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,

该项目的目标是确定与肿瘤发展有关的反复发生的基因改变，并为癌症，特别是实体肿瘤的早期发现和预后评估提供标记(项目现场访问，1997年7月)。这一目标与NCI发起的破译各种癌症的分子解剖学的重大倡议是一致的。这项研究主要集中在人类和小鼠诱导的肝细胞癌(肝细胞癌)，这是使用一系列最先进的分子细胞遗传学程序进行研究的。在人肝细胞癌中，通过比较基因组杂交(CGH)定位了涉及多个位点的DNA拷贝数失衡。17个基因不平衡在肝细胞癌中是新发现的，从而极大地扩展了基因改变的图谱，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图谱分析显示，染色体不平衡的模式相似。在高表达c-myc和转化生长因子-α的转基因小鼠的肝癌中，发现了非随机的染色体改变，其中涉及5号和6号染色体的易位是第一个在小鼠或人的肝癌中报道的平衡改变。该易位的断裂点位于肿瘤易感基因和myc转基因整合部位附近。更具体地说，遗传改变的优势部位被确定为早期发育不良肝脏病变中涉及损害部位的几条染色体反复稳定重排的断点。总之，新的复发基因组改变和与肝细胞癌发生发展相关的基因的识别为了解这种肿瘤的分子基础提供了新的见解，并为进一步研究完成肝癌的基因组解剖学提供了一个框架。结合CGH和光谱核型是检测基因组失衡和整个肿瘤基因组结构重组的最有效的方法。该方法被应用于阐明宫颈癌HeLa细胞克隆性异常染色体的有争议的来源。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蔽易位部位检测到分散的乳头瘤病毒-18拷贝表明，病毒整合引发了基因组不稳定，这是肿瘤发展的关键步骤。在我们对人类肝癌的研究中发现了两个新发现的反复不平衡易位，涉及基因组脆弱和重组区域。脆性组氨酸三联体(FHIT)是一种跨越高脆性区域3p14.2区域的肿瘤抑制基因，在多种癌症中经常发生改变，特别是那些起源于上皮细胞的癌症，并与已知的致癌物质有关。肝细胞癌与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等致癌物质密切相关。我们在61%的肝癌细胞系中发现了3号染色体短臂的染色体重排，66%的细胞系中FHIT mRNA表达降低或缺失，50%的原发肿瘤中FHIT基因内缺失和蛋白表达缺失，表明FHIT改变与肝癌的发生发展有关。本实验室和其他实验室分离到的几个新基因被FISH定位，包括：人GFRα3、Stat 6、细胞周期蛋白I、棕榈醇蛋白、硫酯酶基因和小鼠芳香胺N-乙酰基转移酶基因、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到一个属于卫星1DNA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。这些定位将有助于在相同染色体区域定位不明原因的遗传病的基因座及其与肿瘤的关系。-染色体改变，比较基因组杂交，缺失易位，荧光原位杂交，