Anti-proliferative and anti-estrogenic effects of ICI 164,384 and ICI 182,780 in 4-OH-tamoxifen-resistant human breast-cancer cells.
The effects of the anti-estrogens 4-hydroxytamoxifen (OHTam), ICI 164,384 and ICI 182,780 were tested on the MCF-7/LCC2 breast-carcinoma cell line, which grows significantly in the presence of OHTam and serves as a model for studying anti-estrogen resistance of estrogen-receptor-positive breast cancer. Cell proliferation and cathepsin-D secretion were strongly inhibited by either ICI 182,780 or ICI 164,384 alone or ICI 164,384 in combination with 17-beta-estradiol (E2) or OHTam. ICI 164,384 alone did not affect the cathepsin-D and pS2 mRNA levels, but antagonized the stimulatory effects of E2 or OHTam on these 2 mRNAs. OHTam was more effective than E2 in increasing cathepsin-D mRNA levels, supporting the idea that anti-estrogen-resistant breast cancer continues to overexpress cathepsin-D. These data show that the steroidal anti-estrogens ICI 164,384 and ICI 182,780 retain their ability to inhibit cell proliferation and the estrogen-responsiveness of cathepsin-D and pS2 genes in the OHTam-resistant MCF-7/LCC2 cell lines. These pure anti-estrogens may thus be efficient second-line treatments of some Tamoxifen-resistant tumors.
Coopman
P
P
Unit Hormones and Cancer, INSERM U148, Montpellier, France.
Garcia
M
M
Brünner
N
N
Derocq
D
D
Clarke
R
R
Rochefort
H
H
D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000648:ultrastructure; D002402:Cathepsin D / Q000235:genetics; D002455:Cell Division / Q000187:drug effects; D004351:Drug Resistance; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology / Q000502:physiology; D000077267:Fulvestrant; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000473:pathology / Q000648:ultrastructure; D053284:Polyunsaturated Alkamides; D011506:Proteins; D011960:Receptors, Estrogen / Q000502:physiology; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000071163:Trefoil Factor-1; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D000970:Antineoplastic Agents; D004965:Estrogen Antagonists; D004967:Estrogens; D009363:Neoplasm Proteins; D053284:Polyunsaturated Alkamides; D011506:Proteins; D011960:Receptors, Estrogen; C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D013629:Tamoxifen; C016601:afimoxifene; D000077267:Fulvestrant; D004958:Estradiol; C051781:ICI 164384; D002402:Cathepsin D