A Microfluidic System for the Investigation of Tumor Cell Extravasation

Abstract

Metastatic dissemination of cancer cells is a very complex process. It includes the intravasation of cells into the metastatic pathways, their passive distribution within the blood or lymph flow, and their extravasation into the surrounding tissue. Crucial steps during extravasation are the adhesion of the tumor cells to the endothelium and their transendothelial migration. However, the molecular mechanisms that are underlying this process are still not fully understood. Novel three dimensional (3D) models for research on the metastatic cascade include the use of microfluidic devices. Different from two dimensional (2D) models, these devices take cell–cell, structural, and mechanical interactions into account. Here we introduce a new microfluidic device in order to study tumor extravasation. The device consists of three different parts, containing two microfluidic channels and a porous membrane sandwiched in between them. A smaller channel together with the membrane represents the vessel equivalent and is seeded separately with primary endothelial cells (EC) that are isolated from the lung artery. The second channel acts as reservoir to collect the migrated tumor cells. In contrast to many other systems, this device does not need an additional coating to allow EC growth, as the primary EC that is used produces their own basement membrane. VE-Cadherin, an endothelial adherence junction protein, was expressed in regular localization, which indicates a tight barrier function and cell–cell connections of the endothelium. The EC in the device showed in vivo-like behavior under flow conditions. The GFP-transfected tumor cells that were introduced were of epithelial or mesenchymal origin and could be observed by live cell imaging, which indicates tightly adherent tumor cells to the endothelial lining under different flow conditions. These results suggest that the new device can be used for research on molecular requirements, conditions, and mechanism of extravasation and its inhibition.

The Use of Microfluidic Platforms to Probe the Mechanism of Cancer Cell Extravasation

“…The third chamber features an intact monolayer of endothelial cells bound to fibronectin over poly‐ l ‐lysine. F) Microfluidic device designed by Kühlbach et al Cancer cells flow into the upper channel by a syringe pump and bind to the endothelium (not shown) grown on the porous membrane. Cancer cells that cross the endothelium and membrane collect in the static lower channel.…”

“…A device with simple geometry was engineered to investigate the adhesion of cancer cells on intact endothelium subjected to controlled fluid flow . Two rectangular channels were separated by a membrane with ≈5 µm diameter pores that allowed passage of cells (Figure 2F).…”

Cell Culture Based in vitro Test Systems for Anticancer Drug Screening

“…In this case, endothelial cells showed in vivo-like behavior under flow conditions. The introduced GFP-labeled tumor cells of epithelial or mesenchymal origin were detected using vital imaging, which showed tightly attached tumor cells to the endothelial membrane (Kuhlbach et al, 2018).…”

Conceptual Design of Micro-Bioreactors and Organ-on-Chips for Studies of Cell Cultures

“…However, other organs [ 26 , 27 , 28 , 29 ] have attracted almost the same interest, e.g., pancreas, eye, cartilage, heart, and lung cells [ 28 , 29 ], as well as combinations of several organ cell types on the same chip [ 30 , 31 ]. This is of great interest, as are tumors-on-chips, which are also covered in this special issue [ 32 , 33 ].…”