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,

该项目的目标是识别与肿瘤发展相关的复发性基因改变，并为癌症的早期检测和预后评估提供标记，特别是实体瘤（项目现场访问 1997 年 7 月）。这一目标与 NCI 为破译各种癌症的分子解剖学而发起的重大举措是一致的。该研究主要集中在人类和小鼠诱发的肝细胞癌（HCC）上，并使用一系列最先进的分子细胞遗传学程序对其进行了研究。在人类 HCC 中，通过比较基因组杂交 (CGH)，定位了涉及多个位点的 DNA 拷贝数不平衡。 HCC 中存在 17 个新的遗传失衡，从而显着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。根据乙型肝炎病毒状态和原发肿瘤的地理起源对个体和组合 CGH 谱进行的分析显示出类似的染色体失衡模式。在过度表达 c-myc 和转化生长因子-α 的转基因小鼠的小鼠 HCC 中，鉴定出非随机染色体改变，其中涉及 5 号和 6 号染色体的易位是在小鼠或人类 HCC 中报道的第一个平衡改变。该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，遗传变化的优先位点被确定为涉及早期发育不良肝脏损伤中的损伤位点的几条染色体的反复稳定重排的断点。总体而言，新的复发性基因组改变和与 HCC 发展相关的基因的鉴定为这种肿瘤的分子基础提供了新的见解，并为未来完成肝癌基因组解剖学的研究提供了框架。 CGH 和光谱核型相结合是检测整个肿瘤基因组的基因组失衡和结构重组的最强大方法。该方法用于阐明宫颈癌 HeLa 细胞中克隆异常染色体的有争议的起源。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分辨率水平。此外，在其他技术无法检测到的隐秘易位位点检测到分散的乳头瘤病毒-18副本，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一步。我们在人类肝癌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脆弱性和重组区域。脆性组氨酸三联体 (FHIT) 是一种跨越高脆性区域 3p14.2 的肿瘤抑制基因，在多种癌症中经常发生改变，特别是上皮细胞来源的癌症和与已知致癌物质相关的癌症。 HCC与乙型和丙型肝炎病毒感染、膳食黄曲霉毒素、饮酒和接触化学致癌物等致癌因素密切相关。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，在 66% 的细胞系中发现了 FHIT mRNA 表达减少或缺失，在 50% 的原发性肿瘤中发现了基因内缺失和蛋白质表达缺失，表明 FHIT 改变在病理上与 HCC 的发展相关。我们和其他实验室分离的几个新基因通过 FISH 进行染色体定位，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，从用 SV40 病毒转化的人类细胞中分离出属于卫星 1 DNA 特定序列亚家族的重复序列，并将其独特地分配给 4 号染色体的着丝粒。这些定位将有助于识别未知病因遗传疾病中位于相同染色体区域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、