Permeability across a novel microfluidic blood-tumor barrier model

Tori B. Terrell-Hall,Paul R. Lockman,Amanda G. Ammer,Jessica I. G. Griffith

doi:10.1186/s12987-017-0050-9

Tori B. Terrell-Hall, Paul R. Lockman + Show 2 more

Open Access

https://doi.org/10.1186/s12987-017-0050-9

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Abstract

BackgroundThe lack of translatable in vitro blood-tumor barrier (BTB) models creates challenges in the development of drugs to treat tumors of the CNS and our understanding of how the vascular changes at the BBB in the presence of a tumor.MethodsIn this study, we characterize a novel microfluidic model of the BTB (and BBB model as a reference) that incorporates flow and induces shear stress on endothelial cells. Cell lines utilized include human umbilical vein endothelial cells co-cultured with CTX-TNA2 rat astrocytes (BBB) or Met-1 metastatic murine breast cancer cells (BTB). Cells were capable of communicating across microfluidic compartments via a porous interface. We characterized the device by comparing permeability of three passive permeability markers and one marker subject to efflux.ResultsThe permeability of Sulforhodamine 101 was significantly (p < 0.05) higher in the BTB model (13.1 ± 1.3 × 10−3, n = 4) than the BBB model (2.5 ± 0.3 × 10−3, n = 6). Similar permeability increases were observed in the BTB model for molecules ranging from 600 Da to 60 kDa. The function of P-gp was intact in both models and consistent with recent published in vivo data. Specifically, the rate of permeability of Rhodamine 123 across the BBB model (0.6 ± 0.1 × 10−3, n = 4), increased 14-fold in the presence of the P-gp inhibitor verapamil (14.7 ± 7.5 × 10−3, n = 3) and eightfold with the addition of Cyclosporine A (8.8 ± 1.8 × 10−3, n = 3). Similar values were noted in the BTB model.ConclusionsThe dynamic microfluidic in vitro BTB model is a novel commercially available model that incorporates shear stress, and has permeability and efflux properties that are similar to in vivo data.

Highlights

The lack of translatable in vitro blood-tumor barrier (BTB) models creates challenges in the develop‐ ment of drugs to treat tumors of the CNS and our understanding of how the vascular changes at the blood–brain barrier (BBB) in the pres‐ ence of a tumor
In this study, we evaluate transfer rates of Free sulforhodamine Acid Chlo‐ ride (TRD), Texas Red 3 kDa, Texas Red 70 kDa, and Rhodamine 123 (Rho123) (Fig. 1) in a novel microfluidic BBB and BTB model as validation to previously published literature [34]
Endothelial cells are seeded in the outer compartments, while astrocytes (BBB) or brain seeding breast cancer cells (BTB) are seeded in the central compartment

Summary

Introduction

The lack of translatable in vitro blood-tumor barrier (BTB) models creates challenges in the develop‐ ment of drugs to treat tumors of the CNS and our understanding of how the vascular changes at the BBB in the pres‐ ence of a tumor. One of the leading complications of brain metastases is the inability of drugs to reach the tumor at concentrations adequate to induce cytotoxicity. This is due, in part, to the presence of a partially intact blood–brain barrier (BBB). The BBB is a complex anatomical network, functioning to strictly regulate the movement of molecules and ions from the blood to the brain and back. In addition to the structural components, the BBB is Terrell‐Hall et al Fluids Barriers CNS (2017) 14:3 highly enriched in efflux transporters that actively restrict the entry a large and diverse set of lipophilic solutes from accumulating in the brain [8, 9]

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