Novel Roles of p53 & ROS in Therapy of Refractory CLL

p53 的新角色

• 批准号: 7731919
• 负责人: Peng Huang
• 金额: $ 29.97万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7731919
• 关键词: 17p; Affect; Antibodies; Antioxidants; Apoptosis; Apoptotic; Area; Attenuated; Biochemical; Biology; Cell Death; Cells; Chronic Lymphocytic Leukemia; Clinical; Clinical Treatment; Clinical Trials; Coculture Techniques; Development; Disease; Disease Progression; Disease remission; Drug Combinations; Drug resistance; Drug usage; Europe; Exhibits; Failure; Functional disorder; Gene Mutation; Generations; Genetic; Glutathione; Grant; Health; Human; In Vitro; Lead; Mediating; Mitochondria; Mitochondrial DNA; Molecular Genetics; Morbidity - disease rate; Mus; Mutation; NOD/SCID mouse; Normal Cell; Organ; Outcome; Oxidation-Reduction; Pathway interactions; Patients; Pharmaceutical Preparations; Phenethyl Isothiocyanate; Play; Population; Reactive Oxygen Species; Recurrent disease; Refractory; Research; Research Project Grants; Research Proposals; Resistance; Role; Scientist; Staging; Stress; System; TP53 gene; Testing; Therapeutic; Therapeutic Agents; Time; Toxic effect; Treatment Protocols; United States; Up-Regulation; Vegetables; Western World; Xenograft Model; abstracting; adult leukemia; advanced disease; attenuation; base; cancer cell; clinical application; drug sensitivity; effective therapy; fludarabine; improved; in vivo; insight; killings; leukemia; mitochondrial DNA mutation; mitochondrial dysfunction; mitochondrial membrane; mortality; novel; novel therapeutics; outcome forecast; oxidation; public health relevance; response; therapeutic effectiveness; treatment strategy

DESCRIPTION (provided by applicant): Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the United States and Europe. Recent progress in our understanding of CLL biology and the development of new therapy such as fludarabine-based regimens has led to improvements of the therapeutic outcomes. However, many CLL patients, particularly those with loss of p53 due to chromosome 17p deletion or p53 mutations, are highly resistant to the current therapeutic agents and have very poor prognosis. The underlying mechanisms responsible for the poor therapeutic responses of CLL cells lacking p53 are poorly understood, and effective therapies to treat this population of CLL patients remain to be developed. The current research proposal aims to answer some of the key questions in this area, and to develop novel therapeutic strategies for treating refractory CLL. Our previous studies showed that CLL cells from patients in advanced disease stages exhibit mitochondrial DNA (mtDNA) mutations and dysfunction, elevated generation of reactive oxygen species (ROS), and decreased sensitivity to fludarabine. Furthermore, p53 plays an important role in maintaining mitochondrial genetic integrity through its interaction with mitochondrial pol 3. Importantly, we observed that cancer cells with increased ROS are highly sensitive to further ROS stress induced by a natural compound 2-phenethyl isothiocyanate (PEITC). Our preliminary studies have revealed promising activity of PEITC against refractory CLL cells, leading to major efforts to develop this compound for clinical treatment of CLL. Based on these observations, we hypothesize that CLL cells with p53 deletion are prone to develop mitochondrial mutations and dysfunction leading to a decrease in apoptotic response and resistance to conventional therapeutic agents, but remain sensitive to PEITC which kills drug-resistant CLL cells through ROS-mediated mechanism. This research project will investigate 3 specific aims. (1) We will use primary leukemia cells from CLL patients with different p53 status compare their mtDNA mutation rates, and use a novel CLL culture system to test the role p53 deletion in mitochondrial mutations and attenuation of drug apoptotic response to therapeutic agents. (2) Investigate the ability and mechanisms of PEITC and other ROS-stressing agents to effectively kill primary CLL cells that lack p53 and are resistant to conventional drugs. (3) Test the in vivo therapeutic activity of PEITC, alone or in combination with other drugs, using mouse xenograft models bearing human CLL cells with or without p53 to evaluate if PEITC and other ROS-stressing agents can induce CLL remission and improve survival. This study will reveal the novel roles of p53 in affecting mitochondrial genetic stability and function and drug sensitivity in CLL cells, and provide new strategies to effectively kill refractory CLL cells through ROS-mediated mechanism. Because PEITC is a natural compound found in vegetables with low toxicity to normal cells, its applications for clinical treatment of refractory CLL is feasible and highly significant. PUBLIC HEALTH RELEVANCE: Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the western world and causes a significant health burden both in morbidity and mortality. CLL cells with p53 loss due to chromosome 17p deletion or p53 gene mutation are resistant to current therapeutic agents and these patients have poor clinical outcomes. The main objectives of this research project are to investigate the underlying mechanisms by which the loss p53 leads to mitochondrial dysfunction and drug resistance, and to test novel agents and therapeutic strategies to effectively kill the drug-resistant CLL cells lacking p53. This study will reveal the important role of p53 in affecting mitochondrial function and drug sensitivity in CLL cells, and will identify new therapeutic agents for effective treatment of CLL patients who are refractory to conventional drugs. This research will have directly implications in clinical treatment of this most common adult leukemia.

描述（由申请人提供）：慢性淋巴细胞性白血病（CLL）是美国和欧洲最常见的成年白血病。我们对CLL生物学的理解和新疗法（例如基于氟达拉滨的方案）的发展的最新进展已导致治疗结果的改善。但是，许多CLL患者，特别是因17p染色体缺失或p53突变而导致p53损失的患者，对当前的治疗剂具有高度抗性，并且预后较差。缺乏p53的CLL细胞治疗反应不佳的基本机制知之甚少，并且有效治疗CLL患者群体的有效疗法仍有待发展。当前的研究建议旨在回答该领域的一些关键问题，并制定治疗难治性CLL的新型治疗策略。我们先前的研究表明，来自晚期疾病阶段患者的CLL细胞表现出线粒体DNA（mtDNA）突变和功能障碍，活性氧（ROS）的产生升高以及对氟达拉滨的敏感性降低。此外，p53通过与线粒体pol 3的相互作用来维持线粒体遗传完整性方面起着重要作用。重要的是，我们观察到，具有ROS增加的癌细胞对由天然的2-苯基异硫氰酸盐（PEITC）诱导的进一步的ROS应激高度敏感。我们的初步研究揭示了PEITC对难治性CLL细胞的有希望的活性，从而为开发CLL临床治疗的化合物做出了重大努力。基于这些观察结果，我们假设具有p53缺失的CLL细胞很容易发展线粒体突变和功能障碍，从而导致凋亡反应降低和对常规治疗剂的抗性，但对PEITC仍然敏感，但对PEITC仍然敏感，从而通过玫瑰介导的机制杀死了耐药的CLL细胞。该研究项目将研究3个具体目标。 （1）我们将使用来自不同p53状态的CLL患者的原发性白血病细胞比较其mtDNA突变率，并使用新型的CLL培养系统来测试p53缺失在线粒体突变中的作用p53缺失以及药物凋亡反应的衰减与治疗药物的衰减。 （2）研究PEITC和其他ROSSURSTRANG剂的能力和机制有效杀死缺乏p53并具有耐药性药物的原代CLL细胞。 （3）使用带有或没有p53的人类CLL细胞的小鼠异种移植模型来测试PEITC的体内治疗活性，或与其他药物结合使用，以评估PEITC和其他ROSSRASSSRASTING剂是否可以诱导CLL缓解并提高生存率。这项研究将揭示p53在CLL细胞中影响线粒体遗传稳定性，功能和药物敏感性中的新作用，并提供新的策略，以通过ROS介导的机制有效地杀死难治性CLL细胞。由于PEITC是在对正常细胞毒性低的蔬菜中发现的一种天然化合物，因此其用于难治性CLL临床治疗的应用是可行的且非常重要的。公共卫生相关性：慢性淋巴细胞性白血病（CLL）是西方世界上最常见的成年白血病，在发病率和死亡率方面均产生巨大的健康负担。由于染色体17p缺失或p53基因突变而导致p53损失的CLL细胞对当前的治疗剂有抵抗力，并且这些患者的临床结局较差。该研究项目的主要目标是研究损失p53导致线粒体功能障碍和耐药性的潜在机制，并测试新颖的药物和治疗策略，以有效杀死缺乏p53的药物耐药的CLL细胞。这项研究将揭示p53在影响CLL细胞中线粒体功能和药物敏感性方面的重要作用，并将鉴定出新的治疗剂，以有效治疗对常规药物难治性的CLL患者。这项研究将直接对这种最常见的成年白血病的临床治疗产生影响。