Modeling Breast Cancer in Human Breast Tissue using a Microphysiological System

Summary

This protocol describes the construction of an in vitro microphysiological system for studying breast cancer using primary human breast tissue with off the shelf materials.

Abstract

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials. Therefore, new models are needed to improve our understanding of the disease. The NIH Microphysiological Systems (MPS) program was developed to improve the clinical translation of basic science discoveries and promising new therapeutic strategies. Here we present a method for generating MPS for breast cancers (BC-MPS). This model adapts a previously described approach of culturing primary human white adipose tissue (WAT) by sandwiching WAT between adipose-derived stem cell sheets (ASC)s. Novel aspects of our BC-MPS include seeding BC cells into non-diseased human breast tissue (HBT) containing native extracellular matrix, mature adipocytes, resident fibroblasts, and immune cells; and sandwiching the BC-HBT admixture between HBT-derived ASC sheets. The resulting BC-MPS is stable in culture ex vivo for at least 14 days. This model system contains multiple elements of the microenvironment that influence BC including adipocytes, stromal cells, immune cells, and the extracellular matrix. Thus BC-MPS can be used to study the interactions between BC and its microenvironment.

We demonstrate the advantages of our BC-MPS by studying two BC behaviors known to influence cancer progression and metastasis: 1) BC motility and 2) BC-HBT metabolic crosstalk. While BC motility has previously been demonstrated using intravital imaging, BC-MPS allows for high-resolution time-lapse imaging using fluorescence microscopy over several days. Furthermore, while metabolic crosstalk was previously demonstrated using BC cells and murine pre-adipocytes differentiated into immature adipocytes, our BC-MPS model is the first system to demonstrate this crosstalk between primary human mammary adipocytes and BC cells in vitro.

Introduction

Each year, more than 40,000 US women die of breast cancer (BC)¹. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials^2,3. New models are needed to improve the drug development pipeline and our understanding of BC. The NIH Microphysiological (MPS) Program delineated the features required for breakthrough models for improving translating basic science into clinical success⁴. These included the use of primary human cells or tissues, stable in culture for 4 weeks, and inclusion of native tissue architecture a....

Protocol

All human tissues were collected in accordance to protocol #9189 as approved by the Institutional Review Board Office of LSUHSC.

1. Seeding of Adipose-derived Stem Cells (ASCs) for cell sheets

1. Purchase ASCs from commercial sources or isolate from primary human breast tissue by following established protocols^8,9. Seed human breast ASCs at 70% density (~80,000 cells/cm² surface area) onto 6-well standard tissue culture plates in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum, and 1% Penicillin/Streptomycin (BC-MPS Media). En....

Results

Stability in culture
BC-MPS is a stable microphysiological system that can be cultured in vitro for up to at least 14 days. A brightfield image of the ASC cell sheets was taken at 100x magnification to display the striated pattern of the confluent sheet (Figure 2A). The ASC cell sheets are stable in culture for at least 4 weeks. BC-MPS at 14 days in culture in one well of a 6 well plate was imaged with a color camera demonstrating that th.......

Discussion

New systems for modeling human breast cancer are needed to develop a better understanding of the disease. Development of human microphysiological systems to model disease settings that include native ECM and stromal cells will increase the predictive power of pre-clinical studies. The BC-MPS model presented here is a newly developed system that overcomes the limitations of previous models allows for the evaluation of BC in its native HBT environment. This system can be used with cancer cell lines or with tumor explants a.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Accumax	Innovative Cell Technologies	1333	Cell disassoication solution for separation of BC-MPS
Accutase	Corning	25-058-CI	Cell detachment solution for passaging of cells
BioStor Container 16oz	National Scientific Supply Co	MPCE-T016	For Transport of sterile tissue
Cell Culture 75 cm flasks	Corning	430641U	For culturing ASCs
Conical Tubes 15mL	ThermoScientific	339650
Curved Forceps	ThermoScientific	1631T5	For maneuvering tissue while mincing
DMEM low glucose, w/ Glutamax	Gibco	10567-014	For culturing ASCs and BC-MPS
FBS Qualified	Gibco	26140-079
Gelatin	Sigma	G9391
HBSS 10x	Gibco	14185-052
NaOH	Sigma	221465
Nunc UpCell 6 well plates	ThermoScientific	174901	Top ASC cell sheet
PBS	Gibco	10010-023
Pen/Strep 5,000U	Gibco	15070-063
Petri Dish 150 cm	FisherBrand	FB0875714	For holding tissue while mincing
Razor Blades	VWR	55411-055	Single Edge for mincing tissue
Strainer 250um	ThermoScientific	87791	For separation of BC-MPS
Tissue Culture 6 well plates	Corning	3506	Bottom ASC cell Sheet
Weights/Washers	BCP Fasteners	BCP672	For weighing plungers down 1/2" inner diameter