DEREGULATION OF ONCOGENE EXPRESSION IN HUMAN TUMORS

人类肿瘤中癌基因表达的失调

• 批准号: 3180921
• 负责人: SUSAN M ASTRIN
• 金额: $ 32.35万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-07-01 至 1994-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3180921
• 关键词: B lymphocyte; Burkitt's lymphoma; DNA directed RNA polymerase; DNA footprinting; RNA biosynthesis; RNA splicing; Retroviridae; adenocarcinoma; bioassay; cell transformation; chromosome translocation; colon neoplasms; gel electrophoresis; gene deletion mutation; gene expression; gene rearrangement; gene therapy; genetic enhancer element; genetic mapping; genetic transcription; human population genetics; hybrid cells; immunoglobulin genes; lac operon; major histocompatibility complex; molecular cloning; molecular oncology; neoplasm /cancer genetics; neoplastic cell culture for noncancer research; nucleic acid probes; nucleic acid sequence; oncogenes; point mutation; protooncogene; tissue /cell culture; transcription factor; transfection; transposon /insertion element

The long range objective of this proposal is to elucidate the importance of two classes of mechanisms of deregulation of proto- oncogenes in human tumors; that is, mutations in the proto- oncogenes itself (cis-acting) and mutations in trans-acting regulators. The studies focus on c-myc because this gene is expressed in many different types of human tumors. What is the importance of c-myc expression in these tumors? The expression is presumed to be due to mutation that affect the myc regulatory circuit. What are the different types of mutations that have this effect? The aims of this proposal include an analysis of cis- acting alterations in two different myc loci clones from human tumors. In one case, a LINE-1 sequence (one of a family of repetitive transposable elements present in thousands of copies in the human genome) has become inserted into intron 2 of myc. The insertion is tumor specific. The insertion will be cloned and sequenced and analyzed for the presence of enhancer elements and for the capacity to code for proteins involved in the process of transposition. The second locus under study produces myc message levels 50 times greater than those found in normal leukocytes. The locus contains multiple deletions, insertions, duplications, and point mutations. The exact role of each of these aberrations in the deregulation will e determine. A second aim of this proposal is to analyze trans-acting alterations that result in deregulation of c-myc in two thirds of human adenocarcinomas of the colon. Experiments employing somatic cell hybrids between cells expressing regulated c-myc and colon carcinoma cells expressing deregulated myc result in hybrid cells in which myc is regulated normally. A working hypothesis, based on the results of this experiments, is that genetic defects in the colon carcimona cell parent have inactivated both alleles of a trans-acting locus that regulates myc (such as a repressor) and that the defects are complemented by an intact locus in the parent expressing regulated myc. These experiments will be pursued to determine how many such trans-acting loci there might be, what human chromosomes they map to, an what the molecular mechanism is by which lesions in these loci result in deregulation of c-myc. This work might ultimately have clinical significance in that the normal alleles of these genes could be cloned and supplied to the tumor cells through the use of suitable vectors such aS retroviruses. Through the use of such "gene transplant therapy" the transformed phenotype of the tumor cells might be reversed.

这项提议的长期目标是澄清 论两类原管制放松机制的重要性 人类肿瘤中的癌基因；也就是说，原癌基因突变- 癌基因本身(顺式作用)与反式作用突变 监管者。这些研究集中在c-myc上，因为这个基因是 在许多不同类型的人类肿瘤中表达。什么是 C-myc在这些肿瘤中表达的重要性？表达式是 推测是由于影响myc调控的突变所致 巡回赛。有哪些不同类型的突变会导致这种情况 效果如何？这项建议的目的包括分析独联体-- 人类两个不同myc基因座克隆的作用改变 肿瘤。在一种情况下，行-1序列( 重复的转座元件存在于数千个拷贝中 人类基因组)已插入myc的内含子2。这个 插入是肿瘤特有的。插入内容将被克隆并 对增强子元件的存在进行了测序和分析 对于编码参与蛋白质的过程的能力 换位。研究中的第二个基因座产生myc消息 其含量是正常白细胞的50倍。 该基因座包含多个缺失、插入、重复、 和点突变。每一种像差的确切作用 在放松管制的情况下，将会决定。这样做的另一个目的是 建议是分析导致以下情况的交互变化 C-myc基因在三分之二的人肺腺癌中的表达 冒号。利用体细胞在细胞间杂交的实验 表达调控的c-myc与结肠癌细胞表达 解除对myc的调控导致杂交细胞中的myc受到调控 通常是这样的。一个工作假说，基于这一结果 实验表明，结肠癌细胞中的基因缺陷 父母已经灭活了一个反式作用基因座的两个等位基因 调节myc(如抑制子)，并且缺陷是 由亲本中完整的基因座补充，表达受调控 MYC。这些实验将继续进行，以确定有多少这样的 可能有反式作用的基因座，它们映射了哪些人类染色体 这些病变的分子机制是什么？ 基因座导致c-myc基因失控。这项工作最终可能 具有临床意义的是这些基因的正常等位基因 基因可以被克隆并通过 使用适当的载体，如逆转录病毒。通过使用 这种“基因移植疗法”改变了人的表型。 肿瘤细胞可能会逆转。