Israeli R S, Powell C T, Corr J G, Fair W R, Heston W D
Urologic Oncology Research Laboratory, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Cancer Res. 1994 Apr 1;54(7):1807-11.
We have recently cloned a 2.65-kilobase complementary DNA (cDNA) encoding the prostate-specific membrane antigen (PSM) recognized by the 7E11-C5.3 anti-prostate monoclonal antibody. Immunohistochemical analysis of the LNCaP, DU-145, and PC-3 prostate cancer cell lines for PSM expression using the 7E11-C5.3 antibody reveals intense staining in the LNCaP cells with no detectable expression in both the DU-145 and PC-3 cells. Coupled in vitro transcription/translation of the 2.65-kilobase full-length PSM cDNA yields an M(r) 84,000 protein corresponding to the predicted polypeptide molecular weight of PSM. Posttranslational modification of this protein with pancreatic canine microsomes yields the expected M(r) 100,000 PSM antigen. Following transfection of PC-3 cells with the full-length PSM cDNA in a eukaryotic expression vector, we detect expression of the PSM glycoprotein by Western analysis using the 7E11-C5.3 monoclonal antibody. Ribonuclease protection analysis demonstrates that the expression of PSM mRNA is almost entirely prostate specific in human tissues. PSM expression appears to be highest in hormone-deprived states and is hormonally modulated by steroids, with 5-alpha-dihydrotestosterone down-regulating PSM expression in the human prostate cancer cell line LNCaP by 8-10-fold, testosterone down-regulating PSM by 3-4-fold, and corticosteroids showing no significant effect. Normal and malignant prostatic tissues consistently show high PSM expression, whereas we have noted heterogeneous, and at times absent, expression of PSM in benign prostatic hyperplasia. LNCaP tumors implanted and grown both orthotopically and s.c. in nude mice abundantly express PSM, providing an excellent in vivo model system to study the regulation and modulation of PSM expression.
我们最近克隆了一段2.65千碱基的互补DNA（cDNA），它编码由7E11-C5.3抗前列腺单克隆抗体识别的前列腺特异性膜抗原（PSM）。使用7E11-C5.3抗体对LNCaP、DU-145和PC-3前列腺癌细胞系进行PSM表达的免疫组织化学分析显示，LNCaP细胞中有强烈染色，而DU-145和PC-3细胞中未检测到表达。对2.65千碱基的全长PSM cDNA进行体外转录/翻译偶联，产生一种分子量为84,000的蛋白质，与PSM预测的多肽分子量相对应。用犬胰腺微粒体对该蛋白质进行翻译后修饰，产生预期的分子量为100,000的PSM抗原。在真核表达载体中用全长PSM cDNA转染PC-3细胞后，我们使用7E11-C5.3单克隆抗体通过蛋白质印迹分析检测到PSM糖蛋白的表达。核糖核酸酶保护分析表明，PSM mRNA的表达在人体组织中几乎完全是前列腺特异性的。PSM表达在激素剥夺状态下似乎最高，并且受到类固醇的激素调节，5-α-二氢睾酮可使人类前列腺癌细胞系LNCaP中的PSM表达下调8至10倍，睾酮下调PSM表达3至4倍，而皮质类固醇则无显著影响。正常和恶性前列腺组织始终显示出高PSM表达，而我们注意到良性前列腺增生中PSM的表达存在异质性，有时甚至缺失。原位和皮下植入裸鼠体内生长的LNCaP肿瘤大量表达PSM，为研究PSM表达的调节和调控提供了一个出色的体内模型系统。
