Transmembrane Proteins Involved in Human Tumor Expansion

描述(申请人提供)：转移，恶性细胞从原发肿瘤扩散到继发部位，是一个高度复杂的、多步骤的过程。为了从机制上理解肿瘤转移的过程，有必要确定那些对肿瘤扩散和继发部位生长有特殊作用的分子和途径。为了帮助实现我们在转移中识别功能相关分子的目标，我们使用消减免疫来产生针对高度侵袭性的人类肿瘤HEp3的独特的功能阻断单抗(MAbs)。这些单抗首先在最近改进的鸡胚试验中作为转移级联的抑制物在体内进行筛选，然后在SCID小鼠转移模型中得到证实。利用消减产生的单抗和分析蛋白质组学技术，在我们的转移模型中，已经确定了两个与肿瘤进展有关的膜锚定蛋白抗原。一个抗原是新的I型跨膜糖蛋白SIMA-135/CDCP-1(SIMA-135)，另一个抗原是Tetraspanin家族的已知成员PETA3/CD151(PETA3)。具体目标是：(1)。目的：阐明新抗原SIMA-135在人类肿瘤转移中的作用。SIMA-135基因在转移细胞中的表达将下调，在非侵袭性细胞中上调，由此产生的细胞分离株将被分析体内行为的变化。还将搜索潜在的SIMA-135合作伙伴分子。(2)。目的：阐明Tetraspanin PETA3在肿瘤转移过程中的作用机制。将阐明PETA3在转移级联中的作用，并对PETA3进行体内结构-功能分析。(3)。目的：探讨SIMA-135和PETA3抗原的表达、形态和分布与人类恶性疾病临床特征的关系。(4)。通过将这些体内实验方法应用于其他表现出不同恶性表型的人类肿瘤细胞系，扩大消减免疫和功能阻断单抗的应用。总体目标是确定在转移过程中直接起作用的蛋白质抗原。这种抗原可以作为人类癌症的潜在诊断标记或治疗靶点。

DESCRIPTION (provided by applicant): Metastasis, the dissemination of malignant cells from the primary tumor to secondary sites, is a highly complex, multi-step process. In order to understand mechanistically the process of metastasis it will be necessary to identify those molecules and pathways that specifically contribute to tumor dissemination and secondary site growth. To help achieve our goal of identifying functionally relevant molecules in metastasis, we have used subtractive immunization to generate unique function-blocking monoclonal antibodies (mAbs) raised against the highly aggressive human tumor HEp3. The mAbs are screened in vivo as inhibitors of the metastatic cascade first in a recently-modified chick embryo assay and are then confirmed in the SCID mouse metastasis model. Utilizing the subtractive-generated mAbs and analytical proteomics technology, two membrane-anchored protein antigens that contribute to tumor progression in our metastasis models have been identified. One antigen is a new type I transmembrane glycoprotein SIMA-135/CDCP-1 (SIMA-135), and the other is a known member of the tetraspanin family, PETA3/CD151 (PETA3). The Specific Aims are: (1). To elucidate the functional role of the new antigen, SIMA-135, in human tumor metastasis. Expression of the SIMA-135 gene will be downregulated in metastatic cells, upregulated in non-aggressive cells and the resulting cell isolates will be analyzed for in vivo alterations in behavior. A search for potential SIMA-135 partner molecules also will be conducted. (2). To demonstrate the mechanism and role of the tetraspanin, PETA3, in the metastatic process. The position where PETA3 functions in the metastatic cascade will be elucidated and an in vivo structure-function analysis of PETA3 will be carried out. (3). To correlate the expression, appearance, and distribution of SIMA-135 and PETA3 antigens with clinical aspects of human malignant disease. (4). To extend the utilization of subtractive-immunization and function-blocking mAbs by applying these in vivo experimental approaches to other human tumor cell lines manifesting distinct malignant phenotypes. The overall goal is to identify protein antigens that function directly in the metastatic process. Such antigens could serve as potential diagnostic markers or therapeutic targets for human cancer.