Lazennec G, Alcorn J L, Katzenellenbogen B S
Department of Molecular and Integrative Physiology, University of Illinois, Urbana 61801-3704, USA.
Mol Endocrinol. 1999 Jun;13(6):969-80. doi: 10.1210/mend.13.6.0318.
Dominant negative estrogen receptors are transcriptionally inactive, altered forms of the estrogen receptor (ER) that can dimerize with the ER and have the potential to inactivate the biological functions of this receptor. Here, we provide the first report that adenoviral delivery of a dominant negative ER to ER-positive breast cancer cells is able to effectively suppress estrogen-stimulated cell proliferation and the hormonal induction of endogenous genes. We constructed recombinant adenoviral vectors expressing a dominant negative ER (S554 fs, Ad-fs) or, for comparison, antisense ER (Ad-AS), or the sense wild-type ER (Ad-WT). Expression of the dominant negative ER or antisense ER, but not wild-type ER, blocked estradiol stimulation of the estrogen-responsive genes pS2 and c-myc. The dominant negative ER also fully abolished the estradiol-induced increase in proliferation of MCF-7 breast cancer cells, as did the antisense ER. The antiproliferative effects of the dominant negative and antisense ERs are explained by an increase in the number of cells in the G0/G1 stage of the cell cycle and decrease in the number of cells in G2/M as determined by flow cytometry, and also by a significant increase in the percentage of cells undergoing apoptosis. Our data strongly support the idea that targeting ER action using recombinant viral delivery of dominant negative ERs is an effective way to suppress ER-positive breast cancer cell proliferation and suggests the potential attractiveness of dominant negative gene therapy approaches targeted to the ER for the treatment of hormone-responsive breast cancer.
显性负性雌激素受体是转录无活性的、雌激素受体(ER)的变异形式,它可与雌激素受体二聚化,并有可能使该受体的生物学功能失活。在此,我们首次报道,将显性负性ER通过腺病毒载体导入ER阳性乳腺癌细胞能够有效抑制雌激素刺激的细胞增殖以及内源性基因的激素诱导。我们构建了表达显性负性ER(S554 fs,Ad-fs)的重组腺病毒载体,作为对照,还构建了表达反义ER(Ad-AS)或有义野生型ER(Ad-WT)的重组腺病毒载体。显性负性ER或反义ER的表达可阻断雌二醇对雌激素反应性基因pS2和c-myc的刺激作用,而野生型ER则无此作用。显性负性ER也完全消除了雌二醇诱导的MCF-7乳腺癌细胞增殖增加,反义ER也有同样的作用。通过流式细胞术检测发现,显性负性ER和反义ER的抗增殖作用是由于细胞周期G0/G1期细胞数量增加、G2/M期细胞数量减少,以及凋亡细胞百分比显著增加所致。我们的数据有力地支持了这样一种观点,即通过重组病毒载体递送显性负性ER来靶向ER作用是抑制ER阳性乳腺癌细胞增殖的有效方法,并提示针对ER的显性负性基因治疗方法在治疗激素反应性乳腺癌方面具有潜在的吸引力。