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Relationship: 2969

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Activation, estrogen receptor alpha leads to Epigenetic modification process

Upstream event

The causing Key Event (KE) in a Key Event Relationship (KER). More help

Activation, estrogen receptor alpha

Downstream event

The responding Key Event (KE) in a Key Event Relationship (KER). More help

Epigenetic modification process

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name	Adjacency	Weight of Evidence	Quantitative Understanding	Point of Contact	Author Status	OECD Status
Activation of uterine estrogen receptor-alfa leading to endometrial adenocarcinoma, via epigenetic modulation	adjacent			Barbara Viviani (send email)	Under development: Not open for comment. Do not cite	Under Review

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 KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER. More help

Term	Scientific Term	Evidence	Link
Vertebrates	Vertebrates		NCBI

Sex Applicability

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

Sex	Evidence
Female

Life Stage Applicability

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

Term	Evidence
All life stages

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

ERa is one of the receptor-recruited by 17β-estradiol (E2) able to influences a wide range of biological phenomena, from fertility to memory formation (Dahlman-Wright et al., 2006). Ligand-activated ERα interacts with the estrogen responsive elements (EREs) on the DNA, in turn inducing or repressing gene transcription. Transcriptional regulation is ruled by the interaction with coregulators that can enhance or decrease the transcriptional activity. Coregulators such as p300/CBP and CARM1 may affect chromatin modification and remodelling through epigenetic activity (Liang & Shang, 2013). In addition, for several target genes the specific mechanisms by which E2 regulates their expression remains unknown because they lack canonical EREs in the promoter. It has thus been hypothesized that besides the classical genomic action through ERE E2 may regulate gene expression downstream to the activation of epigenetic mechanisms.

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings. Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

The development of the KER is based on a systematic review (EFSA 2010) of records:

- retrieved after ad hoc combinations of search terms with relevance to the field of epigenetics, DNA repair and accumulation of mutations

- selected for their link to the epigenetic regulation in a context of endometrial uterine adenocarcinoma

- appraised for Risk of Bias (RoB) according to OHAT/NTP

Results concerning human, in vivo and in vitro lines of evidence have been taken into account. Empirical evidence, essentiality and concordance table have been derived from records with Tier 1 and Tier 2 RoB or Tier 3 RoB but presenting evidence on three (human, in vivo and in vitro) or two lines of evidence (human and in vitro, human and in vivo or in vivo and in vitro) unless specified.

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

Biological Plausibility

Addresses the biological rationale for a connection between KEupstream and KEdownstream. This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured. More help

The transcriptional activity of ERα is based on the recruitment of several coregulators, that are able to interact with the transcription machinery or to modify the chromatin (Liang & Shang, 2013). Some of these coregulators belong to the SRCs family, which include SRC-1, 2 and 3 (Li & Shang, 2007). These proteins recruit coactivators that are involved in epigenetic mechanisms, modifying chromatin and/or histones (Liang & Shang, 2013). SRCs are also characterized by a weak activity as histone acetyltransferases (Spencer et al., 1997; Chen et al., 1997). The three SRCs members recruit distinct coactivators, leading to a fine regulation of ER activity (Liang et al., 2009). One important coregulator, with epigenetic activity is CARM1 (coactivator-associated arginine methyltransferase 1), which is able to dimethylate arginine residues on histone H3 and histone acetyltransferases (Schurter et al., 2001; Chevillard-Briet et al., 2002), therefore regulating gene transcription mediated by ERα.

Human specimens of endometrial adenocarcinoma positive for ER-a display altered transcript levels of enzymes that catalyzes the transfer of methyl groups to DNA or histones. Both up-regulation and down-regulation have been observed in relation to the methylating enzymes. mRNA expression of DNMT1 increases (Simmons et al. 2011) while a decrease is observed in RIZ-1 mRNA (Yang et al. 2017). The decrease of RIZ-1 observed in human specimens is paralleled in endometrial carcinoma cell lines expressing ER-a compared to primary normal endometrial epithelial cells (Yang et al. 2017). A decreased expression of specific histone deacetylase (HDAC3 but not HDAC6 and 9) has also been reported (Simmons et al., 2011).

RIZ1 (retinoblastoma-interacting zinc-finger 1) is a member of the nuclear protein methyltransferase superfamily with a role in transcriptional repression (Steele-Perkins et al. 2001, Derunes et al. 2005, Du et al. 2001). Several human cancers are characterized by RIZ1 silencing or frameshift mutations, therefore suggesting its role as tumor suppressor (Piao et al., 2000; Sakurada et al., 2000; Steele-Perkins et al. 2001; Cheng et al., 2010). The ability of estradiol-ER to bind to RIZ protein has been demonstrated in MCF-7 cells (Abbondanza et al., 2000). ER binds RIZ through the AF-2 domain once linked to estrogens and RIZ, in addition to the ability to bind to Rb protein, therefore being involved estradiol-mediated proliferation and growth (Abbondanza et al., 2000), it is also involved in the methyltransferase activity on histone H3 (lysine 9) (Kim et al., 2003), inducing therefore transcriptional repression. The expression of RIZ-1 significantly decreases in tissues from endometrial cancer patients and in endometrial cancer cell lines positive for ER-a (Yang et al. 2017).

Empirical Evidence

Provides specific (citable) evidence that supports the idea of a change in the upstream KE (KEupstream) leading to, or being associated with, a subsequent change in the downstream KE (KEdownstream), assuming the perturbation of KEupstream is sufficient. More help

According to the selected criteria of inclusion, large part of the empirical evidence supporting this KER come for in vitro studies in human cancer cell lines mainly addressing hypomethylation (Pandey et al. 2017; Yang et al., 2017) and 1 study performed in vivo a standard 3-day uterotrophic assay (Zierau et al. 2018). These observations suggest the coexistence of different epigenetic mechanisms activated by E2. TAM acts for the factors investigated similarly to E2.

Methylation – In vitro evidences

Pandey et al. 2017 - TAM (0.01-100 mM) dose-dependently increases Trefoil factor 3 (TFF3) promoter activity in ER-α + (Ishikawa and ECC-1) but not ER-α - (RL95/AN3). In addition, increasing concentrations of TAM (0.1-100 mM) increases luminescence in an estrogen response element reporter assay. TAM (5mM)-stimulated upregulation of TFF3 through hypomethylation of its proximal promoter region corresponding to binding sites for the transcription factors c-JUN and SP1.

Yang et al. 2017 - The role of RIZ1 in endometrial cancer was investigated. Endometrial epithelial cancer cells display a reduced expression of the methylase RIZ-1 compared to control endometrial epithelial cells, which is further decreased in RL95-2 or Ishikawa cells (expressing ER-a) treated with 1 or 0.1 mM E2 respectively (decrease mRNA at 7h; decrease protein at 48h ).

miRNA and LncRNA – in vivo and in vitro evidence

Zierau et al. 2018 investigated miRNA expression in uterine samples from a standard 3-day uterotrophic assay using young female adult Lewis rats to identify E2-regulated miRNAs. Microarray analysis identified 47 E2 down-regulated miRNAs including miR-30a, and 25 E2-up-regulated miRNAs including miR-672, miR-203, and miR-146b, after 24h from the last treatment of Lewis rat with E2 4mg/kg bw s.c. E2-upregulated miR-203 was selected for further analysis.

Harekrushna et al. 2012 (1418) – Exposure of Ishikawa cells at 0.01 mM did not affected the expression of miR-200c after 24h

Essentiality

Pandey et al. 2017 - (TFF3) promoter activity triggered by TAM is evident only in ER-α + (Ishikawa and ECC-1) but not ER-α - (RL95/AN3).

Yang et al. 2017 – Overexpression of ER-a significantly decreased RIZ-1 expression (mRNA and protein) and ER-a silencing increased it (mRNA and protein) in both in RL95-2 or Ishikawa cells. Accordingly, RIZ-1 increased expression (mRNA and protein) is observed in RL95-2 or Ishikawa cells exposed to 1mM ICI 182780, an ER-a selective antagonist.

Uncertainties and Inconsistencies

Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

RIZ-1 decreased expression is also evident in SPEC2 (Serous Papillary Endometrial Carcinoma-2) (Yang et al. 2017) considered representative of type II (ER insensitive) endometrial adenocarcinoma (Van Nyen et al. 2018).

Pandey et al. 2017: time of exposure of cells to TAM is not clear

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references. More help

Quantitative Understanding of the Linkage

Captures information that helps to define how much change in the upstream KE, and/or for how long, is needed to elicit a detectable and defined change in the downstream KE. More help

A quantitative relationship has been established between E2 or Tamoxifen inducing ERa activation and epigenetic modulation. ERa activation for both TAM and E2 is inferred by the indirect transcription of genes under the control of estrogen responsive element (ERE), a specific DNA sequence found in the regulatory region of genes under estrogenic control. At a concentration between 0.01-100 mM TAM was shown to increase the promoter activity of TFF3 (trefoil factor, promoting proliferation) which include an ERE. Increased hypomethylation of TFF3 is observed at TAM 5 mM (Pandey et al. 2017).

EC50 or PC50 (50 % of the response induced by the positive control: E2, 1nM) of E2 in the transactivation (ERa) assay (TG 455) is 5.63 ´ 10^-12 M (BG1Luc ER TA Assays) and <1.00 × 10^-11 M (Stably Transfected TA assay (STTA) using the (h) ERα-HeLa-9903), respectively.

In vivo, E2 4mg/kg per day increases miR-203 in rat uterine samples after 4 days from the exposure (Zierau et al. 2017).

In endometrial cancer cells, E2 reduces the expression of the methyltransferase RIZ-1 at 1mM in RL95-2 cells and at 0.1 mM in Ishikawa cells.

No dose response is available related to epigenetic modulation.

Time concordance: all studies were conducted at a single evaluation time point. Hypomethylation of TFFR promoter was observed after 48h treatment (Pandey et al. 2017), reduction of the methyltransferase RIZ-1 expression was observed after 7h for mRNA and 48h for the protein (Yang et al. 2017).

Response-response Relationship

Provides sources of data that define the response-response relationships between the KEs. More help

Time-scale

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help

Known Feedforward/Feedback loops influencing this KER

Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

References

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

Abbondanza, C., Medici, N., Nigro, V., Rossi, V., Gallo, L., Piluso, G., Belsito, A., Roscigno, A., Bontempo, P., Puca, A. A., Molinari, A. M., Moncharmont, B., & Puca, G. A. (2000). The retinoblastoma interacting zinc-finger protein RIZ is a downstream effector of estrogen action. Proceedings of the National Academy of Sciences of the United States of America, 97(7), 3130–3135. https://doi.org/10.1073/pnas.97.7.3130

Chen H, Lin RJ, Schiltz RL, Chakravarti D, Nash A, et al. 1997. Nuclear receptor coactivator ACTR is a novel histone acetyltransferase and forms a multimeric activation complex with P/CAF and CBP/p300. Cell 90: 569–80

Cheng, H. Y., Gao, Y., & Lou, G. (2010). DNA methylation of the RIZ1 tumor suppressor gene plays an important role in the tumorigenesis of cervical cancer. European journal of medical research, 15(1), 20–24. https://doi.org/10.1186/2047-783x-15-1-20

Chevillard-Briet M, Trouche D, Vandel L. 2002. Control of CBP co-activating activity by arginine methylation. EMBO J. 21: 5457–66

Dahlman-Wright, K.; Cavailles, V.; Fuqua, S.A.; Jordan, V.C.; Katzenellenbogen, J.A.; Korach, K.S.; Maggi, A.; Muramatsu, M.; Parker, M.G.; Gustafsson, J.A. International Union of Pharmacology. LXIV. Estrogen receptors. Pharmacol. Rev. 2006, 58, 773–781.

Derunes C., K. Briknarova, L. Geng, S. Li, C.R. Gessner, K. Hewitt, S. Wu, S. Huang, V.I. Woods Jr., K.R. Ely, Characterization of the PR domain of RIZ1 histone methyltransferase, Biochem. Biophys. Res. Commun. 333 (2005) 925e934.

Du Y., T. Carling, W. Fang, Z. Piao, J.C. Sheu, S. Huang, Hypermethylation in human cancers of the RIZ1 tumor suppressor gene, a member of a histone/ protein methyltransferase superfamily, Cancer Res. 61 (2001) 8094e8099.

EFSA, (2010). Application of systematic review methodology to food and feed safety assessments to support decision making: EFSA Guidance for those carrying out systematic reviews. EFSA Journal 8(6): 1637 (90p.)

Liang J, Zhang H, Zhang Y, Zhang Y, Shang Y. 2009. GAS, a new glutamate-rich protein, interacts differentially with SRCs and is involved in oestrogen receptor function. EMBO Rep. 10: 51–57

Liang, J., & Shang, Y. (2013). Estrogen and cancer. Annual review of physiology, 75, 225–240. https://doi.org/10.1146/annurev-physiol-030212-183708

OHAT/NTP https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/handbook/index.html

Pandey V., Zhang M., Chong Q., You M., Rushdiana Raquib A., Pandey A. K., Liu D., Liu L., Ma L., Jha S., Wu Z., Zhu T., Lobie P. E. et al Hypomethylation associated enhanced transcription of trefoil factor-3 mediates tamoxifen-stimulated oncogenicity of ER+ endometrial carcinoma cells. Oncotarget. 2017; 8: 77268-77291. Retrieved from https://www.oncotarget.com/article/20461/

Piao Z, Fang W, Malkhosyan S, Kim H, Horii A, Perucho M, Huang S. Frequent frameshift mutations of RIZ in human gastrointestinal and endometrial carcinomas with microsatellite instability. Cancer Res. 2000;60:4701–4704.

Sakurada K, Furukawa T, Kato Y, Kayama T, Huang S, Horii A. RIZ, the retinoblastoma protein interacting zinc finger gene, is mutated in genetically unstable cancers of the pancreas, stomach, and colorectum. Genes Chromosomes Cancer. 2001;30:207–211.

Simmons CD, Pabona JM, Heard ME, Friedman TM, Spataro MT, Godley AL, Simmen FA, Burnett AF, Simmen RC. Krüppel-like factor 9 loss-of-expression in human endometrial carcinoma links altered expression of growth-regulatory genes with aberrant proliferative response to estrogen. Biol Reprod. 2011 Aug;85(2):378-85. doi: 10.1095/biolreprod.110.090654. Epub 2011 May 4. PMID: 21543766; PMCID: PMC3142261.

Schurter BT, Koh SS, Chen D, Bunick GJ, Harp JM, et al. 2001. Methylation of histone H3 by coactivator-associated arginine methyltransferase 1. Biochemistry 40: 5747–56

Spencer TE, Jenster G, Burcin MM, Allis CD, Zhou J, et al. 1997. Steroid receptor coactivator-1 is a histone acetyltransferase. Nature 389: 194–98

Steele-Perkins G.,W.Fang,X.H.Yang,M.VanGele,T.Carling,J.Gu,I.M.Buyse, J.A. Fletcher, J. Liu, R. Bronson, R.B. Chadwick, A. de la Chapelle, X. Zhang, F. Speleman, S. Huang, Tumor formation and inactivation of RIZ1, an Rb- binding member of a nuclear protein-methyltransferase superfamily, Genes Dev. 15 (2001) 2250e2262.

Van Nyen T, Moiola CP, Colas E, Annibali D, Amant F. Modeling Endometrial Cancer: Past, Present, and Future. International Journal of Molecular Sciences. 2018; 19(8):2348. https://doi.org/10.3390/ijms19082348

Yang T, Ren C, Jiang A, Yu Z, Li G, Wang G, Zhang Q. RIZ1 is regulated by estrogen and suppresses tumor progression in endometrial cancer. Biochem Biophys Res Commun. 2017 Jul 22;489(2):96-102. doi: 10.1016/j.bbrc.2017.05.095. Epub 2017 May 18. PMID: 28528974.

Zierau O, Helle J, Schadyew S, Morgenroth Y, Bentler M, Hennig A, Chittur S, Tenniswood M, Kretzschmar G. Role of miR-203 in estrogen receptor-mediated signaling in the rat uterus and endometrial carcinoma. J Cell Biochem. 2018 Jul;119(7):5359-5372. doi: 10.1002/jcb.26675. Epub 2018 Mar 14. PMID: 29331043.