第53届美国血液学年会热点和重要进展报道

 目的　探讨抑癌基因FBXW7在Notch1诱导的小鼠白血病发展中的表达变化规律。方法　采用Notch1过表达小鼠急性T淋巴细胞白血病移植模型,在发病不同阶段分离骨髓单个核细胞,并在发病晚期用流式分选CD45.2+GFP+白血病细胞。实时定量PCR方法检测FBXW7的表达变化。结果　对照组和白血病组小鼠骨髓细胞均表达FBXW7。Notch1过表达导致的小鼠白血病发展过程中,FBXW7在对照小鼠中表达水平逐渐升高;而在白血病小鼠中,随着白血病的发展,表达水平逐渐下降,第12天降至对照组的1／6。分选后的CD45.2+GFP+白血病细胞低表达FBXW7。结论　FBXW7在小鼠白血病模型中低表达,提示FBXW7介导的泛素化降解途径异常可能与Notch1诱导的小鼠白血病的发生及发展相关。     

P2X家族受体在急性T淋巴细胞白血病小鼠中表达的特点

摘 要 目的：探讨不同P2X家族受体在小鼠急性T淋巴细胞白血病发展中的表达变化规律。方法：制备Notch1过表达小鼠GFP+T细胞急性淋巴细胞白血病移植模型,流式术分选CD45.2+GFP+白血病细胞,实时定量PCR检测P2X受体家族的表达变化,荧光分光光度计检测P2X7受体介导的钙离子浓度的变化。结果：对照组和白血病组小鼠骨髓细胞表达除P2X5外的其他6种P2X家族受体。Notch1过表达导致的小鼠白血病发展过程中,P2X7的表达水平逐渐升高,P2X1和P2X3的表达水平逐渐降低,而P2X2、P2X4和P2X6表达水平没有显著变化;分选后的CD45.2+GFP+白血病细胞中,P2X家族受体的表达呈现相同的规律。对照组和白血病组小鼠骨髓细胞中P2X7受体在激动剂苯甲酰-苯甲酸ATP（BzATP）的刺激下都能介导细胞内钙离子浓度升高,但白血病组小鼠骨髓细胞内钙离子处于持续高浓度状态,而对照组小鼠细胞内钙离子浓度短暂升高后逐渐下降;P2X7介导的这种钙离子反应可被其特异的拮抗剂KN62所阻断。结论：P2X受体家族中P2X1、P2X3和P2X7的表达变化与小鼠急性T淋巴细胞白血病的发展相关,提示其介导的细胞间通讯可能在白血病发展中发挥重要作用。     

头颈鳞癌Notch1的表达与顺铂敏感性的关系

背景与目的：Notch1属于Notch跨膜受体家族,在肿瘤细胞增殖和凋丁。过程中发挥着重要作用。已有研究表明Notch1影响化疗药物敏感性。而Notch1与头颈鳞癌顺铂敏感性的关系仍未被阐明。本研究旨在明确Notch1在头颈鳞癌中的表达状况,探讨Notch1表达水平对头颈鳞癌顺铂敏感性的影响。方法：收集25例头颈鳞癌新鲜手术标本进行原代细胞培养,肿瘤原代细胞胶原凝胶体包埋化疗药物敏感性检测（collagengeldropletembeddedculture—drugsensitivitytest,CD—DST）技术检测顺铂敏感性,．免疫化学染色检洲头颈鳞癌、正常鳞状上皮和舌鳞癌细胞株（Tb3．1）Notch1的表达水平．将经二甲基亚砜（dimethylsulfoxide,DMSO）、DAPT处理后的Tb3．1细胞分4组（DMSO、DAPT、DMS0＋Cisplatin、DAPT＋Cisplatin）,顺铂作用后CD—DST检测各组吸光度值。结果：头颈鳞癌组织Notch1阳性表达,表达水平明显高于正常鳞状上皮（P〈0．001）,且与顺铂敏感性呈负相关（r=-0．705,P〈0．01）,Tb3．1细胞Notch1阳性表达,DMSO组（A值155．4±2.3）与DAPT组（A值154．7±1．2）吸光度值差异无统计学意义（P〉0．05）,而DMSO＋Cisplatin组（A值33．9±1.3）与DAPT＋Cisplatin组（A值26．6±1．1）吸光度值差异具有统计学意义（P〈0．05）。结论：Notch1在头颈鳞癌中表达,且表达水平与顺铂的敏感性呈负相关。Notchl可用于预测头颈鳞癌顺铂的敏感性：DAPT阻断Notch1信号通路可提高Tb3．1细胞顺铂的敏感性。     

骨髓基质细胞通过TSP-1/CD36通路对急性髓系白血病细胞影响的初步研究

目的：探讨骨髓基质细胞（bone marrow-derived mesenchymal stromal cells,BM-MSCs）对急性髓系白血病（acute myeloid leukemia,AML）细胞影响的作用机制。方法：构建MLL-AF9过表达诱导的AML小鼠模型,通过PCR比较AML小鼠和野生型小鼠（WT）BM-MSCs内TSP-1的表达差异。通过慢病毒载体使AML小鼠来源的BM-MSCs高表达TSP-1后,与AML细胞行transwell共培养,检测AML细胞表面TSP-1受体CD36及CD47的表达及AML细胞的生长情况。在共培养体系中加入CD36抑制剂N-油酰基硫代琥珀酰亚胺,检测AML细胞增殖、凋亡的变化。结果：AML小鼠BM-MSCs中TSP-1的表达低于对照组。过表达TSP-1的BM-MSCs与AML细胞行transwell共培养后AML细胞的生长受到抑制,且AML细胞表面的CD36受体表达升高,但CD47表达无明显差异。在共培养体系中加入CD36抑制剂N-油酰基硫代琥珀酰亚胺后,AML细胞增殖加快,凋亡减少。结论：TSP-1/CD36信号通路有望成为治疗AML...     

FBXW7调控非小细胞肺癌上皮间质转化的作用机制

目的:研究FBXW7在非小细胞肺癌上皮间质转化(epithelial-mesenchymal transformation,EMT)过程中发挥的作用。方法:收集100对非小细胞肺癌组织和对应的癌旁组织，利用免疫组化检测FBXW7在癌组织和癌旁组织中的表达。利用Western blot检测FBXW7在细胞系中的表达及FBXW7对EMT部分标志蛋白的影响。利用Transwell实验检测FBXW7对NSCLC细胞迁移能力的影响。免疫共沉淀实验和泛素化的Western blot验证FBXW7与Snail1的关系。结果:FBXW7在NSCLC组织中的表达明显低于对应癌旁组织中的表达。FBXW7在正常肺上皮细胞中的表达也明显高于4种非小细胞肺癌细胞系中的表达。FBXW7过表达显著抑制A549细胞的迁移能力。FBXW7过表达也明显抑制NSCLC细胞的EMT。机制研究发现，FBXW7可以直接结合并泛素化降解Snail1蛋白，并且Snail1部分逆转FBXW7对NSCLC细胞EMT标志蛋白的影响。结论:FBXW7对NSCLC细胞EMT的调控部分依赖于泛素化降解Snail1蛋白。     

FBXW7α对结直肠癌细胞中热休克转录因子1表达和定位的影响

目的 探讨FBXW7对结直肠癌细胞中热休克转录因子1（HSF1）表达和定位的影响。方法 Western blot法检测敲除FBXW7及WT的结直肠癌细胞系HCT116和DLD1中HSF1及pHSF1^Ser326蛋白的表达;免疫荧光和Western blot检测在热休克及恢复期细胞中pHSF1^Ser326的核蛋白表达和定位。结果 过表达FBXW7α的DLD1细胞中HSF1蛋白表达显著降低（P<0.01）;敲除FBXW7的HCT116和DLD1细胞中HSF1和pHSF1^Ser326总蛋白表达显著升高（均P<0.05）。与WT组比较,敲除FBXW7的细胞中HSF1和pHSF1^Ser326主要累积在细胞核,而胞质表达较弱;温热刺激后,WT细胞中HSF1及pHSF1^Ser326表达恢复至未刺激水平,而敲除FBXW7的细胞中HSF1及pHSF1^Ser326在核中有较强表达（均P<0.01）。结论 敲除FBXW7的结直肠癌细胞热刺激后,细胞核HSF1水平恢复受阻,可能与缺失FBXW7不能降解胞核HSF1有关。     

miR-let-7c-5p靶向c-myc在白血病细胞定向单核/巨噬细胞分化中的作用机制研究

目的 探讨miR-let-7c-5p/c-myc信号轴在白血病细胞定向单核/巨噬细胞分化中的调控作用。方法 采用PMA+LPS+IFN-γ诱导THP-1白血病细胞向单核/巨噬细胞定向分化,PBS作为对照组。诱导48 h后CCK8法测定细胞增殖水平;流式细胞仪测定细胞CD11b与CD14分化抗原表达水平;RT-qPCR检测白血病细胞分化前后miR-let-7c-5p和c-myc的表达变化;蛋白质印迹法检测c-myc蛋白表达变化;双荧光素酶结合实验检测miR-let-7c-5p与c-myc的3′UTR靶向结合和活性调控关系;转染miR-let-7c-5p mimic观察c-myc表达变化后细胞的增殖分化水平变化;过表达c-myc拯救实验观察miR-let-7c-5p对PMA+LPS+IFN-γ诱导的THP-1细胞增殖分化的影响。THP-1细胞转染miR-let-7c-5p inhibitor,观察c-myc表达变化对THP-1定向分化为M1样巨噬细胞的影响。结果 与PBS对照组相比,PMA+LPS+IFN-γ诱导48 h后,THP-1细胞的增殖能力明显降低(0.64±0.01 vs 0.3...     

miR-27a促进胃癌细胞AGS增殖与侵袭及其机制探讨

目的:探究miR-27a对胃癌细胞AGS增殖与侵袭能力的影响,并进一步探讨能否靶向调控盐诱导激酶1(salt induce kinase 1,SIK1)和F框/WD_40域蛋白7(F-box and WD_40 repeat domain protein 7,FBXW7)。方法:利用TCGA数据库分析胃癌组织与邻近正常胃组织之间miR-27a表达水平的差异;利用脂质体LipofectamineTM2000将miR-27a mimics和miR-27a NC转入AGS细胞中,实时定量聚合酶链反应(Real-time PCR)检测miR-27a的表达,CCK-8实验检测细胞增殖活力,细胞平板克隆形成实验检测细胞克隆能力,Transwell实验检测细胞侵袭能力。生物信息学预测miR-27a的靶基因,通过蛋白印迹实验验证miR-27a对SIK1的调控作用;通过双荧光酶素报告基因、Real-time PCR和蛋白印迹实验验证miR-27a对FBXW7的调控作用。利用TCGA数据库分析胃癌组织与邻近正常胃组织之间FBXW7 mRNA表达水平的差异,分析FBXW7 mRNA表达水平与胃癌患者5年生存率的关系。结果:TCGA数据库分析表明miR-27a在胃癌组织中的表达高于邻近正常胃组织。Real-time PCR表明miR-27a在模拟物组中的表达较对照组高,细胞功能实验表明过表达miR-27a能促进胃癌细胞的增殖与侵袭能力;TargetScan预测SIK1为miR-27a的潜在靶基因,蛋白印迹实验表明SIK1不能被 miR-27a靶向负性调控。TargetScan预测FBXW7为miR-27a的潜在靶基因,双荧光素酶报告基因结果表明miR-27a可抑制FBXW7 3' UTR双荧光素酶活性,突变其结合位点后抑制作用消失。Real-time PCR和蛋白印迹实验表明过表达miR-27a后FBXW7的蛋白与mRNA表达均明显下调。TCGA数据库分析表明胃癌组织中FBXW7 mRNA的表达较邻近正常胃组织明显下降,FBXW7 mRNA表达低的组胃癌患者5年生存率更低。结论:过表达miR-27a能增强胃癌细胞AGS的增殖与侵袭能力,可能是通过负性调控FBXW7发挥的促瘤作用。在胃癌细胞AGS中,SIK1不能被miR-27a负性调控,可能被FBXW7靶向介导泛素化降解。     

Notch1基因表达对急性T淋巴细胞白血病SupT1细胞增殖、凋亡的影响及其机制

目的探讨Notch信号通路与急性T淋巴细胞白血病发生、发展的关系。方法利用携带Notch1特异性和非特异性shRNA的慢病毒载体包装成的病毒颗粒感染急性T淋巴细胞白血病SupT1细胞,采用CCK．8法检测细胞抑制率;采用流式细胞术检测细胞凋亡率（AnnexinV＋／7-AAD一和AnnexinV＋／7-AAD＋）;采用实时荧光定量PCR法检测Notch1受体基因及下游靶基因的表达水平。结果Notch1干扰组、空白对照组和空载体组96h的细胞增殖抑制率分别为0．902±0．013、0、0．486±0．084,干扰组较空白对照组、空载体组升高（均P〈0．05）;三组细胞早期凋亡率分别为（15．27±0．31）％、（5．57±0．25）％、（5．80±0．20）％,干扰组较空白对照组、空载体组升高（均P〈0．05）;而各组细胞晚期凋亡率无明显变化（均P〉0．05）。干扰组细胞中Notch1受体基因及其下游靶基因Hes1、c-myc、NF-κB在48、72、96h的mRNA相对表达量均较空白对照组及空载体组降低（均P〈0．05）。结论特异性Notch1-shRNA可有效下调Notch1mRNA的表达,并降低其下游靶基因的表达水平。Notch1表达下调可以抑制急性T淋巴细胞白血病SupT1细胞增殖,促进supT1细胞的早期凋亡。     

FBXW7基因点突变对结直肠癌HCT-116细胞的增殖、迁移、侵袭和抗 凋亡能力的影响

目的： 探讨FBXW7基因点突变对结直肠癌细胞株HCT-116增殖、凋亡、迁移和侵袭的影响。 方法： 通过构建FBXW7 基因野生型及突变型过表达的重组载体,并将其转染HCT-116细胞,应用Western blotting检测转染后FBXW7蛋白表达情况。 CCK-8检测细胞增殖能力,平板细胞克隆形成实验(HTCA)检测肿瘤细胞克隆形成能力,流式细胞术检测细胞凋亡情况,划痕及 Transwell细胞迁移实验检测细胞迁移和侵袭能力。 结果： 转染野生型FBXW7基因的HCT-116细胞中FBXW7蛋白表达水平高 于对照组（转染突变型FBXW7基因的HCT-116细胞）、阴性对照组（转染空质粒载体pEZ-M90的HCT-116细胞）及空白对照组（未 进行任何特殊处理的HCT-116细胞） （均P<0.05）。转染野生型FBXW7的HCT-116细胞的增殖、克隆形成、迁移和侵袭能力相较 于其余各组均显著下降（均P<0.05）,且细胞凋亡率显著升高（P<0.05）。 结论： FBXW7基因点突变可使其蛋白表达水平降低,从 而促进结直肠癌HCT-116细胞的增殖、迁移和侵袭,并抑制其凋亡。     

应用X线照射后的Balb/c小鼠制备白血病模型的方法学研究

目的:探索用SPF级Balb/c小鼠经X线照射后,尾静脉注射转染GFP及NeoR基因的K562细胞株以制备白血病模型的方法。方法:实验组小鼠分别经X线照射2Gy和3Gy,24小时后取对数生长期的K562(GFP+/Neo+)细胞尾静脉注射2×106个/只。对照组不予特殊处理。结果:实验组在接种5-7天时发病,分别于30、24天内全部死亡;生存天数显著短于对照组(P<0.01)。体重较对照组显著下降(P<0.05)。小鼠的白血病发病率为100%,无自发缓解。随照射剂量的增加,小鼠的存活时间缩短,且外周血及骨髓中白血病细胞所占比例增加。流式细胞仪测定及PCR方法也证实了GFP+细胞和NeoR基因在外周血、骨髓、肝、脾中的存在。结论:Balb/c小鼠经照射后从尾静脉注射K562细胞株可以获得白血病模型。     

应用X线照射后的Balb／c小鼠制备白血病模型的方法学研究

目的：探索用SPF级Balb／c小鼠经x线照射后,尾静脉注射转染GFP及NeoR基因的K562细胞株以制备白血病模型的方法。方法：实验组小鼠分别经x线照射2Gy和3Gy,24小时后取对数生长期的K562（GFP＋／Neo＋）细胞尾静脉注射2×10 6个／只。对照组不予特殊处理。结果：实验组在接种5—7天时发病,分别于30、24天内全部死亡;生存天数显著短于对照组（P〈0．01）。体重较对照组显著下降（p〈0．05）。小鼠的白血病发病率为100％,无自发缓解。随照射剂量的增加,小鼠的存活时间缩短,且外周血及骨髓中自血病细胞所占比例增加。流式细胞仪测定及PCR方法也证实了GFP＋细胞和NeoR基因在外周血、骨髓、肝、脾中的存在。结论：Balb／c小鼠经照射后从尾静脉注射K562细胞株可以获得白血病模型。     

Hes1对急性髓系白血病患者骨髓CD34+CD38-细胞的作用及其机制研究

  目的  研究Hes1对急性髓系白血病(AML)患者骨髓CD34+CD38-细胞的作用及其机制。  方法  收集初治AML患者及正常供者骨髓样本后，通过密度梯度离心法获取单个核细胞，流式细胞术检测CD34+CD38-细胞比例及其细胞周期。通过免疫磁珠法分选CD34+CD38-细胞后，体外集落形成实验(CFC)检测其增殖能力，并通过Realtime PCR检测其Hes1的表达量。构建Hes1过表达逆转录病毒载体，感染正常供者骨髓CD34+细胞后，流式细胞术分析其细胞周期的改变，CFC检测其增殖的改变。  结果  AML患者骨髓CD34+CD38-细胞比例明显低于正常对照，流式细胞术结果显示患者来源CD34+CD38-细胞大多数进入静止期，CFC结果显示患者CD34+CD38-细胞体外扩增能力下降。Realtime PCR结果发现患者CD34+CD38-细胞中Hes1表达上调。提高正常供者CD34+细胞中Hes1的表达后，细胞增殖减少，进入静止期。  结论  在AML中CD34+CD38-细胞比例下降，进入静止期，与Hes1的表达上调有关。      

Vaccination with leukemia cells expressing cell-surface-associated GM-CSF blocks leukemia induction in immunocompetent mice

The fundamental basis for immunotherapy of leukemia is that leukemic cells express specific antigens that are not expressed by normal hematopoietic cells. However, the host immune system appears to be tolerant to leukemia cells. To overcome this tolerance, we vaccinated immunocompetent mice with murine leukemia cells (WEHI-3B and BCR-ABL+ 32D cells) transduced with a specifically constructed transmembrane form of granulocyte-macrophage colony-stimulating factor (tmGM-CSF). The transduced cells expressed tmGM-CSF on the cell-surface. To determine whether tmGM-CSF-expressing WEHI-3B leukemia cells would prevent leukemia formation as a vaccine, immunocompetent mice (BALB/c and C3H/HEJ) were immunized with lethally irradiated murine leukemia cells expressing cell-surface tmGM-CSF before challenging mice with murine leukemia cells. Two immunocompetent mouse models were investigated, either WEHI-3B cells in BALB/c mice or BCR-ABL+ 32D cells in C3H/HEJ mouse. The results showed that 100% of WEHI-3B/tmGM-CSF-vaccinated BALB/c mice and about 65% of 32D+ BCR-ABL/tmGM-CSF-vaccinated C3H/HEJ mice were protected from leukemia after leukemia cell challenge, whereas all non-vaccinated mice succumbed to leukemia. Spleen and marrow cell suspensions from vaccinated mice challenged with WEHI-3B cells lacked detectable GFP+ WEHI-3B cells at 82 days post-challenge. A significant delay of death was observed in C3H/HEJ mice challenged with the very aggressive DA-1 cell line expressing BCR-ABL. Vaccination of mice with WEHI-3B/CD40L cells protected 80% of the mice from the WEHI-3B challenge. Notably, 60% of the WEHI-3B/BALB/c mice were also protected from leukemia when WEHI-3B/tmGM-CSF vaccination was carried out after the leukemia challenge. In order to determine whether cellular immunity is involved in this vaccine-mediated protection, either CD4+ or CD8+ T cells were depleted from mice after the WEHI-3B/tmGM-CSF vaccination. The results indicate that CD8+ T-cells mediated the protective immune response provided by the irradiated tmGM-CSF-expressing WEHI-3B cells. In addition, vaccination of nude mice did not provide protection from WEHI-3B leukemia induction. Importantly, 80% of non-vaccinated mice were also protected from a WEHI-3B cell challenge after receiving spleen cells from vaccinated mice 1 day before challenge with leukemia cells. These results indicate that overexpression of tmGM-CSF on the leukemia cell-surface can enhance the recognition of leukemic cells by CD8+ T cells, and can either prevent or significantly delay leukemia induction. These findings suggest that injection of irradiated leukemia cells expressing cell-surface-bound GM-CSF has the potential as an immunological approach to treat leukemia.     

BCR/ABL-mediated downregulation of genes implicated in cell adhesion and motility leads to impaired migration toward CCR7 ligands CCL19 and CCL21 in primary BCR/ABL-positive cells.

The mechanism underlying p210(BCR/ABL) oncoprotein-mediated transformation in chronic myelogenous leukemia (CML) is not fully understood. We hypothesized that p210(BCR/ABL) suppresses expression of genes which may explain at least some of the pathogenetic features of CML. A subtractive cDNA library was created between BCR/ABL-enhanced-green-fluorescent-protein (GFP)-transduced umbilical cord blood (UCB) CD34+ cells and GFP-transduced UCB CD34+ cells to identify genes whose expression is downregulated by p210(BCR/ABL). At least 100 genes were identified. We have confirmed for eight of these genes that expression was suppressed by quantitative real-time-RT-PCR (Q-RT-PCR) of additional p210(BCR/ABL)-transduced CD34+ UCB cells as well as primary early chronic phase (CP) bone marrow (BM) CML CD34+ cells. Imatinib mesylate reversed downregulation of some genes, to approximately normal levels. Several of the genes are implicated in cell adhesion and motility, including L-selectin, intercellular adhesion molecule-1 (ICAM-1), and the chemokine receptor, CCR7, consistent with the known defect in adhesion and migration of CML cells. Compared with GFP UCB or normal (NL) BM CD34+ cells, p210 UCB and CML CD34+ cells migrated poorly towards the CCR7 ligands, CCL19 and CCL21, suggesting a possible role for CCR7 in the abnormal migratory behavior of CML CD34+ cells.     

Wnt5a修饰的bMSCs对白血病小鼠造血及白血病细胞生长的影响

探讨Wnt5a基因修饰的骨髓间充质干细胞（bMSCs）对急性髓系白血病小鼠体内造血和白血病细胞生长的影响。方法:外周血瑞氏染色、骨髓流式细胞仪鉴定移植性HL60人白血病重度联合免疫缺陷(SCID)小鼠模型。造模成功的SCID小鼠,随机分为实验组（A组:Ad5-Wnt5a-bMSCs+模型小鼠）;对照组（B组:Ad5-GFP-bMSC+模型小鼠;C组:bMSC+模型小鼠;D组:模型小鼠）。RT-PCR检测外源性Wnt5a基因经骨髓腔移植入白血病小鼠模型后的定植情况。骨髓MSC及CFU-Mix培养、流式细胞仪、组织细胞化学及组织病理检测白血病小鼠移植前后各组外周血、骨髓、肝、脾、肾中的白血病细胞以及骨髓造血的变化。结果:成功建立急性髓性白血病模型;外源性Wnt5a基因转染人bMSCs,转染率达37.38%。外源性Wnt5a基因成功定植于受体骨髓中。Wnt5a基因修饰bMSCs移植后,与对照组比较,实验组SCID小鼠生存率明显提高,差异有统计学意义（P<0.05）;外周血有核细胞及瘤细胞计数明显降低,差异有统计学意义（P<0.05）;CFU-Mix和MSC集落生长恢复较快,集落数明显增多,差异有统计学意义（P<0.05）;小鼠骨髓、肺、肝、脾、肾CD33阳性率明显降低,差异有统计学意义（P<0.05）。结论:Wnt5a基因修饰的bMSCs在体内能有效地抑制白血病细胞生长,支持骨髓造血。      

Engraftment of chronic myeloid leukemia in SCID mice

Chronic myeloid leukemia (CML) is a clonal disorder of primitive hematopoietic stem cells characterized by a reciprocal translocation between chromosomes 9 and 22. Animal models of CML would be useful to study the biology and potential therapies in this disease. Mice with severe combined immunodeficiency (SCID) which will accept human xenografts have been useful in the study of a variety of human malignancies. CML has been difficult to establish in SCID mice possibly due to the lack of a functioning human stroma and relevant cytokines. To facilitate engraftment we injected cells in matrigel which is a soluble extract of basement membranes; is liquid below 22 degrees C and gels at 37 degrees C. CD34+ myeloid blast crisis cells (2 x 10(6)) were mixed in matrigel and injected subcutaneously into 10 SCID mice. All mice developed large tumours which spread to the mouse BM and spleen. However the percentage of human cells in the mouse BM and spleen was variable and ranged from 1 to 50 per cent. In contrast chronic phase (CP) CML cells mixed in matrigel did not form subcutaneous tumours and spread to the BM and spleen was detectable by PCR and not macroscopically. Groups of mice were injected with matrigel containing 1-20 x 10(7) MNC (2-20 x 10(5) CD34+ cells) from five patients with CP CMP. Bcr-abl sequences were detected by RT-PCR in the peripheral blood (PB) of 38/84 (45 per cent) mice at 3-10 weeks following injection of the CML cells but rarely at later time points. In addition, 33/75 (44 per cent) of mice sacrificed between 7 and 35 weeks following injection of CML cells were bcr/abl positive in the bone marrow and 17/70 (24 per cent) were positive in the spleen. Bcr-abl positive human CFU-GM colonies were also cultured from the murine bone marrow of several mice indicating that hematopoietic progenitor cells were able to migrate from the matrigel and engraft in murine hematopoietic organs. Engraftment of CP-CML was more successful in mice given higher numbers of CD34+ cells. Histological examination revealed that myeloid cells grow locally in the matrigel for several weeks, during which time the matrigel is infiltrated by blood vessels which may allow for the migration of CML progenitors to the murine bone marrow. This model system may be useful for studying the role of immunotherapy after allogeneic and autologous bone marrow transplantation.     

SAMHD1基因在初诊急性髓细胞白血病患者中的表达及其临床意义

目的:探讨SAMHD1基因在初诊急性髓细胞白血病（AML)患者中的表达及其临床意义。方法:实时定量PCR方法检测13例成人初诊AML患者与7例非恶性血液病患者SAMHD1 mRNA的表达,分析其临床意义。利用SPSS统计学方法分析SAMHD1基因表达高低与初诊白血病患者临床和实验室特征之间的相关性,采用Kaplan-Meier法以及COX回归模型进行多因素生存分析。结果:SAMHD1基因在AML患者中的表达低于非恶性血液病患者（P＜0.05）,且SAMHD1基因表达高低与患者性别、年龄、初诊时WBC、HGB、PLT、骨髓原始细胞百分比分布差异均无统计学意义;SAMHD1表达高低在预后良好与预后不良组间差异比较有统计学意义（P＜0.05),其中低表达组的OS低于高表达组。结论:SAMHD1基因在AML与非恶性血液病患者中表达差异具有统计学意义,且其可作为影响初诊AML患者OS的独立预后因素。