Analysis of the Novel Tumor Suppressor Gene SNF5/INI1

新型抑癌基因SNF5/INI1的分析

• 批准号: 6555413
• 负责人: CHARLES ROBERTS
• 金额: $ 13.58万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6555413
• 关键词: cell growth regulation; gene induction /repression; gene targeting; genetically modified animals; laboratory mouse; microarray technology; neoplasm /cancer genetics; neoplastic transformation; pediatric neoplasm /cancer; protein structure function; tumor suppressor genes; tumor suppressor proteins

DESCRIPTION (provided by applicant): Malignant rhabdoid tumor (MRT) is an aggressive, highly lethal cancer that strikes young children. Tumors occur in various locations including kidney, brain, and soft tissues. Despite intensive therapy, 80 percent of affected children die, often within 1 year of diagnosis. The vast majority of MRTs have sustained bi-allelic inactivating mutations of the hSNF5/INI1 gene, suggesting that SNF5 may act as a tumor suppressor. Supporting this idea is the fact that 15 percent of children with MRT have somatic mutations in one allele of SNF5 and loss of the remaining allele in their tumors. SNF5 is a core member of the SWI/SNF chromatin remodeling complex, which is required for regulated expression of a subset of genes. In humans, SNF5 binds to HIV integrase and stimulates integration of HIV into human DNA. Studies have also shown that SNF5 binds to EBNA, MLL/ALL- 1, trithorax, and c-MYC and stimulates transcription by these factors. Another member of the SWI/SNF complex, Brg1, directly interacts with pRb and is required for Rb mediated cell cycle arrest. Haploinsufficiency of Brg1 predisposes mice to tumor formation and Brg1 is deficient in several breast cancer cell lines. Together, these data suggest a widespread role for SWI/SNF in tumor suppression. While it is clear that SNF5 and SWI/SNF are involved in tumor suppression, chromatin remodeling and transcriptional activation, their mechanism of action and the relationship between these processes is not clear. We have used gene targeting to inactivate SNF5 in mice. Absence of SNF5 results in embryonic lethality while haploinsufficiency results in 15 percent of mice developing tumors histologically indistinguishable from human MRT. The specific aims of the proposed project are to generate SNF5 deficient cells to determine the function of SNF5 in growth regulation and oncogenic transformation. Second, to improve the MRT model by generating conditionally targeted mice that develop MRT with high penetrance in locations where human tumors occur. Third, to identify genes downstream of SNF5 through use of conditionally targeted cells in DNA micro-array analysis. Lastly, to investigate the function of SNF5 in transcriptional regulation by analysis of SNF5 deficient cells using in vitro transcriptional assays. Since SNF5 is an invariant subunit present in all SWI/SNF complexes, elucidation of its function will provide insight into a newly appreciated mechanism of tumor suppression and may identify new targets for therapeutic intervention against a lethal pediatric cancer. This proposal directly addresses scientific priorities identified by the BT-PRG arm of the NCI.

描述(申请人提供)：恶性横纹肌样瘤是一种 侵袭性的、高致命性的癌症，发作在幼儿身上。肿瘤发生在 各种部位，包括肾脏、脑和软组织。尽管 强化治疗，80%的受影响儿童死亡，通常在1年内 诊断。绝大多数MRT持续存在双等位基因失活 HSNF5/INI1基因突变提示SNF5可能作为一种肿瘤 抑制者。支持这一观点的事实是，15%的儿童患有 MRT发现SNF5的一个等位基因发生体细胞突变，其余的等位基因丢失 他们肿瘤中的等位基因。SNF5是SWI/SNF染色质的核心成员 重塑复合体，这是调节表达的子集所必需的 基因。在人类中，SNF5与HIV整合酶结合并刺激整合 艾滋病病毒进入人类DNA。研究还表明，SNF5与EBNA、MLL/ALL- 1、三胸和c-myc，并通过这些因子刺激转录。 SWI/SNF复合体的另一个成员BRG1直接与PRB相互作用，并 是RB介导的细胞周期停滞所必需的。BRG1单倍体功能不全 使小鼠易于形成肿瘤，BRG1在几个乳房中缺乏 癌细胞系。总而言之，这些数据表明，SWI/SNF发挥着广泛的作用 在肿瘤抑制方面。 虽然很明显SNF5和SWI/SNF参与了肿瘤抑制， 染色质重塑和转录激活及其作用机制 而这些过程之间的关系尚不清楚。我们已经使用了基因 靶向灭活小鼠SNF5。SNF5缺失导致胚胎发育 单倍体不足导致15%的小鼠发育而致死 组织学上无法与人类MRT区分的肿瘤。的具体目标 建议的项目是生成SNF5缺陷细胞以确定 SNF5在生长调控和致癌转化中的作用第二, 通过生成有条件靶向的小鼠来改进MRT模型 在人类肿瘤发生的地方开发高透视率的MRT。 第三，通过条件性识别SNF5下游基因 DNA微阵列分析中的靶细胞。最后，为了调查 从SNF5基因缺陷分析SNF5在转录调控中的作用 细胞使用体外转录分析。由于SNF5是一个不变量 亚基存在于所有SWI/SNF复合体中，其功能的阐明将 洞察到一种新的肿瘤抑制机制和 可能会确定针对致命病毒的治疗干预的新靶点 儿科癌症。这项提议直接涉及科学优先事项。 由NCI的BT-PRG部门识别。