Georgakis Georgios V, Li Yang, Rassidakis Georgios Z, Martinez-Valdez Hector, Medeiros L Jeffrey, Younes Anas
Department of Lymphoma and Myeloma, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Clin Cancer Res. 2006 Jan 15;12(2):584-90. doi: 10.1158/1078-0432.CCR-05-1194.
Heat shock protein 90 (HSP90) is a chaperone for several client proteins involved in transcriptional regulation, signal transduction, and cell cycle control. HSP90 is abundantly expressed by a variety of tumor types and has been recently targeted for cancer therapy. The objective of this study was to determine the role of HSP90 in promoting growth and survival of Hodgkin's lymphoma and to determine the molecular consequences of inhibiting HSP90 function by the small-molecule 17-allylamino-17-demethoxy-geldanamycin (17-AAG) in Hodgkin's lymphoma.
HSP90 expression in Hodgkin's lymphoma cell lines was determined by Western blot and in primary lymph node sections from patients with Hodgkin's lymphoma by immunohistochemistry. Cell viability was determined by the 3-(4,5-dimethyl-thiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Apoptosis and cell cycle fractions were determined by flow cytometry. Expression of intracellular proteins was determined by Western blot.
HSP90 is overexpressed in primary and cultured Hodgkin's lymphoma cells. Inhibition of HSP90 function by 17-AAG showed a time- and dose-dependent growth inhibition of Hodgkin's lymphoma cell lines. 17-AAG induced cell cycle arrest and apoptosis, which were associated with a decrease in cyclin-dependent kinase (CDK) 4, CDK 6, and polo-like kinase 1 (PLK1), and induced apoptosis by caspase-dependent and caspase-independent mechanisms. Furthermore, 17-AAG depleted cellular contents of Akt, decreased extracellular signal-regulated kinase (ERK) phosphorylation, and reduced cellular FLICE-like inhibitory protein levels (FLIP), and thus enhanced the cytotoxic effect of doxorubicin and agonistic anti-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor antibodies.
Inhibition of HSP90 function induces cell death and enhances the activity of chemotherapy and anti-tumor necrosis factor-related apoptosis-inducing ligand death receptor antibodies, suggesting that targeting HSP90 function might be of therapeutic value in Hodgkin's lymphoma.
热休克蛋白90（HSP90）是参与转录调控、信号转导和细胞周期控制的多种客户蛋白的伴侣蛋白。HSP90在多种肿瘤类型中大量表达，最近已成为癌症治疗的靶点。本研究的目的是确定HSP90在促进霍奇金淋巴瘤生长和存活中的作用，并确定小分子17-烯丙基氨基-17-去甲氧基格尔德霉素（17-AAG）抑制HSP90功能在霍奇金淋巴瘤中的分子后果。
通过蛋白质免疫印迹法测定霍奇金淋巴瘤细胞系中HSP90的表达，并通过免疫组织化学法测定霍奇金淋巴瘤患者原发性淋巴结切片中HSP90的表达。通过3-（4,5-二甲基噻唑-2-基）-5-（3-羧甲氧基苯基）-2-（4-磺基苯基）-2H-四唑（MTS）试验测定细胞活力。通过流式细胞术测定凋亡和细胞周期分数。通过蛋白质免疫印迹法测定细胞内蛋白的表达。
HSP90在原发性和培养的霍奇金淋巴瘤细胞中过表达。17-AAG对HSP90功能的抑制显示出对霍奇金淋巴瘤细胞系的时间和剂量依赖性生长抑制。17-AAG诱导细胞周期停滞和凋亡，这与细胞周期蛋白依赖性激酶（CDK）4、CDK 6和polo样激酶1（PLK1）的减少有关，并通过半胱天冬酶依赖性和半胱天冬酶非依赖性机制诱导凋亡。此外，17-AAG消耗了Akt的细胞内含量，降低了细胞外信号调节激酶（ERK）的磷酸化，并降低了细胞FLICE样抑制蛋白水平（FLIP），从而增强了阿霉素和激动性抗肿瘤坏死因子相关凋亡诱导配体（TRAIL）死亡受体抗体的细胞毒性作用。
抑制HSP90功能可诱导细胞死亡，并增强化疗和抗肿瘤坏死因子相关凋亡诱导配体死亡受体抗体的活性，这表明靶向HSP90功能可能对霍奇金淋巴瘤具有治疗价值。
