EXAMINATION OF UNDEFINED MOLECULAR ALTERATIONS IN GLIOMAS

神经胶质瘤中未定义的分子改变的检查

• 批准号: 6237237
• 负责人: Peter A Steck
• 金额: $ 12.95万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-17 至 1998-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6237237
• 关键词: artificial chromosomes; athymic mouse; carcinogenesis; chromosome deletion; chromosomes; clinical research; gene expression; gene mutation; genetic library; genetic mapping; glioblastoma multiforme; glioma; human genetic material tag; human subject; hybrid cells; molecular oncology; neoplasm /cancer genetics; neoplastic cell; neoplastic process; northern blottings; nucleic acid sequence; plasmids; pulsed field gel electrophoresis; southern blotting; tumor suppressor genes

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.

致瘤能力的获得和进展 肿瘤细胞涉及基因改变，导致激活 癌基因和抑癌基因功能丧失。这 该项目的累积目标是确定并描述 抑癌基因定位于4号染色体长臂 最近发现其参与了恶性进展 人类神经胶质瘤。之前已经进行了一些分子改变 已确定发生在神经胶质瘤中，尽管有其他遗传位点 预计会造成多次改动造成的损坏 肿瘤发生所需的。最近，我们展示了意想不到的 涉及 4 号染色体肿瘤抑制位点。这是 通过微细胞介导将 4 号染色体转移到 神经胶质瘤细胞和杂交细胞抑制的证明 致瘤表型。对照染色体转移没有表型 影响。插入的 4 号染色体被打碎，因此只有一小部分 染色体片段保留在受抑制的杂交细胞中。 该片段已被部分表征并显示包含三个 4 号染色体区域；两个大约 1-2 CM 的区域和另一个 约 7-8 厘米。这些区域已被分子鉴定并 YAC 重叠群已生成，跨越相关区域。最初的 胶质瘤和头颈鳞状细胞的等位基因型分析 癌症标本，后者先前已被报道 涉及 4 号染色体上的缺失，涉及保留的染色体之一 区域表现出一致的杂合性丢失（LOH）。这 两种人类癌症的定位表现出一致的 LOH 和我们的 染色体片段独立识别相同的小区域 4号染色体，为肿瘤的存在提供了有力的证据 抑制基因。为了确定负责的基因，修改了位置 将推行克隆战略。最初，该地区将 广泛分析损失或其他可能的地标 识别含有抑癌基因的关键区域。还， 杂交中抑制区域可能的删除或重排 将对细胞进行功能和分子评估。分离的粘粒 将利用本地化到各个地区来进一步确定 关键区域和粘粒重叠群的生成。一旦关键 区域被定义后，该区域内表达的基因序列将是 识别并分析相关肿瘤的变化。这 功能和分子方法的结合已经确定了一种新颖的 肿瘤抑制位点，并为我们提供了一种独特的方法来识别 负责的基因。