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Myoepithelial cell-specific expression of stefin A as a suppressor.pdf (310.17 kB)

Myoepithelial cell-specific expression of stefin A as a suppressor of early breast cancer invasion

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posted on 2021-08-12, 06:32 authored by Hendrika M Duivenvoorden, Jai Rautela, Laura E Edgington-Mitchell, Alex Spurling, David GreeningDavid Greening, Cameron J Nowell, Timothy J Molloy, Elizabeth Robbins, Natasha Brockwell, Cheok Soon Lee, Maoshan Chen, Anne Holliday, Cristina I Selinger, Min Hu, Kara L Britt, David A Stroud, Matthew Bogyo, Andreas Möller, Kornelia Polyak, Bonnie F Sloane, Sandra A O'Toole, Belinda ParkerBelinda Parker
Mammography screening has increased the detection of early pre-invasive breast cancers, termed ductal carcinoma in situ (DCIS), increasing the urgency of identifying molecular regulators of invasion as prognostic markers to predict local relapse. Using the MMTV-PyMT breast cancer model and pharmacological protease inhibitors, we reveal that cysteine cathepsins have important roles in early-stage tumorigenesis. To characterize the cell-specific roles of cathepsins in early invasion, we developed a DCIS-like model, incorporating an immortalized myoepithelial cell line (N1ME) that restrained tumor cell invasion in 3D culture. Using this model, we identified an important myoepithelial-specific function of the cysteine cathepsin inhibitor stefin A in suppressing invasion, whereby targeted stefin A loss in N1ME cells blocked myoepithelial-induced suppression of breast cancer cell invasion. Enhanced invasion observed in 3D cultures with N1ME stefin A-low cells was reliant on cathepsin B activation, as addition of the small molecule inhibitor CA-074 rescued the DCIS-like non-invasive phenotype. Importantly, we confirmed that stefin A was indeed abundant in myoepithelial cells in breast tissue. Use of a 138-patient cohort confirmed that myoepithelial stefin A (cystatin A) is abundant in normal breast ducts and low-grade DCIS but reduced in high-grade DCIS, supporting myoepithelial stefin A as a candidate marker of lower risk of invasive relapse. We have therefore identified myoepithelial cell stefin A as a suppressor of early tumor invasion and a candidate marker to distinguish patients who are at low risk of developing invasive breast cancer, and can therefore be spared further treatment. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.


We gratefully thank Peter Lock of the LIMS Microscopy and Imaging Facility, the staff at La Trobe University Central Animal House for technical assistance, and the La Trobe Comprehensive Proteomics Platform for access to equipment and expertise employed in this study. We express our gratitude to Dr Elgene Lim for the gift of the CAL120 cell line. We also thank Dr Kaylene Simpson and Dr Iva Nikolic from the Peter MacCallum Cancer Centre for their assistance with siRNA. This work was supported by grant funding from the National Health and Medical Research Council (NHMRC) (BSP 1047748 and 1127754); fellowship support to BSP from the ARC (FT130100671), DAS from the NHMRC (1070916), and SOT from the NBCF (Practitioner Fellowship PRAC-16-006); and scholarship support from the Cancer Council Victoria (to HMD). Support from the Sydney Breast Cancer Foundation is also gratefully acknowledged.


Publication Date



Journal of Pathology






14p. (p. 496-509)





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