DNA Repair in Human Cancer-Prone Genetic Diseases

人类易患癌症的遗传疾病中的 DNA 修复

• 批准号: 8937627
• 负责人: KENNETH H KRAEMER
• 金额: $ 147.93万
• 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/8937627
• 关键词: 12 year old; 20 year old; 22q; Adult; Affect; Aminoglycosides; Autopsy; B-Lymphocytes; BRAF gene; Biological Assay; CDKN2A gene; Cataract; Cell Line; Cells; Cessation of life; Child; Chromosomes; Clinical; Cockayne Syndrome; Collaborations; Collection; Communities; DNA; DNA Damage; DNA Repair; DNA Repair Gene; Defect; Development; Developmental Gene; Disease; Dominant-Negative Mutation; ERCC1 gene; ERCC3 gene; Enrollment; Epidemiologist; Equilibrium; Eye; Eye Abnormalities; Family; Family member; Fetal Development; Frequencies; Functional disorder; General Population; Genes; Goals; Gynecologist; Hereditary Disease; Heterogeneity; Heterozygote; Histologic; Human; Human Development; Hypersensitivity; Individual; Infant; International; Investigation; Laboratories; Lead; Malignant Neoplasms; Messenger RNA; Methods; Molecular; Mothers; Mutation; Natural History; Necrosis, Aseptic, of Femur Head; Neurologic; Nevi and Melanomas; Nonsense Codon; Nucleotide Excision Repair; Operative Surgical Procedures; Ophthalmologist; PTEN gene; Pathway interactions; Patients; Point Mutation; Polymerase; Postoperative Period; Pregnancy; Pregnancy Complications; Process; Proteins; Protocols documentation; Publishing; RNA Splicing; Rare Diseases; Reporting; Research Personnel; Risk; Role; Series; Site; Skin Carcinoma; Sun Exposure; System; Testing; Toxic effect; Trichothiodystrophy; Tumor Suppressor Genes; Ultraviolet Rays; United States National Institutes of Health; Walking; XPA gene; Xeroderma Pigmentosum; boys; brain size; cancer prevention; cancer risk; cell bank; cohort; comparative genomic hybridization; deafness; exome sequencing; fetal; follow-up; hearing impairment; human FRAP1 protein; improved; infancy; insight; melanoma; offspring; pre-clinical; radiologist

1. XERODERMA PIGMENTOSUM We have been examining XP patients at NIH since 1971. We performed long term follow-up studies of cancer, of hearing loss and of eye abnormalities in XP patients. We found that the XP patients under age 20 years had a 10,000-fold increased risk of non-melanoma skin cancer (NMSK) and a 2000-fold increased risk of melanoma. In our natural history protocol we ascertained and intensively examined 87 XP or Cockayne Syndrome (CS) patients and 55 TTD or XP/TTD patients at NIH and are collaborating with international researchers to study additional patients. We published detailed autopsy reports of 4 XP patients - including the first autopsy of an XP-D patient. The XP-A and XP-D patients were adults with severe neurological degeneration and were found to have infant sized brains. We have now identified mutations in all of the 9 currently known DNA nucleotide excision repair (NER) genes (XPA, XPB, XPC, XPD, XPE, XPF, XPG, ERCC1 and TTDA), in the error-prone polymerase, pol eta and in TTDN1 in nearly 200 XP or TTD patients. We have established several hundred carefully documented cell lines and contributed them to cell banks for use of the general scientific community. We are using array comparative genome hybridization (aCGH) and whole exome sequencing to look for mutations in other genes in cells from XP and TTD patients who do not have mutations in these genes. Our laboratory is the major center in the US for basic, clinical and translational expertise concerning DNA repair related disorders. We are actively seeking and have developed the expertise to recognize unusual patients who have unique disease features that provide insights into the functioning of DNA repair genes. These studies have enabled us to identify some remarkable XP patients and better characterize different mechanisms of DNA repair. For example, we found XPC patients with splice lariat branch point mutations who had 3 to 5% of XPC mRNA but mild disease indicating that only a small amount of XPC is sufficient for some cancer protection. We found that NER proteins accumulate and persist at sites of DNA damage in XP-B cells. In contrast, these NER proteins rapidly accumulate but fail to persist in UV damaged XP-E cells. We found that the melanomas and nevi in the XP patients were different from those in the general population both clinically and histologically. They had a high proportion of mutations in the PTEN tumor suppressor gene (90% UV type), a lower frequency of mutations in BRAF, NRAS or KIT and rarely had the BRAF V600E mutation found in the general population. We plan to develop a protocol to attempt to reduce the melanoma risk in the XP patients by inhibition of the PTEN, mTOR pathway. About 12% of genetic diseases involve premature stop codons (PTC). We developed sensitive assay systems to detect readthrough of premature stop codons using cells from our collection with PTC in the XPC DNA repair gene. We found the aminoglycoside, gentamycin, can improve DNA repair in selected patients, permitting precise targeting of therapy to responsive individual cell lines. We are performing pre-clinical tests to determine if topical aminoglycosides can increase DNA repair without systemic toxicity. We found a 12 year old boy with melanoma, deafness and reduced DNA repair had a balanced translocation between chromosomes 9p and 22q which produced a dominant negative regulator of the tumor suppressor gene, p14arf, and the fetal developmental gene, TBX1. We are collaborating with NCI epidemiologists to study clinically normal family members of XP patients to determine if XP heterozygotes, who are much more frequent than XP patients, have increased cancer risk. We have 218 XP patients and family members in 50 families enrolled in this protocol. 2. TRICHOTHIODYSTROPHY In contrast to the profound environmental influence of sun exposure on XP, TTD is a disease of altered development. In our current natural history protocol we have ascertainedand intensively examined 55 TTD or XP/TTD patients and 104 TTD family members. This is the largest cohort of patients with this rare disorder in the world. In collaboration with gynecologists and epidemiologists we published 3 studies on pregnancy abnormalities in TTD. There was a high frequency of gestational abnormalities in pregnancies resulting in TTD affected offspring compared to pregnancies resulting in unaffected offspring from the same mothers or to the general population. These pregnancy complications were present only in pregnancies that had XP-D mutations that resulted in TTD offspring but not in XP-D mutations resulting in XP offspring. These observations provide important insights into the role of DNA repair genes in human pregnancy and fetal development. In collaboration with the ophthalmologists, we published a detailed report of the eye findings of 32 TTD patients we studied from 2001 to 2010. Infantile cataracts were present in more than half of these patients. Several young children with TTD have lost the ability to walk due to aseptic necrosis of the femoral head. Unfortunately, surgical treatment was followed by a series of post-operative complications leading to death. We are collaborating with radiologists to attempt to determine early signs of this problem and guide management. We have also found patients with features of more than one disease. Thus we identified 12 XP/TTD patients who have features of both XP and TTD and increased cancer risk. We are attempting to further define this entity by use of laboratory testing of DNA repair.

1. 色素性干皮病 自 1971 年以来，我们一直在 NIH 对 XP 患者进行检查。我们对 XP 患者的癌症、听力损失和眼睛异常进行了长期随访研究。我们发现，20 岁以下的 XP 患者患非黑色素瘤皮肤癌 (NMSK) 的风险增加 10,000 倍，患黑色素瘤的风险增加 2000 倍。在我们的自然史方案中，我们确定并深入检查了 NIH 的 87 名 XP 或科凯恩综合症 (CS) 患者和 55 名 TTD 或 XP/TTD 患者，并与国际研究人员合作研究更多患者。我们发表了 4 名 XP 患者的详细尸检报告，其中包括首次尸检 XP-D 患者。 XP-A 和 XP-D 患者是患有严重神经退行性变的成年人，并且被发现具有婴儿大小的大脑。我们现已鉴定出所有 9 个目前已知的 DNA 核苷酸切除修复 (NER) 基因（XPA、XPB、XPC、XPD、XPE、XPF、XPG、ERCC1 和 TTDA）中的突变，这些基因位于易错聚合酶、pol eta 和近 200 名 XP 或 TTD 患者中存在 TTDN1。我们已经建立了数百个经过仔细记录的细胞系，并将它们贡献给细胞库以供一般科学界使用。我们正在使用阵列比较基因组杂交 (aCGH) 和全外显子组测序来寻找 XP 和 TTD 患者细胞中其他基因的突变，这些患者的基因中没有突变。我们的实验室是美国有关 DNA 修复相关疾病的基础、临床和转化专业知识的主要中心。我们正在积极寻求并开发了专业知识来识别具有独特疾病特征的不寻常患者，从而深入了解 DNA 修复基因的功能。这些研究使我们能够识别出一些出色的 XP 患者，并更好地表征不同的 DNA 修复机制。例如，我们发现具有剪接套索分支点突变的 XPC 患者具有 3% 至 5% 的 XPC mRNA，但病情较轻，表明仅少量的 XPC 就足以提供某些癌症保护作用。我们发现 NER 蛋白在 XP-B 细胞的 DNA 损伤位点积累并持续存在。相比之下，这些 NER 蛋白在紫外线损伤的 XP-E 细胞中迅速积累，但无法持续存在。我们发现 XP 患者的黑色素瘤和痣在临床和组织学上都与普通人群不同。他们的 PTEN 抑癌基因（90% UV 型）突变比例较高，BRAF、NRAS 或 KIT 突变频率较低，并且很少有一般人群中发现的 BRAF V600E 突变。我们计划制定一项方案，尝试通过抑制 PTEN、mTOR 通路来降低 XP 患者患黑色素瘤的风险。大约 12% 的遗传病涉及过早终止密码子 (PTC)。我们开发了灵敏的检测系统，使用我们收集的 XPC DNA 修复基因中带有 PTC 的细胞来检测过早终止密码子的通读。我们发现氨基糖苷类庆大霉素可以改善特定患者的 DNA 修复，从而可以将治疗精确靶向有反应的个体细胞系。我们正在进行临床前测试，以确定外用氨基糖苷类药物是否可以增强 DNA 修复而不产生全身毒性。我们发现一名患有黑色素瘤、耳聋和 DNA 修复减少的 12 岁男孩在 9p 和 22q 染色体之间存在平衡易位，产生肿瘤抑制基因 p14arf 和胎儿发育基因 TBX1 的显性负调节因子。我们正在与 NCI 流行病学家合作，研究 XP 患者临床正常的家庭成员，以确定 XP 杂合子（比 XP 患者更常见）是否会增加癌症风险。我们有 50 个家庭的 218 名 XP 患者和家庭成员参加了该方案。 2. 毛硫营养不良症 与阳光照射对 XP 的深刻环境影响相比，TTD 是一种发育改变的疾病。在我们目前的自然史方案中，我们已经确定并深入检查了 55 名 TTD 或 XP/TTD 患者和 104 名 TTD 家庭成员。这是世界上最大的患有这种罕见疾病的患者群体。我们与妇科医生和流行病学家合作，发表了 3 项关于 TTD 妊娠异常的研究。与同一母亲或一般人群的未受影响后代的怀孕相比，导致 TTD 影响后代的妊娠异常发生率较高。这些妊娠并发症仅存在于具有导致 TTD 后代的 XP-D 突变的妊娠中，但不存在于导致 XP 后代的 XP-D 突变的妊娠中。这些观察结果为了解 DNA 修复基因在人类妊娠和胎儿发育中的作用提供了重要的见解。我们与眼科医生合作，发表了一份关于 2001 年至 2010 年间研究的 32 名 TTD 患者眼部检查结果的详细报告。其中一半以上的患者患有婴儿白内障。一些患有 TTD 的幼儿因股骨头无菌性坏死而丧失了行走能力。不幸的是，手术治疗后出现了一系列术后并发症，导致死亡。我们正在与放射科医生合作，试图确定这个问题的早期迹象并指导管理。我们还发现患者患有不止一种疾病的特征。因此，我们确定了 12 名 XP/TTD 患者，他们同时具有 XP 和 TTD 特征，且癌症风险增加。我们正尝试通过 DNA 修复实验室测试来进一步定义这个实体。