Anti-tumor effects and lack of side effects in mice of an immunotoxin directed against human and plouse prostate-specific membrane antigen
Anti-tumor effects and lack of side effects in mice of an immunotoxin directed against human and plouse prostate-specific membrane antigen
复制标题
DOI：
10.1002/pros.20074
复制
发表时间：
2004-09-15
期刊：
影响因子：
2.8
通讯作者：
Thorpe, PE
中科院分区：
文献类型：
--
作者：
Huang, XM;Bennett, M;Thorpe, PE
背景资料。前列腺特异性膜抗原(PSMA)是一种跨膜蛋白，主要局限于人的前列腺上皮细胞，并强烈上调前列腺癌细胞的表达。在人类肿瘤血管内皮细胞上也有表达。但不是在正常组织的血管系统上。在几个正常组织的非血管细胞上也发现了低水平的PSMA表达，尤其是在人类的大脑和肾脏。PSMA是靶向前列腺癌或各种实体肿瘤的肿瘤血管的极佳候选者。这些药物的高潜在临床益处促使人们寻找一种动物模型来评估基于抗PSMA单抗(MAb)的治疗的有效性和安全性。方法使用传统的杂交瘤技术制备能识别鼠和人PSMA的鼠单抗E6。采用酶联免疫吸附试验、免疫印迹和免疫组织化学等方法对抗体进行了鉴定。用化学方法制备了由E6、抗体和脱糖蓖麻毒素A链(DGA)组成的免疫毒素。结果：E6在EL ISA、免疫印迹和免疫组织化学方法中均能识别人和小鼠PSMA的胞外区。E6对人类肿瘤的血管内皮细胞有强烈的染色，但对小鼠的肿瘤血管内皮细胞不染色。E6在小鼠和人类肾脏的近端小管以及小鼠和人类的海马神经元中染色，但与人类不同的是，在小鼠的前列腺或小肠中没有检测到染色的上皮细胞。E6-DGA免疫结合物强烈抑制LNCaP肿瘤移植瘤的生长，对小鼠无明显毒性。组织学观察表明，其抗肿瘤作用是通过对肿瘤细胞的直接细胞毒作用实现的。结论：我们制备并鉴定了一种能与Bota人和小鼠PSMA发生特异性反应的大鼠单抗(E6)，并证明了由E6构建的免疫毒素对裸鼠皮下生长的人前列腺癌细胞是安全有效的。(C)2004年Wiley-Liss公司
BACKGROUND. Prostate-specific membrane antigen (PSMA) is a trans membrane protein that is largely restricted to prostatic epithelial cells in humans and is strongly upregulated on prostatic carcinoma cells. It is also expressed on the endothelium of tumor vasculature in humans. but not on the vasculature of normal tissues. Expression of low levels of PSMA has also been found on non-vascular cells in several normal tissues, most prominently on the brain and kidney in humans. PSMA is an excellent candidate for targeting prostate cancer or targeting tumor vasculature of various solid tumors. The high potential clinical benefit of these agents has prompted the search for an animal model in which to assess the efficacy and safety of anti-PSMA monoclonal antibody (mAb)-based therapies.METHODS. A rat monoclonal antibody, E6 that recognizes both mouse and human PSMA was generated using conventional hybridoma techniques. The antibody was characterized by enzyme-linked immunosorbent assay (ELISA), Western blot, and immunohistochemistry. An immunotoxin composed of E6, antibody and deglycosylated ricin A-chain (dgA) was prepared chemically. The anti-tumor effects of the immunotoxin were determined in vitro and in mice bearing subcutaneous LnCaP human prostate tumors, which express PSMA on the tumor cell surface.RESULTS. E6 recognizes the extracellular domain of both human and mouse PSMA in ELISA, immunoblot and by immunohistochemistry. E6 strongly stained the vascular endothelium of tumors from humans but not from mice. E6 stained proximal tubules in mouse and human kidneys, and neurons in the mouse and human hippocampus but, unlike the human, did not detectably stain epithelial cells in mouse prostate or small intestine. An E6-dgA immunoconjugate strongly inhibited the growth of LnCaP tumor xenografts without causing apparent toxicity to the mice. Histological observation indicated that the anti-tumor effects were mediated through direct cytotoxic effects on the tumor cells.CONCLUSIONS. We have generated and characterized a rat mAb (E6) that reacts specifically with bota human and mouse PSMA and have demonstrated that an immunotoxin constructed from E6 is safe and effective against human prostatic carcinoma cells growing subcutaneously in nude mice. (C) 2004 Wiley-Liss, Inc.