Fuqua S A, Schiff R, Parra I, Friedrichs W E, Su J L, McKee D D, Slentz-Kesler K, Moore L B, Willson T M, Moore J T
Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA.
Cancer Res. 1999 Nov 1;59(21):5425-8.
It has been shown in previous studies that a variety of estrogen receptor (ER) beta mRNA transcripts are expressed in human breast cancer cell lines and tumors. To complement the RNA expression studies, we have developed ER-beta-specific antibodies to characterize ER-beta protein expression in breast cancer cell lines and tumors. Monoclonal antibodies were made against a peptide representing the first 18 amino acids of the longest ER-beta open reading frame reported to date, and polyclonal antibodies were made against a peptide within the ER-beta B domain. By Western blot analysis, we show that ER-beta protein is expressed in all cancer cell lines tested and in three of five breast tumor samples. The breast cancer cell lines showed variation in the size of the expressed ER-beta protein. The longest form detected was consistent with the 530-amino acid, full-length ER-beta sequence. Shorter ER-beta isoforms were detected in the ER-alpha-negative MDA-MB-231 and MDA-MB-435 breast cancer cell lines, likely corresponding to previously described COOH-terminal RNA variant isoforms.
先前的研究表明，多种雌激素受体（ER）β mRNA转录本在人乳腺癌细胞系和肿瘤中表达。为补充RNA表达研究，我们已开发出ER-β特异性抗体，以表征乳腺癌细胞系和肿瘤中ER-β蛋白的表达。针对代表迄今报道的最长ER-β开放阅读框的前18个氨基酸的肽制备了单克隆抗体，并针对ER-β B结构域内的肽制备了多克隆抗体。通过蛋白质印迹分析，我们表明ER-β蛋白在所测试的所有癌细胞系以及五个乳腺肿瘤样本中的三个中表达。乳腺癌细胞系中表达的ER-β蛋白大小存在差异。检测到的最长形式与530个氨基酸的全长ER-β序列一致。在ER-α阴性的MDA-MB-231和MDA-MB-435乳腺癌细胞系中检测到较短的ER-β异构体，可能对应于先前描述的COOH末端RNA变异异构体。
