Transmembrane Proteins Involved in Human Tumor Expansion

描述（由申请人提供）：转移，即恶性细胞从原发肿瘤向继发部位的扩散，是一个高度复杂的多步骤过程。为了从机制上理解转移的过程，有必要鉴定那些特异性促进肿瘤播散和继发部位生长的分子和途径。为了帮助实现我们鉴定转移中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人类肿瘤HEp 3的独特功能阻断单克隆抗体（mAb）。首先在最近修改的鸡胚测定中在体内筛选mAb作为转移级联的抑制剂，然后在SCID小鼠转移模型中确认。利用消减产生的单克隆抗体和分析蛋白质组学技术，在我们的转移模型中鉴定了两种有助于肿瘤进展的膜锚定蛋白抗原。一种抗原是新的I型跨膜糖蛋白SIMA-135/CDCP-1（SIMA-135），另一种是四跨膜蛋白家族的已知成员PETA 3/CD 151（PETA 3）。具体目标是：（1）。目的探讨新抗原SIMA-135在肿瘤转移中的作用。SIMA-135基因的表达将在转移性细胞中下调，在非侵袭性细胞中上调，并且将分析所得细胞分离物的体内行为改变。还将进行对潜在的SIMA-135伴侣分子的搜索。（二）.目的：探讨四跨膜蛋白PETA 3在肿瘤转移过程中的作用机制。将阐明PETA 3在转移级联中起作用的位置，并将进行PETA 3的体内结构-功能分析。（三）、将SIMA-135和PETA 3抗原的表达、外观和分布与人类恶性疾病的临床方面相关联。（四）、通过将这些体内实验方法应用于表现出不同恶性表型的其他人肿瘤细胞系，扩展消减免疫和功能阻断mAb的利用。总体目标是鉴定在转移过程中直接起作用的蛋白质抗原。这些抗原可以作为人类癌症的潜在诊断标志物或治疗靶点。

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.