Cathepsin B-labile dipeptide linkers for lysosomal release of doxorubicin from internalizing immunoconjugates: Model studies of enzymatic drug release and antigen-specific in vitro anticancer activity
Cathepsin B-labile dipeptide linkers for lysosomal release of doxorubicin from internalizing immunoconjugates: Model studies of enzymatic drug release and antigen-specific in vitro anticancer activity
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DOI：
10.1021/bc025536j
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发表时间：
2002-07-01
影响因子：
4.7
通讯作者：
Trail, PA
中科院分区：
文献类型：
--
作者：
Dubowchik, GM;Firestone, RA;Trail, PA
抗癌药物多柔比星（DOX）已经通过两个溶酶体可裂解的二肽Phe-Lys和Val-Cit连接到嵌合BR 96，嵌合BR 96是一种内化单克隆抗体，其结合刘易斯（γ）相关的肿瘤相关抗原，得到免疫缀合物72和73。在二肽和DOX之间需要一个自分解的对氨基苯氧基羰基（PABC）间隔基以快速和定量地产生游离药物。DOX从模型底物Z-Phe-Lys-PABC-DOX 49的释放比从单独使用半胱氨酸蛋白酶组织蛋白酶B的Z-Val-Cit-PABC-DOX 42的释放快30倍，但在大鼠肝溶酶体制备物中的速率相同，表明不止一种酶的参与。偶联物72和73显示与组织蛋白酶B和在溶酶体制剂中的快速和接近定量的药物释放，同时在人血浆中表现出优异的稳定性。针对具有不同水平的BR96表达的肿瘤细胞系，两种缀合物均显示出有效的抗原特异性细胞毒活性，表明它们将有效地将DOX选择性地递送至抗原表达癌。
The anticancer drug doxorubicin (DOX) has been linked to chimeric BR96, an internalizing monoclonal antibody that binds to a Lewis(y)-related, tumor-associated antigen, through two lysosomally cleavable dipeptides, Phe-Lys and Val-Cit, giving immunoconjugates 72 and 73. A self-immolative p-aminoben-zyloxycarbonyl (PABC) spacer between the dipeptides and the DOX was required for rapid and quantitative generation of free drug. DOX release from model substrate Z-Phe-Lys-PABC-DOX 49 was 30-fold faster than from Z-Val-Cit-PABC-DOX 42 with the cysteine protease cathepsin B alone, but rates were identical in a rat liver lysosomal preparation suggesting the participation of more than one enzyme. Conjugates 72 and 73 showed rapid and near quantitative drug release with cathepsin B and in a lysosomal preparation, while demonstrating excellent stability in human plasma. Against tumor cell lines with varying levels of BR96 expression, both conjugates showed potent, antigen-specific cytotoxic activity, suggesting that they will be effective in delivering DOX selectively to antigen-expressing carcinomas.