MOLECULAR CYTOGENETICS OF SOLID TUMORS

实体瘤的分子细胞遗传学

• 批准号: 6289309
• 负责人: NICOLAE POPESCU
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6289309
• 关键词: Kaposi's sarcoma; animal genetic material tag; artificial chromosomes; cervix neoplasms; chromosome aberrations; chromosome deletion; chromosome translocation; cytogenetics; early diagnosis; fluorescent in situ hybridization; genetic mapping; genetic markers; hamsters; human genetic material tag; human tissue; karyotype; laboratory rat; loss of heterozygosity; molecular oncology; neoplasm /cancer diagnosis; neoplasm /cancer genetics; nucleic acid probes; prognosis

The objective of this project is the identification of recurrent genetic alterations that are relevant to neoplastic development and to provide markers for early detection and prognostic assessment of cancer, particularly in solid tumors (project Site Visit July 1997). This objective is consistent with the major initiative launched by the NCI to decipher the molecular anatomy of various cancers. The research focuses primarily on human- and mouse-induced hepatocellular carcinoma (HCC) that were investigated using a battery of the most advanced molecular cytogenetic procedures. In human HCC, by comparative genomic hybridization (CGH), DNA copy-number imbalances involving multiple sites were localized. Seventeen genetic imbalances are novel in HCC, thus extending significantly the map of genetic changes and providing a starting point for the isolation of new genes relevant in pathogenesis of liver neoplasia, as well as providing molecular probes for both diagnosis and monitoring treatment of the disease. The analysis of individual and combined CGH profiles based on hepatitis B-virus status and the geographic origin of the primary tumors showed a similar pattern of chromosome imbalances. In mouse HCC from transgenic mice overexpressing c-myc and transforming growth factor-alpha, nonrandom chromosomal alterations were identified among which a translocation involving chromosomes 5 and 6 is the first balanced alteration reported in mouse or human HCC. The breakpoint of this translocation is located near a tumor susceptibility gene and the site of myc transgene integration. More particularly, preferential sites of genetic changes were identified as the breakpoints in recurrent stable rearrangements of several chromosomes involved the sites of damage in early dysplastic liver lesions. Overall, the identification of novel recurrent genomic alterations and genes relevant to the development of HCC provides new insight in the molecular basis of this neoplasia and serve as a framework for future investigations toward the completion of genomic anatomy of liver cancer. Combined CGH and spectral karyotype is the most powerful approach for detection of genomic imbalances and structural reorganization across the entire tumor genome. This approach was applied to elucidate the disputed origin of clonally abnormal chromosomes in cervical carcinoma HeLa cells. The complete derivation of all complex abnormalities underlines the current level resolution of molecular cancer chromosome analysis. Furthermore, the detection of dispersed copies of papillomavirus-18 at the sites of cryptic translocations undetectable by other techniques demonstrated that viral integration triggered genomic instability, a critical step in tumor development. Two newly discovered recurrent unbalanced translocations identified in our studies of human HCC involved regions of genomic fragility and recombination. Fragile histidine triad (FHIT), a tumor suppressor gene spanning the region 3p14.2 of high fragility, is frequently altered in several cancers, particularly those of epithelial cell origin and associated with known carcinogenic agents. HCC is closely related with carcinogenic agents such as hepatitis B and C virus infections, dietary aflatoxin, alcohol consumption, and exposure to chemical carcinogens. We identified chromosome rearrangements of the short arm of chromosome 3 in 61% of the HCC cell lines, a decreased or absent FHIT mRNA expression in 66% of the lines, and intragenic deletions and absence of protein expression in 50% of primary tumors, indicating that FHIT alterations are pathologically relevant to the development of HCC. Several new genes isolated in our and other laboratories were chromosomally localized by FISH and include: human GFR alpha 3, Stat 6 cyclin I, palmitol-protein, thioesterase genes and mouse arylalkylamine N-acetyltransferase (AANAT), cyclin G2, cyclin I, and Bog genes. In addition, a repetitive sequence belonging to a subfamily of satellite 1 DNA specific sequences was isolated from human cells transformed with SV40 virus and was assigned uniquely to the centromere of chromosome 4. These localizations will facilitate the identification of loci in genetic diseases of unknown etiology mapping at the same chromosomal regions and their involvement in neoplasia. - Chromosome alterations, Comparative genomic hybridization, Deletion translocations, Fluorescence in situ hybridization,

该项目的目的是确定与肿瘤发展有关的复发性基因改变，并为癌症，特别是实体瘤的早期发现和预后评估提供标记（1997年7月项目现场访问）。这一目标与NCI发起的破译各种癌症分子解剖结构的主要倡议是一致的。该研究主要集中在人类和小鼠诱导的肝细胞癌（HCC）上，使用一系列最先进的分子细胞遗传学方法进行了研究。在人类HCC中，通过比较基因组杂交（CGH），涉及多个位点的DNA拷贝数失衡被定位。17种基因失衡在HCC中是新的，从而显著扩展了遗传变化图谱，为分离与肝肿瘤发病机制相关的新基因提供了起点，并为该疾病的诊断和监测治疗提供了分子探针。基于乙肝病毒状态和原发肿瘤地理来源的个体和联合CGH分析显示了类似的染色体失衡模式。在来自过表达c-myc和转化生长因子- α的转基因小鼠的小鼠HCC中，发现了非随机染色体改变，其中涉及5号和6号染色体的易位是首次在小鼠或人类HCC中报道的平衡改变。这种易位的断点位于肿瘤易感基因和myc转基因整合位点附近。更具体地说，遗传变化的优先位点被确定为几个染色体反复稳定重排的断点，这些染色体涉及早期发育不良肝病变的损伤位点。总之，鉴定新的复发性基因组改变和与HCC发展相关的基因为这种肿瘤的分子基础提供了新的见解，并为未来完成肝癌的基因组解剖研究提供了框架。结合CGH和谱核型是检测整个肿瘤基因组的基因组失衡和结构重组最有效的方法。该方法用于阐明宫颈癌HeLa细胞中有争议的克隆异常染色体的起源。所有复杂异常的完整推导强调了分子癌症染色体分析的当前水平分辨率。此外，在其他技术无法检测到的隐易位位点检测到分散的乳头瘤病毒-18拷贝，这表明病毒整合引发了基因组不稳定性，这是肿瘤发展的关键步骤。我们在人类HCC研究中发现的两个新发现的复发性不平衡易位涉及基因组易碎性和重组区域。脆性组氨酸三联体（FHIT）是一种跨越3p14.2高脆性区域的肿瘤抑制基因，在几种癌症中经常发生改变，特别是那些上皮细胞起源的癌症，并与已知的致癌物质相关。HCC与致癌物密切相关，如乙型和丙型肝炎病毒感染、饮食黄曲霉毒素、饮酒和接触化学致癌物。我们在61%的HCC细胞系中发现了3号染色体短臂的染色体重排，66%的细胞系中FHIT mRNA表达减少或缺失，50%的原发肿瘤中基因内缺失和蛋白表达缺失，表明FHIT改变与HCC的发展在病理上相关。我们和其他实验室分离的几个新基因通过FISH进行了染色体定位，包括：人GFR α 3、Stat 6细胞周期蛋白I、棕榈醇蛋白、硫酯酶基因和小鼠芳基烷基胺n -乙酰转移酶（AANAT）、细胞周期蛋白G2、细胞周期蛋白I和Bog基因。此外，从SV40病毒转化的人细胞中分离出一个属于卫星1 DNA特异性序列亚家族的重复序列，并将其唯一地分配到4号染色体的着丝粒上。这些定位将有助于在同一染色体区域定位未知病因的遗传疾病的位点及其与肿瘤的关系。-染色体改变，比较基因组杂交，缺失易位，荧光原位杂交，