Arsenic Trioxide and Acute Myeloid Leukemia

三氧化二砷与急性髓系白血病

• 批准号: 6757838
• 负责人: YONGKUI JING
• 金额: $ 24.15万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-15 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6757838
• 关键词: JUN kinase; SCID mouse; acute myelogenous leukemia; apoptosis; arsenic; ascorbate; biological signal transduction; cell line; clinical research; combination chemotherapy; drug screening /evaluation; enzyme activity; flow cytometry; glutathione peroxidase; glutathione transferase; hydrogen peroxide; mitogen activated protein kinase; molecular cloning; myeloperoxidase; neoplasm /cancer chemotherapy; neoplastic cell; nonhuman therapy evaluation; northern blottings; protein structure function; tissue /cell culture; transfection; western blottings

DESCRIPTION (provided by applicant): Arsenic trioxide (As2O3) induced complete remission in acute promyelocytic leukemia (APL, AML-M3) patients that relapsed after all trans retinoic acid (tRA) and chemotherapy treatment. Clinical results indicated that the therapeutic effect of As2O3 in APL correlated with the expression of PML-RARalpha , the product of the t(15;17) translocation, and was mediated by apoptosis and non-terminal differentiation induction. We have found that As2O3 degraded PML-RARalpha and allowed RARalpha (from the wild-type allele) to drive APL cell partly differentiation. However, the connection between PML-RARalpha expression on one hand, and apoptosis induction by As2O3 on the other hand, is unclear. We have found that 1) APL cells contained low amounts of glutathione-s-transferase pi (GSTpi), glutathione peroxidase (GPx), catalase and high amounts of myeloperoxidase (MPO); 2) APL cells were highly sensitive to As2O3-induced apoptosis in vitro by a hydrogen peroxide (H2O2) mediated pathway; 3) Ascorbic acid selectively increased As2O3-induced apoptosis in HL-60 cells (which express high amounts of MPO) not in U937 and normal bone progenitors cells (which do not express MPO). We hypothesize that 1) low levels of GSTpi allow As2O3 to inhibit GPx. GPx inhibition in combination with low catalase expression will result in H2O2 accumulation; 2) accumulated H2O2 is converted into reactive oxygen species by MPO, and then trigger apoptosis; 3) PML-RARalpha sensitizes APL cells to As2O3-induced apoptosis by upregulating MPO and/or downregulating GSTpi, catalase and GPx; 4) Ascorbic acid selectively synergizes As2O3-induced apoptosis in MPO positive AML cells by producing H2O2 and depleting reduced form glutathione (GSH), the substrate of both GSTpi and GPx. The initial aim of the project is to confirm that As2O3 induces apoptosis through H2O2-mediated pathway. This will be tested by comparing H2O2 amount and apoptosis induction in As2O3 treated AML cells. The second aim will determine the central role of GSTpi to control the sensitivity of cells to As2O3-induced H2O2 accumulation and the third aim will examine the functions of MPO in sensitizing As2O3-induced apoptosis. These will be tested by stably transfecting sense or antisense cDNA and using specific inhibitors. The fourth aim will dissect the connection between PML-RARalpha expression and the levels of GSTpi, GPx, catalase and MPO. PML-RARalpha stably transfected cells will be used for this purpose. Our last aim will evaluate the selective apoptosis-induction and the mechanism of As2O3 in combination with ascorbic acid among AML cells with/without expressing MPO in vitro. SCID models bearing AML cells will be used to test the in vivo effect. Successful completion of the proposed studies will not only contribute to elucidation of the mechanism of As2O3-induced remission in APL, but may also provide innovative usage of As2O3 in other forms of AML.

描述(申请人提供)：三氧化二砷(As2O3)诱导急性早幼粒细胞白血病(APL，AML-M3)患者完全缓解，这些患者在所有反式维甲酸(Tra)和化疗后复发。临床结果表明，三氧化二砷对急性早幼粒细胞白血病的治疗作用与t(15；17)易位产物PML-RARpha的表达有关，并通过细胞凋亡和非终末分化诱导发挥作用。我们发现As_2O_3降解PML-RARpha，并允许RARpha(来自野生型等位基因)驱动APL细胞部分分化。然而，PML-RARpha的表达与As_2O_3诱导的细胞凋亡之间的关系尚不清楚。我们发现：1)急性早幼粒细胞白血病细胞表达低水平的谷胱甘肽-S转移酶pi、谷胱甘肽过氧化物酶、过氧化氢酶和高水平的髓过氧化物酶；2)体外培养的急性早幼粒细胞白血病细胞对As_2O_3通过过氧化氢(H_2O_2)途径诱导的凋亡高度敏感；3)抗坏血酸选择性地增加了As_2O_3诱导的HL-60细胞(高表达MPO)的凋亡，而U937和正常骨祖细胞(不表达MPO)则不表达。我们推测：1)低水平的GSTpi允许As2O3抑制GPx。GPX的抑制结合过氧化氢酶的低表达将导致过氧化氢的积累；2)积累的过氧化氢被MPO转化为活性氧物种，进而触发细胞凋亡；3)PML-RARpha通过上调MPO和/或下调GSTpi、过氧化氢酶和GPx而使APL细胞对As_2O_3诱导的凋亡敏感；4)抗坏血酸通过产生H_2O_2和耗尽GSTpi和GPx的底物还原型谷胱甘肽(GSH)选择性地协同作用于As_2O_3诱导的AML细胞的凋亡。该项目的初步目的是证实As2O_3通过过氧化氢介导的途径诱导细胞凋亡。这将通过比较过氧化氢的含量和对AML细胞的凋亡诱导来检验。第二个目的将确定GSTpi在控制细胞对As_2O_3诱导的H_2O_2积累的敏感性中的中心作用，第三个目的将研究MPO在敏化As_2O_3诱导的细胞凋亡中的作用。这些将通过稳定地转染正义或反义cdna并使用特定的抑制剂来进行测试。第四个目的是分析PML-RARpha表达与GSTpi、GPX、CAT和MPO水平之间的关系。稳定转染PML-RARpha的细胞将用于此目的。本研究的最后目的是探讨As2O3联合抗坏血酸对表达MPO和不表达MPO的AML细胞的选择性诱导凋亡作用及其机制。带有AML细胞的SCID模型将用于测试体内效应。这些研究的成功完成不仅有助于阐明As_2O_3诱导急性早幼粒细胞白血病缓解的机制，而且可能为As_2O_3在其他形式的急性髓系白血病中的创新应用提供参考。