Functional analysis of leukemic CREBBP mutations

白血病CREBBP突变的功能分析

• 批准号: 8683126
• 负责人: Charles G. Mullighan
• 金额: $ 35.22万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8683126
• 关键词: ABL1 gene; Acetylation; Acute Lymphocytic Leukemia; Affect; Aftercare; Apoptosis; B-Cell Acute Lymphoblastic Leukemia; B-Cell NonHodgkins Lymphoma; Binding; Biological; CREB-binding protein; CREBBP gene; Cancer Relapse; Cells; Cessation of life; Characteristics; Common Neoplasm; Data; Deacetylase; Development; Diagnosis; EP300 gene; Epigenetic Process; Family; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Genomics; Genotype; Glucocorticoid Receptor; Glucocorticoids; Goals; Histone Acetylation; Histone Deacetylase Inhibitor; Human; Immunocompromised Host; In Vitro; Knock-in Mouse; Knock-out; Knockout Mice; Knowledge; Lead; Lesion; Leukemic Cell; Malignant Childhood Neoplasm; Malignant Neoplasms; Measures; Mediating; Modeling; Mus; Mutate; Mutation; N-terminal; Nuclear; Outcome; Outcome Study; Pathway interactions; Patient Care; Pharmaceutical Preparations; Pharmacotherapy; Predisposition; Primary Neoplasm; Protein Acetylation; Proteins; Publishing; Recurrent disease; Relapse; Research; Resistance; Sampling; System; Testing; Therapeutic Uses; Vorinostat; Work; Xenograft procedure; alternative treatment; base; bladder transitional cell carcinoma; cancer therapy; cancer type; chromatin immunoprecipitation; histone acetyltransferase; histone modification; human CREBBP protein; in vivo; inhibitor/antagonist; insight; leukemia; mutant; neoplastic cell; null mutation; receptor function; response; therapy resistant; treatment response; tumor

DESCRIPTION (provided by applicant): The constellation of mutations and epigenetic alterations (e.g. histone modifications) that promote cancer development and its resistance to treatment are incompletely understood. Significantly, recent genomic sequencing studies to define the mutational spectrum of relapsed acute lymphoblastic leukemia (ALL), B cell non-Hodgkin lymphoma, and transitional cell carcinoma of the bladder have identified lesions in the two genes encoding the KAT3 family of histone acetyltransferases, CREB-binding protein (CBP, CREBBP) and EP300 (p300). ALL is the most common childhood cancer and the focus of this proposal. Relapsed ALL is the leading cause of non-traumatic death in young people, and resistance to glucocorticoids is a hallmark of treatment resistant ALL cells, the basis of which is poorly understood. CREBBP alterations found in ALL include N-terminal frame-shift and termination mutations that disturb or delete many domains, but also lesions that specifically affect the histone acetyltransferase (HAT) domain and the Nuclear Coactivator Binding Domain (NCBD) that is involved in glucocorticoid receptor function. The long-term goal is to understand how CREBBP mutations contribute to leukemia progression and its resistance to treatment. The objective for this proposal is to determine how CREBBP leukemic mutations affect glucocorticoid-responsive transcription and the response of leukemia cells to glucocorticoid and histone deacetylase inhibitor (HDACi) therapies. Based upon the applicants' published and preliminary data, the central hypothesis states that leukemic cells with null and hypomorphic mutations in CREBBP have altered gene expression that decreases apoptosis in response to glucocorticoids, but such cells have increased susceptibility to drug therapies that increase protein acetylation. The rationale for the proposed research is that ALL-associated mutations found in certain functional domains of the transcriptional "hub" protein CREBBP provide clues to the altered biological pathways that promote leukemia progression and resistance to standard therapies. Once identified, these pathway alterations in CREBBP mutant ALL cells can potentially be exploited by the use of alternative treatments. Three specific aims test the central hypothesis. Aim 1 is to define how mutant Crebbp affects glucocorticoid-responsive gene expression. Aim 2 is to determine how Crebbp mutations enhance the progression of leukemia in mice. Aim 3 is to establish how CREBBP mutations affect the response of human ALL xenografts to histone deacetylase inhibitors and glucocorticoids. The expected outcome of these studies will provide new mechanistic insight into ALL by determining how ALL-associated CREBBP mutations impact: 1) the transcriptional response to glucocorticoids, 2) the development and progression of leukemia, and 3) the anti-leukemia effects of glucocorticoids and histone deacetylase inhibitors. The translational impact of the results will be to enhance the knowledge-driven therapeutic use of glucocorticoids and HDACi to treat leukemia based on tumor cell genotype.

描述（由申请人提供）：促进癌症发展及其对治疗的抵抗力的一系列突变和表观遗传改变（例如组蛋白修饰）尚不完全清楚。值得注意的是，最近的基因组测序研究确定了复发性急性淋巴细胞白血病 (ALL)、B 细胞非霍奇金淋巴瘤和膀胱移行细胞癌的突变谱，发现了编码组蛋白乙酰转移酶 KAT3 家族的两个基因、CREB ​​结合蛋白 (CBP、CREBBP) 和 EP300（p300）。 ALL 是最常见的儿童癌症，也是本提案的重点。复发性 ALL 是年轻人非创伤性死亡的主要原因，而对糖皮质激素的抵抗是治疗抵抗性 ALL 细胞的一个标志，其基础是 不太了解。 ALL 中发现的 CREBBP 改变包括 N 端移码和终止突变，这些突变会扰乱或删除许多结构域，而且还包括特异性影响组蛋白乙酰转移酶 (HAT) 结构域和参与糖皮质激素受体功能的核辅激活剂结合结构域 (NCBD) 的病变。长期目标是了解 CREBBP 突变如何导致白血病进展及其对治疗的耐药性。该提案的目的是确定 CREBBP 白血病突变如何影响糖皮质激素反应性转录以及白血病细胞对糖皮质激素和组蛋白脱乙酰酶抑制剂 (HDACi) 疗法的反应。根据申请人已发表的初步数据，中心假设指出，CREBBP中具有无效突变和低等态突变的白血病细胞已经改变了基因表达，从而减少了响应糖皮质激素的细胞凋亡，但此类细胞对增加蛋白质乙酰化的药物治疗的敏感性增加。这项研究的基本原理是，在转录“中心”蛋白 CREBBP 的某些功能域中发现的 ALL 相关突变为促进白血病进展和对标准疗法产生耐药性的生物途径改变提供了线索。一旦确定，CREBBP 突变 ALL 细胞中的这些途径改变可能可以通过使用替代疗法来利用。三个具体目标考验中央 假设。目标 1 是确定突变体 Crebbp 如何影响糖皮质激素反应基因表达。目标 2 是确定 Crebbp 突变如何促进小鼠白血病的进展。目标 3 是确定 CREBBP 突变如何影响人类 ALL 异种移植物对组蛋白脱乙酰酶抑制剂和糖皮质激素的反应。这些研究的预期结果将通过确定 ALL 相关 CREBBP 突变如何影响 ALL 提供新的机制见解：1）对糖皮质激素的转录反应，2）白血病的发生和进展，以及 3）糖皮质激素和组蛋白脱乙酰酶抑制剂的抗白血病作用。结果的转化影响将是增强糖皮质激素和 HDACi 的知识驱动治疗用途，以治疗基于肿瘤细胞基因型的白血病。