EXAMINATION OF UNDEFINED MOLECULAR ALTERATIONS IN GLIOMAS

神经胶质瘤中未定义的分子改变的检查

基本信息

批准号：
6300397
负责人：
Peter A Steck
金额：
$ 14.15万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-16 至 2002-01-31
项目状态：
已结题

项目摘要

The acquisition and progression of the tumorigenic capabilities of neoplastic cells involves genetic alterations leading to the activation of oncogenes and the loss of function of tumor suppressor genes. The cumulative objective of this project is to identify and characterize a tumor suppressor gene localized to the long arm of chromosome 4 that we have recently identified to be involved in the malignant progression of human gliomas. A number of molecular alterations have previously been identified to occur in gliomas, although additional sites of genetic damage would be anticipated to account for the multiple alterations required for oncogenesis. Recently, we have demonstrated the unexpected involvement of a chromosome 4 tumor suppressive locus. This was accomplished by the microcell-mediated transfer of a chromosome 4 into a glioma cell and demonstration of a suppression of the hybrids cells tumorigenic phenotype. Control chromosomal transfers had no phenotypic effects. The inserted chromosome 4 was fragmented, thus only a small segment of the chromosome was retained in the suppressed hybrid cells. This fragment has been partially characterized and shown to contain three regions of chromosome 4; two regions of approximately 1-2 CM and another approximately 7-8 CM. These regions have been molecularly identified and YAC contigs have been generated spanning the involved regions. Initial allelotyping analyses of gliomas and head and neck squamous cell carcinomas specimens, the latter of which have previously been reported to involve deletions on chromosome 4, have implicated one of the retained regions to display consistent loss of heterozygosity (LOH). The localization of two human cancers exhibiting consistent LOH and our chromosomal fragment to independently identify the same small region of chromosome 4, provides strong evidence for the presence of a tumor suppressor gene. To identify the responsible gene, a modified positional cloning strategy will be pursued. Initially, the region will be extensively analyzed for losses or other possible landmarks that may identify the critical region containing the tumor suppressor gene. Also, the possible deletion or rearrangement of the suppressive region in hybrid cells will be functionally and molecularly assessed. Isolated cosmids localized to the various regions will be utilized to further identify the critical region and for generation of cosmid contigs. Once the critical region is defined, expressed gene sequences within the region will be identified and analyzed for alterations in involved neoplasms. This combination of functional and molecular approaches has identified a novel tumor suppressive locus and provided us with an unique means to identify the responsible gene.

肿瘤性能力的获取和进展肿瘤细胞涉及遗传改变，导致激活肿瘤基因和肿瘤抑制基因功能的丧失。这该项目的累积目标是识别和表征我们的肿瘤抑制基因局部位于染色体4的长臂上最近已确定与恶性进展有关人神经胶质瘤。以前有许多分子改变鉴定出在神经胶质瘤中，尽管遗传的其他位点预计损害将考虑多次更改肿瘤形成所必需的。最近，我们证明了意外的 4号染色体抑制基因座的参与。这是通过将染色体4染色体转移到A 神经胶质瘤细胞和抑制杂种细胞的表现肿瘤表型。对照染色体转移没有表型效果。插入的染色体4被碎片，因此只有一个小染色体的片段保留在抑制的杂化细胞中。该片段已被部分表征，并证明包含三个染色体4的区域；大约1-2厘米的两个区域，另一个区域约7-8厘米。这些区域已被分子鉴定，并且已经生成了跨越相关区域的YAC重叠群。最初的神经胶质瘤和头颈部鳞状细胞的分类分析癌标本，后者以前已报道涉及4染色体上的缺失，已牵涉到保留的之一显示杂合性损失（LOH）一致的区域。这两种人类癌的本地化表现出一致的loh和我们染色体碎片独立识别相同的小区域染色体4，为存在肿瘤的存在提供了有力的证据抑制基因。为了识别负责任的基因，修改了位置克隆策略将被追求。最初，该地区将是对可能的损失或其他可能的地标进行了广泛的分析确定含有肿瘤抑制基因的关键区域。还，混合动力车中抑制区域的可能删除或重排细胞将在功能和分子上进行评估。孤立的宇宙本地化与各个区域的本地化将用于进一步确定关键区域和生成宇宙重叠群。一旦批判定义了区域，该区域内表达的基因序列将是确定并分析了所涉及的肿瘤的改变。这功能和分子方法的结合已经确定了一种新颖肿瘤抑制基因座，并为我们提供了一种独特的方法来识别负责的基因。