BREAST CANCER IMAGING ANTIBODY DERIVED SMALL MOLECULES

小分子衍生的乳腺癌成像抗体

• 批准号: 2717573
• 负责人: ALAN H STOLPEN
• 金额: $ 11.86万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2717573
• 关键词: athymic mouse; autoradiography; breast neoplasms; cell line; clearance rate; indium; iodine; monoclonal antibody; neoplastic cell; oncoproteins; radiotracer; receptor binding; technetium; tumor antigens

Nearly one-third of all human breast cancers, including most of the highly aggressive comedo- and inflammatory-type breast cancers, over express the neu/c-erbB-2 oncogene product p185 on their plasma membranes. The goal of the proposed work is to develop radioligands targeted to the p185 receptor. The hypothesis is that scintigraphic imaging can detect tumor-associated p185 accurately and noninvasively and, thereby, improve the accuracy of breast cancer staging and surveillance in the subset of patients whose tumors over express p185. Although monoclonal antibodies (mAb) reactive with the human p185 receptor are available, tumor imaging with radiolabeled Mab has been largely disappointing; tumor localization is poor and background activity is high. Intact Mab fail as site-directed biological probes because of: 1) large size (150 kDa); 2) non-specific binding; 3) slow plasma clearance rate; and 4) immunogenicity. To circumvent these limitations, the investigators propose to target the p185 receptor using newly-developed antibody-derived small molecules (less than 2 Kda) that mimic the antibody complementarily determining region (CDR). Dr. Mark Greene and his co-workers developed a conformationally constrained, aromatically-modified peptide analogue based on the heavy chain CDR3 of 4D5, a murine mAb reactive with human p185. This CDR analogue is called 4D5.AME, where AME stands for Aromatic Modified Exocyclic. Preliminary studies with 4D5.AME demonstrate excellent binding affinity and exceptional bioactivity against human breast cancers that over express p185. Thus, 4D5.AME is a potentially superb site-directed biological probe for delivery of gamma-emitting radionuclides to tumor-associated p185. Accordingly, the specific aims are to: 1) radiolabel 4D5.AME with iodine-123, technetium-99m and indium-111; 2) determine the stability, affinity, and specificity of 4D5.AME radioligands in vitro using human breast cancer cell lines; 3) determine the redistribution and plasma clearance rates of 4D5.AME radioligands in vivo using a xenograft tumor model in nude mice; and 4) perform, optimize, and evaluate planar scintigraphic imaging of 4D5.AME radioligands in tumor-bearing mice. The proposed imaging agents incorporate significant design improvements compared with existing agents. However, it is impossible to predict whether radiolabeling will disturb critical residues in the 4D5.AME receptor binding site. Any promising 4D5.AME radioligands developed during this R21 granting period will be used as preliminary data in support of a future R01 proposal.

近三分之一的人类乳腺癌，包括大多数乳腺癌 高度侵袭性粉刺型和炎症型乳腺癌 在血浆中表达 neu/c-erbB-2 癌基因产物 p185 膜。 拟议工作的目标是开发放射性配体 靶向 p185 受体。假设是闪烁照相 成像可以准确无创地检测肿瘤相关p185 从而提高乳腺癌分期的准确性 对肿瘤过度表达 p185 的患者亚组进行监测。 尽管单克隆抗体 (mAb) 与人类 p185 发生反应 受体可用，放射性标记的单克隆抗体肿瘤成像已 很大程度上令人失望；肿瘤定位较差且背景 活跃度高。 完整的单克隆抗体作为定点生物探针失败 因为： 1) 大尺寸（150 kDa）； 2）非特异性结合； 3）慢 血浆清除率； 4)免疫原性。为了规避这些 局限性，研究人员建议使用 p185 受体作为目标 新开发的抗体衍生小分子（小于 2 Kda） 模拟抗体互补决定区（CDR）。 马克博士 格林和他的同事开发了一种构象受限的、 基于重链 CDR3 的芳香族修饰肽类似物 4D5，一种与人 p185 发生反应的鼠类单克隆抗体。 该 CDR 类似物称为 4D5.AME，其中AME代表芳香族改性外环。 初步的 4D5.AME 研究表明具有出色的结合亲和力 对过度表达的人类乳腺癌具有特殊的生物活性 第 185 页。 因此，4D5.AME是一种潜在的极好的定点生物 用于将伽马发射放射性核素递送至肿瘤相关细胞的探针 第 185 页。因此，具体目标是：1) 放射性标记 4D5.AME 碘 123、锝 99m 和铟 111； 2）确定稳定性， 使用人类体外 4D5.AME 放射性配体的亲和力和特异性 乳腺癌细胞系； 3) 确定再分配和等离子体 使用异种移植肿瘤体内 4D5.AME 放射性配体的清除率 裸鼠模型； 4) 执行、优化和评估平面 荷瘤小鼠中 4D5.AME 放射性配体的闪烁显像。 所提出的显像剂包含重大的设计改进 与现有代理商相比。 然而，无法预测 放射性标记是否会干扰 4D5.AME 中的关键残基 受体结合位点。 开发出任何有前景的 4D5.AME 放射性配体 在此 R21 授予期内将用作初步数据 支持未来的 R01 提案。