Bernardini Sergio, Nuccetelli Marzia, Noguera Nélida I, Bellincampi Lorenza, Lunghi Paolo, Bonati Antonio, Mann Koren, Miller Wilson H, Federici Giorgio, Lo Coco Francesco
Department of Internal Medicine, University of Rome Tor Vergata, Viale Oxford 81, 00133, Rome, Italy.
Ann Hematol. 2006 Oct;85(10):681-7. doi: 10.1007/s00277-006-0139-8. Epub 2006 May 30.
Arsenic trioxide (As2O3) is a highly effective agent in the treatment of acute promyelocytic leukemia (APL), whereas other hematopoietic tumors are less responsive to this agent and mechanisms underlying As2O3,-resistance are poorly understood. To better understand the complex network of GSH-related pathways in As2O3 sensitivity, we investigated the role of GSH and GSH-relevant enzymes in an APL cell line sensitive to As2O3 (NB4) and in a resistant subclone (AsR). Cell proliferation, viability, and apoptosis were investigated in NB4 cells before and after treatment with 1 muM As2O3 and in AsR cells. In these experimental cell models, GSTP1-1, JNK1 and JNK2 proteins were analyzed by immunoblotting, and a kinase assay for JNK1 was performed. GSH levels as well as the activities of the enzymes glutathione peroxidase, glutathione transferase, gamma-Glutamylcysteynilsinthetase and superoxide dismutase were measured. NB4 cells treated with As2O3 showed a high level of oxidative stress and an increase of GSH levels. GSTP1-1 polymerization and JNK1 activation were detectable after 24 h and were followed by an increase of the apoptotic rate starting at 72 h. Neither GSTP1-1 polymerization nor JNK activation was found in AsR cells that showed a very low apoptotic rate. Our results suggest that APL sensitivity to As2O3 might be, at least in part, mediated by the balance between association and dissociation of JNK from GSTP1-1, depending on the redox status of the cell. Further investigation is warranted to find a way to interfere with this balance, whenever it might represent a mechanism of drug resistance.
三氧化二砷（As2O3）是治疗急性早幼粒细胞白血病（APL）的一种高效药物，而其他造血肿瘤对该药物的反应较差，且对As2O3耐药的潜在机制了解甚少。为了更好地理解谷胱甘肽（GSH）相关通路在As2O3敏感性方面的复杂网络，我们研究了GSH及与GSH相关的酶在对As2O3敏感的APL细胞系（NB4）和耐药亚克隆（AsR）中的作用。在用1 μM As2O3处理前后的NB4细胞以及AsR细胞中，研究了细胞增殖、活力和凋亡情况。在这些实验细胞模型中，通过免疫印迹分析GSTP1-1、JNK1和JNK2蛋白，并对JNK1进行激酶测定。测量了GSH水平以及谷胱甘肽过氧化物酶、谷胱甘肽转移酶、γ-谷氨酰半胱氨酸合成酶和超氧化物歧化酶的活性。用As2O3处理的NB4细胞表现出高水平的氧化应激和GSH水平升高。24小时后可检测到GSTP-1聚合和JNK1激活，随后从72小时开始凋亡率增加。在凋亡率非常低的AsR细胞中未发现GSTP1-1聚合和JNK激活。我们的结果表明，APL对As2O3的敏感性可能至少部分由JNK与GSTP1-1的结合和解离之间的平衡介导，这取决于细胞的氧化还原状态。每当这种平衡可能代表耐药机制时，有必要进行进一步研究以找到干扰这种平衡的方法。
