Design optimization and characterization of Her2/neu-targeted immunotoxins: comparative in vitro and in vivo efficacy studies.
Design optimization and characterization of Her2/neu-targeted immunotoxins: comparative in vitro and in vivo efficacy studies.
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DOI：
10.1038/onc.2012.612
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发表时间：
2014-01-23
期刊：
影响因子：
8
通讯作者：
Rosenblum MG
中科院分区：
文献类型：
--
作者：
Cao Y;Marks JW;Liu Z;Cheung LH;Hittelman WN;Rosenblum MG
靶向治疗剂具有显著的治疗潜力，因为它们对常规治疗耐药的肿瘤具有选择性和有效性。本研究的目的是确定与重组白树毒素（rGel）融合的单价工程化抗Her 2/neu免疫毒素与含二价IgG的免疫缀合物的活性的比较活性。利用赫赛汀及其衍生的人源化单链抗体（scFv）（命名为4D 5），我们产生了二价化学赫赛汀/rGel缀合物沿着相应的单价重组免疫毒素，其具有两个方向：4D 5/rGel和rGel/4D 5。所有构建体对Her 2/neu过表达癌细胞显示出相似的亲和力，但表现出显著不同的抗肿瘤活性。rGel/4D 5定向构建体和赫赛汀/rGel缀合物在体外和体内功效方面上级4D 5/rGel构建体。增强的活性归因于改善的细胞内毒素摄取到靶细胞中和Her 2/neu相关信号通路的有效下调。Her 2/neu靶向免疫毒素有效靶向Her 2/neu表达水平>1.5×105位点/细胞的细胞。对赫赛汀或化疗药物耐药的细胞对基于rGel的免疫毒素没有交叉耐药。针对SK-0 V-3肿瘤异种移植物，具有优异的肿瘤渗透性的rGel/4D 5构建体显示出令人印象深刻的肿瘤抑制。尽管赫赛汀/rGel偶联物显示出相对较长的血清半衰期，但偶联物的体内功效与rGel/4D 5融合物相似。这些比较研究表明，单价工程化rGel/4D 5构建体显示出与二价赫赛汀/rGel缀合物相当的体外和体内抗肿瘤功效。免疫毒素的方向可以显著影响这些试剂的整体功能和性能。具有出色的肿瘤渗透和快速血液清除能力的重组rGel/4D 5构建体在给予患者时可以避免对正常组织产生不必要的毒性，值得考虑进行进一步的临床评估。
Targeted therapeutics have significant potential as therapeutic agents because of their selectivity and efficacy against tumors resistant to conventional therapy. The goal of this study was to determine the comparative activity of monovalent, engineered anti-Her2/neu immunotoxins fused to recombinant gelonin (rGel) to the activity of bivalent IgG-containing immunoconjugates. Utilizing Herceptin and its derived humanized single chain antibody (scFv) (designated 4D5), we generated a bivalent chemical Herceptin/rGel conjugate along with corresponding monovalent recombinant immunotoxins in two orientations: 4D5/rGel and rGel/4D5. All the constructs showed similar affinity to Her2/neu overexpressing cancer cells but demonstrated significantly different antitumor activities. The rGel/4D5 orientation construct and Herceptin/rGel conjugate were superior to the 4D5/rGel construct in in vitro and in vivo efficacy. The enhanced activity was attributed to improved intracellular toxin uptake into target cells and efficient downregulation of Her2/neu-related signaling pathways. The Her2/neu-targeted immunotoxins effectively targeted cells with Her2/neu expression level >1.5×105 sites per cell. Cells resistant to Herceptin or chemotherapeutic agents were not cross-resistant to rGel-based immunotoxins. Against SK-OV-3 tumor xenografts, the rGel/4D5 construct with excellent tumor penetration showed impressive tumor inhibition. Although the Herceptin/rGel conjugate demonstrated comparatively longer serum half-life, the in vivo efficacy of the conjugate was similar to the rGel/4D5 fusion. These comparative studies demonstrate that the monovalent, engineered rGel/4D5 construct displayed comparable in vitro and in vivo antitumor efficacy to that of the bivalent Herceptin/rGel conjugate. Immunotoxin orientation can significantly impact the overall functionality and performance of these agents. The recombinant rGel/4D5 construct with excellent tumor penetration and rapid blood clearance may avoid unwanted toxicity to normal tissues when administered to patients and warrants consideration for further clinical evaluation.