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Cell Commun Signal. 2015 May 15;13:26. doi: 10.1186/s12964-015-0106-x.

Stimulus-dependent differences in signalling regulate epithelial-mesenchymal plasticity and change the effects of drugs in breast cancer cell lines.

Author information

1
Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Building 193, Parkville, VIC, 3010, Australia. joseph.cursons@unimelb.edu.au.
2
ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Melbourne School of Engineering, University of Melbourne, Parkville, VIC, 3010, Australia. joseph.cursons@unimelb.edu.au.
3
The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia. leuchowius@wehi.edu.au.
4
Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia. leuchowius@wehi.edu.au.
5
St. Vincent's Institute, Melbourne, VIC, Australia. mwaltham@unimelb.edu.au.
6
St. Vincent's Institute, Melbourne, VIC, Australia. evatc@uow.edu.au.
7
Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Building 193, Parkville, VIC, 3010, Australia. mforoutan@student.unimelb.edu.au.
8
Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, 5000, Australia. Cameron.Bracken@health.sa.gov.au.
9
Discipline of Medicine, University of Adelaide, Adelaide, SA, 5005, Australia. Cameron.Bracken@health.sa.gov.au.
10
Royal Perth Hospital, Perth, Australia. Andrew.Redfern@health.wa.gov.au.
11
Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Building 193, Parkville, VIC, 3010, Australia. edmund.crampin@unimelb.edu.au.
12
ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Melbourne School of Engineering, University of Melbourne, Parkville, VIC, 3010, Australia. edmund.crampin@unimelb.edu.au.
13
School of Mathematics and Statistics, Faculty of Science, University of Melbourne, Parkville, VIC, 3010, Australia. edmund.crampin@unimelb.edu.au.
14
School of Medicine, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, 3010, Australia. edmund.crampin@unimelb.edu.au.
15
The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia. istreet@wehi.EDU.AU.
16
Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia. istreet@wehi.EDU.AU.
17
Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Building 193, Parkville, VIC, 3010, Australia. melissa.davis@unimelb.edu.au.
18
St. Vincent's Institute, Melbourne, VIC, Australia. e2.thompson@qut.edu.au.
19
Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland Institute of Technology, Brisbane, Australia. e2.thompson@qut.edu.au.
20
University of Melbourne Department of Surgery, St. Vincent's Hospital, Melbourne, Australia. e2.thompson@qut.edu.au.

Abstract

INTRODUCTION:

The normal process of epithelial mesenchymal transition (EMT) is subverted by carcinoma cells to facilitate metastatic spread. Cancer cells rarely undergo a full conversion to the mesenchymal phenotype, and instead adopt positions along the epithelial-mesenchymal axis, a propensity we refer to as epithelial mesenchymal plasticity (EMP). EMP is associated with increased risk of metastasis in breast cancer and consequent poor prognosis. Drivers towards the mesenchymal state in malignant cells include growth factor stimulation or exposure to hypoxic conditions.

METHODS:

We have examined EMP in two cell line models of breast cancer: the PMC42 system (PMC42-ET and PMC42-LA sublines) and MDA-MB-468 cells. Transition to a mesenchymal phenotype was induced across all three cell lines using epidermal growth factor (EGF) stimulation, and in MDA-MB-468 cells by hypoxia. We used RNA sequencing to identify gene expression changes that occur as cells transition to a more-mesenchymal phenotype, and identified the cell signalling pathways regulated across these experimental systems. We then used inhibitors to modulate signalling through these pathways, verifying the conclusions of our transcriptomic analysis.

RESULTS:

We found that EGF and hypoxia both drive MDA-MB-468 cells to phenotypically similar mesenchymal states. Comparing the transcriptional response to EGF and hypoxia, we have identified differences in the cellular signalling pathways that mediate, and are influenced by, EMT. Significant differences were observed for a number of important cellular signalling components previously implicated in EMT, such as HBEGF and VEGFA. We have shown that EGF- and hypoxia-induced transitions respond differently to treatment with chemical inhibitors (presented individually and in combinations) in these breast cancer cells. Unexpectedly, MDA-MB-468 cells grown under hypoxic growth conditions became even more mesenchymal following exposure to certain kinase inhibitors that prevent growth-factor induced EMT, including the mTOR inhibitor everolimus and the AKT1/2/3 inhibitor AZD5363.

CONCLUSIONS:

While resulting in a common phenotype, EGF and hypoxia induced subtly different signalling systems in breast cancer cells. Our findings have important implications for the use of kinase inhibitor-based therapeutic interventions in breast cancers, where these heterogeneous signalling landscapes will influence the therapeutic response.

PMID:
25975820
PMCID:
PMC4432969
DOI:
10.1186/s12964-015-0106-x
[Indexed for MEDLINE]
Free PMC Article

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