急性髓系白血病的分子机制和靶向治疗

急性髓系白血病(AML)是一类具有异质性的造血系统恶性肿瘤,其分子机制涉及基因组和表观遗传学多个层面的改变.急性早幼粒细胞白血病(APL)是AML中的特殊类型,全反式维甲酸(ATRA)和亚砷酸(ATO)的联合应用使APL成为白血病靶向治疗史上最成功的范例.四十年来AML的标准化疗方案几近未变,近年来靶向新药的涌现和免疫...     

PNAS：研究发现急性髓系白血病诱因

近日来自上海交通大学医学院附属瑞金医院、中科院上海生命科学研究院以及美国布兰迪斯大学的研究人员,在模型小鼠中证实了C—KIT突变与全长AML／ETO融合基因是急性髓系白血病（AMJL）的共同诱因,从而为急性髓系白血病的治疗提供了新的理论依据和潜在靶点。这一研究成果公布在美国《国家科学院院刊》（PNAS）上。     

急性白血病基因突变与多步骤发病机制和临床相关性

急性髓细胞白血病(AML)是一组在发病机制和临床行为方面差异较大的疾病.在急性早幼粒细胞白血病中(APL),PML-RARα是APL的关键驱动(driver)突变,具有显性负的调控作用,影响髓系分化、凋亡和DNA复制和修复,其特殊结构使其成为全反式维甲酸和三氧化二砷的靶标.随着第二代测序技术的发展,在AML中发现了一些新的基因突变,其中DNA甲基转移酶3A(DNMT3A)突变是与表观遗传学相关的、与AML较差预后有关的基因事件.在1185例AML的基因分析中,研究发现与表观遗传学相关的第Ⅲ类突变与老年、高WBC及较差的临床预后有关.AML的发病是多步骤的,涉及不同通路上不同分子事件的相互作用,目前认为影响转录因子和信号传导通路的分子事件相互作用是AML完全发病的重要模式之一.     

靶向CD123抗原嵌合受体T细胞治疗急性髓系白血病的研究

急性髓系白血病(AML)是一种预后较差的血液系统恶性肿瘤,迫切需要新的治疗手段。随着嵌合抗原受体(CAR)T细胞(CAR-T)技术的发展并在B细胞肿瘤中取得显著疗效,人们把目光投入更多的实体瘤与血液肿瘤靶点中。CD123分子是CAR-T治疗AML的潜在靶点,抗CD123 CAR-T具有靶向清除白血病干细胞(LSCs)及原始细胞的能力。本研究总结了目前在靶向CD123 CAR-T治疗急性髓系白血病目前的研究进展。     

急性髓系白血病发病机制的研究进展

急性髓系白血病(acute myeloid leukemia,AML)是白血病中最常见的类型。传统治疗以联合化疗为主,而患者完全缓解率和长期无病生存率均较低。随着研究的深入,发现AML主要的发病机制包括融合基因、信号通路、白血病干细胞(leukemia stem cells,LSCs)以及骨髓微环境的改变等。该文旨在总结目前AML发生、发展机制的研究进展,并探讨其未来可能的治疗研究方向。     

急性单核细胞白血病M5转为急性红白血病M6一例病例分析及文献复习

目的:红白血病为临床少见的急性髓系白血病亚型,白血病克隆转换不常见,在国内外文献中有关报道少见.通过对一例由急性单核细胞白血病转化的急性红白血病(acute erythroid leukemias,AEL)的病例分析,学习并探讨急性红白血病的临床特点及实验室检查特征,提高对急性红白血病疾病特点及白血病克隆转化的认识.方法:报道一例初诊为急性单核细胞白血病,后转为急性红白血病的患者.期间对其进行持续的细胞形态学,遗传学及分子生物学监测.结果:患者首次入院诊断为急性单核细胞白血病,经过一个疗程化疗后,骨穿显示从急性单核细胞白血病转为急性红白血病.随后再进行了一个疗程化疗,化疗结束后患者好转出院.后因经济原因,患者未继续治疗,2月后随访,患者死亡.结论:本例急性单核细胞性白血病化疗后转为红白血病.究其机制,可能有:一.发病是粒-单定向祖细胞和红系定向祖细胞同时受损,只是早期单核细胞系异常表现明显,红系异常早期表现不明显.或疾病起源于更早期造血干细胞,导致单核系和红系均有异常.二.在疾病过程中,骨髓微环境的变化,诱导红系异常而导致红白血病的发生.经过分析,本病例中,疾病可能起源于更早期造血干细胞的可能性较大,而骨髓微环境在疾病变化过程中则起到了重要的作用.这一结果有待进一步临床观察研究和肯定.提醒临床医生,提高动态的诊断和治疗意识,将有助于该疾病的预防、诊断和治疗.     

PNAS：研究发现急性髓系白血病诱因

近日来自上海交通大学医学院附属瑞金医院、中科院上海生命科学研究院以及美国布兰迪斯大学的研究人员。在模型小鼠中证实了C-KIT突变与全长AML／ETO融合基因是急性髓系白血病（AML）的共同诱因,从而为急性髓系白血病的治疗提供了新     

Cancer Cell:我国科学家有望开发出治疗急性髓性白血病的新疗法

正近日,刊登在国际杂志Cancer Cell上的ー项研究报告中,来自上海交通大学医学院等机构的研究人员通过研究发现了治疗急性髓性白血病(AML)的新型治疗靶点和新型疗法,急性髓性白血病是ー种血液骨髓癌症,通常需要及时且积极的疗法对这种癌症进行治疗。研究者Wei Jia博士指出,目前我们急需新型靶点和药物来改善急性髓性白血病患者的预后情况而且我们发现患者机体中果糖的使用水平会增加,这种特殊的代谢特性就能够帮助预测患者的治疗预后情况,这项研究还为研究者提供了强大的证据来表明,利用小分子药物阻断机体果     

缓解与未缓解髓系白血病干细胞表面抗原CD34~+CD123~+表达差异研究

目的:探索缓解与未缓解急性髓系白血病干细胞表面抗原表达差异,为判定化疗疗效及其预后提供依据。方法:按照急性白血病诊断标准,根据患者入院时骨髓白血病细胞数量多少分成临床缓解与未缓解两组,以流式细胞仪分别检测骨髓中白血病干细胞表面相关抗原表达情况,比较二者之间差异。其中经标准化疗方案治疗结束后,通过复查骨髓象判定疗效并比较化疗前后白血病干细胞表面相关抗原表达变化。结果:与缓解的急性髓系白血病患者骨髓白血病干细胞相关抗原表达值相比,未缓解的患者骨髓白血病干细胞表面相关抗原表达明显升高,差异具有统计学意义(P0.05,0.001);未缓解的患者经标准方案化疗后骨髓虽然已经获得完全缓解,但依然具有白血病干细胞表面抗原高表达,提示这部分患者依然有复发的可能性。结论:急性髓系白血病患者的白血病干细胞相关抗原表达值升高是急性白血病复发难治的根源之一。     

Nature medicine:应用BCL-2抑制剂治疗急性髓系白血病

近日,来自斯坦福大学医学院的科学家们在国际期刊nature medicine上在线发表了他们的最新研究进展,他们通过大规模RNAi筛选的方法,发现在急性髓系白血病中,IDH1R132H突变对抗凋亡基因BCL-2具有很强依赖性,用BCL-2特异性抑制剂处理,会导致含有IDH1R132H突变的细胞更易发生凋亡。在之前研究中已经发现在急性髓系白血病细胞中,突变的异柠檬酸脱氢酶1和2会导致细胞内表观遗传图谱的改变。研究人员通过大规模     

The combination of DNA methyltransferase inhibitor therapy and immunotherapy for acute myeloid leukemia

Acute myeloid leukemia (AML), the most common form of acute leukemia in adults, is characterized by abnormal proliferation and blocked maturation and differentiation of myeloid precursor cells. AML is an aggressive cancer that progresses rapidly without treatment. Therefore, effective treatment modalities should be implemented immediately after diagnosis. The mainstay of classical AML therapy has been chemotherapy, which is not suitable for relapsing or refractory patients, especially elderly patients. Among emerging novel therapeutic approaches for AML, epigenetic therapy and immunotherapy represent two exciting therapeutic developments. This review focuses on discussion of the therapeutic considerations for AML from the perspective of combination treatment, which incorporates both DNA methyltransferase inhibitor therapy, as one of the most promising epigenetic therapies, and immune checkpoint inhibitor or dendritic cell-based vaccination treatments, as examples of immunotherapy. Both challenges and rationale in the optimization of therapeutic approaches, as well as recent clinical trial developments, along this line are summarized.     

DNA damage accumulation and repair defects in acute myeloid leukemia: implications for pathogenesis,disease progression,and chemotherapy resistance

DNA damage repair mechanisms are vital to maintain genomic integrity. Mutations in genes involved in the DNA damage response (DDR) can increase the risk of developing cancer. In recent years, a variety of polymorphisms in DDR genes have been associated with increased risk of developing acute myeloid leukemia (AML) or of disease relapse. Moreover, a growing body of literature has indicated that epigenetic silencing of DDR genes could contribute to the leukemogenic process. In addition, a variety of AML oncogenes have been shown to induce replication and oxidative stress leading to accumulation of DNA damage, which affects the balance between proliferation and differentiation. Conversely, upregulation of DDR genes can provide AML cells with escape mechanisms to the DDR anticancer barrier and induce chemotherapy resistance. The current review summarizes the DDR pathways in the context of AML and describes how aberrant DNA damage response can affect AML pathogenesis, disease progression, and resistance to standard chemotherapy, and how defects in DDR pathways may provide a new avenue for personalized therapeutic strategies in AML.     

Increased PRAME-Specific CTL Killing of Acute Myeloid Leukemia Cells by Either a Novel Histone Deacetylase Inhibitor Chidamide Alone or Combined Treatment with Decitabine

As one of the best known cancer testis antigens, PRAME is overexpressed exclusively in germ line tissues such as the testis as well as in a variety of solid and hematological malignant cells including acute myeloid leukemia. Therefore, PRAME has been recognized as a promising target for both active and adoptive anti-leukemia immunotherapy. However, in most patients with PRAME-expressing acute myeloid leukemia, PRAME antigen-specific CD8⁺ CTL response are either undetectable or too weak to exert immune surveillance presumably due to the inadequate PRAME antigen expression and PRAME-specific antigen presentation by leukemia cells. In this study, we observed remarkably increased PRAME mRNA expression in human acute myeloid leukemia cell lines and primary acute myeloid leukemia cells after treatment with a novel subtype-selective histone deacetylase inhibitor chidamide in vitro. PRAME expression was further enhanced in acute myeloid leukemia cell lines after combined treatment with chidamide and DNA demethylating agent decitabine. Pre-treatment of an HLA-A0201⁺ acute myeloid leukemia cell line THP-1 with chidamide and/or decitabine increased sensitivity to purified CTLs that recognize PRAME^100–108 or PRAME^300–309 peptide presented by HLA-A0201. Chidamide-induced epigenetic upregulation of CD86 also contributed to increased cytotoxicity of PRAME antigen-specific CTLs. Our data thus provide a new line of evidence that epigenetic upregulation of cancer testis antigens by a subtype-selective HDAC inhibitor or in combination with hypomethylating agent increases CTL cytotoxicity and may represent a new opportunity in future design of treatment strategy targeting specifically PRAME-expressing acute myeloid leukemia.     

Right on target: eradicating leukemic stem cells

Less than a third of adults with acute myeloid leukemia (AML) are cured by current treatments, emphasizing the need for new approaches to therapy. The discovery over a decade ago that myeloid leukemias originate from rare stem-like cells that can transfer the disease to immunodeficient mice suggested that these 'leukemia stem cells' (LSCs) are responsible for relapse of leukemia following conventional or targeted cancer therapy and that eradication of LSCs might be necessary to cure the disease permanently. Several recent studies have provided insight into the signaling pathways underlying the LSC phenotype and have also described approaches to eliminate LSCs with antibodies. Here, we review recent advances in LSC research and discuss novel therapeutic strategies to specifically target LSCs.     

MicroRNA in leukemia: Tumor suppressors and oncogenes with prognostic potential

Leukemia is known as a progressive malignant disease, which destroys the blood-forming organs and results in adverse effects on the proliferation and development of leukocytes and their precursors in the blood and bone marrow. There are four main classes of leukemia including acute leukemia, chronic leukemia, myelogenous leukemia, and lymphocytic leukemia. Given that a variety of internal and external factors could be associated with the initiation and progression of different types of leukemia. One of the important factors is epigenetic regulators such as microRNAs (miRNAs) and long noncoding RNAs (ncRNA). MiRNAs are short ncRNAs which act as tumor suppressor (i.e., miR-15, miR-16, let-7, and miR-127) or oncogene (i.e., miR-155, miR-17-92, miR-21, miR-125b, miR-93, miR-143-p3, miR-196b, and miR-223) in leukemia. It has been shown that deregulation of these molecules are associated with the initiation and progression of leukemia. Hence, miRNAs could be used as potential therapeutic candidates in the treatment of patients with leukemia. Moreover, increasing evidence revealed that miRNAs could be used as diagnostic and prognostic biomarkers in monitoring patients in early stages of disease or after received chemotherapy regimen. It seems that identification and development of new miRNAs could pave to the way to the development new therapeutic platforms for patients with leukemia. Here, we summarized various miRNAs as tumor suppressor and oncogene which could be introduced as therapeutic targets in treatment of leukemia.     

Epigenetic modulators for brain cancer stem cells: Implications for anticancer treatment

Primary malignant brain tumors are a major cause of morbidity and mortality in both adults and children, with a dismal prognosis despite multimodal therapeutic approaches. In the last years, a specific subpopulation of cells within the tumor bulk, named cancer stem cells(CSCs) or tumor-initiating cells, have been identified in brain tumors as responsible for cancer growth and disease progression. Stemness features of tumor cells strongly affect treatment response, leading to the escape from conventional therapeutic approaches and subsequently causing tumor relapse. Recent research efforts have focused at identifying new therapeutic strategies capable of specifically targeting CSCs in cancers by taking into consideration their complex nature. Aberrant epigenetic machinery plays a key role in the genesis and progression of brain tumors as well as inducing CSC reprogramming and preserving CSC characteristics. Thus, reverting the cancer epigenome can be considered a promising therapeutic strategy. Three main epigenetic mechanisms have been described: DNA methylation, histone modifications, and non-coding RNA, particularly micro RNAs. Each of these mechanisms has been proven to be targetable by chemical compounds, known as epigeneticbased drugs or epidrugs, that specifically target epigenetic marks. We review here recent advances in the study of epigenetic modulators promoting and sustaining brain tumor stem-like cells. We focus on their potential role in cancer therapy.     

Epigenetic therapy of leukemia: An update

Carcinogenesis is classically thought to result from genetic alterations in DNA sequence such as deletions, mutations, or chromosomal translocations. These in turn may lead to the activation of oncogenes, inactivation of tumor suppressor genes or formation of chimeric oncoproteins. Epigenetics, in contrast, refers to a number of biochemical modifications of chromatin, either to DNA directly or to its associated protein complexes that affect gene expression without altering the primary sequence of DNA [Robertson KD, Wolffe AP. DNA methylation in health and disease. Nat Rev Genet 2000;1:11-9; Jones PA, Baylin SB. The epigenomics of cancer. Cell. 2007;128:683-92]. A fundamental difference between genetic and epigenetic alterations is the irreversible nature of genetic lesions whereas epigenetic ones are potentially reversible, allowing for therapeutic intervention. In the last decade, it has become apparent that epigenetic changes play an important role in cancer, particularly in leukemia. Significant advances have been made in the elucidation of these processes as well as in translating this knowledge to the clinic, as in the development of new prognostic biomarkers or targeted therapies. In this review, we will focus on recent advances in epigenetic therapy in leukemia.     

Cancer Pharmacogenomics May Require Both Qualitative and Quantitative Approaches

Resistance to chemotherapy is a major cause of mortality in patients receiving treatment for most types of cancer, and overcoming drug resistance has become an important focus of current research. A major clinical challenge is the fact that most anticancer drugs have a narrow therapeutic range, that is, their effective dose is relatively close to that associated with substantial toxicity. Significant advances have been achieved in event-free survival of patients with many types of cancer (most dramatically childhood acute lymphoblastic leukemia, ALL) through a better understanding of the pathobiology of human cancers, the cellular mechanisms of cancer chemotherapy, and the determinants of inter-individual differences in drug effects and treatment response. It is anticipated that expanding our knowledge of these areas will lead to the development of new anticancer agents and to more effective use of existing cancer chemotherapy. Pharmacogenomics research aims to elucidate the genetics determinants of drug efficacy and toxicity. Results of recent studies indicate that both qualitative and quantitative genomic analyses may be required for precise pharmacogenomic characterization of some types of human cancer.     

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.