Radiosensitization with Recombinant Antibodies to EGFr

EGFr 重组抗体的放射增敏

• 批准号: 6472299
• 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/6472299
• 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.

已知抗EGFr单克隆抗体C225及其较小的Fab片段在体外和体内过表达EGFr的细胞中引起生长抑制并加重辐射诱导的生长抑制。 这一发现在人类模型中也得到了证实，目前正在进行国家III期试验。（J Bonner，PI）正在测试C225和放射疗法相对于单独放射疗法在晚期头颈部恶性肿瘤中的功效，因为几乎所有头颈部恶性肿瘤表达EGFr并且大多数过表达EGFr。（关于渗透到肿瘤中）和针对抗体的免疫应答的可能性。 这些事实可能会阻止单克隆抗体在靶肿瘤中引起最佳可能的反应。 最近，已经开发了制备人重组抗体的技术，所述人重组抗体是单链分子（scFv）并且仅含有抗体和目标靶抗原的关键可变轻链和重链区。 我们已经构建了这些分子的其他抗原，并已分离出几个候选克隆对EGFr。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剂的技术，该方法允许通过插入适当的肽从细胞中分泌这些药剂。 因此，假设这种基于基因治疗的方法将允许以完全抗体不可能的方式在目标抗原附近递送高浓度的抗EGFr scFv。 因此，提出了衍生几种针对EGFr的重组抗体（scFv），并且1）使这些scFv的抗增殖作用最大化; 2）使这些scFv的放射增敏性质最大化;以及3）通过基于基因治疗的方法以将利用试剂的抗增殖和放射增敏性质的方式递送分泌性scFv。 人类头颈癌细胞系将被用来测试这些问题在体外和体内，目的是了解可行的影响，相对于细胞固有的EGFr表达和放射敏感性。 初步数据表明，单克隆抗体诱导的EGFr阻断通过凋亡机制导致生长抑制和放射增敏。此外，凋亡事件与抗凋亡蛋白磷酸化STAT-3的显著重定向相关。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。