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Event: 1457

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Induction, Epithelial Mesenchymal Transition

Short name

The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help

EMT

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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help

Level of Biological Organization
Cellular

Cell term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place. For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable. For individual/population events, the organ context is not applicable. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Organ term

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor). Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help

AOP Name	Role of event in AOP	Point of Contact	Author Status	OECD Status
Latent TGFbeta1 activation leads to pulmonary fibrosis	KeyEvent	Marvin Martens (send email)	Under development: Not open for comment. Do not cite
PPARγ inactivation leading to lung fibrosis	KeyEvent	Jinhee Choi (send email)	Under development: Not open for comment. Do not cite	Under Development
α-diketone-induced bronchiolitis obliterans	KeyEvent	Marvin Martens (send email)	Under development: Not open for comment. Do not cite
TLR4 activation, PPAR gamma activation and Pulmonary fibrosis	KeyEvent	Seokjoo Yoon (send email)	Under development: Not open for comment. Do not cite
AHR activation leading to lung fibrosis via TGF-β dependent fibrosis tox path	KeyEvent	Dianke Yu (send email)	Under development: Not open for comment. Do not cite
AHR activation leading to lung fibrosis via IL-6 tox path	KeyEvent	Dianke Yu (send email)	Under development: Not open for comment. Do not cite
DNA damage and metastatic breast cancer	KeyEvent	Usha Adiga (send email)	Under development: Not open for comment. Do not cite	Under Development

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help

Term	Scientific Term	Evidence	Link
humans	Homo sapiens	High	NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help

Life stage	Evidence
Not Otherwise Specified	Not Specified

Sex Applicability

An indication of the the relevant sex for this KE. More help

Term	Evidence
Unspecific	Not Specified

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

Process:transition of epithelial cells to mesenchymal Object: epithelial cells

Action:increased

Process:transition of epithelial cells to mesenchymal Object: epithelial cells

Action:increased

Biological state

An epithelial-mesenchymal transition (EMT) is a biologic process in which epithelial cells are polarized, interact through their basal surface with basement membrane, and undergo biochemical changes to assume a mesenchymal cell phenotype.

This phenotypic transformation has various characters such as enhanced migratory capacity, high invasiveness, elevated resistance to apoptosis, and greatly increased production of ECM components (Kalluri, R., and Neilson, E.G. 2003). The completion of an EMT is signalled by the degradation of the underlying basement membrane and the formation of a mesenchymal cell that can migrate away from the epithelial layer in which it originated.

EMT has a number of distinct molecular processes like activation of transcription factors, expression of specific cell surface proteins, reorganization and expression of cytoskeletal proteins, production of ECM-degrading enzymes, and changes in the expression of specific microRNAs. These factors are used as biomarkers to demonstrate the passage of a cell through an EMT.

Biological compartment

Cellular

Role in General Biology:

Excessive proliferation of epithelial cells and angiogenesis mark the initiation and early growth of primary epithelial cancers. (Hanahan, D., and Weinberg, R.A. 2000). The subsequent acquisition of invasiveness, initially manifest by invasion through the basement membrane, is thought to herald the onset of the last stages of the multi-step process that leads eventually to metastatic dissemination, with life-threatening consequences. There has been an intense research going on in the genetic controls and biochemical mechanisms underlying the acquisition of the invasive phenotype and the subsequent systemic spread of the cancer cell. Activation of an EMT program has been proposed as the critical mechanism for the acquisition of malignant phenotypes by epithelial cancer cells (Thiery, J.P. 2002).

Pre-clinical experiments such as mice models and cell culture experiments has demonstrated that carcinoma cells can acquire a mesenchymal phenotype and express mesenchymal markers such as α-SMA, FSP1, vimentin, and desmin (Yang, J., and Weinberg, R.A. 2008). These cells are seen at the invasive front of primary tumors and are considered to be the cells that eventually enter into subsequent steps of the invasion-metastasis cascade, i.e., intravasation, transport through the circulation, extravasation, formation of micro metastases, and ultimately colonization (the growth of small colonies into macroscopic metastases) (Thiery, J.P. 2002, Fidler, I.J., and Poste, G. 2008, Brabletz, T., et al. 2001).

An apparent paradox comes from the observation that the EMT-derived migratory cancer cells typically establish secondary colonies at distant sites that resemble, at the histopathological level, the primary tumor from which they arose; accordingly, they no longer exhibit the mesenchymal phenotypes ascribed to metastasizing carcinoma cells. Reconciling this behaviour with the proposed role of EMT as a facilitator of metastatic dissemination requires the additional notion that metastasizing cancer cells must shed their mesenchymal phenotype via a MET during the course of secondary tumor formation (Zeisberg, M et al 2005). The tendency of disseminated cancer cells to undergo EMT likely reflects the local microenvironments that they encounter after extravasation into the parenchyma of a distant organ, quite possibly the absence of the heterotypic signals they experienced in the primary tumor that were responsible for inducing the EMT in the first place (Thiery, J.P. 2002, Jechlinger, M et al 2002, Bissell, M.J et al 2002). These evidences indicate that induction of an EMT is likely to be a centrally important mechanism for the progression of carcinomas to a metastatic stage and implicates MET during the subsequent colonization process. However, many steps of this mechanistic model still require direct experimental validation. It remains unclear at present whether these phenomena and molecular mechanisms relate to and explain the metastatic dissemination of non-epithelial cancer cells.

The entire spectrum of signaling agents that contribute to EMTs of carcinoma cells remains unclear. One theory suggests that the genetic and epigenetic alterations undergone by cancer cells during the course of primary tumor formation render them especially responsive to EMT-inducing heterotypic signals originating in the tumor-associated stroma. Oncogenes induce senescence, and recent studies suggest that cancer cell EMTs may also play a role in preventing senescence induced by oncogenes, thereby facilitating subsequent aggressive dissemination (Smit, M.A., and Peeper, D.S. 2008, Ansieau, S., et al. 2008, Weinberg, R.A. 2008). In the case of many carcinomas, EMT-inducing signals emanating from the tumor-associated stroma, notably HGF, EGF, PDGF, and TGF-β, appear to be responsible for the induction or functional activation in cancer cells of a series of EMT-inducing transcription factors, notably Snail, Slug, zinc finger E-box binding homeobox 1 (ZEB1), Twist, Goosecoid, and FOXC2 (Thiery, J.P. 2002, Jechlinger, M et al 2002, Shi, Y., and Massague, J. 2003, Niessen, K., et al. 2008, Medici, D et al 2008, Kokudo, T., et al. 2008). Once expressed and activated, each of these transcription factors can act pleiotropically to choreograph the complex EMT program, more often than not with the help of other members of this cohort of transcription factors. The actual implementation by these cells of their EMT program depends on a series of intracellular signaling networks involving, among other signal- transducing proteins, ERK, MAPK, PI3K, Akt, Smads, RhoB, β-catenin, lymphoid enhancer binding factor (LEF), Ras, and c-Fos as well as cell surface proteins such as β4 integrins, α5β1 integrin, and αVβ6 integrin (Tse, J.C., and Kalluri, R. 2007). Activation of EMT programs is also facilitated by the disruption of cell-cell adherens junctions and the cell-ECM adhesions mediated by integrins (Yang, J., and Weinberg, R.A. 2008, Weinberg, R.A. 2008, Gupta, P.B et al 2005, Yang, J et al 2006, Mani, S.A., et al. 2007, Mani, S.A., et al. 2008, Hartwell, K.A., et al. 2006, Taki, M et al 2006)..

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

Loss of E-cadherin and cell polarity is considered to be a fundamental event in epithelial-mesenchymal transition. The simultaneous expression of epithelial (e.g. E-cadherin) and mesenchymal markers (e.g. N-cadherin and vimentin) within the airway epithelium are indicative for ongoing transition (Borthwick et al. 2009, 2010).

Method/ measurement referenc

Reliability

Strength of evidence

Assay fit for purpose

Repeatability/ reproducibility

Direct measure

Human cell line

qRT-PCR,cell viability assay,

Western blotting,EdU incorporation assay

Strong

Yes

Human

IHC,micro array,qPCR, SNP array

Moderate

Yes

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided). More help

Regulation of miRNA expression by DNA replication,damage and repair responses,transcription and translation has been proved in animals like mice,canine and cell line experiments.

References

List of the literature that was cited for this KE description. More help

Borthwick, L. A., Parker, S. M., Brougham, K. A., Johnson, G. E., Gorowiec, M. R., Ward, C., … Fisher, A. J. (2009). Epithelial to mesenchymal transition (EMT) and airway remodelling after human lung transplantation. Thorax, 64(9), 770–777. https://doi.org/10.1136/thx.2008.104133

Borthwick, L. A., McIlroy, E. I., Gorowiec, M. R., Brodlie, M., Johnson, G. E., Ward, C., … Fisher, A. J. (2010). Inflammation and epithelial to mesenchymal transition in lung transplant recipients: Role in dysregulated epithelial wound repair. American Journal of Transplantation, 10(3), 498–509. https://doi.org/10.1111/j.1600-6143.2009.02953.x

Al Saleh, S., Al Mulla, F., & Luqmani, Y. A. (2011). Estrogen receptor silencing induces epithelial to mesenchymal transition in human breast cancer cells. PloS one, 6(6), e20610.

Bissell, M. J., Radisky, D. C., Rizki, A., Weaver, V. M., & Petersen, O. W. (2002). The organizing principle: microenvironmental influences in the normal and malignant breast. Differentiation, 70(9-10), 537-546.

Bouris, P., Skandalis, S. S., Piperigkou, Z., Afratis, N., Karamanou, K., Aletras, A. J., ... & Karamanos, N. K. (2015). Estrogen receptor alpha mediates epithelial to mesenchymal transition, expression of specific matrix effectors and functional properties of breast cancer cells. Matrix Biology, 43, 42-60.

Brabletz, T., Jung, A., Reu, S., Porzner, M., Hlubek, F., Kunz-Schughart, L. A., ... & Kirchner, T. (2001). Variable β-catenin expression in colorectal cancers indicates tumor progression driven by the tumor environment. Proceedings of the National Academy of Sciences, 98(18), 10356-10361.

idler, I. J., & Poste, G. (2008). The “seed and soil” hypothesis revisited. The lancet oncology, 9(8), 808.

Gupta, P. B., Mani, S., Yang, J., Hartwell, K., & Weinberg, R. A. (2005, January). The evolving portrait of cancer metastasis. In Cold Spring Harbor symposia on quantitative biology (Vol. 70, pp. 291-297). Cold Spring Harbor Laboratory Press.

Hanahan, D., and Weinberg, R.A. (2000). The hall- marks of cancer. Cell. 100:57–70.

Hartwell, K. A., Muir, B., Reinhardt, F., Carpenter, A. E., Sgroi, D. C., & Weinberg, R. A. (2006). The Spemann organizer gene, Goosecoid, promotes tumor metastasis. Proceedings of the National Academy of Sciences, 103(50), 18969-18974.

Jechlinger, M., Grünert, S., & Beug, H. (2002). Mechanisms in epithelial plasticity and metastasis: insights from 3D cultures and expression profiling. Journal of mammary gland biology and neoplasia, 7(4), 415-432.

Kalluri, R., & Neilson, E. G. (2003). Epithelial-mesenchymal transition and its implications for fibrosis. The Journal of clinical investigation, 112(12), 1776-1784.

Kokudo, T., Suzuki, Y., Yoshimatsu, Y., Yamazaki, T., Watabe, T., & Miyazono, K. (2008). Snail is required for TGFβ-induced endothelial-mesenchymal transition of embryonic stem cell-derived endothelial cells. Journal of cell science, 121(20), 3317-3324. Lin, H. Y., Liang, Y. K., Dou, X. W., Chen, C. F., Wei, X. L., Zeng, D., ... & Zhang, G. J. (2018). Notch3 inhibits epithelial–mesenchymal transition in breast cancer via a novel mechanism, upregulation of GATA-3 expression. Oncogenesis, 7(8), 1-15.

Liu, Y., Liu, R., Fu, P., Du, F., Hong, Y., Yao, M., ... & Zheng, S. (2015). N1-Guanyl-1, 7-diaminoheptane sensitizes estrogen receptor negative breast cancer cells to doxorubicin by preventing epithelial-mesenchymal transition through inhibition of eukaryotic translation initiation factor 5A2 activation. Cellular Physiology and Biochemistry, 36(6), 2494-2503.

Mani, S. A., Yang, J., Brooks, M., Schwaninger, G., Zhou, A., Miura, N., ... & Weinberg, R. A. (2007). Mesenchyme Forkhead 1 (FOXC2) plays a key role in metastasis and is associated with aggressive basal-like breast cancers. Proceedings of the National Academy of Sciences, 104(24), 10069-10074.

Mani, S. A., Guo, W., Liao, M. J., Eaton, E. N., Ayyanan, A., Zhou, A. Y., ... & Weinberg, R. A. (2008). The epithelial-mesenchymal transition generates cells with properties of stem cells. Cell, 133(4), 704-715. Medici, D., Hay, E. D., & Olsen, B. R. (2008). Snail and Slug promote epithelial-mesenchymal transition through β-catenin–T-cell factor-4-dependent expression of transforming growth factor-β3. Molecular biology of the cell, 19(11), 4875-4887.

Niessen, K., Fu, Y., Chang, L., Hoodless, P. A., McFadden, D., & Karsan, A. (2008). Slug is a direct Notch target required for initiation of cardiac cushion cellularization. The Journal of cell biology, 182(2), 315-325.

Shi, Y., & Massagué, J. (2003). Mechanisms of TGF-β signaling from cell membrane to the nucleus. cell, 113(6), 685-700.

Smit, M. A., & Peeper, D. S. (2008). Deregulating EMT and senescence: double impact by a single twist. Cancer cell, 14(1), 5-7.

Taki, M., Verschueren, K., Yokoyama, K., Nagayama, M., & Kamata, N. (2006). Involvement of Ets-1 transcription factor in inducing matrix metalloproteinase-2 expression by epithelial-mesenchymal transition in human squamous carcinoma cells. International journal of oncology, 28(2), 487-496.

Thiery, J. P. (2002). Epithelial–mesenchymal transitions in tumour progression. Nature reviews cancer, 2(6), 442-454.

Tse, J. C., & Kalluri, R. (2007). Mechanisms of metastasis: epithelial‐to‐mesenchymal transition and contribution of tumor microenvironment. Journal of cellular biochemistry, 101(4), 816-829.

Weinberg, R. A. (2008). Twisted epithelial–mesenchymal transition blocks senescence. Nature cell biology, 10(9), 1021-1023.

Wik, E., Ræder, M. B., Krakstad, C., Trovik, J., Birkeland, E., Hoivik, E. A., ... & Salvesen, H. B. (2013). Lack of estrogen receptor-α is associated with epithelial–mesenchymal transition and PI3K alterations in endometrial carcinoma. Clinical Cancer Research, 19(5), 1094-1105.

Yang, J., & Weinberg, R. A. (2008). Epithelial-mesenchymal transition: at the crossroads of development and tumor metastasis. Developmental cell, 14(6), 818-829.

Yang, J., Mani, S. A., & Weinberg, R. A. (2006). Exploring a new twist on tumor metastasis. Cancer research, 66(9), 4549-4552.

Ye, Y., Xiao, Y., Wang, W., Yearsley, K., Gao, J. X., Shetuni, B., & Barsky, S. H. (2010). ERα signaling through slug regulates E-cadherin and EMT. Oncogene, 29(10), 1451-1462.

Zeisberg, M., Shah, A. A., & Kalluri, R. (2005). Bone morphogenic protein-7 induces mesenchymal to epithelial transition in adult renal fibroblasts and facilitates regeneration of injured kidney. Journal of Biological Chemistry, 280(9), 8094-8100.

Zeng, Q., Zhang, P., Wu, Z., Xue, P., Lu, D., Ye, Z., ... & Yan, X. (2014). Quantitative proteomics reveals ER-α involvement in CD146-induced epithelial-mesenchymal transition in breast cancer cells. Journal of proteomics, 103, 153-169.

Zeng, Q., Zhang, P., Wu, Z., Xue, P., Lu, D., Ye, Z., ... & Yan, X. (2014). Quantitative proteomics reveals ER-α involvement in CD146-induced epithelial-mesenchymal transition in breast cancer cells. Journal of proteomics, 103, 153-169.