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使用 果蝇作为模型系统，调查一系列事件的级联 始于肿瘤抑制基因功能的功能，并在 介导这种侵入性的效应基因表达的改变 作为明胶酶及其抑制剂。七个果蝇肿瘤抑制剂 基因已通过引起幼虫过度生长的突变鉴定 大脑。这种类型的最佳研究基因的突变，致命的巨人 幼虫，导致正常组织结构的丧失，并失去了能力 想象神经细胞的区分。神经母细胞瘤的侵入性 将这种突变大脑衍生的细胞移植到成年 使用细胞自主标记证实了宿主。一个目的 建议是使用这种细胞标记方法来分析侵入性 六个突变引起的果蝇神经母细胞瘤的潜力 其他肿瘤抑制基因。该分析将包括定性 研究宿主组织特异性侵袭和A的研究 侵入性程度的定量比较。 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。一个是检查 七个已经鉴定的基因的遗传层次结构。另一个是 在恶性脑肿瘤基因中使用温度敏感突变 筛选第二个位点突变，这些突变识别下游基因 表达侵入性表型需要功能。 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增加。这些或两个 过程可以由明胶酶介导。初步工作导致了 检测三种具有明胶活性的果蝇蛋白和 证明这三个在大脑中的积累增加了 从致命的巨型幼虫突变体和侵入性神经母细胞瘤中解剖 源自这种突变大脑。该明胶酶是一种49KDA蛋白 7.2的PI与针对人类的抗体进行交叉反应 明胶酶A.其他六个突变引起的神经母细胞瘤 基因也将筛选以增加该蛋白的积累 作为另外两个明胶酶。 明胶酶7.2基因将被克隆，并且 突变将在其中恢复。这些明胶酶的后果 由七个肿瘤突变引起的侵入性表型的突变 将检查抑制突变。这些突变将被用作 识别调节表达表达的上游基因的起点 明胶酶7.2肿瘤中的基因。最初专注于 明胶酶7.2已由初步结果决定， 免疫试剂的可用性，并且通过已经取得的进展 朝着明胶酶7.2基因的克隆。初步工作也有 显示了果蝇幼虫中明胶酶假定抑制剂的证据。 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。