聚焦慢性粒细胞白血病

随着靶向治疗时代的到来,慢性粒细胞白血病 （CML）已经从不治之症转变为基本可控的慢性病。患者生存率有了显著提高,当然在疗效、耐受性及耐药性方面仍有提升的空间。长期以来,酪氨酸激酶抑制剂格列卫（Gleevec）一直被认为是合理药物设计的典范,但更有效的二代药物已经开始作为一线药物获得认可。然而,由于缺乏完整的生存期数据,这些二代药物和格列卫相比所具有的优势还有待于进一步去发现。由于患者需要长时间治疗,毒性和成本的可控性更可能成为选择治疗药物的重要推动因素。治疗慢性粒细胞白血病的产品线首先侧重于解决耐药性问题,尤其是在一线药物治疗失败而三线药物又无法满足需求的情况下。如果患者使用酪氨酸激酶抑制剂有效,那么最终的问题是患者是否可以通过这些药物治愈。     

Dasatinib preferentially induces apoptosis by inhibiting Lyn kinase in nilotinib-resistant chronic myeloid leukemia cell line

Nilotinib is approved for treatment of newly diagnosed chronic myeloid leukemia (CML) and it is shown superiority over imatinib in first-line treatment for patients of CML. In this study, we established a nilotinib-resistant cell line, K562NR, and evaluated the resistance to nilotinib and efficacy of dasatinib. We found activation of Lyn plays a dominant role in survival of the nilotinib-resistant cell line. We found dasatinib induces the apoptosis of nilotinib-resistant cells and inhibits Lyn kinase activity. This novel nilotinib-resistant CML cell line may help to explore novel therapy for CML.     

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。     

Case report of isochromosome 17q in acute myeloid leukemia with myelodysplasia-related changes after treatment with a hypomethylating agent

Isochromosome 17q is a relatively common karyotypic abnormality in medulloblastoma, gastric, bladder, and breast cancers. In myeloid disorders, it is observed during disease progression and evolution to acute myeloid leukemia in Philadelphia-positive chronic myeloid leukemia. It has been reported in rare cases of myelodysplastic syndrome, with an incidence of 0.4-1.57%. Two new agents have been approved for treatment of myelodysplastic syndrome/chronic myelomonocytic leukemia. These are the hypomethylating agents, 5-azacytidine and decitabine, recommended by consensus guidelines for high-risk myelodysplastic syndrome patients not eligible for hematopoietic stem cell transplantation. We present a case of chronic myelomonocytic leukemia with normal cytogenetics at diagnosis treated with decitabine (with good response); however, the patient evolved to acute myeloid leukemia with i(17q) shortly after suspending treatment. To the best of our knowledge, this is the first report of acute myeloid leukemia with myelodysplasia-related changes with i(17q) after the use of a hypomethylating agent.     

减低剂量去甲氧柔红霉素联合阿糖胞苷方案治疗老年急性髓细胞白血病的临床研究

目的:探讨减低剂量去甲柔红霉素联合阿糖胞苷(IA)方案治疗老年急性髓细胞白血病(AML)患者的疗效。方法:收集我院老年急性髓细胞白血病患者62例,随机分成减低剂量IA治疗组和标准剂量IA对照组,两组均实施3+7治疗方案。治疗2个疗程,比较两组不良反应和临床疗效。结果:减低剂量IA治疗组总CR率和CCR率分别为75.0%和66.7%;标准剂量IA对照组总CR率和CCR率分别为50.0%和33.3%。减低剂量IA治疗组总生存期25+月较标准剂量IA对照组生存期23+月延长。结论:对于老年急性髓细胞白血病患者,减低剂量IA治疗方案的CR率和CCR率与标准剂量IA治疗方案相比具有明显疗效优势。     

Targeted therapy: The new lease on life for acute promyelocytic leukemia, and beyond

Leukemia, a group of hematological malignancies characterized by abnormal proliferation, decreased apoptosis, and blocked differentiation of hematopoietic stem/progenitor cells, is a disease involving dynamic change in the genome. Chromosomal translocation and point mutation are the major mechanisms in leukemia, which lead to production of oncogenes with dominant gain of function and tumor suppressor genes with recessive loss of function. Targeted therapy refers to treatment strategies perturbing the molecules critical for leukemia pathogenesis. The t(15;17) which generates PML-RARα, t(8;21) that produces AML1-ETO, and t(9;22) which generates BCR-ABL are the three most frequently seen chromosomal translocations in myeloid leukemia. The past two to three decades have witnessed tremendous success in development of targeted therapies for acute and chronic myeloid leukemia caused by the three fusion proteins. Here, we review the therapeutic efficacies and the mechanisms of action of targeted therapies for myeloid leukemia and show how this strategy significantly improve the clinical outcome of patients and even turn acute promyelocytic leukemia from highly fatal to highly curable.     

白血病的精准基因组医学研究与转化应用

白血病是常见的血液系统恶性肿瘤,治疗主要以化疗为主,但总体治疗效果欠佳且发病的分子机制不明。因此,白血病的发病机制以及临床研究急需新的突破口。近年来,研究人员不仅发现了急性髓系白血病耐药的新靶点,揭示不同表观修饰的相互作用加速MLL白血病进展,也阐释了NK细胞白血病发病机制,发现关键表观因子在髓系肿瘤发生中的重要功能。尤其是新抑癌基因SETD2的发现,为急性髓系白血病的治疗提供了新的靶点。此外,在国际上研究人员首次将低剂量化疗方案用于治疗初诊儿童急性髓系白血病,在不影响疗效的基础上显著降低了化疗毒副作用及治疗费用。虽然基因组特征的解析加深了我们对癌症生物学分子机制的理解,但是近年来的研究表明瘤内异质性的克隆演化也是导致白血病临床治疗效果不佳的主要因素,解析不同化疗方案下白血病患者不同的克隆演化模式及其在临床预后评估中的作用是目前的研究热点之一。上述研究为急性髓系白血病诊断及治疗方法的改进提供了新的契机。     

MicroRNAs in Myeloid Hematological Malignancies

MicroRNAs are 19-24 nucleotides noncoding RNAs which silence modulate the expression of target genes by binding to the messenger RNAs. Myeloid malignancies include a broad spectrum of acute and chronic disorders originating from from the clonal transformation of a hematopoietic stem cell. Specific genetic abnormalities may define myeloid malignancies, such as translocation t(9;22) that represent the hallmark of chronic myeloid leukemia. Although next-generation sequencing pro-vided new insights in the genetic characterization and pathogenesis of myeloid neoplasms, the molecular mechanisms underlying myeloid neoplasms are lacking in most cases. Recently, several studies have demonstrated that the expression levels of specific miRNAs may vary among patients with myeloid malignancies compared with healthy individuals and partially unveiled how miRNAs participate in the leukemic transformation process. Finally, in vitro experiments and pre-clinical model provided preliminary data of the safety and efficacy of miRNA inhibitory molecules, opening new avenue in the treatment of myeloid hematological malignancies.     

Adoptive transfer of T cells transduced with a chimeric antigen receptor to treat relapsed or refractory acute leukemia: efficacy and feasibility of immunotherapy approaches

Treatment outcomes of acute leukemia(AL) have not improved over the past several decades and relapse rates remain high despite the availability of aggressive therapies. Conventional relapsed leukemia treatment includes second allogeneic hematopoietic stem cell transplantation(allo-HSCT) and donor lymphocyte infusion(DLI), which in most cases mediate, at best, a modest graft-versus-leukemia effect, although their clinical efficacy is still limited. Although allo-HSCT following myeloablative conditioning is a curative treatment option for younger patients with acute myeloid leukemia(AML) in a first complete remission(CR), allo-HSCT as a clinical treatment is usually limited because of treatment-related toxicity. The overall DLI remission rate is only 15%–42% and 2-year overall survival(OS) is approximately 15%–20%, with a high(40%–60%) incidence of DLI-related graft-versus-host disease(GVHD). Therefore, development of new, targeted treatment strategies for relapsed and refractory AL patients is ongoing. Adoptive transfer of T cells with genetically engineered chimeric antigen receptors(CARs) is an encouraging approach for treating hematological malignancies. These T cells are capable of selectively recognizing tumor-associated antigens and may overcome many limitations of conventional therapies, inducing remission in patients with chemotherapy-refractory or relapsed AL. In this review, we aimed to highlight the current understanding of this promising treatment modality, discussing its adverse effects and efficacy.     

Structural and spectroscopic analysis of the kinase inhibitor bosutinib and an isomer of bosutinib binding to the Abl tyrosine kinase domain

Chronic myeloid leukemia (CML) is caused by the kinase activity of the BCR-Abl fusion protein. The Abl inhibitors imatinib, nilotinib and dasatinib are currently used to treat CML, but resistance to these inhibitors is a significant clinical problem. The kinase inhibitor bosutinib has shown efficacy in clinical trials for imatinib-resistant CML, but its binding mode is unknown. We present the 2.4 Å structure of bosutinib bound to the kinase domain of Abl, which explains the inhibitor''s activity against several imatinib-resistant mutants, and reveals that similar inhibitors that lack a nitrile moiety could be effective against the common T315I mutant. We also report that two distinct chemical compounds are currently being sold under the name “bosutinib”, and report spectroscopic and structural characterizations of both. We show that the fluorescence properties of these compounds allow inhibitor binding to be measured quantitatively, and that the infrared absorption of the nitrile group reveals a different electrostatic environment in the conserved ATP-binding sites of Abl and Src kinases. Exploiting such differences could lead to inhibitors with improved selectivity.     

Autophagy inhibition enhances daunorubicin-induced apoptosis in K562 cells

Anthracycline daunorubicin (DNR) is one of the major antitumor agents widely used in the treatment of myeloid leukemia. Unfortunately, the clinical efficacy of DNR was limited because of its cytotoxity at high dosage. As a novel cytoprotective mechanism for tumor cell to survive under unfavorable conditions, autophagy has been proposed to play a role in drug resistance of tumor cells. Whether DNR can activate to impair the sensitivity of cancer cells remains unknown. Here, we first report that DNR can induce a high level of autophagy, which was associated with the activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Moreover, cell death induced by DNR was greatly enhanced after autophagy inhibition by the pharmacological inhibitor chloroquine (CQ) and siRNAs targeting Atg5 and Atg7, the most important components for the formation of autophagosome. In conclusion, we found that DNR can induce cytoprotective autophagy by activation of ERK in myeloid leukemia cells. Autophagy inhibition thus represents a promising approach to improve the efficacy of DNR in the treatment of patients with myeloid leukemia.     

Protective effect of Bosutinib with caspase inhibitors on human K562 cells

IntroductionCancer therapy has become increasingly focused on molecularly targeted medications. Despite the fact that multi-cytotoxic medication regimens have proven to be highly effective, many investigations in targeted treatments have focused on a single agent. The precise molecular mechanism of action of second-generation BCR–ABL tyrosine kinase inhibitors, which includes different targets and pathways, can help rationalize therapy in chronic myelogenous leukemia (CML) and other diseases affected by BCR–ABL tyrosine kinase inhibitors (TKIs).AimThe purpose of this study was to analyze if bosutinib (BOS) combined with Boc-D-FMK effectively suppressed proliferation and induced apoptosis in K562 cells to a lesser extent, implying that bosutinib is an effective leukemia treatment and that its combination with Boc-D-FMK is a mild chemotherapeutic agent against leukemia.MethodsIn this study, bosutinib was obtained together with other materials to perform a cell culture experiment with human cell lines, as well as additional drug treatment. Furthermore, cell viability (MTT assay) and flow cryometry such as viability and cell cycle assays are performed. The target profile of the dual SRC/ABL inhibitor bosutinib was studied in this study as a first kinase inhibitor to target K562 cells, which has recently been linked to the proliferation of myelogenous leukaemia cells, these results suggest the effectiveness of inhibitory activity on cell viability/proliferation, alone generated a potent value of 250 nM (39.27 ± 1.17) for 48 h as optimal dose.ResultsThe cytotoxic effect of bosutinib on the K562 cell line was assessed in vitro using the MTT assay, and the cytotoxicity was further clarified using cell viability and cell cycle assays. Guava Cell Assay software validated the activation of apoptosis. Sub-G1, G0/G1, S, and G2/M phases are depicted. Cell cycle research revealed that K562 cells treated with bosutinib accumulated much more in the sub-G1 phase, which was later validated by a drop peak at the G2/M phase.ConclusionIn conclusion, the nature of bosutinib's reduction of cancer cell growth may open the door to future research into the development of green synthesis medicines, particularly for cancer treatment.     

预激方案HAG及CAG治疗老年初治急性髓性白血病的对比研究

目的:评价含粒细胞集落刺激因子(granulocyte colony-stimulating-factor,G-CSF)的预激HAG及CAG方案治疗老年初治急性髓性白血病(AML)的疗效及不良反应,并对两个方案的疗效及不良反应进行比较。方法:65例老年初治AML分为HAG预激治疗组及CAG预激方案治疗组,31例患者予以HAG预激方案治疗,34例患者予以预激方案CAG方案治疗,所有患者在第1疗程后间歇14d左右进行第2个疗程。结果:HAG预激方案治疗组的完全缓解率为74.2%,总有效率为83.8%;CAG预激治疗组完全缓解(CR)率为67.6%,总有效率达为82.4%。两治疗组的血液系统不良反应及非血液系统毒性不良反应比较无显著性差异。结论:HAG预激方案化疗强度温和、敏感性好、CR率及有效率高、毒副作用小;与CAG预激治疗比较,HAG预激方案可以取的相似的疗效及较少的不良反应,在老年初治AML患者值得推荐应用。     

Randomised controlled trial of interferon alfa (lymphoblastoid interferon) in chronic non-A non-B hepatitis.

OBJECTIVE--To determine the effect of low dose interferon alfa (human lymphoblastoid interferon) on aminotransferase activities in chronic non-A non-B hepatitis. DESIGN--Prospective randomised controlled parallel group study of active treatment versus no treatment carried out over 16 weeks and preceded by baseline measurements at weeks 8 and 4 and time zero. SETTING--HEPATOLOGY outpatient clinics in secondary referral centres. PATIENTS--Fourteen adults with histologically proved chronic hepatitis and persistently raised aminotransferase activities for six months or more. INTERVENTIONS--Seven patients randomised to receive interferon alfa 5 megaunits (MU) daily for one week, reducing to 5 MU thrice weekly for seven weeks, then 3 MU thrice weekly for eight weeks. Controls not treated. END POINT--Control of hepatic enzyme activity in chronic non-A non-B hepatitis. MEASUREMENTS AND MAIN RESULTS--Serum aspartate aminotransferase activity remained raised in controls (mean increase in study period 23.4 U/l) but fell rapidly to normal in the treated group (mean decrease 106.4 U/l). In four cases values were normal by eight weeks and in five cases by 16 weeks. Only minor side effects were recorded (fever, myalgia), which became less common as treatment progressed. CONCLUSIONS--Continuous low dose interferon alfa reduces aspartate aminotransferase activity to normal in most patients with chronic non-A non-B hepatitis and may prevent progression to cirrhosis.     

Imatinib mesylate in chronic myeloid leukemia

Chronic myeloid leukemia has become a paradigm for the discovery of target therapeutic approaches in the field of onco-hematology. Recognition of the tyrosine kinase activity of the p210Bcr-Abl oncoprotein led to the development of compounds targeting against BCR-ABL and then controlling the leukemic proliferation. Imatinib mesylate, one of the first tyrosine kinase inhibitors developed, was found effective and safe. According to five-years experience with this drug, it is recommended that the golden standard for initial treatment of newly diagnosis chronic myeloid leukemia patients should be 400 mg Imatinib daily. In this brief review, we discuss the current tools for the effective management of chronic myeloid leukemia with Imatinib, providing the updated results of IRIS and RIGHT clinical trials and then the suggestions how Imatinib-treated patients should be monitored.     

Synergistic and additive antiproliferative effects on human leukemia cell lines induced by combining acetylenehexacarbonyldicobalt complexes with the tyrosine kinase inhibitor imatinib

The tyrosine kinase inhibitor imatinib is successfully used in the treatment of chronic myeloid leukemia, but the occurrence of resistance phenomena can significantly limit therapeutic impact. Imatinib shows synergistic effects with cisplatin, suggesting that the coadministration of different cytostatics might reestablish the efficacy of treatment. We recently demonstrated that cobalt alkyne (or acetylenehexacarbonyldicobalt) complexes induce antiproliferative activity in human leukemia and lymphoma cells. The present study evaluates the effects of cobalt alkyne compounds containing propargylic acid esters on human acute (HL-60) and chronic myeloid (LAMA-84 and CML-T1) leukemia cell lines. The cell growth inhibitory activities (IC(50) values of 9.5 microM and higher) and induction of apoptosis (maximum 5.5-fold increase of single-stranded DNA at a drug concentration of 50 microM) achieved with the single agents were moderate. Interestingly, suboptimal concentrations of the cobalt complexes (10 microM) together with imatinib (0.1 microM), when coadministered, showed an additive or synergistic effect on cellular proliferation inhibition. The most promising results were obtained with complexes containing ligands derived from the nonsteroidal antiinflammatory drugs acetylsalicylic acid and naproxene.     

Response to treatment with imatinib mesylate in previously treated chronic-phase chronic myeloid leukemia patients in a hospital in Brazil

We analyzed the results of treatment with imatinib mesylate in 70 patients with chronic-phase chronic myeloid leukemia who had previously been treated (with second-line or higher imatinib), many of them in a late chronic phase. The median follow-up period was 60.5 months (range 3-100 months). Our objective was to assess the efficacy and safety of treatment. The mean dose was 400 mg per day. The hematologic response rate was 92.1% at six months, while the cumulative rates of major and complete cytogenetic responses were 73.6 and 66.3%, respectively. Molecular response rate improved slowly and steadily over time, reaching 65.8% at 60 months, remaining stable for up to 96 months. The five-year progression-free survival and overall survival were 84 and 89%, respectively. Cytogenetic response by 12 months significantly correlated with overall survival (P = 0.0007) and progression-free survival (P = 0.0280). Sokal risk score did not differ significantly between subgroups. The medication was well tolerated, with only 16% of patients showing hematologic toxicity grades 3 and 4. At the end of the assessment, 57% of the patients were still on imatinib mesylate; most of those who discontinued treatment (17/30) did so because of unsatisfactory response. Treatment with imatinib mesylate in previously treated chronic-phase chronic myeloid leukemia induced durable responses in a high proportion of patients and was related to satisfactory long-term and event-free survival.     

Serum haptoglobin types and leukemia

Summary Haptoglobin types were determined on 211 patients with leukemia of the four most common types: acute lymphatic (ALL), chronic lymphatic (CLL), acute myeloid (AML), and chronic myeloid leukemia (CML). Frequency distributions of the three common Hp types in patients differed significantly from the control population. A significant increase in the relative incidence of Hp 1-1 was observed in patients with ALL, AML, and CML, but not with CLL. A similar trend was consistant in the data from previously published studies for the same three types of leukemia but not for CLL. Our results and the analysis of data from previous studies, suggest an association of Hp type with some leukemias, which is expressed in a consistent elevation of Hp 1-1 type among leukemia patients with ALL, AML, and CML.     

ATP depletion triggers acute myeloid leukemia differentiation through an ATR/Chk1 protein-dependent and p53 protein-independent pathway

Despite advances in oncology drug development, most commonly used cancer therapeutics exhibit serious adverse effects. Often the toxicities of chemotherapeutics are due to the induction of significant DNA damage that is necessary for their ability to kill cancer cells. In some clinical situations, the direct induction of significant cytotoxicity is not a requirement to meet clinical goals. For example, differentiation, growth arrest, and/or senescence is a valuable outcome in some cases. In fact, in the case of acute myeloid leukemia (AML), the use of the differentiation agent all-trans-retinoic acid (ATRA) has revolutionized the therapy for a subset of leukemia patients and led to a dramatic survival improvement. Remarkably, this therapeutic approach is possible even in many elderly patients, who would not be able to tolerate therapy with traditional cytotoxic chemotherapy. Because of the success of ATRA, there is widespread interest in identifying differentiation strategies that may be effective for the 90-95% of AML patients who do not clinically respond to ATRA. Utilizing an AML differentiation agent that is in development, we found that AML differentiation can be induced through ATP depletion and the subsequent activation of DNA damage signaling through an ATR/Chk1-dependent and p53-independent pathway. This study not only reveals mechanisms of AML differentiation but also suggests that further investigation is warranted to investigate the potential clinical use of low dose chemotherapeutics to induce differentiation instead of cytotoxicity. This therapeutic approach may be of particular benefit to patients, such as elderly AML patients, who often cannot tolerate traditional AML chemotherapy.