The effects of α-zearalanol and estradiol benzoate on expression of c-myc, c-fos and epidermal growth factor receptor mRNAs in breast tissues implanted into nude mice.
This study was designed to evaluate the effects of a novel phytoestrogen, α-zearalanol (α-ZAL), and estradiol benzoate (B-E₂), on c-myc, c-fos, and EGFR expression in normal human breast tissues implanted into nude mice. A xenograft-model, pieces of normal human breast tissue implanted subcutaneously into 9-10-week-old athymic nude mice, was established. The mice were divided into five groups subjected to the following treatments: normal saline (Controls); α-ZAL at 1 and 5 mg/kg; and estradiol benzoate (B-E₂) at 1 and 5 mg/kg. Treatment was given every other day, and human breast tissues were removed for experiments after treatment for 30 days. The expression of c-myc, c-fos, and EGFR mRNAs were determined by in situ hybridization. α-ZAL decreased expression of c-myc (p < 0.05). About 1 mg/kg α-ZAL increased EGFR expression (p < 0.05) and two dosage of α-ZAL increased c-fos expression (p < 0.01) compared with control. B-E₂ significantly increased expression of c-myc, c-fos, and EGFR mRNAs expression compared with controls (p < 0.01). The extents of the increases in EGFRmRNA expression induced by α-ZAL and in c-fos mRNA by 5 mg/kg α-ZAL were lower than those induced by B-E₂ (p < 0.01). These data suggest that the phytoestrogen α-ZAL may be safer than estrogen on breast.
Deng
Wenhui
W
Department of Gynecology and Obstetrics, Beijing Hospital, Beijing, China. dengwenhui@hotmail.com
Dai
Shunling
S
Zhang
Yi
Y
Duan
Jinhong
J
Wu
Yiyong
Y
D000818:Animals; D001940:Breast / Q000187:drug effects* / Q000378:metabolism; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D048789:Phytoestrogens / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D020598:Proto-Oncogene Proteins c-myb / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015029:Zeranol / Q000494:pharmacology*
D048789:Phytoestrogens; D016760:Proto-Oncogene Proteins c-fos; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger; C074283:estradiol 3-benzoate; D004958:Estradiol; D015029:Zeranol; C512478:EGFR protein, human; D066246:ErbB Receptors