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。     

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).     

Next Generation Sequencing of Acute Myeloid Leukemia: Influencing Prognosis

Background

Epilepsy is genetically complex neurological disorder affecting millions of people of different age groups varying in its type and severity. Copy number variants (CNVs) are key players in the genetic etiology of numerous neurodevelopmental disorders and prior findings also revealed that chromosomal aberrations are more susceptible against the pathogenesis of epilepsy. Novel technologies, such as array comparative genomic hybridization (array-CGH), may help to uncover the pathogenic CNVs in patients with epilepsy.

Results

This study was carried out by high density whole genome array-CGH analysis with blood DNA samples from a cohort of 22 epilepsy patients to search for CNVs associated with epilepsy. Pathogenic rearrangements which include 6p12.1 microduplications in 5 patients covering a total region of 99.9kb and 7q32.3 microdeletions in 3 patients covering a total region of 63.9kb were detected. Two genes BMP5 and PODXL were located in the predicted duplicated and deleted regions respectively. Furthermore, these CNV findings were confirmed by qPCR.

Conclusion

We have described, for the first time, several novel CNVs/genes implicated in epilepsy in the Saudi population. These findings enable us to better describe the genetic variations in epilepsy, and could provide a foundation for understanding the critical regions of the genome which might be involved in the development of epilepsy.

     

过表达TRAF6对人急性髓系白血病细胞自噬活性的影响

该文旨在探讨过表达肿瘤坏死因子受体相关因子6(tumor necrosis factor receptorassociated factor 6,TRAF6)对人急性髓系白血病(acute myeloid leukemia,AML)细胞自噬活性的影响。利用基因表达数据库GEO分析TRAF6在AML患者白血病细胞中的mRNA表达水平。通过癌症基因组图谱TCGA分析TRAF6表达与AML患者临床预后的关系。将TRAF6重组质粒载体转染人AML细胞系(KG-1a和THP-1),采用自噬激活剂雷帕霉素(Rapamycin)和自噬相关抑制剂3-甲基腺嘌呤(3-methyladenine,3-MA)、巴弗洛霉素A1(bafilomycin A1,Baf-A1)分别处理AML细胞。荧光定量PCR、蛋白免疫印迹技术检测过表达TRAF6后白血病细胞自噬标志物(LC3和p62)mRNA和蛋白水平;免疫荧光方法检测LC3绿色荧光斑点结构(puncta);流式细胞术检测细胞凋亡率;CCK-8实验检测AML细胞的体外增殖能力。结果显示,AML患者白血病细胞高表达TRAF6(P<0.01);TRAF6高表达的白血病患者总体生存率和无事件生存率均较TRAF6低表达组显著降低(P=0.01)。TRAF6重组质粒转染能够显著增加两株AML细胞系中TRAF6的mRNA和蛋白水平(P<0.05)。Rapamycin处理能够激活AML细胞系自噬水平,过表达TRAF6后AML细胞LC3 mRNA和LC3II蛋白水平表达上调(P<0.05)、p62 mRNA和蛋白水平下调(P<0.05)以及LC3 puncta聚集增多。用Baf-A1处理以阻断过表达TRAF6的白血病细胞系中的自噬流后,LC3II蛋白表达水平显著提高(P<0.05)。3-MA处理过表达TRAF6的白血病细胞后,LC3II蛋白表达减少、p62蛋白表达增加(P<0.05)。此外,过表达TRAF6降低白血病细胞凋亡率和促进细胞的体外增殖(P<0.001),而过表达TRAF6后联合3-MA处理则可逆转TRAF6对白血病细胞的抗凋亡和促增殖作用(P<0.001)。以上研究结果提示,过表达TRAF6能够增强AML细胞的自噬活性,促进AML细胞的生长。     

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.     

All-Trans Retinoic Acid Activity in Acute Myeloid Leukemia: Role of Cytochrome P450 Enzyme Expression by the Microenvironment

Differentiation therapy with all-trans retinoic acid (atRA) has markedly improved outcome in acute promyelocytic leukemia (APL) but has had little clinical impact in other AML sub-types. Cell intrinsic mechanisms of resistance have been previously reported, yet the majority of AML blasts are sensitive to atRA in vitro. Even in APL, single agent atRA induces remission without cure. The microenvironment expression of cytochrome P450 (CYP)26, a retinoid-metabolizing enzyme was shown to determine normal hematopoietic stem cell fate. Accordingly, we hypothesized that the bone marrow (BM) microenvironment is responsible for difference between in vitro sensitivity and in vivo resistance of AML to atRA-induced differentiation. We observed that the pro-differentiation effects of atRA on APL and non-APL AML cells as well as on leukemia stem cells from clinical specimens were blocked by BM stroma. In addition, BM stroma produced a precipitous drop in atRA levels. Inhibition of CYP26 rescued atRA levels and AML cell sensitivity in the presence of stroma. Our data suggest that stromal CYP26 activity creates retinoid low sanctuaries in the BM that protect AML cells from systemic atRA therapy. Inhibition of CYP26 provides new opportunities to expand the clinical activity of atRA in both APL and non-APL AML.     

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。     

Characterization of miRNomes in Acute and Chronic Myeloid Leukemia Cell Lines

Myeloid leukemias are highly diverse diseases and have been shown to be associated with microRNA（miRNA） expression aberrations. The present study involved an in-depth miRNome analysis of two human acute myeloid leukemia（AML） cell lines, HL-60 and THP-1, and one human chronic myeloid leukemia（CML） cell line, K562, via massively parallel signature sequencing. mRNA expression profiles of these cell lines that were established previously in our lab facilitated an integrative analysis of miRNA and mRNA expression patterns. miRNA expression profiling followed by differential expression analysis and target prediction suggested numerous miRNA signatures in AML and CML cell lines. Some miRNAs may act as either tumor suppressors or oncomiRs in AML and CML by targeting key genes in AML and CML pathways. Expression patterns of cell type-specific miRNAs could partially reflect the characteristics of K562, HL-60 and THP-1 cell lines, such as actin filament-based processes, responsiveness to stimulus and phagocytic activity. miRNAs may also regulate myeloid differentiation, since they usually suppress differentiation regulators. Our study provides a resource to further investigate the employment of miRNAs in human leukemia subtyping, leukemogenesis and myeloid development. In addition, the distinctive miRNA signatures may be potential candidates for the clinical diagnosis, prognosis and treatment of myeloid leukemias.     

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 specific PCR,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、U 937、NALM 17),进行SOCS-1基因甲基化水平的研究;同时运用Real-time PCR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﹤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U 937表现有SOCS-1甲基化(50%),Raji和NALM 17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。     

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.     

凋亡抑制蛋白XIAP 在急性髓系白血病和淋巴瘤骨髓组织中 的表达及意义

目的:研究凋亡抑制蛋白(XIAP)在白血病及淋巴瘤骨髓活检组织中的表达及意义。方法:采用免疫组织化学法检测10例急性髓系白血病,13例淋巴瘤,9例非恶性血液病患者骨髓活检组织中XIAP的表达水平。结果:XIAP蛋白在急性髓系白血病、淋巴瘤骨髓活检组织中的阳性表达积分均高于非恶性血液病,差异均有统计学意义(P<0.05)。结论:XIAP的表达水平与白血病及淋巴瘤的发生发展有一定关联,可能与其抑制肿瘤细胞的凋亡有关。     

Effect of High VEGF-C mRNA Expression on Achievement of Complete Remission in Adult Acute Myeloid Leukemia

Although vascular endothelial growth factor-C (VEGF-C) is known to be expressed in acute myeloid leukemia (AML) blasts, the relevance of VEGF-C in the clinical setting remains to be fully explored. We examined the effect of VEGF-C on achievement of complete remission (CR) in adult de novo AML and immune cell population profiles according to VEGF-C mRNA expression. In comparison of VEGF-C expression between the no-CR and CR groups, the CR group showed a trend toward higher levels of plasma VEGF-C (P = .088), whereas mRNA expression of VEGF-C was downregulated (P = .008). Next, patients with continuous data for VEGF-C were divided into two groups (low vs. high) by a ROC curve analysis. The low- versus high-level groups for plasma VEGF-C (RR of 0.20, P = .030), mRNA expression of VEGF-C (RR of 18.75, P = .003), and the ratio of plasma level to mRNA expression (RR of 0.05, P = .007) were potential predictors of CR on univariate analysis. After adjusting for potential clinical factors including genetic group, multivariate analyses revealed that high VEGF-C mRNA expression was an independent risk factor for failure of induction chemotherapy. Furthermore, patients with high VEGF-C mRNA expression had a lower frequency of NKT and CD8⁺ cells and showed a trend for a lower frequency of NK cells. These results suggest that interruption of VEGF-C signaling might be a potential therapeutic target for antileukemic treatment in AML patients.     

Inhibition of FLT3 Expression by Green Tea Catechins in FLT3 Mutated-AML Cells

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by a block in differentiation and uncontrolled proliferation. FLT3 is a commonly mutated gene found in AML patients. In clinical trials, the presence of a FLT3-ITD mutation significantly correlates with an increased risk of relapse and dismal overall survival. Therefore, activated FLT3 is a promising molecular target for AML therapies. In this study, we have shown that green tea polyphenols including (−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin (EGC), and (−)-epicatechin-3-gallate (ECG) suppress the proliferation of AML cells. Interestingly, EGCG, EGC and ECG showed the inhibition of FLT3 expression in cell lines harboring FLT3 mutations. In the THP-1 cells harboring FLT3 wild-type, EGCG showed the suppression of cell proliferation but did not suppress the expression of FLT3 even at the concentration that suppress 100% cell proliferation. Moreover, EGCG-, EGC-and ECG-treated cells showed the suppression of MAPK, AKT and STAT5 phosphorylation. Altogether, we suggest that green tea polyphenols could serve as reagents for treatment or prevention of leukemia harboring FLT3 mutations.