the obtained results to in vivo context, showing that the choice of a model that fulfills the biological BBB characteristics is essential. Therefore, we compared pre-established and currently used in vitro models from different origins (bovine, mice, human) in order to define the most appropriate tool to study interactions between breast cancer cells and the BBB. On each model, the BBB properties and the adhesion capacities of breast cancer cell lines were evaluated. As endothelial cells represent the physical restriction site of the BBB, all the models consisted of endothelial cells from animal or human origins. Among these models, only the in vitro BBB model derived from human stem cells both displayed BBB properties and allowed measurement of meaningful different interaction capacities of the cancer cell lines. Importantly, the measured adhesion and transmigration were found to be in accordance with the cancer cell lines molecular subtypes. In addition, at a molecular level, the inhibition of ganglioside biosynthesis highlights the potential role of glycosylation in breast cancer cells adhesion capacities.

New experimental models of the blood-brain barrier for CNS drug discovery

“…Here, we provide details on the design and applications of current stem cell BBB modeling (see Table 4) including model-specific limitations. Considerable evidence indicates the utility of cord blood hematopoietic progenitor cells (CD34 + CD45 + CD31 + KDR − vWF − CD14 − cells) to develop a reproducible human BBB model in vitro [112, 113] for studying the mechanisms underlying the transmigration of breast cancer cells across the BBB endothelium in brain metastasis [114, 115]. For example, Ponio and colleagues reported that directed differentiation of endothelial progenitor cell colonies derived from cord blood stem cells in the presence of astrocytes induced BBB-like properties with increased monolayer integrity similar to hCMEC/D3 cell line [112].…”

“…Similarly, hematopoietic stem cell-derived ECs when co-cultured with pericytes display a mature and functionally responsive BBB EC phenotype with sustained barrier tightness for many days and the ability to predict human brain drug distribution [113]. However, it should be noted that despite relatively low barrier permeability compared to direct differentiation with astrocytes [113] or hCMEC/D3 cell line under static conditions [96], TEER values obtained with hematopoietic stem cell based BBB models are still below 200Ω × cm 2 [113, 114] (see Table 4). Thus, the model stability in vitro is outweighed by its relatively poor barrier tightness, compared to other in vitro BBB platforms [112, 116, 117].…”

“…Despite high reproducibility of cord blood stem cell-derived BBB models, their relatively low barrier tightness could be a potential limitation [112, 113, 114]. By contrast, hPSC derived BMEC monolayers suffers from reproducibility and stability deficits.…”

ST6GALNAC5 Expression Decreases the Interactions between Breast Cancer Cells and the Human Blood-Brain Barrier

“…The protocol was performed as previously described [15]. The endothelial permeability coefficients (Pe) of the molecules are expressed in cm/min.…”

Biomimetic strategies to recapitulate organ specific microenvironments for studying breast cancer metastasis

“…Together, the insert and the well act as an in vitro BBB model. This model is modular and can also be coupled with permeability measuring techniques for capturing permeability changes of the in vitro BBB . Using such a model, studies have elucidated how COX2, heparin binding epithelial growth factors, epiregulins, cancer associated fibroblasts and BCC derived extracellular vesicles ( e.g ., microRNA‐181c‐containing extracellular vesicles) lower the permeability of BBB facilitating BCC extravasation .…”