Decreased expression of e6-associated protein in breast and prostate carcinomas.
The E6-associated protein (E6-AP) is a dual function protein. It acts as an E3 ubiquitin-protein ligase as well as a steroid hormone receptor coactivator. Considering the influence of steroid hormone receptors and their coactivators in the normal development and tumorigenesis of reproductive organs of both genders, we examined the roles of E6-AP in the tumorigenesis of breast and prostate tissues. We demonstrated that the expression of E6-AP protein is decreased in human invasive breast and prostate carcinomas compared with their adjacent normal tissues, and this down-regulation of E6-AP is accompanied by the up-regulation of estrogen receptor (ER)-alpha in breast and androgen receptor (AR) in prostate carcinomas. Furthermore, our in vivo data from E6-AP-knockout animals indicated that the expression levels of ERalpha and AR are increased in E6-AP-null mammary and prostate glands, respectively, when compared with that of normal control animals, suggesting that E6-AP modulates the protein levels of ERalpha in breast and AR in prostate glands.
Gao
Xiuhua
X
Cancer Center, Criss III, Room 352, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, USA.
Mohsin
Syed K
SK
Gatalica
Zoran
Z
Fu
Guilian
G
Sharma
Poonam
P
Nawaz
Zafar
Z
D000818:Animals; D001943:Breast Neoplasms / Q000737:chemistry*; D002278:Carcinoma in Situ / Q000737:chemistry; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry; D047628:Estrogen Receptor alpha / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D011471:Prostatic Neoplasms / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex / Q000502:physiology; D011944:Receptors, Androgen / Q000032:analysis; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000032:analysis* / Q000502:physiology
D047628:Estrogen Receptor alpha; D011944:Receptors, Androgen; D025801:Ubiquitin; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex