伊马替尼治疗慢性髓系白血病耐药机制研究进展

慢性粒细胞白血病(chronic myeloid leukemia,CML)是一种克隆性造血系统恶性肿瘤,其特征性费城染色体阳性及BCR-ABL融合基因形成,而BCR-ABL融合基因是靶向治疗的位点。TKI的广泛使用,更是将CML患者的治疗带入一个全新的时代,但近年来伊马替尼(Imatinib,IM)在治疗CML的过程中,其耐药现象不断发生。因此,本文主要就BCR-ABL激酶区突变、BCR-ABL基因扩增、能量代谢异常、体内伊马替尼药代学、白血病干细胞所致伊马替尼耐药的机制研究进展进行综述。     

伊马替尼治疗慢性髓系白血病的血药浓度研究进展

伊马替尼通过选择性地抑制bcr-abl融合蛋白的高酪氨酸激酶活性,成为第一个瞄准慢性髓系白血病(CML)致病原因的小分子靶向药物[1-2].最新伊马替尼国际随机研究(IRIS)[3]显示伊马替尼应用于CML慢性期患者,8年总体生存率已达到85％,无事件生存率达81％.然而仍有15％ ～25％的患者发生伊马替尼原发或继发耐药[4-5].引起伊马替尼耐药的机制主要包括伊马替尼血药浓度的差异,bcr-abl基因的突变、扩增,肿瘤细胞的药物转运和外排系统,肿瘤细胞信号传导途径的异常,以及干细胞的休眠等[6].近年来,伊马替尼血药浓度对其临床疗效的指导意义越来越受到关注,我们就伊马替尼血药浓度的研究进展进行综述.     

伊马替尼治疗尼洛替尼不耐受的慢性髓系白血病

目的:探讨慢性髓系白血病(慢性期)个体化治疗方案的选择。方法:对1例尼洛替尼不耐受的慢性髓系白血病(慢性期)患者的临床资料及治疗过程进行分析。结果:患者在完善相关检查确诊为慢性髓系白血病(慢性期)后给予尼洛替尼治疗。治疗3个月时评估病情,患者虽然获得了主要分子学缓解(MMR)和完全细胞遗传学缓解(CCy R),但在治疗的过程中发生3-4级的肝毒性,经过药物的减量及对症治疗,患者在3次停药后换用伊马替尼治疗,7个月时评估病情达MMR及CCy R。目前患者无任何不良反应,耐受良好。结论:伊马替尼可作为慢性髓系白血病(慢性期)患者对第二代TKI治疗不耐受时的一种治疗方法,其不良事件发生率低且疗效确切。     

尼洛替尼治疗伊马替尼耐药或不耐受慢性髓系白血病患者的临床研究

本研究目的旨在评价尼洛替尼治疗伊马替尼耐药或不耐受的慢性髓系白血病（CML）患者的疗效及安全性。23例伊马替尼耐药或不耐受的CML患者纳入本研究。患者每日口服尼洛替尼600-800 mg,对他们的疗效、总体生存和耐受情况进行评估。结果表明,23例接受尼洛替尼治疗的患者中,全部获得完全血液学缓解（CHR）,19例（82.6%）获得完全细胞遗传学缓解（CCyR）,13例（56.5%）获得完全分子学缓解（CMR）,中位尼洛替尼治疗时间13.5（1-44）个月,中位随访时间40（12-102）个月。尼洛替尼治疗后的不良反应大半为轻微的,而且可以逆转。结论：尼洛替尼治疗伊马替尼耐药的CML患者疗效佳,患者耐受性好。     

Lyn激酶在伊马替尼耐药的慢性髓系白血病中的作用

本研究探讨Lyn激酶在伊马替尼耐药的慢性髓系性白血病（CML）中的作用。76例CML患者分为初治组、伊马替尼耐药组和伊马替尼治疗有效组,用Western blot方法检测CML患者骨髓单个核细胞中Lyn蛋白的表达水平,比较各组患者Lyn的表达差异,分析Lyn与I临床特征、BCR／ABL融合基因和染色体的关系。结果表明,76例CML均表达Lyn;伊马替尼耐药组Lyn表达明显高于正常对照组、初治组及伊马替尼治疗有效组（P〈0．05）,初治组和伊马替尼治疗有效组的Lyn表达水平与正常对照组无明显差别（P〉0．05）。Lyn表达水平与性别、年龄、平均血红蛋白水平、平均血小板计数、外周血幼稚细胞比例和脾脏大小无明显相关（P〉0．05）,但与初诊时外周血白细胞计数增高相关（P〈0．05）。Lyn表达与BCR／ABL融合基因定量无明显相关性（P〉0．05）;10例伊马替尼耐药的CML中,1例患者存在t（6;22）和t（2;9）改变,与Ph染色体共存,其余9例患者仅存在Ph染色体改变。结论：CML患者和正常人骨髓细胞均表达Lyn,Lyn在伊马替尼耐药的CML中表达明显增高,Lyn高表达与CML患者初诊时白细胞计数明显增高相关。     

肿瘤干细胞在伊马替尼耐药慢性髓系白血病细胞株中的表征

背景:慢性髓细胞白血病因为伊马替尼的应用出现了重大转机。但由于伊马替尼的耐药性,应用该药治疗的白血病患者预后较差,特别是对于急变期白血病患者。目的:观察肿瘤干细胞在伊马替尼ST1571耐药的慢性髓细胞白血病细胞系K562中的表征,阐明白血病细胞系对伊马替尼ST1571耐药的机制。设计:观察性对比实验。单位:河南省肿瘤医院,河南省血液病研究所。材料:选用5周龄BALB/c-nu/nu小鼠30只,雌性,由中国医学科学院动物中心提供。ST1571由北京诺华制药有限公司提供。足叶乙甙(Vp16)购自德国Bristol-Myers Squibb;抗P-gp购自美国Santa Cruz公司。抗ab1购自美国BD Biosciences公司。实验过程中对动物的处置符合动物伦理学标准。方法:实验于2003-09/2005-11在河南省血液病研究所完成。经过对K562细胞系长期的足叶乙甙(Vp16)诱导和克隆筛选,建立了一株耐药细胞系K562Np16;利用于细胞高效能将Hoechst 33342荧光染料泵出细胞的特性,采用流式细胞分选方法从K562/Vp16细胞系中分选出一小群细胞,即边缘细胞(SP),称为K562/Vp16 SP细胞,余下部分为K562/Vp16非SP细胞。为了分析白血病细胞对伊马替尼ST1571耐药的机制,分别检测K562,K562/Vp16非SP细胞或K562/Vp16 SP细胞中MDR1,Bcr-Abl和P-gp的表达。另外,按每只BALB/c-nu/nu小鼠1000个K562、K562/Vp16非SP细胞或K562/Vp16 SP细胞的数量分别对其进行腹腔注射。主要观察指标:K562/Vp16非SP细胞或K562/Vp16 SP细胞对ST1571的耐药性和致瘤性。结果:Bcr/Abl和Abl蛋白在K562细胞、K562/Vp16 SP细胞及K562/Vp16非SP细胞中的表达水平差异无显著性意义(P>0.05);P-gp在K562细胞中不表达,在K562/Vp16 SP及K562Np16非SP细胞中均高表达且表达水平一致(P>0.05);与K562/Vp16非SP细胞比较,K562/Vp16 SP细胞对伊马替尼的耐药性更强,并且这种抗性几乎不能被多种多药耐药逆转剂逆转;另外,体内外实验显示,K562/Vp16细胞的致瘤性几乎全部来源于K562/Vp16 SP细胞。结论:Bcr/Abl基因的扩增、过度表达和多药耐药基因及其蛋白表达产物P-gp的高表达,也许并不是白血病细胞产生对伊马替尼临床耐药的重要机制;白血病细胞对伊马替尼具有一定的抗性.可能与数量极少的白血病干细胞有直接的关系。因此,这类数量极少的干细胞样的肿瘤细胞应当成为有效治疗肿瘤的靶细胞。     

干扰素联合伊马替尼治疗慢性髓系白血病疗效及安全性分析

伊马替尼在目前被认为是慢性粒细胞白血病（CML）初治的首选治疗药物,但只有少部分患者能获得完全分子学缓解（CMR）。近年来临床和基础研究发现,干扰素联合伊马替尼有可能提高CML疗效。本研究分析多项临床研究结果,以伊马替尼单药治疗的结果为对照,系统评价干扰素联合伊马替尼方案治疗CML的疗效及安全性。本研究在ClinicalTrial网站和Cochrane协作网检索联合治疗的临床试验,并通过PubMed、EM等国内外文献数据库检索相关文献,对比联合治疗与单药治疗的疗效及不良事件数据。结果表明,共有7项临床研究,相关12篇文献符合纳入标准,病例总数697例。联合治疗组与单药组比较：完全细胞遗传学缓解（CCgR）6个月时为58％：42％（P=0．0001）,12个月时74％：68％（P=0．004）;主要分子学缓解（MMR）6个月时为58％：34％（P=0．0001）,12个月时66％：47％（P〈0．0001）;CMR6个月时为13％：2％（P=0．0002）,12个月时14％：5％（P=0．0009）。联合治疗不良反应主要有皮疹、乏力、水肿、肌肉疼痛,较单药治疗更易引起中性粒细胞减少、血小板减少和轻度贫血。结论：干扰素联合伊马替尼治疗CML疗效优于伊马替尼单药治疗,并且能更早获得细胞遗传学和分子学缓解且安全性良好。     

HO-1基因表达对伊马替尼耐药的慢性髓系白血病细胞增殖的影响

目的 通过氯高血红素(Hemin)诱导伊马替尼耐药慢性髓系白血病(CML)细胞株K562/A02-IM 中血红素加氧酶-1(HO-1)基因表达,探讨HO-1基因对伊马替尼耐药CML细胞增殖的影响,为治疗CML多药耐药及新药的开发提供思路和实验依据.方法 采用RT-PCR法检测20例CML伊马替尼耐药患者骨髓细胞中HO-1基因的表达,半定量RT-PCR法和Western blot法分别检测不同剂量Hemin处理K562/A02-IM细胞不同时间后HO-1的表达,通过Annexin V/PI双染色法检测细胞凋亡情况,采用MTT法检测Hemin诱导及锌原卟啉抑制HO-1表达与细胞存活率的关系.结果 RT-PCR结果显示耐药患者骨髓细胞中HO-1基因阳性表达,半定量RT-PCR和Western blot法显示,不同浓度的Hemin(0、10、20及40 μmol/L)处理K562/A02-IM细胞16 h后,HO-1的表达量随Hemin浓度的升高而增加,存在剂量依赖关系,而20 μmol/L Hemin分别处理K562/A02-IM细胞0、8、16、24 h后,HO-1的表达肇在处理16 h组最高.Annexin V/PI法检测显示,0、10、20及40 μmol/L Hemin作用于K562/A02-IM细胞16 h后细胞凋亡率分别为(17.61±0.01)%、(12.13±0.11)%、(7.94±0.03)%和(4.62±0.15)%,其抗凋亡的作用呈剂量依赖性;20 μmol/L Hemin作用K562/A02-IM细胞8、16及24 h的细胞凋亡率分别为(14.72±0.05)%、(8.15±0.07)%和(16.37±0.13)%.MTT法检测显示与对照组相比,Hemin诱导K562/A02-IM细胞HO-1基因表达促进了细胞的增殖,且作用存在剂量依赖关系;而锌原卟啉抑制HO-1的表达,促进了细胞的凋亡(P<0.05).结论 CML伊马替尼耐药患者骨髓细胞HO-1基因阳性表达,HO-1 是一种可诱导表达型基因,具有抗细胞凋亡及促进细胞增殖的作用,抑制HO-1 表达可能成为治疗CML耐药的新方法.

Abstract：

Objective To investigate the effect of heme oxygenase-1 (HO-1 ) expression on cell growth and apoptosis in imatinib resistant chronic myeloid leukemia (CML) cells ( K562/A02-IM) , and explore the relationship between HO-1 gene and CML. Methods The expression of HO-1 in 20 drug-resistant CML patients was detected by RT-PCR. Different concentrations of hemin were used to induce HO-1 expression of K562/A02-IM, HO-1 expression at different time was detected by RT-PCR and Western blot analysis. Cell apoptosis was detected by Annexin V/PI staining, and MTT assay was used to detect viability of K562/ A02-IM cells after induction or inhibition of HO-1 gene by hemin and zinc protoporphyrin (ZPP). Results RT-PCR showed that HO-1 was expressed in the bone marrow mononuclear cells (BMMNCs). When treated with hemin at different concentrations (0, 10, 20, 40 μmol/L) for 16 h, the expression of HO-1 in K562/ A02-IM was increased in a dose-dependent manner, and peaked at 20 μmol/L of hemin for 16 h. The apoptosis rates were (17.61 ±0.01)%, (12. 13 ±0.11)%, (7.94 ±0.03)% and (4.62 ±0. 15)% at 0,10, 20 and 40 μmol/L of hemin respectively for 16 h and were (14. 7 ± 0.05) % , (8. 1 ± 0. 07) % and (16. 3 ± 0. 13)% at 20 μmol/L of hemin treatment for 8,16, and 24 h respectively. Hemin induced apoptosis of K562/A02-IM cells in a dose-dependent manner. The expression of HO-1 was induced in K562/A02-IM cells in a dose-dependent manner, and the survival of K562/A02-IM cells was significantly increased as compared to that of control group. When HO-1 was inhibited by ZPP, the cells survival was sharply decreased compared to that of the control group (P<0.05). Conclusion HO-1 was expressed in the BMMNCs. It is a kind of molecules whose expression can be induced and can promote the growth of drug-resistant cells. Inhibition of HO-1 expression probably be used for the treatment of drug-resistant CML.     

伊马替尼治疗慢性粒细胞性白血病耐药机制研究进展

伊马替尼（格列卫,Imatinib）是一种选择性酪氨酸激酶抑制剂,临床应用于慢性粒细胞性白血病（CML）的治疗。尽管取得了良好的疗效,但是药物耐药性一直是困扰和阻碍其临床应用的主要问题。该耐药性的机制尚不清楚,但是许多研究从不同方面对这一问题进行了探讨。本文从药效学和药代动力学两方面对伊马替尼治疗慢性粒细胞性白血病耐药机制的研究进展进行了综述。     

Corynebacterium minutissimum bacteremia in a patient with chronic myeloid leukemia in blast crisis

Serious infections and sepsis due to nondiphtheria Corynebacteria have been well described. A patient with chronic myeloid leukemia in blast crisis, who developed Corynebacterium minutissimum bacteremia, is described in this report. Corynebacterium minutissimum is the causative agent of erythrasma and to our knowledge, this is the first published report of septicemia due to this organism.     

多重荧光原位杂交检测慢性粒细胞白血病急变期复杂核型异常

目的 探讨多重荧光原位杂交（M—FISH）技术检测慢性粒细胞白血病急变期（CML—BC）复杂核型异常（CCA）的价值。方法 应用M—FISH技术对26例常规细胞遗传学（CC）分析显示CCA的CML—BC患者进行检测分析。结果 除标准t（9；22）（q34；q11）外，通过M—FISH技术共检出69种结构异常，其中10种为平衡易位，59种为不平衡易位，不平衡易位包括1种插入、6种缺失及52种易位及衍生染色体；另外还检出23种数目异常。26例CML—BC患者中所有染色体均涉及异常，除标准t（9；22）外异常最多涉及的染色体是17号、2号、8号及16号。1例标本M—FISH未检出CCA，6例标本检出了CC分析未发现的异常核型。M—FISH明确了16种CC分析未确定的异常，纠正了5种CC分析识别错误的异常，还发现了CC分析未检出的35种染色体易位，其中der（9）t（16；6；9；22）和der（18）t（16；18；19）在既往文献中未见报道。结论 对伴有CCA的CML—BC以M—FISH技术可以发现和纠正CC分析漏检及误检的染色体异常。伴有CCA的CML—BC与CML常见的附加异常不同。     

慢性粒细胞白血病急变相关基因研究进展

慢性粒细胞白血病（ＣＭＬ）是一种起源于多能造血干细胞的血液系统恶性疾病。根据其临床进展,可分为慢性期（ＣＰ）,加速期（ＡＰ）和急变期（ＢＣ）。加速期和急变期表现为分化受阻,不受髓细胞生成调节因子的调节。研究ＣＭＬ急变的分子机制一直成为国内外的研究热点...     

FTY720, a new alternative for treating blast crisis chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphocytic leukemia

Blast crisis chronic myelogenous leukemia (CML-BC) and Philadelphia chromosome-positive (Ph1-positive) acute lymphocytic leukemia (ALL) are 2 fatal BCR/ABL-driven leukemias against which Abl kinase inhibitors fail to induce a long-term response. We recently reported that functional loss of protein phosphatase 2A (PP2A) activity is important for CML blastic transformation. We assessed the therapeutic potential of the PP2A activator FTY720 (2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride), an immunomodulator in Phase III trials for patients with multiple sclerosis or undergoing organ transplantation, in CML-BC and Ph1 ALL patient cells and in in vitro and in vivo models of these BCR/ABL+ leukemias. Our data indicate that FTY720 induces apoptosis and impairs clonogenicity of imatinib/dasatinib-sensitive and -resistant p210/p190(BCR/ABL) myeloid and lymphoid cell lines and CML-BC(CD34+) and Ph1 ALL(CD34+/CD19+) progenitors but not of normal CD34+ and CD34+/CD19+ bone marrow cells. Furthermore, pharmacologic doses of FTY720 remarkably suppress in vivo p210/p190(BCR/ABL)-driven [including p210/p190(BCR/ABL)(T315I)] leukemogenesis without exerting any toxicity. Altogether, these results highlight the therapeutic relevance of rescuing PP2A tumor suppressor activity in Ph1 leukemias and strongly support the introduction of the PP2A activator FTY720 in the treatment of CML-BC and Ph1 ALL patients.     

Engraftment with chronic granulocytic leukemia cells in acute myeloid leukemia

A deliberate engraftment with nonirradiated chronic granulocytic leukemia (CGL) cells was performed in a patient with acute myeloid leukemia (AML) at a time when he was resistant to cytotoxic drug chemotherapy, pancytopenic and developed an infection. The CGL engraftment was confirmed by the presence of a Ph1-positive donor clone in the recipient's bone marrow and by the pattern of colony growth of the recipient's bone-marrow cells cultured in vitro. Bone marrow engraftment in the host helped in the resolution of infection and permitted the administration of further cytotoxic drugs, as a result of which a remission of AML occurred.     

Nilotinib for imatinib-resistant or -intolerant chronic myeloid leukemia in chronic phase,accelerated phase,or blast crisis: A single- and multiple-dose,open-label pharmacokinetic study in Chinese patients

Background: Nilotinib, an oral second-generation Bcr-Abi tyrosine kinase inhibitor, is approved in the United States and European Union for the treatment of Philadelphia chromosome-positive (Ph+), chronic-phase (CP) or accelerated-phase (AP) chronic myeloid leukemia (CML) resistant to or intolerant of prior therapy, including imatinib. Information on the pharmacokinetics of nilotinib in Chinese patients with CML is lacking, and regulatory requirements for registration of this drug are needed in China.Objectives: This study assessed the pharmacokinet-ics of single and multiple oral doses of nilotinib in Chinese patients with CML and compared the pharmacokinetic profiles of nilotinib between the Chinese patients and a subgroup of white patients with CML.Methods: Chinese patients aged ≥18 years with Ph+ CML-CP, CML-AP, or CML-BC (blast crisis) resistant to or intolerant of imatinib were eligible. Patients were administered oral nilotinib 400 mg BID for 15 days. Serial blood samples were collected before and at 1, 2, 3, 5, 8, and 12 hours after the administration of a single dose (day 1) and multiple doses (day 15, steady state). Serum nilotinib concentrations were determined using a validated liquid chromatography-tandem mass spectrometry assay, and pharmacokinetic parameters of nilotinib were calculated using a noncompartmental method. Tolerability was assessed using cardiac assessments; laboratory analysis (hematology, blood chemistry, and urinalysis); and physical examination, including vital signs.Results: Twenty-three patients were enrolled (18 men, 5 women; mean age, 40.0 years; mean weight, 68.3 kg; CML-CP, 22 patients; CML-AP, 1). All 23 patients were included in the tolerability analysis. Two patients withdrew consent and discontinued after administration of the first dose; thus, 21 patients were included in the pharmacokinetic analysis. Median T^max was ~2 hours after administration of single and multiple doses. At steady state, C_min was 1025.4 ng/mL and C_max was 2160.7 ng/mL. Mean AUCs from time 0 to the end of the dosing interval τ (AUC_0-τ) were 5076.3 and 17,751.3 ng · h/mL at days 1 and 15, respectively, representing an accumulation factor of 3.92. Apparent oral clearance (CL/F) was 0.39 L/h/kg (range, 0.12–0.74 L/h/ kg) at steady state. The study found a 42% intersubject variability in nilotinib pharmacokinetics. Steady-state C_max, C_min, AUC_0-τ, and CL/F were not significantly different from those previously reported in a subgroup of white patients with CML who received the same 400-mg BID dose. Rash (11/23 patients [47.8%]) and elevated bilirubin, headache, and muscle pain (4 patients each [17.4%]) were the most frequently reported nonhematologic adverse events.Conclusions: In this pharmacokinetic study in Chinese patients with CML resistant to or intolerant of imatinib, nilotinib 400 mg BID was rapidly absorbed after a single dose and multiple doses. The steady-state pharmacokinetic properties in this population were consistent with those reported previously in white patients with CML.     

Extramedullary manifestations of blast crisis in chronic myeloleukemia

The paper is concerned with the development of extramedullary blast infiltrates in Ph-positive chronic myeloid leukemia. Two cases are described. In one case during the blastic phase lasting 27 months, a female patient developed by turn skin leukemids, lesions of the soft tissues in the knee joint, lesions of the stomach, lungs and heart. Administration of the treatment according to the "3 + 7" scheme (an anthracycline antibiotic plus cytosar) and to the TRAMPCOL scheme brought about the reverse development of the infiltrates. In the second case a male patient in the 12th year of the disease developed, in the absence of the blastic phase, massive blast lesions of the lymph nodes of the mediastinum followed by neuroleukemia. The lesions were removed by the treatment according to the ACOP scheme and endolumbal injections of methotrexate and cytosar. Ten months after diagnosing the enlargement of the lymph nodes of the mediastinum the picture of the blood and the bone marrow remained typical of the marked stage of the disease. The authors provide brief data on 27 patients with extramedullary blast infiltrates in the terminal stage of chronic myeloid leukemia together with short reported data.