Molecular Pathogenesis of MDS and CMML

MDS 和 CMML 的分子发病机制

• 批准号: 8197800
• 负责人: Jaroslaw P Maciejewski
• 金额: $ 39.25万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-29 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8197800
• 关键词: Acquired uniparental disomy; Acute Myelocytic Leukemia; Adopted; Affect; Area; Blood Cells; Bone Marrow; CD3 Antigens; Cells; Chromosome abnormality; Chronic Myelomonocytic Leukemia; Clinical; Complement; Cytogenetic Analysis; Cytogenetics; DNA; Defect; Detection; Development; Diagnosis; Diagnostic; Disease; Disease Progression; Dysmyelopoietic Syndromes; Dysplasia; Evolution; Fingers; Frequencies; Gene Mutation; Genes; Genome Scan; Genomics; Germ Lines; Hematopoiesis; Hematopoietic stem cells; Heterogeneity; In Vitro; Individual; Investigation; Karyotype; Karyotype determination procedure; Knock-in Mouse; Lead; Lesion; Link; Loss of Heterozygosity; Maps; Marrow; Mediating; Metaphase; Methods; Molecular; Molecular Target; Mutation; Myelodysplastic/Myeloproliferative Disease; Oncogenes; Oncogenic; Outcome; Pancytopenia; Pathogenesis; Pathologic; Pathway interactions; Patients; Play; Production; Receptor Protein-Tyrosine Kinases; Recurrence; Resolution; Ring Finger Domain; Risk; Role; Sampling; Scheme; Signal Transduction; Signal Transduction Pathway; Single Nucleotide Polymorphism; Sorting - Cell Movement; Testing; Translations; Tumor Suppressor Proteins; Unbalanced Translocation; Uniparental Disomy; Variant; alpha-Thalassemia; attenuation; base; clinical phenotype; clinical practice; cytopenia; design; improved; leukemia; mutant; new therapeutic target; outcome forecast; prognostic; proto-oncogene protein c-cbl; public health relevance; src-Family Kinases; theories; therapeutic target; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): In myelodysplastic syndrome (MDS) chromosomal abnormalities play an important diagnostic and prognostic role, pointing towards possible disease-causing pathways. However, using traditional metaphase cytogenetics (MC), chromosomal lesions can be found in only about 50% of patients; higher resolution methods may allow for detection of cryptic chromosomal lesions in patients with normal and abnormal MC. Detection of such defects could facilitate identification of novel therapeutic targets, aid diagnosis and improve current prognostic schemes by explaining phenotypic heterogeneity within established MDS subtypes. Single nucleotide polymorphism arrays (SNP-A) are a new method for high resolution karyotyping and detection of unbalanced DNA defects including somatic uniparental disomy (UPD). We have demonstrated that somatic UPD is very frequent in MDS and hypothesized that shared regions of UPD may point towards mutations of genes involved in the development of MDS. In particular areas of somatic UPD have been linked to the presence of biallelic mutations, such as Jak2 (UPD9p) and Ftl3 (UPD13q). Based on this theory we mapped invariant UPD and deletions in a large group of patients with MDS and found that UPD11q was particularly frequent in patients with chronic myelomonocytic leukemia. By sequencing the c-Cbl gene, an E3 ubiquitin ligase in this chromosomal region, a mutation involving a critical part of this gene was identified. In this proposal we plan to test the clinical utility of SNP-A karyotyping and establish its impact on prognosis, clinical phenotype and the discovery of new molecular targets in MDS. In SA1 we will analyze paired samples (bone marrow and sorted CD3+ cells as a clonal control) from patients with MDS using the Affymetrix 6.0 SNP array. New invariant clonal lesions, in particular somatic UPD, will be identified, mapped and their impact on clinical phenotypes, survival and progression analyzed. The influence of newly detected lesions will be assessed in the context of IPSS to improve prognostic accuracy. In SA2, as a proof of concept that recurrent somatic UPD points towards important mutations, we will analyze in detail patients with UPD11q and c-Cbl mutations and determine the frequency and clinical outcomes of this mutation associated with this lesion. We will perform in vitro studies to delineate the effect of c-Cbl mutations on tyrosine kinase receptors and Src family kinases and explain whether pathologic mechanisms are mediated by mutant c-Cbl. For example, we will compare functional consequences of ring finger mutant knock-in vs. c-Cbl protein knockdown. Improved cytogenetic diagnostics using SNP-A karyotyping may contribute to a better understanding of the molecular pathogenesis of MDS and has the potential of identification of genes involved in the pathogenesis of MDS, perhaps pointing towards therapeutic targets for development of molecular therapies. Clinically, SNP-A-based karyotyping may complement cytogenetic diagnosis and, through the detection of previously cryptic chromosomal lesions (including UPD), may allow for better prognostic assignment. PUBLIC HEALTH RELEVANCE: Myelodysplastic syndromes (MDS) is a heterogeneous group of bone marrow failure states characterized by dysplastic hematopoiesis, deficient blood cell production and a propensity to progression to acute myelogenous leukemia (AML); this heterogeneity has greatly impeded investigations into the molecular pathogenesis and potential therapies for these diseases. We propose that single nucleotide polymorphisms arrays (SNP-A) can be applied, complementary to metaphase cytogenetics for the identification of chromosomal abnormalities, including a newly recognized class of lesion, somatic uniparental disomy. We will precisely map these lesions, identifying genes that may play a role in the disease and potentially act as targets of therapy.

描述（由申请人提供）：在骨髓增生综合征（MDS）中，染色体异常起着重要的诊断和预后作用，指向可能引起疾病的途径。但是，使用传统的中期细胞遗传学（MC），只有约50％的患者可以发现染色体病变。较高的分辨率方法可能允许检测正常和异常MC患者的隐性染色体病变。这种缺陷的检测可以促进鉴定新的治疗靶标，帮助诊断并通过解释已建立的MDS亚型内表型异质性来改善当前的预后方案。 单核苷酸多态性阵列（SNP-A）是一种高分辨率核分型和检测不平衡DNA缺陷的新方法，包括躯体独立疾病（UPD）。我们已经证明，在MDS中，体细胞UPD非常频繁，并假设UPD的共享区域可能指向MDS开发涉及的基因的突变。在躯体上的特定区域中，UPD已与存在双重突变（例如JAK2（UPD9P）和FTL3（UPD13Q））相关。基于这一理论，我们绘制了大量患有MDS患者的不变性和删除，发现Upd11q在慢性骨髓细胞性白血病患者中特别频繁。通过对该染色体区域中的E3泛素连接酶进行测序，鉴定了涉及该基因临界部分的突变。 在此提案中，我们计划测试SNP-A核分型的临床实用性，并建立对MDS中新分子靶标的预后，临床表型和发现的影响。在SA1中，我们将使用Affymetrix 6.0 SNP阵列分析来自MDS患者的配对样品（骨髓和排序的CD3+细胞作为克隆对照）。将鉴定，映射，及其对临床表型，生存和进展分析的新不变克隆病变，尤其是体细胞UPD。新检测到的病变的影响将在IPS的背景下进行评估，以提高预后准确性。在SA2中，作为概念证明，复发的体细胞upd指向重要的突变，我们将详细分析具有UPD11Q和C-CBL突变的患者，并确定与该病变相关的该突变的频率和临床结果。我们将进行体外研究，以描述C-CBL突变对酪氨酸激酶受体和SRC家族激酶的影响，并解释病理机制是否是由突变体C-CBL介导的。例如，我们将比较环手指突变体敲入与C-CBL蛋白敲低的功能后果。 使用SNP-A核分型改进的细胞遗传学诊断可能有助于更好地理解MDS的分子发病机理，并具有鉴定MDS发病机理的基因的潜力，也许指出了用于发展分子疗法的治疗靶标。在临床上，基于SNP-A的核分型可以补充细胞遗传学诊断，并通过检测先前神秘的染色体病变（包括UPD）可以更好地预后分配。 公共卫生相关性：骨髓增生性综合征（MDS）是一组异质的骨髓衰竭状态，其特征是具有发育不良的造血，血细胞的产生不足以及倾向于急性骨髓性白血病（AML）的倾向；这种异质性极大地阻碍了对这些疾病的分子发病机理和潜在疗法的研究。我们提出，可以应用单核苷酸多态性阵列（SNP-A），互补与中期细胞遗传学互补，以鉴定染色体异常，包括新认识的病变类，躯体疾病。我们将精确地绘制这些病变，鉴定可能在该疾病中起作用的基因并有可能充当治疗的靶标。