Wu Gong, Yang Weilian, Barth Rolf F, Kawabata Shinji, Swindall Michele, Bandyopadhyaya Achintya K, Tjarks Werner, Khorsandi Behrooz, Blue Thomas E, Ferketich Amy K, Yang Ming, Christoforidis Gregory A, Sferra Thomas J, Binns Peter J, Riley Kent J, Ciesielski Michael J, Fenstermaker Robert A
Department of Pathology, The Ohio State University, Columbus 43210, USA.
Clin Cancer Res. 2007 Feb 15;13(4):1260-8. doi: 10.1158/1078-0432.CCR-06-2399.
The purpose of the present study was to evaluate the anti-epidermal growth factor monoclonal antibody (mAb) cetuximab (IMC-C225) as a delivery agent for boron neutron capture therapy (BNCT) of a human epidermal growth factor receptor (EGFR) gene-transfected rat glioma, designated as F98(EGFR).
A heavily boronated polyamidoamine dendrimer was chemically linked to cetuximab by means of the heterobifunctional reagents N-succinimidyl 3-(2-pyridyldithio)-propionate and N-(k-maleimido undecanoic acid)-hydrazide. The bioconjugate, designated as BD-C225, was specifically taken up by F98(EGFR) glioma cells in vitro compared with receptor-negative F98 wild-type cells (41.8 versus 9.1 microg/g). For in vivo biodistribution studies, F98(EGFR) cells were implanted stereotactically into the brains of Fischer rats, and 14 days later, BD-C225 was given intracerebrally by either convection enhanced delivery (CED) or direct intratumoral (i.t.) injection.
The amount of boron retained by F98(EGFR) gliomas 24 h following CED or i.t. injection was 77.2 and 50.8 microg/g, respectively, with normal brain and blood boron values <0.05 mug/g. Boron neutron capture therapy was carried out at the Massachusetts Institute of Technology Research Reactor 24 h after CED of BD-C225, either alone or in combination with i.v. boronophenylalanine (BPA). The corresponding mean survival times (MST) were 54.5 and 70.9 days (P = 0.017), respectively, with one long-term survivor (more than 180 days). In contrast, the MSTs of irradiated and untreated controls, respectively, were 30.3 and 26.3 days. In a second study, the combination of BD-C225 and BPA plus sodium borocaptate, given by either i.v. or intracarotid injection, was evaluated and the MSTs were equivalent to that obtained with BD-C225 plus i.v. BPA.
The survival data obtained with BD-C225 are comparable with those recently reported by us using boronated mAb L8A4 as the delivery agent. This mAb recognizes the mutant receptor, EGFRvIII. Taken together, these data convincingly show the therapeutic efficacy of molecular targeting of EGFR using a boronated mAb either alone or in combination with BPA and provide a platform for the future development of combinations of high and low molecular weight delivery agents for BNCT of brain tumors.
本研究旨在评估抗表皮生长因子单克隆抗体（mAb）西妥昔单抗（IMC-C225）作为硼中子俘获疗法（BNCT）治疗人表皮生长因子受体（EGFR）基因转染大鼠胶质瘤（命名为F98(EGFR)）的递送剂的效果。
通过异双功能试剂N-琥珀酰亚胺基3-(2-吡啶二硫代)-丙酸酯和N-(k-马来酰亚胺十一烷酸)-酰肼将高度硼化的聚酰胺胺树枝状大分子化学连接到西妥昔单抗上。这种生物共轭物命名为BD-C225，与受体阴性的F98野生型细胞相比，其在体外能被F98(EGFR)胶质瘤细胞特异性摄取（分别为41.8微克/克和9.1微克/克）。对于体内生物分布研究，将F98(EGFR)细胞立体定向植入Fischer大鼠脑内，14天后，通过对流增强递送（CED）或直接瘤内（i.t.）注射给予BD-C225。
CED或i.t.注射后24小时，F98(EGFR)胶质瘤保留的硼量分别为77.2微克/克和50.8微克/克，正常脑和血中的硼值<0.05微克/克。在麻省理工学院研究反应堆对BD-C225进行CED 24小时后，单独或与静脉注射硼苯丙氨酸（BPA）联合进行硼中子俘获疗法。相应的平均生存时间（MST）分别为54.5天和70.9天（P = 0.017），有1只长期存活者（超过180天）。相比之下，照射对照组和未治疗对照组的MST分别为30.3天和26.3天。在第二项研究中，评估了通过静脉注射或颈内注射给予BD-C225与BPA加硼卡钠的组合，其MST与BD-C225加静脉注射BPA的结果相当。
用BD-C225获得的生存数据与我们最近报道的使用硼化mAb L8A4作为递送剂的数据相当。这种mAb识别突变受体EGFRvIII。综上所述，这些数据令人信服地表明，单独或与BPA联合使用硼化mAb对EGFR进行分子靶向治疗具有疗效，并为未来开发用于脑肿瘤BNCT的高分子量和低分子量递送剂组合提供了一个平台。
