RQ-PCR based WT1 expression in comparison to BCR-ABL quantification can predict Philadelphia negative clonal evolution in patients with imatinib-treated chronic myeloid leukaemia

A retrospective comparison of WT1 and BCR-ABL1 expression was performed in 40 imatinib-treated chronic myeloid leukaemia patients. The overall correlation of WT1 and BCR-ABL1 was low. In two patients WT1 expression was increasing despite very low BCR-ABL1 levels. As both revealed Ph-negative aberrant clones, a second independent cohort of 20 cases, all with Ph-negative clonal evolution, was analysed. High WT1 expression (5·0–177·0%) was detected in a case with +11 and in four of eight cases with +8, but not in cases with del(20q) or −Y. Thus, increasing WT1 levels in molecular responders may indicate Ph-negative clonal cytogenetic evolution during imatinib treatment.     

伊马替尼治疗慢性粒细胞白血病耐药的机制及新进展

目前,伊马替尼（imatinib mesylate,Gleevec/Glivec）是治疗慢粒的一线药物,属于ABL酪氨酸激酶抑制剂,是以ABL蛋白激酶的ATP结合位点为基础而设计合成。它通过抑制BCR-ABL自身磷酸化和底物磷酸化,而抑制细胞增殖和诱导凋亡。但随着临床     

Targeted therapy of chronic myeloid leukemia

Inhibition of BCR-ABL with kinase inhibitors has become a well-accepted strategy for targeted therapy of Philadelphia-positive (Ph⁺) chronic myeloid leukemia (CML) and has been shown to be highly effective in controlling the disease. However, BCR-ABL kinase inhibitors do not efficiently kill leukemic stem cells (LSCs), indicating that this therapeutic strategy does not lead to a cure of CML. Development of curative therapies of CML require the identification of genes/pathways that play critical roles in survival and self-renewal of LSCs. Targeting of these key BCR-ABL downstream genes provides an opportunity to eradicate LSCs, as shown in our work that identifies the Alox5 gene as a key regulator of the function of CML LSCs. Immediate clinical trials are necessary to test the effectiveness of targeting a key BCR-ABL downstream gene in eradicating LSCs in CML patients. In this review, we will discuss current targeted therapies of CML using BCR-ABL kinase inhibitors, with a focus on the importance of developing a targeted therapy of CML through identification of target genes in CML LSCs.     

甲磺酸伊马替尼对K562细胞bcr/abl、SHIP-2基因表达的影响及意义

目的研究甲磺酸伊马替尼对K562细胞bcr/abl、SHIP2的表达影响及意义。方法采用定量PCR方法检测甲磺酸伊马替尼干预K562细胞后bcr/abl、SHIP2基因表达变化。采用MTT及Western blot方法分别检测细胞增殖与AKT磷酸化水平的变化。结果随着甲磺酸伊马替尼浓度增加及作用时间的延长bcr/abl基因的表达下降（P〈0.01）,SHIP2的表达增加（P〈0.01）。Akt磷酸化水平降低,细胞增殖能力降低。结论甲磺酸伊马替尼能下调bcr/abl基因的表达;SHIP2表达可能受bcr/abl基因的调节,并可能通过调节PI3K/AKT途径影响细胞的增殖。     

早期监测BCR-ABL转录水平和细胞遗传学在评估慢性髓细胞白血病预后中的意义

目的 探讨监测早期BCR-ABL融合基因转录水平和细胞遗传学对评估慢性髓细胞白血病慢性期(CML-CP)预后的意义.方法 分析新疆维吾尔自治区人民医院血液科2007年7月至2012年5月初治的56例CML-CP患者,均予以口服甲磺酸伊马替尼400 mg/d,服药后3个月和6个月分别行BCR-ABL转录水平及细胞遗传学检查.患者中位随访时间为48个月.结果 服药后3个月时BCR-ABL转录水平≤10％的患者5年总生存率和无疾病进展生存(PFS)率均优于BCR-ABL转录水平＞10％的患者(总生存:100％比84.6％,P=0.011;PFS:94.6％比67.7％,P=0.045);细胞遗传学中,费城染色体阳性(Ph+)≤35％的患者5年总生存及PFS优于Ph+ ＞35％的患者(总生存:100％比76.2％,P=0.001;PFS:95.2％比38.1％,P=0.001).服药后6个月时BCR-ABL转录水平≤1％的患者5年总生存及PFS同样优于BCR-ABL转录水平＞1％的患者(总生存:100％比71.4％,P=0.000; PFS:95.2％比47.6％,P=0.001);Ph+=0％的患者5年总生存及PFS优于ph+＞0％的患者(总生存:100％比68.6％,P=O.000; PFS:95.3％比45.7％,P=0.000).结论 早期分子生物学及细胞遗传学监测对评估CML的预后有一定的意义,根据监测结果是否调整治疗策略应综合判断,制定个体化治疗方案.     

BCR-ABL融合基因检测方法的进展

BCR-ABL融合基因可编码产生BCR-ABL融合蛋白,是慢性粒细胞白血病的特征性标志,对慢性粒细胞白血病的诊断、治疗具有重要意义。目前临床有多种方法可对其进行检测,主要有细胞遗传学、荧光原位杂交、聚合酶链式反应、Western Blot印迹法、流式免疫磁珠(CBA)等检测方法。这些检测方法有的费时费力,有的需要专门的实验设备等,故在临床应用中受限。随着对BCR-ABL融合基因检测技术的发展,CBA法对BCR-ABL融合蛋白的检测具有其特有的优越性而得到越来越多的应用。     

Omacetaxine mepesuccinate for the treatment of leukemia

Introduction: Omacetaxine mepesuccinate, formerly known as homoharringtonine, is a first-in-class cephalotaxine that has experienced phases of increasing and waning interest since its first use in traditional Chinese medicine. With activity being reported in patients with chronic myeloid leukemia (CML) resistant to currently available tyrosine kinase inhibitors, renewed interest has recently been generated.

Areas covered: The development of omacetaxine mepesuccinate, with emphasis on synthesis and mode of administration, is addressed. An overview on current clinical results as a single agent or within combination regimens in patients with acute myeloid leukemia (AML) and CML is given.

Expert opinion: Omacetaxine mepesuccinate has a unique mode of action and appreciable activity in AML and CML with generally mild nonhematologic toxicity. In patients with AML, results indicate a role within combination regimens in selected, possibly elderly patient populations. In CML, patients with resistance to tyrosine kinase inhibitors, especially due to the T315I mutation, are the most intensively studied. Despite successful results in some patients, single-agent therapy with omacetaxine mepesuccinate has resulted in modest results. However, upfront combination with tyrosine kinase inhibitor represents an attractive option due their differing mechanisms of action.     

OCT-1 function varies with cell lineage but is not influenced by BCR-ABL

Background

Despite the excellent responses to imatinib therapy observed in patients with chronic phase chronic myeloid leukemia, approximately 25% of patients display primary resistance or suboptimal response. The OCT-1 activity in mononuclear cells reflects the efficiency of active influx of imatinib. OCT-1 activity in mononuclear cells is highly variable between patients and significantly correlates with a patient’s molecular response to imatinib treatment and overall survival. The present study examined whether cell lineage and BCR-ABL expression influenced OCT-1 activity.

Design and Methods

The OCT-1 activity and OCT-1 mRNA expression was assessed in pure populations of neutrophils, monocytes and lymphocytes recovered from chronic myeloid leukemia patients at diagnosis, in cytogenetic remission and normal individuals. The role of BCR-ABL on OCT-1 activity and differentiation was examined in a cell line model of ectopic BCR-ABL expression.

Results

The OCT-1 activity and OCT-1 mRNA expression was highest in the neutrophil population and lowest in lymphocytes (P<0.05). This was observed for patients at diagnosis, in cytogenetic remission and normal individuals. Interestingly, neutrophil OCT-1 activity was not significantly different between patients at diagnosis, in remission and normal donors. This was also observed for monocytes and lymphocytes. Furthermore, OCT-1 activity in mononuclear cells was significantly correlated with the OCT-1 activity in neutrophils (P=0.001). In a cell line model in which BCR-ABL was ectopically expressed, we found no evidence that BCR-ABL directly affected OCT-1 expression and function. However, BCR-ABL stimulated granulocyte differentiation which, in turn, led to significantly increased OCT-1 activity (P=0.024).

Conclusions

These studies suggest that the predictive OCT-1 activity in patient mononuclear cells is strongly related to cell lineage, particularly the presence of neutrophils in the peripheral blood. Furthermore, BCR-ABL expression is unlikely to directly influence OCT-1 activity but may have an indirect role by enhancing granulocyte differentiation.