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Brabletz S, Schuhwerk H, Brabletz T, Stemmler MP. Dynamic EMT: a multi-tool for tumor progression. EMBO J 2021; 40:e108647. [PMID: 34459003 PMCID: PMC8441439 DOI: 10.15252/embj.2021108647] [Citation(s) in RCA: 285] [Impact Index Per Article: 95.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/14/2021] [Accepted: 06/29/2021] [Indexed: 12/20/2022] Open
Abstract
The process of epithelial-mesenchymal transition (EMT) is fundamental for embryonic morphogenesis. Cells undergoing it lose epithelial characteristics and integrity, acquire mesenchymal features, and become motile. In cancer, this program is hijacked to confer essential changes in morphology and motility that fuel invasion. In addition, EMT is increasingly understood to orchestrate a large variety of complementary cancer features, such as tumor cell stemness, tumorigenicity, resistance to therapy and adaptation to changes in the microenvironment. In this review, we summarize recent findings related to these various classical and non-classical functions, and introduce EMT as a true tumorigenic multi-tool, involved in many aspects of cancer. We suggest that therapeutic targeting of the EMT process will-if acknowledging these complexities-be a possibility to concurrently interfere with tumor progression on many levels.
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Affiliation(s)
- Simone Brabletz
- Department of Experimental Medicine 1Nikolaus‐Fiebiger Center for Molecular MedicineFriedrich‐Alexander University of Erlangen‐NürnbergErlangenGermany
| | - Harald Schuhwerk
- Department of Experimental Medicine 1Nikolaus‐Fiebiger Center for Molecular MedicineFriedrich‐Alexander University of Erlangen‐NürnbergErlangenGermany
| | - Thomas Brabletz
- Department of Experimental Medicine 1Nikolaus‐Fiebiger Center for Molecular MedicineFriedrich‐Alexander University of Erlangen‐NürnbergErlangenGermany
| | - Marc P. Stemmler
- Department of Experimental Medicine 1Nikolaus‐Fiebiger Center for Molecular MedicineFriedrich‐Alexander University of Erlangen‐NürnbergErlangenGermany
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Redfern AD, Spalding LJ, Thompson EW. The Kraken Wakes: induced EMT as a driver of tumour aggression and poor outcome. Clin Exp Metastasis 2018; 35:285-308. [PMID: 29948647 DOI: 10.1007/s10585-018-9906-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Epithelial mesenchymal transition (EMT) describes the shift of cells from an epithelial form to a contact independent, migratory, mesenchymal form. In cancer the change is linked to invasion and metastasis. Tumour conditions, including hypoxia, acidosis and a range of treatments can trigger EMT, which is implicated in the subsequent development of resistance to those same treatments. Consequently, the degree to which EMT occurs may underpin the entire course of tumour progression and treatment response in a patient. In this review we look past the protective effect of EMT against the initial treatment, to the role of the mesenchymal state, once triggered, in promoting disease growth, spread and future treatment insensitivity. In patients a correlation was found between the propensity of a treatment to induce EMT and failure of that treatment to provide a survival benefit, implicating EMT induction in accelerated tumour progression after treatment cessation. Looking to the mechanisms driving this detrimental effect; increased proliferation, suppressed apoptosis, stem cell induction, augmented angiogenesis, enhanced metastatic dissemination, and immune tolerance, can all result from treatment-induced EMT and could worsen outcome. Evidence also suggests EMT induction with earlier therapies attenuates benefits of later treatments. Looking beyond epithelial tumours, de-differentiation also has therapy-attenuating effects and reversal thereof may yield similar rewards. A range of potential therapies are in development that may address the diverse mechanisms and molecular control systems involved in EMT-induced accelerated progression. Considering the broad reaching effects of mesenchymal shift identified, successful deployment of such treatments could substantially improve patient outcomes.
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Affiliation(s)
- Andrew D Redfern
- School of Medicine, University of Western Australia (UWA), Harry Perkins Building, Fiona Stanley Hospital Campus, Robin Warren Drive, Murdoch, WA, 6150, Australia.
| | - Lisa J Spalding
- School of Medicine, University of Western Australia (UWA), Harry Perkins Building, Fiona Stanley Hospital Campus, Robin Warren Drive, Murdoch, WA, 6150, Australia
| | - Erik W Thompson
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia.,Translational Research Institute, Woolloongabba, Australia.,Department of Surgery, University of Melbourne, Melbourne, Australia
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Herr R, Halbach S, Heizmann M, Busch H, Boerries M, Brummer T. BRAF inhibition upregulates a variety of receptor tyrosine kinases and their downstream effector Gab2 in colorectal cancer cell lines. Oncogene 2018; 37:1576-1593. [PMID: 29326440 DOI: 10.1038/s41388-017-0063-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/30/2017] [Accepted: 11/19/2017] [Indexed: 12/28/2022]
Abstract
BRAF mutations occur in ~10% of colorectal cancer (CRC) and are associated with poor prognosis. Inhibitors selective for the BRAFV600E oncoprotein, the most common BRAF mutant, elicit only poor response rates in BRAF-mutant CRC as single agents. This unresponsiveness was mechanistically attributed to the loss of negative feedbacks on the epidermal growth factor receptor (EGFR) and initiated clinical trials that combine BRAF (and MEK) inhibitors, either singly or in combination, with the anti-EGFR antibodies cetuximab or panitumumab. First results of these combinatorial studies demonstrated improved efficacy, however, the response rates still were heterogeneous. Here, we show that BRAF inhibition leads to the upregulation of a variety of receptor tyrosine kinases (RTKs) in CRC cell lines, including not only the EGFR, but also human epidermal growth factor receptor (HER) 2 and HER3. Importantly, combination of the BRAF inhibitors (BRAFi) vemurafenib (PLX4032), dabrafenib, or encorafenib with inhibitors dually targeting the EGFR and HER2 (such as lapatinib, canertinib, and afatinib) significantly reduced the metabolic activity and proliferative potential of CRC cells. This re-sensitization was also observed after genetic depletion of HER2 or HER3. Interestingly, BRAF inhibitors did not only upregulate RTKs, but also increased the abundance of the GRB2-associated binders (Gab) 1 and Gab2, two important amplifiers of RTK signaling. An allele-specific shRNA-mediated knockdown of BRAFV600E revealed that Gab2 upregulation was directly dependent on the loss of the oncoprotein and was not caused by an "off-target" effect of these kinase inhibitors. Furthermore, Gab2 and Gab2-mediated Shp2 signaling were shown to be functionally important in BRAFi resistance. These findings highlight potential new escape mechanisms to these targeted therapies and indicate that a broad suppression of RTK signaling might be beneficial and should be taken into account in future research addressing targeted therapy in BRAF-mutant CRC.
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Affiliation(s)
- Ricarda Herr
- Signal Transduction in Tumour Development and Drug Resistance Group, Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Sebastian Halbach
- Signal Transduction in Tumour Development and Drug Resistance Group, Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Miriam Heizmann
- Signal Transduction in Tumour Development and Drug Resistance Group, Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Hauke Busch
- Systems Biology of the Cellular Microenvironment, IMMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Experimental Dermatology and Institute of Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Melanie Boerries
- Systems Biology of the Cellular Microenvironment, IMMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Comprehensive Cancer Centre Freiburg (CCCF), University of Freiburg, Freiburg, Germany
| | - Tilman Brummer
- Signal Transduction in Tumour Development and Drug Resistance Group, Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,Comprehensive Cancer Centre Freiburg (CCCF), University of Freiburg, Freiburg, Germany. .,Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany.
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