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: 6269512
• 负责人: Peter A Steck
• 金额: $ 13.41万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6269512
• 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.

血管内皮细胞致瘤能力的获得和进展 肿瘤细胞涉及导致激活的基因改变 癌基因与肿瘤抑制基因功能的丧失。这个 该项目的累积目标是确定和描述一个 肿瘤抑制基因定位于4号染色体的长臂 最近被确认与恶性进展有关 人类神经胶质瘤。以前已经发生了许多分子变化 被证实发生在胶质瘤中，尽管有更多的遗传位点 预计损害将是造成多处改变的原因 是肿瘤发生所必需的。最近，我们展示了意想不到的 涉及4号染色体肿瘤抑制基因。这是 通过微细胞介导的将4号染色体转移到 胶质瘤细胞及其对杂交瘤细胞的抑制作用 致瘤表型。对照的染色体转移没有表型 效果。插入的4号染色体是碎片化的，因此只有一小部分 在被抑制的杂交细胞中，染色体片段被保留。 该片段已被部分表征，并被证明包含三个 4号染色体的区域；大约1-2 CM的两个区域和另一个区域 大约7-8厘米。这些区域已经被分子识别并 YAC重叠群已经在涉及的区域中产生。首字母 脑胶质瘤和头颈部鳞状细胞的等位基因分型分析 癌症标本，后者以前曾被报道为 涉及4号染色体上的缺失，已牵涉到其中一个保留的 显示一致杂合性缺失(LOH)的区域。这个 两例表现一致杂合性缺失和OUR的人类肿瘤的定位 染色体片段以独立地识别相同的小区域 4号染色体，为肿瘤的存在提供了强有力的证据 抑制子基因。为了确定责任基因，一种修改的位置 将推行克隆战略。最初，该地区将是 广泛分析损失或其他可能的里程碑，可能 确定包含肿瘤抑制基因的关键区域。另外， 杂交种中抑制区可能的缺失或重排 将对细胞进行功能和分子评估。孤立宇宙星 本地化到各个地区将被用来进一步识别 关键区域和粘粒重叠群的产生。曾经的关键人物 区域被定义，区域内的表达基因序列将被 识别和分析受累肿瘤的变化。这 功能和分子方法的结合已经确定了一种新的 肿瘤抑制基因，为我们提供了一种独特的识别手段 负责任的基因。