Id Proteins Promote a Cancer Stem Cell Phenotype in Mouse Models of Triple Negative Breast Cancer via Negative Regulation of Robo1

Wee S Teo; Holly Holliday; Nitheesh Karthikeyan; Aurélie S Cazet; Daniel L Roden; Kate Harvey; Christina Valbirk Konrad; Reshma Murali; Binitha Anu Varghese; Archana P Thankamony; Chia-Ling Chan; Andrea McFarland; Simon Junankar; Sunny Ye; Jessica Yang; Iva Nikolic; Jaynish S Shah; Laura A Baker; Ewan K A Millar; Matthew J Naylor; Christopher J Ormandy; Sunil R Lakhani; Warren Kaplan; Albert S Mellick; Sandra A O'Toole; Alexander Swarbrick; Radhika Nair

doi:10.3389/fcell.2020.00552

Id Proteins Promote a Cancer Stem Cell Phenotype in Mouse Models of Triple Negative Breast Cancer via Negative Regulation of Robo1

Front Cell Dev Biol. 2020 Jul 17:8:552. doi: 10.3389/fcell.2020.00552. eCollection 2020.

Authors

Wee S Teo^{1

2}, Holly Holliday^{1

2}, Nitheesh Karthikeyan³, Aurélie S Cazet^{1

2}, Daniel L Roden^{1

2}, Kate Harvey¹, Christina Valbirk Konrad¹, Reshma Murali³, Binitha Anu Varghese³, Archana P Thankamony^{3

4}, Chia-Ling Chan^{1

2}, Andrea McFarland¹, Simon Junankar^{1

2}, Sunny Ye¹, Jessica Yang¹, Iva Nikolic^{1

2}, Jaynish S Shah⁵, Laura A Baker^{1

2}, Ewan K A Millar^{1

6

7

8}, Matthew J Naylor^{1

2

9}, Christopher J Ormandy^{1

2}, Sunil R Lakhani¹⁰, Warren Kaplan^{1

11}, Albert S Mellick^{12

13}, Sandra A O'Toole^{1

14}, Alexander Swarbrick^{1

2}, Radhika Nair^{1

2

3}

Affiliations

¹ Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
² Faculty of Medicine, St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia.
³ Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India.
⁴ Manipal Academy of Higher Education, Manipal, India.
⁵ Gene & Stem Cell Therapy Program, Centenary Institute, The University of Sydney, Camperdown, NSW, Australia.
⁶ Department of Anatomical Pathology, NSW Health Pathology, St George Hospital, Kogarah, NSW, Australia.
⁷ School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia.
⁸ School of Medicine, Western Sydney University, Penrith, NSW, Australia.
⁹ School of Medical Sciences, Discipline of Physiology & Bosch Institute, University of Sydney, Sydney, NSW, Australia.
¹⁰ UQ Centre for Clinical Research, School of Medicine and Pathology Queensland, Royal Brisbane & Women's Hospital, The University of Queensland, Herston, QLD, Australia.
¹¹ Peter Wills Bioinformatics Centre, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
¹² UNSW Medicine, University of NSW, Kensington, NSW, Australia.
¹³ Medical Oncology Group, Ingham Institute for Applied Medical Research, South Western Sydney Clinical School UNSW & CONCERT Translational Cancer Research Centre, Liverpool, NSW, Australia.
¹⁴ Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.

Abstract

Breast cancers display phenotypic and functional heterogeneity and several lines of evidence support the existence of cancer stem cells (CSCs) in certain breast cancers, a minor population of cells capable of tumor initiation and metastatic dissemination. Identifying factors that regulate the CSC phenotype is therefore important for developing strategies to treat metastatic disease. The Inhibitor of Differentiation Protein 1 (Id1) and its closely related family member Inhibitor of Differentiation 3 (Id3) (collectively termed Id) are expressed by a diversity of stem cells and are required for metastatic dissemination in experimental models of breast cancer. In this study, we show that ID1 is expressed in rare neoplastic cells within ER-negative breast cancers. To address the function of Id1 expressing cells within tumors, we developed independent murine models of Triple Negative Breast Cancer (TNBC) in which a genetic reporter permitted the prospective isolation of Id1⁺ cells. Id1⁺ cells are enriched for self-renewal in tumorsphere assays in vitro and for tumor initiation in vivo. Conversely, depletion of Id1 and Id3 in the 4T1 murine model of TNBC demonstrates that Id1/3 are required for cell proliferation and self-renewal in vitro, as well as primary tumor growth and metastatic colonization of the lung in vivo. Using combined bioinformatic analysis, we have defined a novel mechanism of Id protein function via negative regulation of the Roundabout Axon Guidance Receptor Homolog 1 (Robo1) leading to activation of a Myc transcriptional programme.

Keywords: Id proteins; Myc signature; Robo1; cancer stem cell; metastasis.

Copyright © 2020 Teo, Holliday, Karthikeyan, Cazet, Roden, Harvey, Konrad, Murali, Varghese, Thankamony, Chan, McFarland, Junankar, Ye, Yang, Nikolic, Shah, Baker, Millar, Naylor, Ormandy, Lakhani, Kaplan, Mellick, O'Toole, Swarbrick and Nair.