7JHD

Estrogen Receptor Alpha Ligand Binding Domain Y537S in Complex with TTC-352 and GRIP Peptide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.225 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Rapid Induction of the Unfolded Protein Response and Apoptosis by Estrogen Mimic TTC-352 for the Treatment of Endocrine-Resistant Breast Cancer.

Abderrahman, B.Maximov, P.Y.Curpan, R.F.Fanning, S.W.Hanspal, J.S.Fan, P.Foulds, C.E.Chen, Y.Malovannaya, A.Jain, A.Xiong, R.Greene, G.L.Tonetti, D.A.Thatcher, G.R.J.Jordan, V.C.

(2021) Mol Cancer Ther 20: 11-25

  • DOI: https://doi.org/10.1158/1535-7163.MCT-20-0563
  • Primary Citation of Related Structures:  
    7JHD

  • PubMed Abstract: 

    Patients with long-term estrogen-deprived breast cancer, after resistance to tamoxifen or aromatase inhibitors develops, can experience tumor regression when treated with estrogens. Estrogen's antitumor effect is attributed to apoptosis via the estrogen receptor (ER). Estrogen treatment can have unpleasant gynecologic and nongynecologic adverse events; thus, the development of safer estrogenic agents remains a clinical priority. Here, we study synthetic selective estrogen mimics (SEM) BMI-135 and TTC-352, and the naturally occurring estrogen estetrol (E 4 ), which are proposed as safer estrogenic agents compared with 17β-estradiol (E 2 ), for the treatment of endocrine-resistant breast cancer. TTC-352 and E 4 are being evaluated in breast cancer clinical trials. Cell viability assays, real-time PCR, immunoblotting, ERE DNA pulldowns, mass spectrometry, X-ray crystallography, docking and molecular dynamic simulations, live cell imaging, and Annexin V staining were conducted in 11 biologically different breast cancer models. Results were compared with the potent full agonist E 2 , less potent full agonist E 4 , the benchmark partial agonist triphenylethylene bisphenol (BPTPE), and antagonists 4-hydroxytamoxifen and endoxifen. We report ERα's regulation and coregulators' binding profiles with SEMs and E 4 We describe TTC-352's pharmacology as a weak full agonist and antitumor molecular mechanisms. This study highlights TTC-352's benzothiophene scaffold that yields an H-bond with Glu353, which allows Asp351-to-helix 12 (H12) interaction, sealing ERα's ligand-binding domain, recruiting E 2 -enriched coactivators, and triggering rapid ERα-induced unfolded protein response (UPR) and apoptosis, as the basis of its anticancer properties. BPTPE's phenolic OH yields an H-Bond with Thr347, which disrupts Asp351-to-H12 interaction, delaying UPR and apoptosis and increasing clonal evolution risk.


  • Organizational Affiliation

    Department of Breast Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Estrogen receptor
A, B
251Homo sapiensMutation(s): 1 
Gene Names: ESR1ESRNR3A1
UniProt & NIH Common Fund Data Resources
Find proteins for P03372 (Homo sapiens)
Explore P03372 
Go to UniProtKB:  P03372
PHAROS:  P03372
GTEx:  ENSG00000091831 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP03372
Sequence Annotations
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  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Nuclear receptor coactivator 2
C, D
13Homo sapiensMutation(s): 0 
Gene Names: NCOA2BHLHE75SRC2TIF2
UniProt & NIH Common Fund Data Resources
Find proteins for Q15596 (Homo sapiens)
Explore Q15596 
Go to UniProtKB:  Q15596
PHAROS:  Q15596
GTEx:  ENSG00000140396 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ15596
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.225 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.03α = 90
b = 82.436β = 110.75
c = 58.677γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-3000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-11-25
    Type: Initial release
  • Version 1.1: 2021-01-20
    Changes: Database references
  • Version 1.2: 2021-02-10
    Changes: Derived calculations
  • Version 1.3: 2023-10-18
    Changes: Data collection, Database references, Refinement description