The role of HO-1 in Flt3-ITD positive AML proliferation and drug resistance

HO-1在Flt3-ITD阳性AML增殖和耐药中的作用

• 批准号: 8397967
• 负责人: Mary Irwin
• 金额: $ 4.99万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8397967
• 关键词: Acute Myelocytic Leukemia; Address; Anthracyclines; Antioxidants; Apoptosis; Apoptotic; Area; BAY 54-9085; Biological; Cancer Model; Cell Line; Cell Proliferation; Cell Survival; Cell model; Cells; Clinical; Data; Dependence; Diagnosis; Disease; Drug resistance; Environment; Enzymes; Gene Mutation; Growth; Heat shock proteins; Heme; Human; In Vitro; Life Expectancy; Malignant Neoplasms; Mediating; Messenger RNA; Metabolism; Methods; Modeling; Molecular; Mutation; Neoplasm Metastasis; Oncogenic; Outcome; Oxidation-Reduction; Pathway interactions; Patients; Phenotype; Phosphotransferases; Production; Proteins; Public Health; Reactive Oxygen Species; Receptor Protein-Tyrosine Kinases; Regulation; Relapse; Research; Resistance; Role; Sampling; Signal Transduction; Small Interfering RNA; Specimen; Survival Rate; Techniques; Testing; Therapeutic; Therapeutic Intervention; Tissue Microarray; Transcriptional Regulation; Treatment outcome; Tyrosine Kinase Inhibitor; United States; Up-Regulation; Vascular Endothelial Growth Factor Receptor-1; Work; angiogenesis; cancer cell; cell type; chemical genetics; clinical efficacy; genetic inhibitor; heme oxygenase-1; improved; inhibitor/antagonist; kinase inhibitor; leukemia; mutant; novel; receptor; therapy resistant; tumorigenesis

DESCRIPTION (provided by applicant): With current treatment options, the five-year survival rate for patients with AML is only 25%, thus understanding mechanisms of relapse and resistance is important therapeutically. The most common aberration in AML results in activation of the fms-like receptor 3 (Flt3-ITD), which was recently shown to alter the redox environment of cancer cells. While these changes remain poorly understood, elevations of reactive oxygen species can promote the cancer phenotype. Heme oxygenase 1 (HO-1) is a ROS-induced anti-oxidant that can also inhibit apoptosis and promote metabolism leading to cell survival and drug resistance. Our preliminary data suggest that, Flt3-ITD-expressing cells contain elevated constitutive expression of HO-1 as compared to Flt3-wildtype (WT) expressing cells. Further, knockdown of HO-1 with siRNA results in decreased proliferation and viability of Flt3-ITD expressing cells. We hypothesize that Flt3-ITD-dependent kinase signaling and ROS production increase constitutive expression of HO-1, leading to activation of anti- oxidant and anti-apoptotic pathways and resulting in proliferation and drug resistance in AML. To test our hypothesis, we will 1) Determine the molecular mechanisms by which HO-1 is constitutively expressed in Flt3- ITD positive AML and the functional consequences of this expression and 2) Elucidate the role of HO-1 in therapeutic resistance of AML. The isogenic BaF3 Flt3-WT and Flt3-ITD cell lines will be used in combination with human Flt3-ITD positive AML cell lines MOLM-13 and MV4.11 to test both specific aims. To complete Aim 1, we will examine the Flt3-kinase and ROS dependence of HO-1 expression in Flt3-ITD positive cells. Transcriptional regulation of HO-1 expression will also be evaluated. In vitro findings will be further assessed ex vivo utilizing tisue microarray specimens from AML patients. The effects of HO-1 expression on Flt3-ITD positive AML will be delineated utilizing chemical and genetic inhibitors of HO-1. For Aim 2, we will determine the contribution of HO-1 to chemoresistance of Flt3-ITD expressing cells utilizing the afore mentioned HO-1 inhibition methods. Using similar techniques, we will also evaluate the contribution of HO-1 to de novo and acquired resistance to the Flt3 inhibitors lestaurtinib and sorafenib. These studies together will provide a greater understanding of the redox mechanisms underlying Flt3-ITD expressing AML, and will better equip us to therapeutically target the biological pathways that promote AML progression and drug resistance. PUBLIC HEALTH RELEVANCE: The proposed studies address a research area that has largely been unstudied and focuses on the role of an antioxidant, HO-1, in growth, survival, and drug resistance of Flt3-ITD positive acute myeloid leukemia (AML). This research is relevant to public health because understanding how antioxidants can contribute to growth, survival and drug resistance of cancer cells will enhance our ability to clinically treat the 30% of AML patient whose disease expresses the Flt3-ITD mutation, and possibly extend the life expectancy of patients diagnosed with this disease.

描述（由申请人提供）：在目前的治疗方案下，AML患者的五年生存率仅为25%，因此了解复发和耐药机制在治疗上很重要。AML中最常见的畸变导致fms样受体3（Flt 3-ITD）的活化，其最近被证明改变癌细胞的氧化还原环境。虽然这些变化仍然知之甚少，活性氧的升高可以促进癌症表型。血红素加氧酶1（HO-1）是一种ROS诱导的抗氧化剂，也可以抑制细胞凋亡和促进代谢，导致细胞存活和耐药性。我们的初步数据表明，与表达Flt 3-野生型（WT）的细胞相比，表达Flt 3-ITD的细胞含有升高的HO-1的组成型表达。此外，用siRNA敲低HO-1导致表达Flt 3-ITD的细胞的增殖和活力降低。我们假设Flt 3-ITD依赖性激酶信号传导和ROS产生增加HO-1的组成型表达，导致抗氧化和抗凋亡的活化。 途径，并导致AML的增殖和耐药性。为了验证我们的假设，我们将1）确定HO-1在Flt 3- ITD阳性AML中组成性表达的分子机制以及这种表达的功能后果，2）阐明HO-1在AML治疗耐药性中的作用。等基因BaF 3 Flt 3-WT和Flt 3-ITD细胞系将与人Flt 3-ITD阳性AML细胞系MOLM-13和MV4.11联合使用，以检测两种特定目的。为了完成目标1，我们将检测Flt 3-ITD阳性细胞中HO-1表达的Flt 3-激酶和ROS依赖性。还将评估HO-1表达的转录调控。将利用AML患者的组织微阵列标本离体进一步评估体外结果。HO-1表达对Flt 3-ITD阳性AML的影响将使用HO-1的化学和遗传抑制剂来描述。对于目的2，我们将利用上述HO-1抑制方法确定HO-1对Flt 3-ITD表达细胞的化学抗性的贡献。使用类似的技术，我们还将评估HO-1对Flt 3抑制剂来洛替尼和索拉非尼的从头和获得性耐药性的贡献。这些研究将使我们更好地理解表达AML的Flt 3-ITD的氧化还原机制，并使我们能够更好地治疗靶向促进AML进展和耐药性的生物学途径。 公共卫生关系：拟议的研究涉及一个基本上未研究的研究领域，重点关注抗氧化剂HO-1在Flt 3-ITD阳性急性髓系白血病（AML）的生长、生存和耐药性中的作用。这项研究与公共卫生有关，因为了解抗氧化剂如何有助于癌细胞的生长，存活和耐药性将提高我们临床治疗30%的AML患者的能力，这些患者的疾病表达Flt 3-ITD突变，并可能延长诊断患有这种疾病的患者的预期寿命。