Structure-function relationships of estrogenic triphenylethylenes related to endoxifen and 4-hydroxytamoxifen

J Med Chem. 2010 Apr 22;53(8):3273-83. doi: 10.1021/jm901907u.


Estrogens can potentially be classified into planar (class I) or nonplanar (class II) categories, which might have biological consequences. 1,1,2-Triphenylethylene (TPE) derivatives were synthesized and evaluated against 17beta-estradiol (E2) for their estrogenic activity in MCF-7 human breast cancer cells. All TPEs were estrogenic and, unlike 4-hydroxytamoxifen (4OHTAM) and Endoxifen, induced cell growth to a level comparable to that of E2. All the TPEs increased ERE activity in MCF-7:WS8 cells with the order of potency as followed: E2 > 1,1-bis(4,4'-hydroxyphenyl)-2-phenylbut-1-ene (15) > 1,1,2-tris(4-hydroxyphenyl)but-1-ene (3) > Z 4-(1-(4-hydroxyphenyl)-1-phenylbut-1-en-2-yl)phenol (7) > E 4-(1-(4-hydroxyphenyl)-1-phenylbut-1-en-2-yl)phenol (6) > Z(4-(1-(4-ethoxyphenyl)-1-(4-hydroxyphenyl)but-1-en-2-yl)phenol (12) > 4-OHTAM. Transient transfection of the ER-negative breast cancer cell line T47D:C4:2 with wild-type ER or D351G ER mutant revealed that all of the TPEs increased ERE activity in the cells expressing the wild-type ER but not the mutant, thus confirming the importance of Asp351 for ER activation by the TPEs. The findings confirm E2 as a class I estrogen and the TPEs as class II estrogens. Using available conformations of the ER liganded with 4OHTAM or diethylstilbestrol, the TPEs optimally occupy the 4OHTAM ER conformation that expresses Asp351.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Binding Sites
  • Breast Neoplasms
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Crystallography, X-Ray
  • Estrogen Antagonists / chemistry*
  • Estrogen Antagonists / pharmacology
  • Estrogens, Non-Steroidal / chemical synthesis
  • Estrogens, Non-Steroidal / chemistry*
  • Estrogens, Non-Steroidal / pharmacology
  • Ethylenes / chemical synthesis
  • Ethylenes / chemistry*
  • Ethylenes / pharmacology
  • Female
  • Humans
  • Models, Molecular
  • Receptors, Estrogen / agonists
  • Stereoisomerism
  • Structure-Activity Relationship
  • Tamoxifen / analogs & derivatives*
  • Tamoxifen / chemical synthesis
  • Tamoxifen / chemistry
  • Tamoxifen / pharmacology


  • Estrogen Antagonists
  • Estrogens, Non-Steroidal
  • Ethylenes
  • Receptors, Estrogen
  • Tamoxifen
  • afimoxifene
  • 4-hydroxy-N-desmethyltamoxifen