INVASIVE TUMORS OF DROSOPHILA AS A MODEL OF METASTASIS

果蝇侵袭性肿瘤作为转移模型

• 批准号: 2390809
• 负责人: ALLEN D SHEARN
• 金额: $ 16.02万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-04-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2390809
• 关键词: Drosophilidae; brain neoplasms; collagenase; disease /disorder model; gene mutation; genetic library; genetic mapping; genetic regulation; histochemistry /cytochemistry; host neoplasm interaction; laboratory rabbit; larva; metastasis; molecular cloning; molecular oncology; neoplasm /cancer genetics; neoplasm /cancer invasiveness; neuroblastoma; nucleic acid sequence; phenotype; regulatory gene; temperature sensitive mutant; tissue inhibitor of metalloproteinases; tumor suppressor genes

The long-term objective of the proposed work is to use invasive tumors of Drosophila as a model system to investigate the cascade of events that begins with loss of function of tumor suppressor genes and culminates in the altered expression of effector genes which mediate invasiveness such as gelatinases and their inhibitors. Seven Drosophila tumor suppressor genes have been identified by mutations which cause overgrowth of larval brains. Mutations in the best studied gene of this type, lethal giant larvae, cause loss of normal tissue structure and loss of capacity to differentiate of imaginal neuroblasts. The invasiveness of neuroblastoma cells derived from such mutant brains following transplantation into adult hosts has been confirmed using a cell-autonomous marker. One aim of this proposal is to use this cell marking method to analyze the invasive potential of Drosophila neuroblastomas caused by mutations in the six other tumor suppressor genes. This analysis will include a qualitative study of the host tissue specific susceptibility to invasion and a quantitative comparison of the degree of invasiveness. Two approaches are planned to investigate the cascade of events that begins with loss of function of tumor suppressor genes. One is to examine the genetic hierarchy of the seven already identified genes. The other is to use a temperature sensitive mutation in the malignant brain tumor gene to screen for second site mutations that identify downstream genes whose function is required to express the invasive phenotype. The metastatic phenotype includes loss of normal tissue integrity and increased proteolysis of the extracellular matrix. Either or both of these processes can be mediated by gelatinases. Preliminary work has led to the detection of three Drosophila proteins with gelatinase activity and demonstrated increased accumulation of one of these three in brains dissected from lethal giant larvae mutants and in invasive neuroblastomas derived from such mutant brains. This gelatinase is a 49kDa protein with a pI of 7.2 that cross-reacts with antibody directed against human gelatinase A. The neuroblastomas caused by mutations in the six other genes will be screened for increased accumulation of this protein as well as the two other gelatinases. The gelatinase 7.2 gene will be cloned and mutations will be recovered in it. The consequences of these gelatinase mutations on the invasive phenotype caused by mutations in the seven tumor suppressor mutations will be examined. These mutations will be used as starting points to identify upstream genes that regulate expression of the gelatinase 7.2 gene in tumors. The decision to focus initially on gelatinase 7.2 has been dictated by preliminary results, by the availability of immunological reagents, and by progress already made towards cloning of the gelatinase 7.2 gene. Preliminary work has also shown evidence of putative inhibitors of gelatinase in Drosophila larvae. Ultimately, a similar approach will be applied to the study of the two other gelatinases and these inhibitors.

拟议工作的长期目标是利用侵袭性肿瘤 果蝇作为模型系统来研究级联事件 始于肿瘤抑制基因功能的丧失，最终导致 介导侵袭性的效应基因表达的改变，例如 如明胶酶及其抑制剂。七、果蝇抑癌基因 已通过导致幼虫过度生长的基因突变来鉴定 大脑。这种类型的致命巨人基因的突变 幼虫，导致正常组织结构丧失和丧失能力 成象神经细胞的分化。神经母细胞瘤的侵袭性 将这种突变大脑移植到成人体内后衍生的细胞 宿主已使用细胞自主标记得到确认。这样做的目的之一 建议是使用这种细胞标记方法来分析侵入性 六种基因突变引起果蝇神经母细胞瘤的潜力 其他抑癌基因。该分析将包括定性分析 研究宿主组织对侵袭的特异性易感性和 侵袭程度的定量比较。 计划采用两种方法来调查一系列事件 始于肿瘤抑制基因功能的丧失。一是要检查 七个已识别基因的遗传等级。另一个是 利用恶性脑肿瘤基因中的温度敏感突变 筛选第二位点突变，识别下游基因 需要功能来表达侵入表型。 转移表型包括正常组织完整性的丧失和 细胞外基质的蛋白水解作用增加。其中之一或两者 该过程可以由明胶酶介导。前期工作已取得 检测三种具有明胶酶活性的果蝇蛋白 证明这三种物质之一在大脑中的积累增加 从致命的巨型幼虫突变体和侵袭性神经母细胞瘤中分离出来 源自这种突变的大脑。这种明胶酶是一种 49kDa 的蛋白质， pI 为 7.2，可与针对人类的抗体发生交叉反应 明胶酶 A. 由其他六种基因突变引起的神经母细胞瘤 还将筛选基因以增加该蛋白质的积累 与其他两种明胶酶一样。 明胶酶 7.2 基因将被克隆并 突变将在其中恢复。这些明胶酶的后果 七种肿瘤突变引起的侵袭表型突变 将检查抑制突变。这些突变将被用作 确定调节表达的上游基因的起点 肿瘤中的明胶酶 7.2 基因。最初的决定集中于 明胶酶 7.2 已由初步结果决定，由 免疫试剂的可用性以及已取得的进展 明胶酶 7.2 基因的克隆。前期工作也已 显示了果蝇幼虫中明胶酶的假定抑制剂的证据。 最终，类似的方法将应用于两者的研究 其他明胶酶和这些抑制剂。