Mamot Christoph, Ritschard Reto, Küng Willy, Park John W, Herrmann Richard, Rochlitz Christoph F
Division of Oncology, Department of Internal Medicine, University Hospital of Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
J Drug Target. 2006 May;14(4):215-23. doi: 10.1080/10611860600691049.
We hypothesized that immunoliposomes (ILs) constructed using Fab' from the humanized anti-EGFR monoclonal antibody, EMD72000, can provide efficient intracellular drug delivery in EGFR-overexpressing colorectal tumor cells.ILs were constructed modularly with various MAb fragments, including Fab' from EMD72000 (matuzumab) or C225 (cetuximab, Erbitux) covalently linked to stabilized liposomes containing chemotherapeutic drugs or probes. Immunoliposome preparation was optimized, including Fab' reduction and linkage, and evaluated for specific binding and cytotoxicity in epidermal growth factor receptor (EGFR)--overexpressing colorectal cancer cell lines in vitro. Flow cytometry showed that EGFR-targeted ILs, but not non-targeted liposomes or irrelevant ILs, were efficiently bound and internalized by a variety of EGFR-overexpressing colorectal cancer cells. Linkage of the Fab' to a longer PEG chain (Mal-PEG3400-DSPE) resulted in an increased uptake of immunoliposomal constructs when compared to previously used materials (Mal-PEG2000-DSPE). ILs derived from EMD72000-Fab' were used to deliver doxorubicin to EGFR-overexpressing target cells in vitro. Immunoliposomal doxorubicin was significantly more cytotoxic than the corresponding non-targeted liposomal drug in target cells, such as HCT116, while equivalent in cells lacking EGFR-overexpression, such as Colo205. We conclude that EGFR-targeted ILs derived from the humanized MAb EMD72000 provide efficient and targeted delivery of anticancer drugs in colorectal cancer cells overexpressing EGFR.
我们推测，使用人源化抗表皮生长因子受体（EGFR）单克隆抗体EMD72000的Fab'构建的免疫脂质体（ILs）能够在EGFR过表达的结直肠肿瘤细胞中实现高效的细胞内药物递送。ILs通过模块化方式构建，将各种单克隆抗体片段，包括来自EMD72000（美妥珠单抗）或C225（西妥昔单抗，爱必妥）的Fab'与含有化疗药物或探针的稳定脂质体共价连接。免疫脂质体制备过程得到了优化，包括Fab'的还原和连接，并在体外对表皮生长因子受体（EGFR）过表达的结直肠癌细胞系中的特异性结合和细胞毒性进行了评估。流式细胞术显示，EGFR靶向的ILs，而非非靶向脂质体或无关的ILs，能够被多种EGFR过表达的结直肠癌细胞有效结合并内化。与先前使用的材料（Mal-PEG2000-DSPE）相比，将Fab'连接到更长的聚乙二醇链（Mal-PEG3400-DSPE）上会导致免疫脂质体构建体的摄取增加。源自EMD72000-Fab'的ILs被用于在体外将阿霉素递送至EGFR过表达的靶细胞。免疫脂质体阿霉素在靶细胞（如HCT116）中比相应非靶向脂质体药物具有显著更高的细胞毒性，而在缺乏EGFR过表达的细胞（如Colo205）中则相当。我们得出结论，源自人源化单克隆抗体EMD72000的EGFR靶向ILs能够在EGFR过表达的结直肠癌细胞中实现高效且靶向的抗癌药物递送。
