Genome-wide Identification of DNA Methylation Biomarkers in AML

描述(由申请人提供)：DNA去甲基化药物(HMA)有望显著促进急性髓细胞白血病(AML)的治疗。这些药物在老年患者中耐受性良好，他们既代表了大多数成人AML，也代表了那些传统的强化化疗效果最差的患者。HMAS的剂量和给药时间表强烈地决定了生物活性，但这些药物的药效学知之甚少。缺乏良好的DNA甲基化生物标志物正在减缓AML表观遗传治疗的发展。这项研究的长期目标是开发有效和耐受性良好的AML疗法，其中包括最佳剂量的表观遗传修饰剂。本应用的目的是确定可用于评估AML白血病干细胞/祖细胞(LSPC)中HMAS活性的DNA甲基化生物标志物。中心假设是，当HMA活性的药效学生物标志物在AML LSPC中报告疗效时，它们具有最大的临床/生物学相关性。拟议研究的基本原理是，一旦发现AML特有的DNA甲基化异常，它们就可以用来在临床试验中评估HMAS的药效学活性，该试验旨在优化这些药物用于治疗AML的剂量和给药时间表。这一假说将通过追求两个具体目标来检验：目标1：识别AML的DNA甲基化生物标记物。目的：探讨外周血细胞能否作为评估地他滨诱导的急性髓系白血病细胞DNA低甲基化的替代组织。在第一个目标下，一种已被证明在申请者手中可行的全基因组DNA甲基化分析方法将被用于识别CD34选择的原代人类AML LSPC中的AML特异性异常，与从健康捐赠者获得的正常造血细胞进行比较。第二个目标将使用在几个不同的地西他滨给药方案之前和之后从AML患者那里获得的先前收集的、匹配的血液和骨髓样本，以确定适合于外周血细胞药效监测的AML特异性DNA甲基化生物标记物。这些结果有望为目前和未来的DNA去甲基化药物的临床发展带来积极的影响，因为它们提供了一种长期追求的方法来评估这些药物在体内的生物活性。这一贡献意义重大，因为这是一系列研究中必要的第一步，预计将产生药效学定制剂量的表观遗传修饰剂，最大限度地发挥抗白血病活性，同时将毒性降至最低。提出的这项研究是创新的，因为它与目前在混合细胞群体中几个方便的基因组座位上测量DNA甲基化的标准有很大不同--在DNA HMA交付很长时间后。最终，拟议的在LSPC中识别AML特异性DNA甲基化生物标记物的全基因组范围，以及用于评估药效学的细胞替代品的验证，应该能够使AML的HMA治疗时间表快速优化，甚至个性化。 公共卫生相关性：拟议的研究与公共健康相关，因为药效学的AML特异性DNA甲基化生物标记物的识别最终有望导致DNA低甲基化药物的优化剂量方案，降低毒性和最大的抗白血病活性。这项工作与NIH改善健康的目标是一致的，NCI的使命是支持推进癌症治疗的研究，并对FOA做出回应，考虑到将基础科学转移到临床应用的全部潜在信息特征，为提出DNA甲基化生物标记提供了强有力的理由，以解决目前快速和合理开发用于AML治疗的低甲基化药物的障碍。

DESCRIPTION (provided by applicant): DNA hypomethylating agents (HMA) promise to significantly advance the treatment of acute myelogenous leukemia (AML). The drugs are well tolerated in older patients who represent both the majority of adult AML, and those least well served by traditional, intensive chemotherapy. The dose and delivery schedule of HMAs strongly dictate biological activity but the pharmacodynamics of these agents is poorly understood. The absence of good biomarkers of DNA methylation is slowing the development of epigenetic therapy in AML. The long-term goal of this research is to develop effective and well-tolerated AML therapies that incorporate optimally dosed epigenetic modifiers. The objective of this application is to identify DNA methylation biomarkers that can be used to assess the activity of HMAs in AML leukemia stem/progenitor cells (LSPCs). The central hypothesis is that pharmacodynamic biomarkers of HMA activity have greatest clinical/biological relevance when they report efficacy within AML LSPCs. The rationale for the proposed studies is that, once AML-specific DNA methylation abnormalities are discovered, they can be used to assess the pharmacodynamic activity of HMAs in clinical trials designed to optimize the dose and delivery schedule of these agents for the treatment of AML. The hypothesis will be tested by pursuing two specific aims: Aim 1: Identify DNA methylation biomarkers of AML. Aim 2: Determine whether peripheral blood cells can be used as a surrogate tissue to assess decitabine-induced DNA hypomethylation in AML LSPCs. Under the first aim, a proven method for genome-wide analyses of DNA methylation that has already been established to be feasible in the applicants' hands, will be used to identify AML-specific abnormalities in CD34-selected primary, human AML LSPCs when compared to normal hematopoietic cells obtained from healthy donors. The second aim will use previously collected, matched blood and bone marrow specimens obtained from patients with AML prior to and immediately following, several different decitabine administration schedules to identify AML-specific DNA methylation biomarkers suitable for pharmacodynamic monitoring in peripheral blood cells. These results are expected to have a positive impact on the clinical development of current and future DNA hypomethylating agents by providing a long sought after means to assess the biological activity of these agents in vivo. This contribution is significant be- cause it is a necessary first step in a continuum of research that is expected to yield pharmacodynamically tailored dosing of epigenetic modifiers that maximize anti-leukemic activity while minimizing toxicity. The pro- posed research is innovative because it represents a substantial departure from the current standard of measuring DNA methylation at a few convenient genomic loci in mixed cell populations long-after the delivery of a DNA HMA. Ultimately, the proposed genome-wide identification of AML-specific DNA methylation biomarkers in LSPCs and validation of celular surrogates with which to assess pharmacodynamics should permit rapid optimization, and perhaps personalization, of HMA schedules for the treatment of AML. PUBLIC HEALTH RELEVANCE: The proposed research is relevant to public health because the identification of AML-specific DNA methylation biomarkers for pharmacodynamics is ultimately expected to lead to optimized dosing regimens for DNA hypomethylating agents with reduced toxicity and maximal anti-leukemic activity. This work is consistent with the NIH goal of improving health, with the NCI mission of supporting research to advance the treatment of cancer and is responsive to the FOA in considering of the full array of potentially informative characteristics to trans-late basic science to a clinical application by providing a strong rationae for proposing DNA methylation bio- markers to address a current impediment to the rapid and rational development of hypomethylating agents for the treatment of AML.