错配修复基因hMSH2与慢性粒细胞白血病相关性研究

目的:通过对慢性粒细胞白血病(chronic myeloid leukemia,CML)患者骨髓细胞中错配修复基因(mismatch repair,MMR)h MSH2的表达水平及其调控机制的分析,探讨h MSH2与慢性粒细胞白血病疾病进展的联系。方法:用实时定量PCR方法检测10例对照,27例CML患者(包括慢性期9例,进展期8例,急变期10例)骨髓中4个MMR基因(h MSH2、h MSH6、h MLHl、h PMS2)m RNA的表达;用MSP方法检测MMR基因启动子区甲基化水平;用Western blot方法观察MMR蛋白水平在各组之间的差异。结果:与正常对照比较,CML患者的h MSH2的表达明显降低(P0.05),其表达随疾病恶化而下降,依次为急变期加速期慢性期,而h MLHl、h PMS2、h MSH6的表达却未见异常;27例CML患者中出现3例h MSH2启动子区高甲基化。结论:CML患者的h MSH2表达水平比正常人显著降低,且随着疾病恶化其表达水平逐下降,提示h MSH2可能与CML疾病进展相关。     

慢性粒细胞白血病小鼠动物模型建立的研究进展*

慢性粒细胞白血病(chronic myeloid leukemia,CML)是造血干细胞(hematopoietic stem cells,HSC)恶性克隆性增殖引起的一种血液系统疾病。动物模型是研究CML发病机制及药物靶向治疗的重要载体和工具。研究表明,CML小鼠模型可以通过逆转录病毒介导、转基因和白血病细胞移植的方法建立。三种方法建立的CML小鼠模型均可用于CML发病机制及药物疗效评估研究。实验动物模型进一步通过血常规、血涂片和骨髓涂片、免疫学、分子生物学及病理学等检测手段,判断模型是否建立成功。本文就近年来CML小鼠模型的建立、鉴定及研究应用进展进行综述。     

首个酪氨酸激酶抑制剂药物Gleevec

G1eevec^TM(原名STI571)是第一个被美国食品与药物管理局(FDA)批准上市的酪氨酸激酶抑制剂,能选择性地抑制慢性髓样白血病(CML)患者的Bcr-Abl蛋白酪氨酸激酶活性,对治疗CML取得了很好的疗效。Gleevec治疗CML的实验研究和临床试验都显示出令人满意的结果,分子作用和耐药机制的研究也有了新的认识和发现。该药物的开发成功,带动了酪氨酸激酶抑制剂的研究热潮,成为本世纪抗肿瘤研究的重点。     

慢性髓细胞性白血病病人骨髓单个核细胞中差异表达基因的筛选

目的:筛选慢性髓细胞性白血病(CML)病人骨髓单个核细胞与正常人的差异表达基因,探讨CML的发病机制.方法:提取正常人和CML病人单个核细胞的RNA,逆转录成cDNA并用地高辛标记,应用全基因组表达谱基因芯片对差异表达基因进行研究,采用Jubilant病理/疾病分类法对CML相关差异表达基因进行分析.结果:共筛选出CM...     

慢性粒细胞白血病耐药机制及治疗策略

慢性粒细胞白血病是一类造血干细胞的恶性克隆性疾病,ph染色体是其特征性细胞遗传学标志,即t(9;22)(q34;ql1),存在BCR/ABL融合基因,现阶段造血干细胞移植是当前最有希望治愈CML的疗法,但受年龄、配型等限制,易发生移植物抗宿主病;复发率较高;传统的化疗、干扰素治疗也有副作用,因此,通过信号传导抑制剂抑制BCR-ABL酪氨酸激酶活性,从而阻止一系列信号传导来治疗CML是一个比较好的治疗方法,伊马替尼是一种酪氨酸激酶抑制剂是治疗慢性粒细胞白血病的靶向治疗药物,治疗疗效显著,但是并不能根治慢性粒细胞白血病,需要长期服药,一些患者出现耐药,导致治疗无效或复发。因此,寻求新的治疗方案至关重要。本文就慢性粒细胞白血病的耐药机制及治疗策略做一综述。     

Hck和Lyn激酶与慢性髓细胞性白血病的关系

Src家族激酶（Sre—family kinase,SFK）是一组非受体型酪氨酸蛋白激酶,其家族成员Hck （hemopoietic cell kinase）和Lyn（v-yes-1 Yanaguchi sarcoma viral related oncogene homolog）激酶在慢性髓细胞性白血病（chronic myelogenous leukemia,CML）细胞中被BCR—ABL异常激活,并作用于多种细胞内信号转导分子,影响细胞的增殖、凋亡和迁移。深入研究SFK在CML发生和发展中的作用,对进一步认识CML发病机制及其靶向性治疗有着重要的实际意义。     

LMO2与T细胞白血病

Lmo2基因是LMO(LIM-only)家族的成员之一。作为一个原癌基因,Lmo2的染色体异位t(11;14)(p13;q11)或t(7;11)(q35;p13)与T细胞急性淋巴细胞白血病密切相关。LMO2是细胞中介导转录因子复合物形成的重要接头分子。现对LMO2的分子结构及其在正常和白血病细胞中的调控作用机制的差异作重点介绍。在此基础上还讨论了LMO2成为逆转录病毒介导的基因治疗X染色体连锁的严重联合免疫缺陷综合征过程中成为病毒插入靶位点的可能原因。     

自噬与急性早幼粒细胞白血病

急性早幼粒细胞白血病(APL)是急性髓性白血病的一种亚型,其分子特征是具有t(15;17)(q22;q21)染色体易位,并形成融合肿瘤蛋白,进而阻止早幼粒细胞分化成熟。全反式维甲酸(ATRA)和三氧化二砷(ATO)作为经典的治疗APL的药物,能够通过转录调节并激活泛素-蛋白酶体通路,促进融合肿瘤蛋白降解,发挥其临床抗白血病的功效。最近的研究发现,ATRA与ATO均能够诱导APL细胞自噬,且自噬在融合肿瘤蛋白降解及诱导早幼粒细胞分化中发挥至关重要的作用。我们简要综述近年来APL的研究进展及自噬在APL治疗中的作用。     

抗癌基因及其致癌机理

近年来,分子遗传学技术的广泛应用,推动和促进了肿瘤遗传变异研究的深入发展。有关血液系恶性肿瘤的研究已确认至少有两种涉及原癌基因激活的机理是细胞恶变转化的原因。即:慢性粒细胞性白血病(CML)中c-abl原癌基因被异常激活的质变     

慢性粒细胞白血病细胞选择性培养和净化

近年来,随着体外净化方法的不断发展和完善,以及家庭的日益小型化,使得自体骨髓移植在治疗急性白血病方面越来越受到重视。但对慢性粒细胞性白血病(CML)至今仍未找到理想的净化骨髓的方法,从而使自体骨髓移植在CML中的应用受到很大的限制。 CML是起源于多能干细胞的肿瘤性疾病,疾病的发生、发展、转归、细胞生物学及分子生物学变化     

Lysis of fresh leukemic blasts by interferon-activated human natural killer cells

In a comprehensive study of 30 leukemia patients, it was found that a measurable fraction of fresh leukemic blasts from 8 of 8 adult patients with chronic myelogenous leukemia (CML) in blast crisis and 10 of 11 pediatric patients with childhood acute lymphocytic leukemia (ALL) were efficiently lysed by human peripheral blood natural killer (NK) cells as measured in 4-hour chromium release assays. The observed lysis of these fresh, noncultured, neoplastic blasts was mediated by a population of interferon-augmentable, FcR-positive, non-adherent large granular lymphoid cells from normal donors, which were also able to kill the 'standard' NK target K562. It was of further interest that all 8 of the patients with blast crisis CML exhibited myeloid type morphology. Furthermore, neoplastic lymphoblasts from 9 of 10 patients with NK-susceptible childhood ALL lacked easily detectable B or T cell markers and were of 'null' cell type. In marked contrast to the lytic susceptibility of fresh leukemic blasts from patients with ALL and CML in blast crisis, fresh neoplastic granulocytes from 5 patients with chronic phase CML (2 of which eventually progressed to myeloid type blast crisis), as well as leukemic blasts from 8 patients with acute myeloid leukemias (AML, AMMoL, and AMoL) were resistant to lysis as mediated by human NK cells from normal donors. The clinical implications of these findings are discussed.     

Identification of 3q21q26 syndrome by "multipoint" interphase FISH analyses in childhood myeloid leukemia

Cytogenetic syndrome involving bands 3q21 and 3q26, known as "3q21q26 syndrome" has been observed in adult patients with acute myelogenous leukemia (0.5-2%), chronic myelogenous leukemia in blast crisis (20%), myelodysplastic syndromes and myeloproliferative disorders. In the present study bone marrow samples from two boys (12 and 16 years), diagnosed with CML and AML respectively, were investigated using conventional cytogenetic methods, interphase "multipoint" fluorescence in situ hybridization (FISH), dual color-FISH and multiplex FISH. The "multipoint" FISH analysis identified in de novo childhood AML case an inv(3)(q21q26) and a complex 3q rearrangement including inversion and duplication in the CML case. The "3q21q26 syndrome" is associated with normal or elevated platelet counts with marked abnormalities of megakaryocytopoiesis, involvement of multiple hematopoietic lineages. The affected patients were resistant to conventional chemotherapy and had a short survival. This syndrome is very rare in de novo childhood AML, and simultaneous presence of 3q inversion and duplication, to our knowledge, has not yet been identified in hematological malignancies. The results of our study emphasize the importance of classical and modern cytogenetic analysis in the diagnosis of hematologic malignancies, because in the majority of cases they can provide additional diagnostic information for the clinicians in deciding the best therapeutic approach, precise classification and prognosis of the disease.     

Short interfering RNA (siRNA) targeting the Lyn kinase induces apoptosis in primary, and drug-resistant, BCR-ABL1(+) leukemia cells

We studied the effects of Lyn ablation on the survival of drug-resistant chronic myelogenous leukemia (CML) blast crisis cells using siRNA. Lyn siRNA reduced Lyn protein in both normal hematopoietic cells and BCR-ABL1-expressing (BCR-ABL1(+)) blasts by 80-95%. Within 48 h, siRNA-treated BCR-ABL1(+) blasts underwent apoptosis, whereas normal cells remained viable. This increased dependence on Lyn signaling for BCR-ABL1(+) blast survival provides the basis for rational treatment of drug-resistant CML blast crisis, particularly when lymphoid in nature.     

A biological marker model for predicting disease transitions

For patients with chronic myelogenous leukemia (CML), the effect of elevated blood levels of adenosine deaminase (ADA) is studied as a marker for transitions from stable disease to blast crisis and then to death. Data in the form of snapshots over time, with day, state of disease, and ADA level, are analyzed for 55 patients. A simple three-state Markov model with one-way transition probabilities dependent on ADA is used to determine if the marker has a significant effect on the prediction of changes from stable disease to blast crisis.     

ATM-dependent DNA damage-response pathway as a determinant in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) begins with an indolent chronic phase, and subsequently progresses to an accelerated or blastic phase. Although several genes are known to be involved in the progression to blastic phase, molecular mechanisms for the evolution toward blast crisis have not been fully identified. Oncogenic stimuli enforce cell proliferation, which requires DNA replication. Unscheduled DNA replication enforced by oncogenic stimuli leads to double strand breaks on DNA. We found the DNA damage-response pathway is activated in bone marrow of chronic-phase CML patients possibly due to an enforced proliferation signal by BCR-ABL expression. Since ataxia telangiectasia mutated (ATM) is a central player of the DNA damage-response pathway, we studied whether loss of this pathway accelerates blast crisis. We crossed Atm-knockout mice with BCR-ABL transgenic mice to test this hypothesis. Interestingly, the loss of one of the Atm alleles was shown to be enough for the acceleration of the blast crisis, which is supported by the finding of increased genomic instability as assayed by breakage–fusion–bridge (BFB) cycle formation. In light of these findings, the DNA damage-response pathway plays a vital role for determination of susceptibility to blast crisis in CML.     

Acute leukemia in adults: assessment of remission induction with combination chemotherapy by clinical and cell-culture criteria.

Remission induction was assessed by clinical and cell-culture criteria for 65 patients with acute myelogenous leukemia (AML), 11 patients with chronic myelogenous leukemia (CML) in blast crisis and 19 patients with acute lymphoblastic leukemia (ALL). Cyclophosphamide, cytosine arabinoside and vincristine (CAV) therapy resulted in complete remission in 23 of 50 previously untreated patients with AML and in 3 of the 11 patients with CML. Fourteen patients with ALL responded to vincristine-prednisone induction therapy and two to induction therapy with CAV. The median duration of survival of the responding patients was 2.2 years, compared with 4 months for the patients who did not respond to treatment. Granulopoietic colony formation, assessed by assay of colony-forming units dependent on colony-stimulating activity in culture (CFU-C), was abnormal in 37 of 42 bone marrow aspirates from patients with AML before treatement. CFU-C concentration increased when leukocyte-conditioned medium (LCM) was added to the cultures; 13 cultures had normal or elevated CFU-C concentration with LCM. Marrow cells of patients with ALL or CML in blast crisis demonstrated a similar pattern. Serial studies of marrow CFU-C concentration of 31 patients with AML demonstrated a change to a normal pattern with successful remission induction. Results of this study suggest that administration of purified LCM to leukemic patients might increase granulocyte production from potential but unstimulated granulopoietic precursors. This therapy would lessen the probability of death from infection during remission induction.     

Detection of an antigen, associated with cells during the blast crisis of chronic myeloleukemia, in a cytotoxic test using xenogenic antibodies]

The immune antimyeloblast serum (AMS) was obtained from horses immunized with white blood cells from patients suffering from chronic myeloid leukemia (CML) at the blast crisis stage; the serum was completely absorbed with normal red blood cells and white blood cells (WBC). The absorbed antiserum remained cytotoxic to blast cells from 20 of 42 patients with CML at the blast crisis stage. AMS failed to react with the WBC from patients with CML in its chronic phase, and from patients with other types of leukemia Morphological studies indicated a possibility of identification of the antigen associated with myeloblasts from the blood of patients with CML blast crisis, by means to AMS.     

A new case of chronic myelogenous leukemia with 14q+ marker and review of the literature

We report a new case of Ph 1 positive chronic myelogenous leukemia (CML) with 14q+ marker shown during chronic phase (CP) and subsequently in blastic crisis (BC). After a review of the literature, we discuss the biological significance of 14q+ marker in developing lymphoid cellular differentiation, during evolution of CML, that remains still unclear. Besides, we also discuss the prognostic value of this change, concluding that a larger number of cases may clarify this question, as also the unresponsivity to chemotherapy of the patient studies so far, may not be related to 14q+ marker.     

Cytogenetic findings in chronic myelogenous leukemia

Cytogenetic findings in chronic myeloic leukemia are represented in a survey. More than 90 per cent of CML are characterized by Ph1 chromosomes, with more than 90 per cent of the cases being involved in a translocation (9; 22). Further, non-incidental aberrations are +Ph1, isochromosome (17q) and +8 which particularly develop at the acute stage. Isochromosome 17q is assumed to be a marker for a straightly impending development of a blast crisis. Ph1-negative CML is connected with a comparatively bad prognosis for the patient. Partial trisomy 9q+ is indicated here as a marker chromosome. For the patient concerned congenital chromosome defects, such as the Down-syndrome, represent a higher risk of being affected with leukemia.     

Chromosomal rearrangements with a common breakpoint at 6p23 in five cases of myeloid leukemia

Rearrangement of the short arm of chromosome 6 with a breakpoint at 6p23 was found in five patients with myeloid leukemia. Three of them had different morphological variants of AML (M2, M3, M4) and two blastic crisis of Ph1 negative and Ph1 positive CML. Identical translocation, t(6;9)(p23;q34), was revealed in two patients. One of them had AML (M2), the other blastic crisis of Ph1 negative CML. The blast cells of the last patient were morphologically similar to those in the M2 variant of AML. Translocation (6;9)(p23;q34) was also detected in two AML patients of Rowley and Potter (1976). The role of the breakpoint at 6p23 in myeloid malignancies needs further investigation.