Effect of 4-hydroxytamoxifen isomers on growth and ultrastructural aspects of normal human breast epithelial (HBE) cells in culture.
In the search for a breast cancer prevention strategy which would avoid undesirable effects of orally administered tamoxifen, the percutaneous administration of the highly active metabolite 4OHTamoxifen (4OHTam) has been proposed. Percutaneous 4OHTam penetrates the skin to reach breast tissues. It, thus, avoids the hepatic first pass effect, and offers an optimal local/systemic effect. However, trans-4OHTamoxifen can spontaneously isomerize into the cis-isomer, which may have estrogen agonist action. The aim of this study was to examine the effect of cis-4OHTam on normal human breast epithelial (HBE) cells in culture. Spontaneous isomerization of trans- into cis-4OHTam occurred within 24-48h, but stabilized rapidly at a trans/cis ratio of 70/30, whether in stock solution, culture medium or cultured cells. The cis-4OHTam did not stimulate HBE cell growth according to histometric cell counts and scanning electron microscopy analysis, but inhibited E(2)-induced cell growth, albeit two to three times less than trans-4OHTam. In conclusion, spontaneous isomerization of trans- to cis-4-OHTam is limited and 4OHTam retains a marked antiestrogenic effect. It may prove to be a useful alternative to tamoxifen in breast cancer prevention, especially if administered percutaneously.
Malet
Catherine
C
Department of Endocrinology and Reproductive Medicine, Hôpital Necker, 149 rue de Sèvres, 75743 Paris Cedex 15, France.
Spritzer
Poli
P
Cumins
Caroline
C
Guillaumin
Delhy
D
Mauvais-Jarvis
Pierre
P
Kuttenn
Frédérique
F
D001940:Breast / Q000187:drug effects* / Q000648:ultrastructure; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects* / Q000648:ultrastructure*; D004958:Estradiol / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D013237:Stereoisomerism; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
D004965:Estrogen Antagonists; D013629:Tamoxifen; C016601:afimoxifene; D004958:Estradiol; D013936:Thymidine