开发抗CD44抗体治疗急性髓系白血病

为了探讨抗CD44 抗体对急性髓系白血病(AML)细胞增殖和分化的影响,为肿瘤靶向药物的开发提供前提和基础．应用流式细胞术检测抗CD44单克隆抗体HI313的亲和力,MTS检测HI313是否抑制NB4细胞生长,并检测细胞周期的变化,与初筛AML病人标本共培养检测其促分化作用．结果显示HI313抑制NB4细胞生长,能使细胞周期停留在 G0/G1期,并能有效诱导AML病人血细胞的分化．通过以上实验证明抗CD44抗体HI313对NB4细胞具有增殖抑制作用,作用机制可能与阻滞细胞周期于G0/G1期相关, 并对AML病人的细胞有一定的促分化作用,提示此抗体具有针对AML进行靶向治疗的潜力,为HI313人抗体的进一步基因工程改造及临床应用奠定了基础．     

组蛋白去乙酰化酶抑制剂在急性髓系白血病中的应用

急性髓系白血病（AML）是造血干/祖细胞恶性克隆性疾病,以骨髓、血液和其他组织中髓系起源的异常原始细胞增殖为特征。“3+7”诱导方案（蒽环类药物联合阿糖胞苷）一直是治疗AML的基石,但仍有部分AML患者无法耐受强化疗或完全缓解后复发,目前AML的总体疗效仍不乐观。因此,寻找新药物以提高AML患者疗效具有重要的临床意义。越来越多的研究证明,表观遗传对AML的发生、发展起重要作用。组蛋白去乙酰化酶抑制剂（HDACi）是表观遗传修饰的分子靶向药物,可抑制组蛋白去乙酰化酶（HDAC）的活性,上调组蛋白赖氨酸的乙酰化水平,目前已应用于AML临床研究中,在联合治疗中显现出良好的耐受性与治疗效果。本综述介绍了HDAC和HDACi的分类依据以及在临床上的应用,阐述了伏立诺他、贝利司他、帕比司他、戊丙酸、恩替诺特、西达本胺等6种HDACi在AML中的临床前研究结果和临床应用研究进展,讨论了HDACi与其他抗癌药物联用在AML中的作用机制,并对HDACi今后的发展提出了建议,期望为临床治疗AML提供参考。     

腺苷酸活化蛋白激酶：肿瘤治疗新靶点

腺苷酸活化蛋白激酶（AMP—activated proteinkinase,AMPK）是真核细胞内发现的一类与细胞能量代谢有关激酶家族中的一员,被称之为“能量感应器”。当细胞内AMP／ATP值升高时,AMPK被激活。研究发现,在肿瘤细胞中,活化的AMPK可协同相关抑癌因子调节细胞周期、细胞凋亡以及蛋白质合成,最终影响细胞的增殖。因而,AMPK可以通过感应细胞能量水平的变化来调节细胞增殖。这给肿瘤治疗提供了一定的启示,即以肿瘤细胞能量代谢特点而探寻抑制肿瘤细胞增殖的途径。     

Nestin基因在髓系白血病的表达及意义

Nestin蛋白是一种神经干细胞标志物,参与组织修复,并且在一些肿瘤细胞中表达。最近研究报道称nestin可能参与肿瘤细胞恶性增殖及细胞侵袭。在急性淋巴细胞白血病(acute lymphoid leukemia,ALL)小鼠模型中,白血病增殖细胞(leukemia-propagating cells,LPCs)可形成一个抗药性niche,其中nestin阳性细胞参与该niche形成。为探索nestin基因在白血病患者的临床表达情况,通过RT-PCR和Western-blot实验方法 ,检测了50位髓系白血病患者的nestin基因的临床表达情况。结果发现,在50位髓系白血病患者(38位AML,12位CML)中,42位患者表达nestin基因mRNA,6位患者表达nestin蛋白,并且nestin基因表达水平和患者血红蛋白、血小板、细胞因子和T淋巴细胞数并不存在相关性,但是高白细胞白血病患者表现出nestin基因mRNA水平高表达。虽然nestin基因和患者完全缓解率(complete remission,CR)并不存在联系,但是nestin基因在髓系白血病异常表达,说明其可能作为一种诊断AML或CML的生物标记物。     

Synthesis and Characterization of Novel 2-Amino-Chromene-Nitriles that Target Bcl-2 in Acute Myeloid Leukemia Cell Lines

The anti-apoptotic protein Bcl-2 is a well-known and attractive therapeutic target for cancer. In the present study the solution-phase T3P-DMSO mediated efficient synthesis of 2-amino-chromene-3-carbonitriles from alcohols, malanonitrile and phenols is reported. These novel 2-amino-chromene-3-carbonitriles showed cytotoxicity in human acute myeloid leukemia (AML) cell lines. Compound 4g was found to be the most bioactive, decreasing growth and increasing apoptosis of AML cells. Moreover, compound 4g (at a concentration of 5 µM) increased the G2/M and sub-G1 (apoptosis) phases of AML cells. The AML cells treated with compound 4g exhibited decreased levels of Bcl-2 and increased levels of caspase-9. In silico molecular interaction analysis showed that compound 4g shared a similar global binding motif with navitoclax (another small molecule that binds Bcl-2), however compound 4g occupies a smaller volume within the P2 hot spot of Bcl-2. The intermolecular π-stacking interaction, direct electrostatic interactions, and docking energy predicted for 4g in complex with Bcl-2 suggest a strong affinity of the complex, rendering 4g as a promising Bcl-2 inhibitor for evaluation as a new anticancer agent.     

A Novel Application of Furazolidone: Anti-Leukemic Activity in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most common malignant myeloid disorder of progenitor cells in myeloid hematopoiesis and exemplifies a genetically heterogeneous disease. The patients with AML also show a heterogeneous response to therapy. Although all-trans retinoic acid (ATRA) has been successfully introduced to treat acute promyelocytic leukemia (APL), it is rather ineffective in non-APL AML. In our present study, 1200 off-patent marketed drugs and natural compounds that have been approved by the Food and Drug Administration (FDA) were screened for anti-leukemia activity using the retrovirus transduction/transformation assay (RTTA). Furazolidone (FZD) was shown to inhibit bone marrow transformation mediated by several leukemia fusion proteins, including AML1-ETO. Furazolidone has been used in the treatment of certain bacterial and protozoan infections in human and animals for more than sixty years. We investigated the anti-leukemic activity of FZD in a series of AML cells. FZD displayed potent antiproliferative properties at submicromolar concentrations and induced apoptosis in AML cell lines. Importantly, FZD treatment of certain AML cells induced myeloid cell differentiation by morphology and flow cytometry for CD11b expression. Furthermore, FZD treatment resulted in increased stability of tumor suppressor p53 protein in AML cells. Our in vitro results suggest furazolidone as a novel therapeutic strategy in AML patients.     

A Comparison of Azacitidine and Decitabine Activities in Acute Myeloid Leukemia Cell Lines

Background

The cytidine nucleoside analogs azacitidine (AZA) and decitabine (DAC) are used for the treatment of patients with myelodysplastic syndromes and acute myeloid leukemia (AML). Few non-clinical studies have directly compared the mechanisms of action of these agents in a head-to-head fashion, and the agents are often viewed as mechanistically similar DNA hypomethylating agents. To better understand the similarities and differences in mechanisms of these drugs, we compared their in vitro effects on several end points in human AML cell lines.

Methodology/Principal Findings

Both drugs effected DNA methyltransferase 1 depletion, DNA hypomethylation, and DNA damage induction, with DAC showing equivalent activity at concentrations 2- to 10-fold lower than AZA. At concentrations above 1 µM, AZA had a greater effect than DAC on reducing cell viability. Both drugs increased the sub-G1 fraction and apoptosis markers, with AZA decreasing all cell cycle phases and DAC causing an increase in G2-M. Total protein synthesis was reduced only by AZA, and drug-modulated gene expression profiles were largely non-overlapping.

Conclusions/Significance

These data demonstrate shared mechanisms of action of AZA and DAC on DNA-mediated markers of activity, but distinctly different effects in their actions on cell viability, protein synthesis, cell cycle, and gene expression. The differential effects of AZA may be mediated by RNA incorporation, as the distribution of AZA in nucleic acid of KG-1a cells was 65∶35, RNA∶DNA.     

High-Dose Cytarabine in Acute Myeloid Leukemia Treatment: A Systematic Review and Meta-Analysis

The optimal dose, scheme, and clinical setting for Ara-C in acute myeloid leukemia (AML) treatment remain uncertain. In this study, we performed a meta-analysis to systematically assess the impact of high-dose cytarabine (HDAC) on AML therapy during the induction and consolidation stages. Twenty-two trials with a total of 5,945 de novo AML patients were included in the meta-analysis. Only patients less than 60 year-old were included in the study. Using HDAC in induction therapy was beneficial for RFS (HR = 0.57; 95% CI, 0.35–0.93; P = 0.02) but not so for CR rate (HR = 1.01; 95% CI, 0.93–1.09; P = 0.88) and OS (HR = 0.83; 95% CI, 0.66–1.03; P = 0.1). In consolidation therapy, HDAC showed significant RFS benefits (HR = 0.67; 95% CI, 0.49–0.9; P = 0.008) especially for the favorable-risk group (HR = 0.38; 95% CI, 0.21–0.69; P = 0.001) compared with SDAC (standard dose cytarabine), although no OS advantage was observed (HR = 0.84; 95% CI, 0.55–1.27; P = 0.41). HDAC treatment seemed less effective than auto-BMT/allo-BMT treatment (HR = 1.66, 95% CI, 1.3–2.14; P<0.0001) with similar OS. HDAC treatment led to lower relapse rate in induction and consolidation therapy than SDAC treatment, especially for the favorable-risk group. Auto-BMT/allo-BMT was more beneficial in prolonging RFS than HDAC.     

减低剂量去甲氧柔红霉素联合阿糖胞苷方案治疗老年急性髓细胞白血病的临床研究

目的:探讨减低剂量去甲柔红霉素联合阿糖胞苷(IA)方案治疗老年急性髓细胞白血病(AML)患者的疗效。方法:收集我院老年急性髓细胞白血病患者62例,随机分成减低剂量IA治疗组和标准剂量IA对照组,两组均实施3+7治疗方案。治疗2个疗程,比较两组不良反应和临床疗效。结果:减低剂量IA治疗组总CR率和CCR率分别为75.0%和66.7%;标准剂量IA对照组总CR率和CCR率分别为50.0%和33.3%。减低剂量IA治疗组总生存期25+月较标准剂量IA对照组生存期23+月延长。结论:对于老年急性髓细胞白血病患者,减低剂量IA治疗方案的CR率和CCR率与标准剂量IA治疗方案相比具有明显疗效优势。     

Integrative Meta-Analysis of Differential Gene Expression in Acute Myeloid Leukemia

Background

Acute myeloid leukemia (AML) is a heterogeneous disease with an overall poor prognosis. Gene expression profiling studies of patients with AML has provided key insights into disease pathogenesis while exposing potential diagnostic and prognostic markers and therapeutic targets. A systematic comparison of the large body of gene expression profiling studies in AML has the potential to test the extensibility of conclusions based on single studies and provide further insights into AML.

Methodology/Principal Findings

In this study, we systematically compared 25 published reports of gene expression profiling in AML. There were a total of 4,918 reported genes of which one third were reported in more than one study. We found that only a minority of reported prognostically-associated genes (9.6%) were replicated in at least one other study. In a combined analysis, we comprehensively identified both gene sets and functional gene categories and pathways that exhibited significant differential regulation in distinct prognostic categories, including many previously unreported associations.

Conclusions/Significance

We developed a novel approach for granular, cross-study analysis of gene-by-gene data and their relationships with established prognostic features and patient outcome. We identified many robust novel prognostic molecular features in AML that were undetected in prior studies, and which provide insights into AML pathogenesis with potential diagnostic, prognostic, and therapeutic implications. Our database and integrative analysis are available online (http://gat.stamlab.org).     

Breakthrough Invasive Fungal Infections in Patients with Acute Myeloid Leukemia

Mycopathologia - We sought to determine the occurrence, risk factors, effect of antifungal prophylaxis, and outcomes of invasive fungal infections (IFIs) in patients with acute myeloid leukemia...     

Mammalian Target of Rapamycin (mTOR) Activity Dependent Phospho-Protein Expression in Childhood Acute Lymphoblastic Leukemia (ALL)

Modern treatment strategies have improved the prognosis of childhood ALL; however, treatment still fails in 25–30% of patients. Further improvement of treatment may depend on the development of targeted therapies. mTOR kinase, a central mediator of several signaling pathways, has recently attracted remarkable attention as a potential target in pediatric ALL. However, limited data exists about the activity of mTOR. In the present study, the amount of mTOR activity dependent phospho-proteins was characterized by ELISA in human leukemia cell lines and in lymphoblasts from childhood ALL patients (n = 49). Expression was measured before and during chemotherapy and at relapses. Leukemia cell lines exhibited increased mTOR activity, indicated by phospho-S6 ribosomal protein (p-S6) and phosphorylated eukaryotic initiation factor 4E binding protein (p-4EBP1). Elevated p-4EBP1 protein levels were detected in ALL samples at diagnosis; efficacy of chemotherapy was followed by the decrease of mTOR activity dependent protein phosphorylation. Optical density (OD) for p-4EBP1 (ELISA) was significantly higher in patients with poor prognosis at diagnosis, and in the samples of relapsed patients. Our results suggest that measuring mTOR activity related phospho-proteins such as p-4EBP1 by ELISA may help to identify patients with poor prognosis before treatment, and to detect early relapses. Determining mTOR activity in leukemic cells may also be a useful tool for selecting patients who may benefit from future mTOR inhibitor treatments.     

Driver Mutations in Acute Myeloid Leukemia with Inversion of Chromosome 16

Molecular Biology - Certain subtypes of acute myeloid leukemia occur as a result of the cooperation of several events these are, the formation of fusion genes as a result of chromosomal...     

成人急性髓性白血病SOCS-1基因及其甲基化的研究

目的：通过检测成人急性髓性白血病中SOCS．1基因表达水平及其甲基化水平,研究其在白血病发病中的作用。方法：运用甲基化特异性PCR（Methylation specificPCR,MSP）方法,对24例急性髓性白血病患者和4株白血病细胞株（Jurkat、Raji、U937、NALM17）,进行SOCS-1基因甲基化水平的研究;同时运用Real—timePCR法定量分析SOCS—1基因表达水平。以10例健康人为正常对照组。结果：24例成人急性髓性白血病患者中,15例有SOCS-1基因甲基化（62．5％）,而正常对照组无SOCS-1基因甲基化（0％）,二者有显著差异（P〈0．05）;SOCS-1基因甲基化组与无SOCS-1基因甲基化组相比较,其SOCS—1基因相对表达量明显减少（P口0．05）;与患者临床病理特征相结合比较,发现SOCS-1基因的甲基化与患者年龄、性别和病程阶段无相关。4株白血病细胞株中,Jurkat和U937表现有SOCS—1甲基化（50％）,Raji和NALM17无SOCS—1甲基化,前者SOCS-1基因表达量较后者也明显降低（P〈0．05）。结论：SOCS—1基因在成人急性髓性白血病中甲基化水平明显增高,且SOCS-1基因甲基化后表达水平受到抑制,提示SOCS-1基因及其甲基化在急性髓性白血病的发生发展中可能具有一定作用。