Abstract PO002: Microfluidic tissue culture device to mimic the bone marrow sinusoidal niche of cancer cells
Authors: Sui Chao , Zilberberg Jenny , Lee Woo 
Published: March 2021

Abstract
The goal of this study is to develop a microfluidic tissue culture device that mimics in vitro the sinusoidal niche of cancer cells in bone marrow (BM). BM is highly vascularized by sinusoids to support the trafficking of blood, immune, and tumor cells. We envision that the microfluidic device can be developed and used as a new means of studying the trafficking of tumor cells through sinusoidal endothelium and the phenotypic development of cancer cells through interactions with stromal cells in BM. The microfluid device was designed to contain sinusoid and stroma chambers. The sinusoidal blood circulation was mimicked by culture medium flow which exerts the physiologically relevant flow-induced shear stress of 0.1 Pascals on endothelial cells (ECs). The sinusoidal endothelium was constructed by culturing ECs (EA.hy926 cell line) on a membrane (10 μm pores) placed between the sinusoid and stroma chambers. The BM stroma was mimicked by dispersing and culturing fibroblastic stromal cells (HS-5 cell line) in collagen. The device was also designed for: (1) industry-standard 96-well plate format for high-throughput culture and characterization and (2) convenient placement of cells and biomaterials to construct tissues. The device was placed inside a conventional incubator and connected to a peristaltic pump for medium circulation for dynamic culture for up to 24 days. ECs formed a confluent layer on the membrane and exhibited a cobble-stone morphology within 4 h while stroma cells could be uniformly dispersed in collagen and cultured in the stroma chamber. Upon further culture, CD31 was strongly expressed at contact regions of ECs, indicating the formation of intercellular junctions. The effects of flow-induced shear stress were evident on the morphological alignment of endothelial cells and the re-arranged cortical organization of F-actin. The effects of cancer cells on the barrier function of endothelium were examined by culturing human multiple myeloma cancer cells (MM.1S cell line) with HS-5 cells in the stroma chamber. The permeability of endothelium, which was measured using a fluorescein isothiocyanate–dextran solution (70 kDa), significantly increased from 5.8±0.2 × 10−6 to 9.3±0.1 × 10−6 cm/s with introducing MM.1S cells (p &lt;0.0001 determined by t-test). The increased permeability was supported by the formation of larger and more gaps formed at EC junctions. Also, stromal cell-derived factor 1 was introduced as a chemoattract in the sinusoid chamber to induce the transmigration of MM.1S cells through the endothelium layer from the stroma chamber while maintaining the uniform dispersion of HS-5 cells in the stroma chamber. In conclusion, the results suggest that the device could be used to study the adverse effects of cancer cells on the barrier function of sinusoidal endothelium (e.g., less organized and more loosely connected ECs) and further mimic the trafficking of cancer cells through the BM stroma.
Citation Format: Chao Sui, Jenny Zilberberg, Woo Lee. Microfluidic tissue culture device to mimic the bone marrow sinusoidal niche of cancer cells [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr PO002.