Targeting Metastatic Breast Cancer with Human Antibodies

描述(申请人提供)：当今先进的技术可以检测出非常早期的乳房肿瘤。然而，目前乳腺癌的预后标准并不能准确地指出肿瘤的侵袭性有多大，是否已经开始扩散，以及应该选择哪些治疗方案才能在每个病例中获得最好的结果。乳腺癌转移到肺、肝、骨和脑涉及肿瘤细胞通过血流扩散，体外和体内研究表明，转移的人类乳腺癌细胞亚群以结构性激活的功能形式表达黏附受体，整合素αvbeta3。这种受体使细胞能够结合血小板并在血液流动过程中停止，正如在循环中发现的那样，它还支持侵袭性肿瘤细胞的迁移和存活。长期目标是针对转移性乳腺癌细胞的功能标记物，如激活的整合素ava3，以早期发现、预防和抑制转移性疾病。我们使用抗体噬菌体展示技术和对人乳腺癌细胞模型低转移和高转移变体的消减平移策略来分离人单链抗体(ScFv)，这些抗体通过靶向整合素ava3的激活构象来识别转移的乳腺癌细胞。这些抗体具有配体模拟特性和抑制功能，可以干扰人乳腺癌细胞在小鼠模型中的肺定植，并抑制现有的转移性疾病。这项工作的目的是检验这样一种假设，即针对激活的ava3和其他转移乳腺癌细胞的新标记物的人单链抗体可以优化为1.报告转移疾病，2.检测有转移倾向的细胞，以及3.抑制乳腺癌转移。单链抗体将通过化学和分子工程进行修饰，以提高其活性，以适应每一种预期的应用。成像系统将使用标记的scFv抗体来追踪循环中的转移细胞，并识别微转移灶。含有小的、剧毒的化合物的新型免疫结合物将被测试它们对转移性乳腺癌的效果。如果成功，这项工作将有助于改善目前的抗癌治疗。

DESCRIPTION (provided by applicant): Today's advancing technologies can detect very early breast tumors. However, current prognostic criteria for breast cancer do not accurately indicate how aggressive a tumor is, whether it has already begun to spread, and which treatment options should be chosen to achieve the best possible outcome in each individual case. Breast cancer metastasis to the lungs, liver, bone and brain involves tumor cell dissemination via the blood stream, and studies, in vitro and in vivo, showed that a metastatic subset of human breast cancer cells expresses an adhesion receptor, the integrin alphavbeta3, in a constitutively activated functional form. This receptor enables the cells to bind platelets and arrest during blood flow, as found in the circulation, and it also supports invasive tumor cell migration and survival. The long-term objective is to target functional markers of metastatic breast cancer cells, such as the activated integrin ava3, for early detection, prevention and inhibition of metastatic disease. We used antibody phage display technology and a subtractive panning strategy on poorly versus highly metastatic variants of a human breast cancer cell model to isolate human single chain Fv (scFv) antibodies that identify metastatic breast cancer cells by targeting the activated conformation of integrin ava3. These antibodies have ligand mimetic properties and inhibitory functions that interfere with lung colonization by human breast cancer cells in a mouse model, and they inhibit existing metastatic disease. The goal of this work is to test the hypothesis that human scFvs against activated ava3, and other novel markers of metastatic breast cancer cells can be optimized to 1. report metastatic disease, 2. detect cells with a metastatic propensity, and 3. inhibit breast cancer metastasis. The scFvs will be modified by chemical and molecular engineering to enhance their activity for each intended application. Imaging systems will use tagged scFv antibodies to track metastatic cells in the circulation and to identify micro-metastatic lesions. Novel immunoconjugates containing small, highly toxic compounds will be tested for their effects on metastatic breast cancer. If successful, this work will contribute to an improvement of current anti-cancer treatment.