High-content siRNA 3D co-cultures to identify myoepithelial cell-derived breast cancer suppressor proteins

Hendrika M Duivenvoorden,Belinda S Parker,Kaylene J Simpson,Natasha K Brockwell,Cameron J Nowell

doi:10.1038/s41597-021-00924-9

Hendrika M Duivenvoorden, Belinda S Parker + Show 3 more

Open Access

https://doi.org/10.1038/s41597-021-00924-9

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Abstract

Understanding how cancer cells interact with the surrounding microenvironment early in breast cancer development can provide insight into the initiation and progression of invasive breast cancers. The myoepithelial cell layer surrounding breast ducts acts as a physical barrier in early breast cancer, preventing cancer cells from invading the surrounding stroma. Changes to the expression profile and properties of myoepithelial cells have been implicated in progression to invasive carcinoma. Identifying the molecular drivers of myoepithelial cell-mediated tumour suppression may offer new approaches to predict and block the earliest stages of cancer invasion. We employed a high-content approach to knock down 87 different genes using siRNA in an immortalised myoepithelial cell line, prior to co-culture with invasive breast cancer cells in 3D. Combined with high-content imaging and a customised analysis pipeline, this system was used to identify myoepithelial proteins that are necessary to control cancer cell invasion. This dataset has identified prospective myoepithelial suppressors of early breast cancer invasion which may be used by researchers to investigate their clinical validity and utility.

Highlights

Background & SummaryBreast cancer that is confined to the ductal system has a 5-year survival rate of 99%
The myoepithelial cells and basement membrane constitute the ‘boundary’ of the breast ducts and it is the presence of myoepithelial cells that is a distinguishing factor between DCIS and invasive ductal carcinoma (IDC)
Whilst tumour cells in DCIS and IDC appear transcriptionally similar, expression profiling of myoepithelial cells derived from DCIS or normal breast tissue have revealed distinct changes that suggest myoepithelial cells may play an important role in dictating the DCIS to IDC transition[3,4]

Summary

Introduction

Background & SummaryBreast cancer that is confined to the ductal system (ductal carcinoma in situ, DCIS) has a 5-year survival rate of 99%. In order to investigate whether other protease inhibitors or adhesion proteins were integral to myoepithelial cell control of tumour cell invasion, we combined high-content siRNA screening with our 3D co-culture system (Fig. 1). Knockdown of protein expression via siRNA in myoepithelial cells (Fig. 2) was followed by co-culture with tumour cells in our 3D model.

Results

Conclusion