Radiosensitization with Recombinant Antibodies to EGFr

EGFr 重组抗体的放射增敏

• 批准号: 6624085
• 负责人: JAMES A BONNER
• 金额: $ 23.86万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624085
• 关键词: Adenoviridae; apoptosis; athymic mouse; biotechnology; combination cancer therapy; epidermal growth factor; gene delivery system; gene expression; gene targeting; gene therapy; growth factor receptors; head /neck neoplasm; immunologic substance development /preparation; monoclonal antibody; nonhuman therapy evaluation; radiation sensitivity; radiosensitizer

It is known that the anti-EGFr monoclonal antibody C225 and its smaller Fab fragment cause growth inhibition and accentuate radiation-induced growth inhibition in vitro and in vivo in cells that overexpress EGFr. This finding has been suggested in the human model as well, and currently a National Phase III trial (J Bonner, PI) is underway to test the efficacy of C225 and radiotherapy vs radiotherapy alone in advanced head and neck malignancies as almost all head and neck malignancies express EGFr and the majority overexpress it. It is known that monoclonal antibodies are limited by the size of the molecule (with respect to penetration into tumor) and the possibility of immune responses against the antibody. These facts may prevent the monoclonal antibodies from eliciting the best possible response in target tumors. Recently technology has been developed to make human recombinant antibodies that are single chain molecules (scFvs) and contain just the critical variable light and heavy chain regions of the antibody and target antigens of interest. We have constructed these molecules for other antigens and have isolated several candidate clones against EGFr. We have also developed the technology to deliver these agents through an adenoviral vector gene therapy-based approach that allows for the secretion of these agents from the cells by the insertion of appropriate peptides. Therefore, it is hypothesized that this gene therapy-based approach will allow for the delivery of high concentrations of anti-EGFr scFv in close proximity to the antigen of interest in a manner that is not possible with the full antibody. Therefore, it is proposed to derive several recombinant antibodies (scFvs) against EGFr and, 1) maximize the anti-proliferative effects of these scFvs; 2) maximize the radiosensitizing properties of these scFvs; and 3) deliver secretory scFvs through a gene therapy-based approach in a manner that will capitalize on the anti-proliferative and radiosensitizing properties of the agents. Human head and neck carcinoma lines will be used to test these questions in vitro and in vivo with an aim toward understanding viable effects with respect to the cells inherent EGFr expression and radiosensitivity. Preliminary data suggests that monoclonal antibody-induced blockade of EGFr results in growth inhibition and radiosensitization through an apoptotic mechanisms. Additionally, the apoptotic events are associated with a dramatic redirection in the anti-apoptotic protein; phosphorylated STAT-3. Studies will be performed to assess the mechanism of scFv-induced growth inhibition and radiosensitization in the context of the above finding.

众所周知，抗 EGFr 单克隆抗体 C225 及其较小的 Fab 片段会在过度表达 EGFr 的细胞中引起生长抑制，并在体外和体内加剧辐射诱导的生长抑制。 这一发现也已在人体模型中得到证实，目前正在进行一项国家 III 期试验（J Bonner，PI），以测试 C225 和放疗与单独放疗在晚期头颈恶性肿瘤中的疗效，因为几乎所有头颈恶性肿瘤都表达 EGFr，并且大多数过度表达。 众所周知，单克隆抗体受到分子大小（相对于渗透到肿瘤中）和针对抗体的免疫反应的可能性的限制。 这些事实可能会阻止单克隆抗体在靶肿瘤中引起最佳反应。 最近开发出的技术可以制造单链分子 (scFv) 的人类重组抗体，并且仅包含抗体的关键可变轻链和重链区域以及感兴趣的靶抗原。 我们已经为其他抗原构建了这些分子，并分离了几个针对 EGFr 的候选克隆。我们还开发了通过基于腺病毒载体基因治疗的方法递送这些药物的技术，该方法允许通过插入适当的肽从细胞中分泌这些药物。 因此，假设这种基于基因治疗的方法将允许以全抗体不可能的方式将高浓度的抗EGFr scFv递送到接近目标抗原的位置。 因此，建议衍生几种针对EGFr的重组抗体（scFv），并且，1）最大化这些scFv的抗增殖作用； 2) 最大化这些 scFv 的放射增敏特性； 3) 通过基于基因治疗的方法递送分泌型 scFv，其方式将利用药剂的抗增殖和放射增敏特性。 人类头颈癌细胞系将用于在体外和体内测试这些问题，目的是了解对细胞固有 EGFr 表达和放射敏感性的可行影响。 初步数据表明，单克隆抗体诱导的 EGFr 阻断通过细胞凋亡机制导致生长抑制和放射增敏。此外，细胞凋亡事件与抗细胞凋亡蛋白的显着重定向有关。磷酸化 STAT-3。在上述发现的背景下，将进行研究以评估 scFv 诱导的生长抑制和放射增敏的机制。