Interrogation of Phenotypic Plasticity between Epithelial and Mesenchymal States in Breast Cancer

Sugandha Bhatia; James Monkman; Tony Blick; Cletus Pinto; Mark Waltham; Shivashankar H Nagaraj; Erik W Thompson

doi:10.3390/jcm8060893

Interrogation of Phenotypic Plasticity between Epithelial and Mesenchymal States in Breast Cancer

J Clin Med. 2019 Jun 21;8(6):893. doi: 10.3390/jcm8060893.

Authors

Sugandha Bhatia^{1

2

3}, James Monkman^{4

5

6}, Tony Blick^{7

8

9}, Cletus Pinto^{10

11}, Mark Waltham^{12

13}, Shivashankar H Nagaraj^{14

15

16}, Erik W Thompson^{17

18

19

20}

Affiliations

¹ Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059, Australia. sugandha.bhatia@hdr.qut.edu.au.
² School of Biological/Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD 4000, Australia. sugandha.bhatia@hdr.qut.edu.au.
³ Translational Research Institute, Brisbane, QLD 4102, Australia. sugandha.bhatia@hdr.qut.edu.au.
⁴ Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059, Australia. james.monkman@qut.edu.au.
⁵ School of Biological/Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD 4000, Australia. james.monkman@qut.edu.au.
⁶ Translational Research Institute, Brisbane, QLD 4102, Australia. james.monkman@qut.edu.au.
⁷ Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059, Australia. blick_tony@yahoo.com.au.
⁸ School of Biological/Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD 4000, Australia. blick_tony@yahoo.com.au.
⁹ Translational Research Institute, Brisbane, QLD 4102, Australia. blick_tony@yahoo.com.au.
¹⁰ Invasion and Metastasis Unit, St. Vincent's Institute, Melbourne, VIC 3065, Australia. cletusp136@gmail.com.
¹¹ University of Melbourne Department of Surgery, St. Vincent's Hospital, Melbourne, VIC 3065, Australia. cletusp136@gmail.com.
¹² Invasion and Metastasis Unit, St. Vincent's Institute, Melbourne, VIC 3065, Australia. mwaltham@unimelb.edu.au.
¹³ University of Melbourne Department of Surgery, St. Vincent's Hospital, Melbourne, VIC 3065, Australia. mwaltham@unimelb.edu.au.
¹⁴ Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059, Australia. shiv.nagaraj@qut.edu.au.
¹⁵ School of Biological/Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD 4000, Australia. shiv.nagaraj@qut.edu.au.
¹⁶ Translational Research Institute, Brisbane, QLD 4102, Australia. shiv.nagaraj@qut.edu.au.
¹⁷ Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059, Australia. e2.thompson@qut.edu.au.
¹⁸ School of Biological/Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD 4000, Australia. e2.thompson@qut.edu.au.
¹⁹ Translational Research Institute, Brisbane, QLD 4102, Australia. e2.thompson@qut.edu.au.
²⁰ Invasion and Metastasis Unit, St. Vincent's Institute, Melbourne, VIC 3065, Australia. e2.thompson@qut.edu.au.

Abstract

Dynamic interconversions between transitional epithelial and mesenchymal states underpin the epithelial mesenchymal plasticity (EMP) seen in some carcinoma cell systems. We have delineated epithelial and mesenchymal subpopulations existing within the PMC42-LA breast cancer cell line by their EpCAM expression. These purified but phenotypically plastic states, EpCAM^High (epithelial) and EpCAM^Low (mesenchymal), have the ability to regain the phenotypic equilibrium of the parental population (i.e., 80% epithelial and 20% mesenchymal) over time, although the rate of reversion in the mesenchymal direction (epithelial-mesenchymal transition; EMT) is higher than that in the epithelial direction (mesenchymal-epithelial transition; MET). Single-cell clonal propagation was implemented to delineate the molecular and cellular features of this intrinsic heterogeneity with respect to EMP flux. The dynamics of the phenotypic proportions of epithelial and mesenchymal states in single-cell generated clones revealed clonal diversity and intrinsic plasticity. Single cell-derived clonal progenies displayed differences in their functional attributes of proliferation, stemness marker (CD44/CD24), migration, invasion and chemo-sensitivity. Interrogation of genomic copy number variations (CNV) with whole exome sequencing (WES) in the context of chromosome count from metaphase spread indicated that chromosomal instability was not influential in driving intrinsic phenotypic plasticity. Overall, these findings reveal the stochastic nature of both the epithelial and mesenchymal subpopulations, and the single cell-derived clones for differential functional attributes.

Keywords: copy number variations (CNV); epithelial-mesenchymal transition (EMT); intratumoral heterogeneity; mesenchymal-epithelial transition (MET); phenotypic plasticity; single cell-derived clones; whole exome sequencing.