Notch信号与急性T细胞淋巴瘤白血病关系的研究进展

 Notch信号不仅能调节T细胞分化、发育,参与T细胞淋巴瘤/白血病（Acute T lymphocty lymphoma/leukemia, T-ALL）的发生、发展,还影响造血干、祖细胞生长、分化和自我更新。最常见的Notch1突变为HD区域和PEST区域的突变,活化突变的Notch信号通过PI3K/Akt信号通路、mTOR、NF-κB信号通路等诱导T-ALL的发病与发展。多项研究表明Notch受体不仅能调节T细胞发育,还参与急性髓系白血病（acute myeloid leukemia, AML）和异基因造血干细胞移植（allogeneic hematopoietic stem cell transplantation, allo-HSCT）后移植物抗宿主病（Graft-versus-host Disease, GVHD）的发生,调节造血干、祖细胞生长、分化和自我更新,对造血干细胞移植后造血重建以及造血微环境的动态平衡均发挥重要作用。本文对Notch信号通路与造血系统疾病的关系及其治疗进展作一综述。     

造血干细胞移植治疗白血病的现状与展望

造血干细胞移植治疗白血病的现状与展望北京医科大学血液病研究所（１０００４４）陆道培，刘开彦造血干细胞移植是目前治疗白血病最为有效的方法，骨髓移植（ＢＭＴ）的本质是造血干细胞移植。因此，根据造血干细胞的来源不同，可将造血干细胞移植分为：（１）ＢＭＴ，包...     

骨髓微环境调控白血病干细胞的研究进展

随着化疗和造血干细胞移植治疗手段的进步和完善,白血病患者的无病生存期得以延长,但白血病干细胞（leukemic stem cells,LCSs）的微小残留依然是白血病复发的主要原因。近年来的重要进展之一是在骨髓微环境对造血干细胞（hematopoietic stem cells,HSCs）的调节研究基础上,发现白血病骨髓微环境不仅有利于白血病干细胞增殖,而且能够招募正常造血干细胞并转化为白血病干细胞,成为白血病复发的研究新热点。现将骨髓微环境与白血病干细胞之间的相互作用综述如下,也许能为未来新的治疗指明方向。     

白血病干细胞耐药机制及靶向治疗

白血病是一类常见的严重危害人类健康的造血系统恶性肿瘤,耐药与复发是其治疗失败两大主要原因。越来越多的研究表明,白血病复发和耐药的根本原因是白血病干细胞（LSC）的存在。其原因除了与LSC具有正常造血干细胞（HSC）相似的细胞生物学特性有关外,主要在于LSC自身特有的生物学特性及微环境的相互作用。对LSC耐药机制的研究,将有助于发现白血病新的靶点治疗方法。     

自体骨髓移植及其净化技术

自体骨髓移植及其净化技术刘海川自本骨髓移植（ＡＢＭＴ）属于造血干细胞移植范畴。当前，造血干细胞移植治疗白血病、淋巴瘤及其它一些恶性肿瘤进展很快，其疗效明显优于化疗，提高了白血病及其它恶性肿瘤的长期生存率和治愈率，亦为基因治疗创造了条件，是目前国内外研...     

非血缘及HLA配型不合造血干细胞移植的临床研究

 目的 探讨非血缘及HLA配型不全相合造血干细胞移植在白血病治疗中的应用。方法非血缘脐血移植治疗儿童白血病3例,非血缘异基因外周血造血干细胞移植治疗白血病1例,HLA配型不全相合外周血造血干细胞移植治疗白血病1例。结果 5例患者完全植入,+15～+25天白细胞（WBC）＞1.0×109／L-1,＋35～＋51天血小板（Plt）＞20×109／L-1。例1出现急性移植物抗宿主病（aGVHD）Ⅰ度;例4 aGVHD Ⅳ度;例5出现肝静脉闭塞综合征（VOD）、aGVHDⅠ度、出血性膀胱炎（HC）;例2移植后6个月复发,放弃治疗死亡;余4例正常生活或工作。结论　非血缘及HLA配型不全相合造血干细胞移植治疗白血病是安全有效的。     

白血病干细胞研究进展

对白血病干细胞（1eukemia stem cells,LSCs）研究有十年之多,目前已经成为血液病学研究的热点。LSCs是一类具有自我更新、无限增殖和分化潜能的细胞亚群。体外长期细胞培养和动物模型实验证实LSCs能够引起白血病的发生、发展。近年来,随着研究的不断深入,人们对LSCs生物学特征及其靶向治疗等有了进一步的认识。研究已经证实LSCs与白血病靶向治疗、复发及耐药有密切的关系。目前已经在急性髓系细胞白血病（AML）、急性淋巴细胞白血病（ALL）、慢性髓系细胞白血病（CML）和慢性淋巴细胞白血病（CLL）中发现存在LSCs。     

造血干细胞移植在儿童白血病治疗中的应用

 白血病是儿童时期最常见的恶性肿瘤,约占该时期所有恶性肿瘤的35 %,对于传统化疗难以治愈的高危急性白血病和慢性粒细胞白血病,造血干细胞移植（HSCT）是主要的治疗手段。目前国际上推荐首选HLA匹配相关供者（MRD）的HSCT。由于80 %的儿童白血病患者缺少这种供者,自体造血干细胞移植（auto-HSCT）也被选择性地应用于急性淋巴细胞白血病（ALL）和急性髓系白血病（AML）的治疗。据统计有30 %～40 %的患者接受了匹配的无关供者（MUD）的HSCT治疗。近年来,无关脐血移植（UDCBT）和HLA不相匹配的相关供者HSCT呈上升趋势。就近年来该方面的进展作一综述。     

ABO血型不合异基因造血干细胞移植后单纯红细胞再生障碍性贫血二例并文献复习

 【摘要】　目的　分析ABO血型不合异基因造血干细胞移植（allo-HSCT）后发生单纯红细胞再生障碍性贫血（PRCA）造血功能紊乱的发病机制,了解造血干细胞移植过程中特殊的免疫功能状态。方法　回顾性分析2例急性髓系白血病（AML）行allo-HSCT后发生PRCA患者的临床资料并复习相关文献。结果　停用环孢素A（CsA）、加用糖皮质激素、丙种球蛋白等治疗该患者后血型转化,造血恢复。结论　ABO血型不合allo-HSCT易出现红系造血延迟及PRCA,应用糖皮质激素、丙种球蛋白治疗有效。     

急性髓系白血病异基因造血干细胞移植后发生气肿性肾盂肾炎一例并文献复习

目的:探讨急性髓系白血病异基因造血干细胞移植后发生气肿性肾盂肾炎（EPN）患者的临床特征及CT表现。方法:回顾性分析中国医学科学院血液病医院1例急性髓系白血病异基因造血干细胞移植后发生EPN患者的临床及CT影像资料,并复习相关文献。结果:患者移植后+20天出现腹痛、恶心及发热,抗感染治疗后体温下降,但出现明显腹胀、右上腹痛伴右侧腰背部疼痛,腹部CT检查提示右肾周感染。抗感染治疗后病情进行性加重,肾周及肾实质出现大量积气;经穿刺抽液并积极抗感染治疗仍无好转,最终死于多脏器衰竭。结论:异基因造血干细胞移植后发生EPN患者病情进展迅速,需积极治疗以改善患者预后;CT表现有特征性,能够为早期诊断、治疗及预后评估提供重要信息。     

SALL4基因在恶性血液病中的研究

SALL4与造血系统恶性肿瘤的发生有密切关系.深入研究SALL4基因及蛋白的功能,将有助于阐明白血病的发病机制,为治疗白血病提供新靶点.     

Gene expression profiles of AML derived stem cells; similarity to hematopoietic stem cells.

Tumors contain a fraction of cancer stem cells that maintain the propagation of the disease. The CD34(+)CD38(-) cells, isolated from acute myeloid leukemia (AML), were shown to be enriched leukemic stem cells (LSC). We isolated the CD34(+)CD38(-) cell fraction from AML and compared their gene expression profiles to the CD34(+)CD38(+) cell fraction, using microarrays. We found 409 genes that were at least twofold over- or underexpressed between the two cell populations. These include underexpression of DNA repair, signal transduction and cell cycle genes, consistent with the relative quiescence of stem cells, and chromosomal aberrations and mutations of leukemic cells. Comparison of the LSC expression data to that of normal hematopoietic stem cells (HSC) revealed that 34% of the modulated genes are shared by both LSC and HSC, supporting the suggestion that the LSC originated within the HSC progenitors. We focused on the Notch pathway since Jagged-2, a Notch ligand was found to be overexpressed in the LSC samples. We show that DAPT, an inhibitor of gamma-secretase, a protease that is involved in Jagged and Notch signaling, inhibits LSC growth in colony formation assays. Identification of additional genes that regulate LSC self-renewal may provide new targets for therapy.     

Notch信号与造血系统疾病关系的研究进展

 急性T细胞淋巴细胞白血病（T - ALL）是小儿白血病常见的一种类型,发现超过50％的T-ALL患者存在有突变Notch1激活,这使得人们对致癌Notch信号机制产生很大兴趣,并且提出针对Notch信号通路在T-ALL中作用而制备靶向药物的构想。小分子γ-分泌酶抑制剂（GSIs）是可以阻止Notch1激活的一个关键蛋白,可以有效地阻止Notch1突变基因的激活。但临床使用GSIs治疗T-ALL,已报道其胃肠道毒性及仅有较弱治疗白血病疗效。新的治疗策略旨在优化抗Notch1疗法,其中包括与分子靶向药物和糖皮质激素联合疗法等,本文重点回顾Notch1的分子基础,其致癌作用机制及Notch1突变在治疗T- ALL的临床意义。     

Expression of constitutively active Notch4 (Int-3) modulates myeloid proliferation and differentiation and promotes expansion of hematopoietic progenitors.

The Notch family of transmembrane receptors has been implicated in the regulation of many developmental processes. In this study, we evaluated the role of Notch4 in immature hematopoietic progenitors by inducing, with retroviral transduction, enforced expression of Int-3, the oncogenic and constitutively active form of mouse Notch4. Int-3-transduced human myeloid leukemia (HL-60) cells demonstrated significantly delayed expression of differentiation markers following retinoic acid and 12-0-tetradecanoylphorbol 13-acetate treatment. Furthermore, HL-60 cells expressing Int-3 displayed a slower growth rate than cells infected with void virus, and accumulation in the G0/G1 phases of cell cycle. Transduction with deletion mutants of Int-3 defined the importance of individual domains of the protein (in particular, the ANK domain and the C-terminal domain) in the inhibition of differentiation and growth arrest of HL-60 cells. When mouse bone marrow enriched for stem cells (5-fluorouracil-resistant, lineage negative) was transduced and cultured for two weeks, the Int-3-transduced population displayed a lower expression of differentiation markers and a three- to five-fold higher frequency of colony-forming cells (CFU-GM/BFU-E) than control cultures. These results strongly support the notion that Notch signaling inhibits differentiation and promotes expansion of hematopoietic stem/progenitor cells.     

Inappropriate notch activity and limited mesenchymal stem cell plasticity in the bone marrow of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDSs) are a heterogeneous group of hematological disorders characterized by ineffective hematopoiesis, enhanced bone marrow apoptosis and frequent progression to acute myeloid leukemia. Several recent studies suggested that, besides the abnormal development of stem cells, microenvironmental alterations are also present in the MDS bone marrow. In this study, we have examined the relative frequencies of stem and progenitor cell subsets of MDS and normal hematopoietic cells growing on stromal cell layers established from MDS patients and from normal donors. When hematopoietic cells from MDS patients were co-cultured with normal stromal cells, the frequency of either early or late cobblestone area-forming cells (CAFC) was significantly lower compared to the corresponding normal control values in 4 out of 8 patients. In the opposite situation, when normal hematopoietic cells were incubated on MDS stromal cells, the CAFC frequencies were decreased in 5 out of 6 patients, compared to normal stromal layer-containing control cultures. Moreover, a soluble Notch ligand (Jagged-1 protein) was an inhibitor of day-35-42 CAFC when normal hematopoietic cells were cultured with normal or MDS stromal cells, but was unable to inhibit MDS stem and early progenitor cell growth (day-35-42 CAFC) on pre-established stromal layers. These findings suggest that in early hematopoietic cells isolated from MDS patients the Notch signal transduction pathway is disrupted. Furthermore, there was a marked reduction in the plasticity of mesenchymal stem cells of MDS patients compared with those of normal marrow donors, in neurogenic and adipogenic differentiation ability and hematopoiesis supporting capacity in vitro. These results are consistent with the hypothesis that when alterations are present in the myelodysplastic stroma environment along with intrinsic changes in a hematopoietic stem/progenitor cell clone, both factors might equally contribute to the abnormal hematopoiesis in MDS.     

Gene therapy of hematologic malignancies

Gene therapy offers many new and exciting treatment strategies for patients with hematologic malignancies. Through the transfer of genes into hematopoietic stem cells, one can reduce the sensitivity of myeloid cells to chemotherapy. Donor T cells can be modified to become sensitive to otherwise nontoxic prodrugs, allowing for their safer use as effectors in graft-versus-leukemia immune reactions following allogeneic transplantation. Neoplastic cells also may be modified to enhance their sensitivity to various drugs. Finally, neoplastic cells can be modified to enhance their immunogenicity using genes that encode immune stimulatory cytokines or cell surface proteins. Recent studies, for example, indicate that the stealth-like phenotype of leukemia cells can be reversed through transfer of genes such as the one encoding CD154, the ligand for CD40. A phase I clinical trial using autologous CD154-transduced leukemia cells as a cellular vaccine has provided encouraging results. Indeed, we may soon enter an era of effective gene therapy for hematologic malignancies.     

Genetic Mechanisms of Chronic Myeloid Leukemia Blastic Transformation

The BCR-ABL1 oncogenic tyrosine kinase can transform pluripotent hematopoietic stem cells and initiate chronic myeloid leukemia in chronic phase (CML-CP), a myeloproliferative disorder characterized by excessive accumulation of mature myeloid cells. Patients in CML-CP usually respond to treatment with ABL1 tyrosine kinase inhibitors (TKIs) such as imatinib, though some patients who respond initially may become resistant later. CML-CP leukemia stem cells (LSCs) are intrinsically insensitive to TKIs and thus survive in the long term. These LSCs or their progeny may at some stage acquire additional genetic changes that cause the leukemia to transform further, from CML-CP to a more advanced phase, which has been subclassified as either accelerated phase (CML-AP) or blastic phase (CML-BP). CML-BP is characterized by a major clonal expansion of immature progenitors, which have either myeloid or lymphoid features. CML-BP responds poorly to treatment and is usually fatal. This review discusses the role of genomic instability leading to blastic transformation of CML and proposes some novel therapeutic approaches.     

Increased growth inhibition of human chronic myelogenous leukemic cells by a combination of c-myb antisense oligonucleotide and 4-hydroxyperoxycyclophosphamide in vitro

Human chronic myelogenous leukemia (CML) is a unique malignancy in its cellular and molecular phenotypes. High dose therapy followed by stem cell transplantation seems to be one of the most effective treatment modalities for CML. However, allogeneic stem cell transplantation, a curative treatment modality, is limited due to the availability of matched siblings. On the other hand, the autologous stem cell harvests are contaminated with leukemic cells, and therefore a significant reduction of leukemic cells is desired before using the harvest for transplantation. Therefore in the present study, effects of a combination of a suboptimal concentration of 4-hydroxyperoxycyclophosphamide (4HC) and an optimal concentration of c-myb antisense oligonucleotide on the growth of K562 human chronic myelogenous leukemic cells in vitro were determined. The combination significantly (p<0.05) inhibited the growth of K562 cells in vitro when compared to the effects of c-myb oligonucleotide or 4HC alone. The c-myb oligonucleotide alone or in combination with low dose 4HC decreased the expression of c-myb gene as determined by RT-PCR techniques. Cellular uptake and retention of fluoresceinated oligonucleotide in control and treated K562 cells was studied using plain field laser microscopy and flow cytometry. There was an increase in cellular uptake of c-myb oligonucleotide in K562 cells as measured by plain field laser microscopy in the presence of 4HC. The combination of oligonucleotides and 4HC did not significantly decrease the number of hematopoietic stem/progenitor cells from normal hematopoietic stem cell harvests as determined by in vitro colony assays. The combination of low dose 4HC and c-myb antisense oligonucleotides can potentially be applied in CML patients, particularly for purging leukemic cells present in their hematopoietic stem cell harvests.