慢性粒细胞性白血病患者骨髓源bcr/abl融合基因阳性Flk1+CD31-CD34-干细胞体外抗STI571机制的初步研究

为进一步了解STI571对慢性粒细胞性白血病（CML）患者体内bcr/abl融合基因阳性的原始及定向白血病干/祖细胞分化及增殖的影响,更深入阐明部分CML患者在经历一段血液学甚至是细胞遗传学水平上的完全缓解后复发及对STI571的耐药机制,利用从CML患者骨髓分离到的具有血管母细胞特性、bcr/abl融合基因阳性、免疫表型为Flk1＋CD31-CD34-细胞,体外检测了STI571对其在造血集落培养基中的分化及处于分化阶段时的增殖抑制作用.结果显示：浓度为5 μmol/L STI571,维持作用96小时（病人体内维持96小时的STI571浓度只可能达到1-2 μmol/L）,即可有效抑制定向造血祖细胞的增殖.没有充分的证据显示,相对原始的bcr/abl融合基因阳性、免疫表型为Flk1^＋CD31^-CD34^-细胞的分化及增殖受到明显的抑制作用.结论：CML患者体内的原始白血病干/祖细胞对STI571具有一定的抗性,临床上所观察到的CML患者在运用STI571一段时间后出现正常的造血恢复现象,可能仅仅是因为STI571杀死或抑制了定向恶性白血病祖细胞的增殖,但随着时间的推移,在经历了短暂的血液学甚至是细胞遗传学水平上的缓解后,对STI571耐药的原始白血病干/祖细胞终究会再次导致CML的复发.     

STI571治疗BCR/ABL融合基因阳性白血病观察

目的 :观察酪氨酸激酶抑制剂STI5 71在BCR/ABL融合基因阳性表达白血病的治疗效果和副作用。方法 :已确诊BCR/ABL 的 8例慢性粒细胞性白血病 (CML)和 1例急性淋巴细胞白血病 (ALL)患者采用STI5 71 Ara -C治疗。结果 :2例CML -慢性期患者均CR至今 ,6例CML -急粒变患者有 2例CR ,其中 1例CR至今已 3 7周 ,1例ALL在第三次血液学CR后经治疗维持CR2 8周后复发。结论 :STI5 71可诱导BCR/ABL 白血病患者完全缓解 ,降低骨髓BCR/ABL 白血病细胞 ,延长CR期 ,药物副作用轻微易耐受 ,药物作用的个体差异性较大     

Antileukemic drug--a selective inhibitor of BCR-ABL tyrosine kynase, imatinib(STI571)]

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by Philadelphia chromosome and resultant production of the constitutively activated BCR-ABL tyrosine kinase. Imatinib (STI571), selective inhibitor of the ABL-tyrosine kinase, inhibits the activity of BCR-ABL tyrosine kinase. A phase I and II study of STI571 showed remarkable cytogenetic effect in patients with interferon-refractory CML, offering new hope for therapy for CML. It will, however, require long-term follow-up data from phase II and III clinical studies to validate the effect of STI571 on survival. As therapy for CML improves, monitoring minimal residual disease will be important.     

汉防己甲素联合屈洛昔芬对K562细胞bcr/abl表达的影响

为了研究汉防己甲素(Tet)联合屈洛昔芬(DRL)对K562细胞株凋亡相关因子bcr／abl mRNA及蛋白表达的影响，Tet(1μmol／L)和DRL(5μmol／L)单用及联合应用于K562细胞一定时间后，分别采用逆转录聚合酶链反应(RT—PCR)和Western blot方法检测K562细胞bcr／abl mRNA和蛋白表达的变化。结果表明：Tet和DRL单独应用对K562细胞bcr／abl mRNA及蛋白表达均无影响，两药联合应用于48小时K562细胞bcr／abl mRNA表达开始下调，K562细胞P^210 BCR／ABL蛋白表达于72小时开始下调。结论：Tet和DRL联合应用可下调K562细胞bcr／abl的表达，这可能是两药联用逆转耐药的机制之一。     

趋化因子MIP-1α和MCP-1及其受体CCR-1和CCR-2在慢性髓系白血病细胞中的表达

本文旨在研究MIP-1α和MCP-1及其受体CCR-1和CCR-2在慢性髓系白血病细胞中的表达,同时观察P210bcr/abl融合蛋白中酪氨酸激酶对MIP-1α和MCP-1及其受体CCR-1和CCR-2 mRNA表达的影响.在bcr/abl融合基因阴性和阳性慢性髓系白血病细胞中,采用半定量RT-PCR方法检测MIP-1α、MCP-1、CCR-1、CCR-2mRNA的表达水平.结果表明MIP-1αmRNA和CCR-1 mRNA在bcr/abl融合基因阳性细胞中不表达,但在bcr/abl融合基因阴性细胞中表达,而MCP-1 mRNA和CCR-2mRNA在bcr/abl融合基因阳性和阴性细胞中均不表达.当P210bcr/abl融合蛋白中酪氨酸激酶被抑制后,MIP-1α和CCR-1的mRNA表达水平恢复至正常水平.结论：P210bcr/abl融合蛋白抑制慢性髓系白血病细胞中MIP-1α和CCR-1 mRNA的表达,但对MCP-1和CCR-2mRNA的表达无影响.     

Allogeneic stem cell transplantation]

Over the last two decades, four major therapeutic approaches have dramatically changed the prognosis in chronic myelogenous leukemia(CML). Those include allogeneic stem cell transplantation, interferon-alpha based regimen, donor-leukocyte infusions, and the revolutionary BCR/ABL tyrosine kinase inhibitor such as STI571. Each modality has exploited and targeted different aspects of CML biology, and is associated with different risk-benefit ratios. In this section, we update the results of both related and unrelated donor transplantation, donor lymphocyte infusions, and non-myeloablative stem cell transplantation in CML in comparison with the other treatment modalities.     

Tyrosine kinase inhibitors: a cure for chronic myeloid leukemia?

Chronic myeloid leukemia (CML), a malignant transformation of hematopoietic cells, accounts for one-fifth of all leukemias and will be diagnosed in 4,400 individuals in the United States this year. CML has three phases: chronic, accelerated, and blastic. Interferon, hydroxyurea, busulfan, and bone marrow and stem cell transplantation are used to treat CML, but individuals who are in the accelerated phases or blast crisis usually respond poorly to treatment. A new tyrosine kinase inhibitor, STI 571, is being evaluated in clinical trials. STI 571 is highly bioavailable in oral form and produced minimal toxicities in phase I studies. Further research is needed to determine the rate of response and survival data, but STI 571 holds great promise in the treatment of CML.     

伊马替尼耐药CML患者ABL基因激酶区突变检测

目的 研究伊马替尼(imatinib,IM)治疗慢性粒细胞白血病(chronic myeloid leukemia,CML)耐药患者ABL酪氨酸激酶区突变情况.方法 用巢式PCR扩增对IM治疗耐药的56例CML患者骨髓样本ABL基因激酶区序列,通过测序和序列同源性检索分析ABL激酶区突变情况.结果 56例患者检出突变1...     

bcr/abl融合基因对β1整合素和L-选择素基因表达的影响

目的 研究ber／abl融合基因对β1整合素和L-选择素表达的影响。方法 应用半定量RT-PCR方法检测ber／abl融合基因阴性和阳性的慢性髓系白血病(CML)细胞中β1整合素和L-选择素mRNA的表达水平。同时观察酪氨酸激酶抑制剂Rb-C-Box基因转染bcr／abl基因阳性细胞后β1整合素和L-选择素mRNA表达水平的变化。结果 在bcr／abl基因阳性细胞中，L-选择素mRNA表达水平明显低于ber／abl阴性细胞，转入Rb-C-Box基因后，L-选择素mRNA的表达水平与ber／abl阴性细胞相似。bcr／abl阴性和阳性细胞及转染Rb-c-Box基因细胞中β1整合素mRNA表达水平差异均无显性。结论 ber／abl融合基因可抑制CML细胞中L-选择素mRNA的表达，对β1整合素mRNA的表达影响较小。     

β-catenin在慢性粒细胞白血病中的表达及与bcr/abl的关系

本研究检测β-catenin在慢性粒细胞白血病(CML)各期中的表达情况,并与bcr/abl的表达变化相比较,为进一步探讨β-catenin在CML急性变中的意义提供依据。首先分离CML各期患者及正常供者骨髓单个核细胞(BMMNC),提取总RNA,逆转录为cDNA,用实时定量PCR的方法检测β-catenin的表达情况,同时检测部分标本bcr/abl的表达情况,分析二者在CML进展过程中的表达变化及两者的相关性。结果表明:β-catenin在CML急性变期BMMNC的表达明显高于慢性粒细胞白血病(CML)慢性期(p<0.001)、加速期(p=0.016)及正常人(p=0.004),而在后三者之间未见统计学差异。急性变期bcr/abl的表达明显高于慢性期(p=0.001)。β-catenin的表达量与bcr/abl表达水平有明显的相关性(r=0.620,p<0.001)。结论:CML急性变期β-catenin的表达明显升高,并与bcr/abl的表达量有相关性。β-catenin的表达增高可能与CML急性变有关。     

The P190, P210, and P230 forms of the BCR/ABL oncogene induce a similar chronic myeloid leukemia-like syndrome in mice but have different lymphoid leukemogenic activity

The product of the Philadelphia chromosome (Ph) translocation, the BCR/ABL oncogene, exists in three principal forms (P190, P210, and P230 BCR/ABL) that are found in distinct forms of Ph-positive leukemia, suggesting the three proteins have different leukemogenic activity. We have directly compared the tyrosine kinase activity, in vitro transformation properties, and in vivo leukemogenic activity of the P190, P210, and P230 forms of BCR/ABL. P230 exhibited lower intrinsic tyrosine kinase activity than P210 and P190. Although all three oncogenes transformed both myeloid (32D cl3) and lymphoid (Ba/F3) interleukin (IL)-3-dependent cell lines to become independent of IL-3 for survival and growth, their ability to stimulate proliferation of Ba/F3 lymphoid cells differed and correlated directly with tyrosine kinase activity. In a murine bone marrow transduction/transplantation model, the three forms of BCR/ABL were equally potent in the induction of a chronic myeloid leukemia (CML)-like myeloproliferative syndrome in recipient mice when 5-fluorouracil (5-FU)-treated donors were used. Analysis of proviral integration showed the CML-like disease to be polyclonal and to involve multiple myeloid and B lymphoid lineages, implicating a primitive multipotential target cell. Secondary transplantation revealed that only certain minor clones gave rise to day 12 spleen colonies and induced disease in secondary recipients, suggesting heterogeneity among the target cell population. In contrast, when marrow from non- 5-FU-treated donors was used, a mixture of CML-like disease, B lymphoid acute leukemia, and macrophage tumors was observed in recipients. P190 BCR/ABL induced lymphoid leukemia with shorter latency than P210 or P230. The lymphoid leukemias and macrophage tumors had provirus integration patterns that were oligo- or monoclonal and limited to the tumor cells, suggesting a lineage-restricted target cell with a requirement for additional events in addition to BCR/ABL transduction for full malignant transformation. These results do not support the hypothesis that P230 BCR/ABL induces a distinct and less aggressive form of CML in humans, and suggest that the rarity of P190 BCR/ABL in human CML may reflect infrequent BCR intron 1 breakpoints during the genesis of the Ph chromosome in stem cells, rather than intrinsic differences in myeloid leukemogenicity between P190 and P210.     

bcr/abl融合基因检测在慢性粒细胞白血病诊断及残留病灶监测中的应用

目的探讨bcr/abl融合基因检测在诊断慢性粒细胞性白血病(CML)和监测CML残留病灶中的意义。方法采用巢式逆转录PCR(RT-PCR)检测337例CML患者bcr/abl融合基因的表达,并对所有患者进行残留病灶的动态监测,共检测632人次。其中移植(包括外周血干细胞移植、骨髓移植和脐血移植)患者26例;服用格列卫的患者22例;其它治疗方案患者289例。结果在337例CML初诊患者中bcr/abl基因表达阳性者325例,阳性率为96.4%;其中b3a2型转录本占58.5%(190/325),b2a2型转录本占41.2%(134/325),b3a3型转录本占0.3%(1/325)。未发现b2a3型转录本。移植患者bcr/abl融合基因转阴率为88.5%(23/26),时间在30~201 d之间,中位数为55 d;服用格列卫患者融合基因总转阴率59.1%(13/22),转阴时间在用药后90~365d之间,中位数为210 d;其它治疗组患者转阴12例,转阴率为4.1%(12/289)。结论bcr/abl融合基因的检测及动态观察,对CML的临床诊断、疗效及预后判断具有重要意义。     

STI571诱导K562细胞凋亡机制研究

目的　研究格列卫 (Glivec ,STI5 71)诱导P2 10BCR/ABL(+)K5 6 2细胞凋亡机制。方法　采用Annexin Ⅴ /PI双染实验、DNA的PI染色、碘化二己基恶碳菁 (DiOC6 [3])染色、2 ,7 二氯荧光素二乙酸酯 (DCFH DA)染色及DNALadder等方法测定凋亡细胞。利用Westernblot实验分析K5 6 2细胞蛋白酪氨酸磷酸化水平 ,测定Bcl XL、caspase 3蛋白的表达并分别测定线粒体及胞浆部分的细胞色素C(cytoC)蛋白。结果　STI5 71可诱导K5 6 2细胞凋亡 ,出现DNA亚二倍体凋亡峰及DNALadder,线粒体跨膜电位及活性氧物质降低 ,P2 10BCR/ABL酪氨酸磷酸化水平降低 ,Bcl XL、蛋白减少 ,caspase 3蛋白前体活化降解出相对分子质量为 2 0× 10 3 亚单位 ,胞浆部分出现cytoC ,同时线粒体cytoC减少。结论　STI5 71可迅速使P2 10BCR/ABL酪氨酸磷酸化水平下降 ,线粒体cytoC胞浆转位介导的信号通路是STI5 71诱导K5 6 2细胞凋亡的途径之一 ,STI5 71是有效的基因靶向治疗剂     

慢性髓系白血病不同bcr/abl融合基因转录子与临床关系的研究

目的研究慢性髓系白血病(CML)bcr/abl融合基因转录子类型与临床的关系.方法采用RT-PCR技术检测537例临床怀疑CML的患者新鲜骨髓标本三种bcr/abl(M、m及μ型)融合基因的表达.结果 479例CML患者 M-bcr/abl阳性,其中慢性期(CP)370例,加速/急变期(AP/BC)109例,CP期和AP/BC期患者表达b2a2型融合基因转录子的百分率分别为32.4%(370例中120例)及36.7%(109例中40例)(P>0.05),急淋变及急髓变患者b2a2型百分率分别为52.6%(19例中10例)及33.3%(90例中30例) (P>0.05);b3a2型患者初诊时外周血血小板数明显高于b2a2型患者[(485.9±333.8)×109/L] vs [(380.5±321.9)ⅹ109/L](P<0.05);66.0%CP及64.4%AP/BC患者同时表达M-bcr/abl及m-bcr/abl;1例单纯m-bcr/abl(+)患者表现为急性髓系白血病(AML);2例μ-bcr/abl(+)患者均具有典型CML表现.结论典型CML患者几乎均为M-bcr/abl融合基因阳性,大部分患者同时伴有m-bcr/abl表达,个别CML患者可以为μ型;除了急性淋巴细胞白血病(ALL)外,单纯m-bcr/abl(+)也可见于AML或CML急粒变的患者; b3a2型患者初诊时更易有血小板数增高表现.     

酪氨酸激酶抑制剂STI571治疗慢性粒细胞白血病的研究

目的:研究特异性酪氨酸激酶抑制剂STI571对慢性粒细胞白血病(简称慢粒)细胞增殖、凋亡、周期调控及bcr-abl融合基因表达的影响,为慢粒的基因治疗提供理论依据。方法:细胞培养慢粒急变细胞系K562细胞株,通过MTT检测STI571作用下细胞存活率,流式细胞仪检测周期变化,电镜及DNA电泳检测细胞凋亡,半定量RT-PCR检测STI571对bcr-abl融合基因表达的影响。结果:STI571作用后K562细胞中G1期细胞明显增加,S期细胞明显减少。流式细胞图中的二倍体峰前可见一明显亚二倍体峰———凋亡峰(apoptosispeak),提示STI571能明显诱导K562细胞凋亡。电镜发现STI571作用于K562细胞12～72h后,诱导出各期凋亡细胞及凋亡小体。半定量PCR灰度扫描结果显示bcr-abl基因的mRNA表达下降,电泳检测扩增产物,荧光亮度减弱。结论:STI571能明显抑制白血病细胞增殖,细胞阻滞于G0/G1期,且具有明显的诱导凋亡作用,反馈抑制bcr-abl融合基因的表达。     

BCR/ABL-mediated increased expression of multiple known and novel genes that may contribute to the pathogenesis of chronic myelogenous leukemia

The BCR/ABL chimeric protein plays a central role in the pathogenesis of chronic myelogenous leukemia (CML). Intensive research has elucidated many signal transduction pathways activated by BCR/ABL. However, few studies addressed BCR/ABL-dependent alterations in gene expression that may contribute to the pathobiology of CML. To additionally define such downstream genes, we performed a subtractive hybridization between cord blood (CB) CD34(+) cells transduced with an MSCV-retrovirus vector containing either enhanced green fluorescent protein (eGFP) alone or p210(BCR/ABL)-internal ribosome entry site-eGFP. Thirty-four subtracted clones expressed in p210-eGFP but not eGFP-transduced CD34(+) cells have been confirmed by Northern blot and sequenced. Fifty-nine percent represent novel proteins, and 41% are homologous to known genes. Quantitative real-time PCR analysis confirmed that 14 of 14 genes tested were also overexpressed in additional populations of p210(BCR/ABL)-transduced CB CD34(+) cells, as well as in CD34(+) cells from primary newly diagnosed CML patients versus GFP-transduced CB or samples from normal donors. Western blot analysis showed that the known sequences were also overexpressed at the protein level. Treatment of BCR/ABL(+) cells with the Abl-specific tyrosine kinase inhibitor STI571 decreased expression at the mRNA as well as protein level of some but not all of the gene products. This suggests that increased gene expression is in some cases tyrosine kinase-independent. Some of the overexpressed genes are implicated in cellular processes known to be disturbed in CML, including the mitogen-activated protein kinase or the ubiquitin pathway, whereas overexpression of other genes, including RAN and NUP98, may implicate new cellular pathways involved in CML. Additional characterization of downstream genes activated by BCR/ABL may lead to important new insights in the molecular mechanisms underlying CML and identify potentially novel therapeutic targets for CML.     

TEC启动子介导BCR/ABL基因在BaF3细胞中的表达

转P210bcr/abl基因小鼠是研究慢性髓系白血病的理想模型,但广泛表达的启动子容易引起转基因小鼠的胚胎致死,所以应用在造血细胞中特异表达的启动子是成功建立转P210bcr/abl基因小鼠模型的关键。本研究探讨TEC启动子介导BCR/ABL基因在BF3细胞中的表达。从小鼠的基因组中克隆TEC启动子的-364至+22区域,并替换掉IRES2-eGFP载体的CMVie启动子,同时在该载体的EcorⅠ酶切位点插入7.2 kb的P210bcr/abl基因,再将构建好的载体分别转染BaF3细胞和293细胞,观察eGFP基因与P210bcr/abl基因在2种细胞中的表达情况。结果通过荧光显微镜和流式细胞仪检测发现,eGFP基因在BaF3细胞成功表达,表达率在转染后6、24、72 h分别为7.10%、23.35%和64.61%,而在293细胞中未见eG FP基因表达。RT-PCR在BaF3细胞中扩增出BCR/ABL mRNA中372 bp的片段,而在293细胞中未扩增出任何片段。结论:TEC启动子的-364至+22区域能介导相关基因在造血细胞中高效特异性表达,适合于构建转P210bcr/abl基因小鼠模型。     

慢性髓系白血病首发血小板显著增多

本研究探讨以血小板显著增多首发的慢性髓系白血病（CML）临床、细胞遗传学及分子生物学特征。应用骨髓细胞涂片、骨髓活检观察细胞形态学改变;RT-PCR检测bcr／abl融合基因;常规染色体核型分析及FISH检测细胞遗传学变化。结果发现：以血小板显著增多为首发表现的CML是一组具有独特临床和生物学特点的疾病,骨髓细胞涂片和骨髓活检表明,骨髓增生活跃,以巨核系异常增生为主,血小板大片戍堆,可见圆形核小巨核细胞,中等度白细胞增多,经细胞遗传学和分子生物学检测均证实存在有Ph染色体和（或）表达bcr／abl融合基因,对此类患者应该早期进行积极治疗,甚至进行分子生物学水平的干预;而原发性血小板增多症（ET）患者则不宜过多地使用化疗药物,否则反而诱致白血病的发生。结论：对血小板明显增多的患者应及时进行Ph染色体及bcr／abl融合基因表达水平的检测．这对于ET及CML的诊断和鉴别诊断极为重要,以避免误诊、误治。     

Crosstalk between BCR/ABL oncoprotein and CXCR4 signaling through a Src family kinase in human leukemia cells

Stromal-derived factor (SDF)-1 and its G protein-coupled receptor, CXCR4, regulate stem/progenitor cell migration and retention in the marrow and are required for hematopoiesis. We show here an interaction between CXCR4 and the Src-related kinase, Lyn, in normal progenitors. We demonstrate that CXCR4-dependent stimulation of Lyn is associated with the activation of phosphatidylinositol 3-kinase (PI3-kinase). This chemokine signaling, which involves a Src-related kinase and PI3-kinase, appears to be a target for BCR/ABL, a fusion oncoprotein expressed only in leukemia cells. We show that the binding of phosphorylated BCR/ABL to Lyn results in the constitutive activation of Lyn and PI3-kinase, along with a total loss of responsiveness of these kinases to SDF-1 stimulation. Inhibition of BCR/ABL tyrosine kinase with STI571 restores Lyn responsiveness to SDF-1 signaling. Thus, BCR/ABL perturbs Lyn function through a tyrosine kinase-dependent mechanism. Accordingly, the blockade of Lyn tyrosine kinase inhibits both BCR/ABL-dependent and CXCR4-dependent cell movements. Our results demonstrate, for the first time, that Lyn-mediated pathological crosstalk exists between BCR/ABL and the CXCR4 pathway in leukemia cells, which disrupts chemokine signaling and chemotaxis, and increases the ability of immature cells to escape from the marrow. These results define a Src tyrosine kinases-dependent mechanism whereby BCR/ABL (and potentially other oncoproteins) dysregulates G protein-coupled receptor signaling and function of mammalian precursors.