凋亡抑制基因Survivin与肿瘤防治的研究

Survivin是1997年发现的一种新的凋亡抑制基因，是凋亡蛋白抑制因子(inhihitor of apoptosis protein，IAP)家族的成员，它选择性地表达于胚胎发育组织和几乎所有常见的人类恶性肿瘤组织而正常成人终末分化组织中不表达，其表达与多种肿瘤患者的预后密切相关。survivin通过直接抑制凋亡信号传导途径中最下游的效应分子easpase 3的活性而发挥其抑凋亡作用。抑制survivin的表达，以阻断其抑凋亡作用，可以达到治疗肿瘤的目的。此种方法初步验证一般不会产生副作用，治疗中会对患者的生活质量带来正性效应。近年来体外和动物实验中发现，针对此基因的反义核酸及此基因决定基缺失的突变体，能够诱导细胞自发性凋亡和明显抑制肿瘤的生长，为评价肿瘤预后及防治研究提供了新的靶位。     

靶向survivin在肿瘤治疗中的研究进展

Survivin蛋白是人类凋亡抑制因子家族中的一员,具有抗凋亡及调节细胞有丝分裂的双重功能。大量研究证明,survivin与肿瘤的发生、发展间关系密切,对肿瘤的诊断及预后判断具有深远意义。在该基础上,survivin已成为新的抗肿瘤靶点。一些临床前研究已通过不同的人类肿瘤移植模型,证明运用各种策略来降低肿瘤细胞中survivin的表达水平,削弱其功能,可增加肿瘤细胞的凋亡率及其对化疗、放疗的     

Survivin与白血病

Survivin是新近发现的一种凋亡抑制蛋白（inhibitor apoptosis protein,IAP），含有一杆状病毒凋亡抑制蛋白重复序列（baculovirus IAP repeat,BIR），通过抑制半胱天冬蛋白酶（caspase）活性发挥抗凋亡作用。在白血病细胞survivin高表达，且与预后有关。转染survivin天然反义基因、效应细胞蛋白酶受体－1（effector cell protease receptor-1,EPR-1）基因，可降低survivin在白血病细胞中的表达，以达到治疗白血病之目的。     

凋亡抑制基因Survivin与肿瘤防治的研究

Survivin是1997年发现的一种新的凋亡抑制基因,是凋亡蛋白抑制因子(inhibitorofapoptosisprotein,IAP)家族的成员,它选择性地表达于胚胎发育组织和几乎所有常见的人类恶性肿瘤组织而正常成人终末分化组织中不表达,其表达与多种肿瘤患者的预后密切相关。survivin通过直接抑制凋亡信号传导途径中最下游的效应分子caspase3的活性而发挥其抑凋亡作用。抑制survivin的表达,以阻断其抑凋亡作用,可以达到治疗肿瘤的目的。此种方法初步验证一般不会产生副作用,治疗中会对患者的生活质量带来正性效应。近年来体外和动物实验中发现,针对此基因的反义核酸及此基因决定基缺失的突变体,能够诱导细胞自发性凋亡和明显抑制肿瘤的生长,为评价肿瘤预后及防治研究提供了新的靶位。     

凋亡调节蛋白survivin在弥漫大B细胞淋巴瘤中的研究进展

弥漫大B细胞淋巴瘤（diffuse large B-cell lymphoma，DLBCL）是最常见的非霍奇金淋巴瘤，它具有明显的生物异质性。survivin是调亡抑制蛋白家族的独特成员，它在各种肿瘤中包括某些类型的淋巴瘤中过度表达，新近发现凋亡抑制蛋白survivin在DLBCL的发生发展中起着关键的作用，其具有抑制细胞凋亡和增强细胞增生的双重调节功能。许多研究还表明，survivin可作为DLBCL的一个独立的临床预后指标，与国际预后指数（International Prognostic Index，IPI）结合可在早期筛选出常规治疗预后不良的病例，有助于指导治疗、改善预后。survivin选择性表达于肿瘤组织，为治疗肿瘤提供了理想的靶点，调节survivin的表达和功能可能成为治疗DLBCL的一个新途径。本文就survivin的作用机制，在DLBCL中的表达及其在DLBCL诊断治疗中的价值等研究进展和前景进行了综述。     

凋亡蛋白抑制因子Survivin的研究进展

正凋亡抑制蛋白(the inhibitor of apoptosis protein,IAP)家族有8位成员,包括X染色体连锁的凋亡抑制剂(X-linked inhibitor of apoptosis,XIAP),cIAP1,cIAP2,NLR家族(NAIP),livin,IAP相似蛋白2(ILP2),BRUCE和survivin。Survivin是IAP家族中抗凋亡作用最强的成员,于1997年首次被发现。Survivin在正常组织、癌前组织、各种癌症中的表达率均不同,即survivin表达具有特异性,因此,它在肿瘤诊断、预后判断等方面成为核心。近年来survivin与肿瘤的关系受到越来越多人的重视,     

Survivin与白血病

Survivin是新近发现的一种凋亡抑制蛋白(inhibitor apoptosis protein,IAP),含有一杆状病毒凋亡抑制蛋白重复序列(baculovirus IAP repeat,BIR),通过抑制半胱天冬蛋白酶(caspase)活性发挥抗凋亡作用。在白血病细胞中survivin高表达,且与预后有关。转染survivin天然反义基因、效应细胞蛋白酶受体-1(effector cell protease receptor-1,EPR-1)基因,可降低survivin在白血病细胞中的表达,以达到治疗白血病之目的。     

Survivin与妇科肿瘤

凋亡抑制因子（survivin）是由Ambrosini等在1997年利用效应细胞蛋白受体-1（EPR-1）的cDNA在人类基因组库中筛选克隆的IAP家族的一个相对分子量最小的新成员;是肿瘤发生、发展中的枢纽基因;是估计肿瘤预后和复发的重要指标．并与肿瘤放、化疗中的耐药密切相关。已成为肿瘤包括妇科肿瘤诊断和治疗的新靶点。本文就survivin的表达与妇科肿瘤的研究进展综述如下。     

小干扰RNA对人肝癌细胞株HepG2 Survivin基因表达的影响

目的构建Survivin基因特异性小干扰RNA(siRNA),检测siRNA-Survivin对Survivin基因表达的抑制,在人肝癌细胞株HepG2中研究survivin和survivin siRNA对细胞凋亡的影响。方法设计survivin siRNA序列,构建靶向Survivin siRNA真核载体。利用脂质体转染人肝癌HepG2细胞,通过相差显微镜下观察、四甲基偶氮唑盐微量酶反应比色法(MTT法)及反转录-聚合酶链反应(RT-PCR)观察转染后survivin的表达,以及HepG2细胞的凋亡。结果成功构建了survivin siRNA表达载体,并且si-survivin对survivin有明显抑制效应,可显著抑制HepG2细胞的发生凋亡。转染Survivin-siRNA细胞活性受到显著抑制(P<0.05),光镜下出现明显的凋亡形态,DNA电泳出现典型的凋亡"梯状"带。RT-PCR结果显示细胞转染24 h、48 h和72 h后HepG2 Survivin mRNA分别减少了56%、78%和50%,而siR-NA阴性对照与未转染细胞相比差异不显著。结论转染的Survivin-siRNA可特异性抑制肝癌细胞株HepG2凋亡抑制基因的表达,从而为肿瘤的基因治疗提供新的实验基础。     

卵巢上皮性肿瘤中survivin和环氧合酶-2的表达与临床病理因素的关系

目的:探讨凋亡抑制基因蛋白survivin和环氧合酶-2(COX-2)在卵巢上皮性肿瘤中的表达及其相关性。方法:应用免疫组化技术ABC法检测survivin、COX-2在20例正常卵巢组织、20例良性卵巢上皮肿瘤、24例交界性卵巢上皮肿瘤、86例卵巢上皮癌中的表达情况,分析survivin和COX-2的表达与卵巢上皮癌临床病理因素的关系及两者的相关性。结果:Survivin和COX-2均在正常卵巢组织中无表达,在良性卵巢上皮肿瘤、交界性卵巢上皮肿瘤、卵巢上皮癌中的阳性表达率逐渐升高。Survivin蛋白表达与卵巢上皮癌组织的组织学分级、临床病理分期相关,与年龄及病理类型不相关;COX-2的表达与年龄、组织学分级、病理类型和手术病理分期均不相关。Survivin与COX-2在86例卵巢上皮癌组织中的表达有显著正相关性。结论:Survivin与COX-2蛋白在卵巢上皮癌的高表达提示两者可能在卵巢上皮癌的发生、发展中起重要作用,survivin蛋白与COX-2蛋白密切相关,提示两者可能存在共同的激活机制。     

miRNA-155与恶性血液病

微小RNA（miRNA）是一系列在植物、动物及病毒中都可发现的非编码RNA,在转录后水平调控基因表达。miRNA-155（miR-155）是一种表达在造血细胞的miRNA,通过转录后调控靶基因的表达参与恶性血液病的发病机制。近来研究表明,miR-155通过影响参与细胞增殖、分化、凋亡的细胞信号转导途径,作为癌基因在恶性血液病的发生发展中起到重要作用。miR-155对恶性淋巴瘤、急性髓系白血病及骨髓增生异常综合征等恶性血液病的诊断治疗、预后具有重要临床意义。把能够下调miR-155表达的药物如反义寡核苷酸与经典的细胞毒性治疗联合应用,可有效控制恶性血液病的发展。本文综述了近年来miR-155对恶性血液病发病机制作用的研究进展并对其潜在的治疗靶点作用进行了展望。     

Survivin致敏的树突状细胞疫苗激活抗白血病T细胞的实验研究

为研究survivin致敏树突状细胞（DC）疫苗对特异性T细胞的激活影响及对白血病细胞生长抑制作用，采用共聚焦显微镜及免疫沉淀-Western印迹等方法检测急性白血病细胞survivin表达；外周血单个核细胞体外培养，诱导DC细胞的形成；体外进行survivin抗原负载，制备survivin DC疫苗；survivin DC激发同基因型T细胞，用流式细胞术进一步分析T细胞表型；^3H-TdR法测定刺激指数（SI）；并用^51Cr释放法测定特异性的抗白血病CTL细胞毒活性。结果表明，检测19例初治急性白血病患survivin的表达率为84.2％；其荧光分布均在细胞胞浆内；免疫沉淀-Western印迹进一步分析证实其survivin蛋白表达；外周血单个核细胞体外诱导形成的DC细胞具有典型的DC的形态学特征；survivinDC可显刺激T细胞的活化增殖；survivin激活的T细胞中，CD4^ TH比例显较DC组高，DC激发的T细胞则以表达CD8和CD56为主；同时survivinDC显抑制白血病细胞的生长。结论：急性白血病细胞表达survivin抗原，利用survivinDC疫苗可有效地抑制白血病细胞的生长，为DC治疗白血病开辟了一条新途径。     

SDF-1/CXCR4与血液系统恶性肿瘤的关系研究进展

基质细胞衍生因子（SDF—1）及其受体CXCR4相互作用转导特定信号，在许多生理和病理过程中都发挥了重要的效应，CXCR4在多种血液系统肿瘤中高表达，与疾病的预后、耐药、复发密切相关。用SDF-1抗体或CXCR4抗体能有效的抑制肿瘤细胞的生长，为治疗血液系统肿瘤开辟了新途径。本文就SDF—I／CXCR4在血液系统肿瘤中的表达，及其与预后、耐药、复发和治疗关系的研究进展作一综述，     

贲门癌组织中生存素与p53基因表达的相关性研究

目的探讨凋亡抑制基因生存素(survivin)在贲门癌组织中表达的临床意义,及其与p53基因表达的相关性。方法采用免疫组化技术(二步法),检测66例术前未经化疗的贲门癌组织中survivin和p53基因的表达情况。结果66例贲门癌组织中,survivin阳性表达41例,阳性率为62.1%(41/66);而p53阳性率为51.5%(34/66)。survivin表达与贲门癌组织学类型、临床分期和淋巴结转移有明显相关性(P<0.05);survivin在p53阳性和阴性患者中阳性率分别为82.4%(28/34)和40.6%(13/32),两者间差异有统计学意义(P<0.05)。结论贲门癌组织中survivin高表达导致的凋亡抑制在贲门癌的发生、发展中可能起重要作用。survivin在贲门癌组织中的表达与p53基因表达密切相关,提示二者可能存在协同作用,构成抑制贲门癌细胞凋亡的多种途径。survivin和p53阳性的贲门癌可能有较强的侵袭性,预后不良。     

Clinically useful information provided by the flow cytometric immunophenotyping of hematological malignancies: current status and future directions.

BACKGROUND: At present, immunophenotyping of hematological malignancies represents one of the most relevant clinical applications of flow cytometry. In recent years, its use has extended from clinical research to diagnostic laboratories. The aim of this report is to critically review the type of information provided by the flow cytometric immunophenotyping of hematological malignancies and its clinical impact as well as to highlight its potential future applications. METHODS: The currently available information, including that provided by different international consensus groups on the phenotypic characterization of hematologic malignancies, was reviewed. Additionally, recent reports on the immunophenotypic analysis of hematological malignancies published in hematology, oncology, pathology, immunology, and cell biology journals were also analyzed. RESULTS: A careful review of the literature showed that in spite of the well-established utility of immunophenotyping for the diagnosis, classification, prognostic stratification, and monitoring of hematological malignancies, only a small part of the information on the immunophenotypic characteristics of pathological hemopoietic cells has been used routinely. Specific and sensitive identification of neoplastic cells and their accurate enumeration and phenotypic characterization represent the major aims of these procedures. Similarities between leukemic and healthy cells allow the establishment of the lineage and maturation stage of the pathologic cells, this information being of great utility for the diagnosis, classification, and prognostic evaluation of different subtypes of hematological malignancies. On the other hand, the phenotypic aberrations displayed by leukemic cells could allow the selection of cases carrying specific genetic abnormalities in which further confirmatory molecular studies will be performed. CONCLUSIONS: The information provided by the flow cytometric immunophenotyping of hematological malignancies is of great clinical utility, with a major challenge for the near future being the standardization of technical procedures, data interpretation, and reporting.     

Programmed death-1 checkpoint blockade in acute myeloid leukemia

Introduction: Immune checkpoints are regulatory pathways induced in activated T lymphocytes that regulate antigen responsiveness. These immune checkpoints are hijacked by tumors to promote dysfunction of anti-tumor effector cells and consequently of tumor escape from the host immune system.

Areas covered: Programmed death-1/programmed death ligand (PD-1/PDL-1), a checkpoint pathway, has been extensively investigated in leukemia mouse models. Expression of PD-1 on the surface of activated immune cells and of its ligands, PD-L1 and PD-L2, on leukemic blasts has been documented. Clinical trials with PD-1 inhibitors in patients with hematological malignancies are ongoing with promising clinical responses.

Expert opinion: Therapy of hematological cancers with antibodies blocking inhibitory receptors is expected to be highly clinically effective. Checkpoint inhibitory receptors and their ligands are co-expressed on hematopoietic cells found in the leukemic milieu. Several distinct immunological mechanisms are likely to be engaged by antibody-based checkpoint blockade. Co-expression of multiple inhibitory receptors on hematopoietic cells offers an opportunity for combining blocking antibodies to achieve more effective therapy. Up-regulation of receptor/ligand expression in the leukemic milieu may provide a blood marker predictive of response. Finally, chemotherapy-induced up-regulation of PD-1 on T cells after conventional leukemia therapy creates a solid rationale for application of checkpoint blockade as a follow-up therapy.     

Alloantigen expression on non-hematopoietic cells reduces graft-versus-leukemia effects in mice

Allogeneic hematopoietic stem cell transplantation (HSCT) is used effectively to treat a number of hematological malignancies. Its beneficial effects rely on donor-derived T cell–targeted leukemic cells, the so-called graft-versus-leukemia (GVL) effect. Induction of GVL is usually associated with concomitant development of graft-versus-host disease (GVHD), a major complication of allogeneic HSCT. The T cells that mediate GVL and GVHD are activated by alloantigen presented on host antigen-presenting cells of hematopoietic origin, and it is not well understood how alloantigen expression on non-hematopoietic cells affects GVL activity. Here we show, in mouse models of MHC-matched, minor histocompatibility antigen–mismatched bone marrow transplantation, that alloantigen expression on host epithelium drives donor T cells into apoptosis and dysfunction during GVHD, resulting in a loss of GVL activity. During GVHD, programmed death–1 (PD-1) and PD ligand–1 (PD-L1), molecules implicated in inducing T cell exhaustion, were upregulated on activated T cells and the target tissue, respectively, suggesting that the T cell defects driven by host epithelial alloantigen expression might be mediated by the PD-1/PD-L1 pathway. Consistent with this, blockade of PD-1/PD-L1 interactions partially restored T cell effector functions and improved GVL. These results elucidate a previously unrecognized significance of alloantigen expression on non-hematopoietic cells in GVL and suggest that separation of GVL from GVHD for more effective HSCT may be possible in human patients.     

Inhibition of the Akt/survivin pathway synergizes the antileukemia effect of nutlin-3 in acute lymphoblastic leukemia cells

The phosphatidylinositol 3-kinase (PI3K)/Akt and p53 pathways play antiapoptotic and proapoptotic roles in cell death, respectively. Cancer cell growth and progression are associated with high levels of PI3K/Akt activation by loss of PTEN expression and the inactivation of p53 by MDM2 overexpression. We report that inhibition of PI3K/Akt, either by the PI3K inhibitor Ly294002 or by expression of PTEN, synergized the ability of the MDM2 antagonist nutlin-3 to induce apoptosis in acute lymphoblastic leukemia (ALL). We used a set of ALL cell lines with wild-type p53 and MDM2 overexpression, but different status of PTEN expression/PI3K/Akt activation, to test the ability of nutlin-3 to induce p53 and apoptosis. Nutlin-3 activated p53 in all the ALL cell lines; however, induction of apoptosis was dependent on PTEN status. Nutlin-3 induced potent apoptosis in cells with PTEN expression but not in those without PTEN, suggesting that PTEN/PI3K/Akt pathway may play a role in this process. Furthermore, nutlin-3 significantly down-regulated survivin expression in PTEN-positive cells but not in PTEN-negative cells. When these nutlin-3-resistant cells were either pretransfected with the PTEN gene or simultaneously treated with the PI3K inhibitor Ly294002, survivin was down-regulated and sensitivity to nutlin-3 was increased. Furthermore, direct silencing of survivin by small interfering RNA also increased the proapoptotic effect of nutlin-3 on the PTEN-negative, nutlin-3-resistant ALL cells. Our results suggest that Akt-mediated survivin up-regulation in PTEN-negative ALL cells may counteract the proapoptotic effect of nutlin-3, and indicate that a combination of MDM2 antagonist and PI3K/Akt inhibitor may be a promising approach for treating refractory ALL.     

Survivin反义寡核苷酸诱导胃癌细胞凋亡的研究

目的探讨生存素反义寡核苷酸(ASODN)对人胃癌细胞SGC7901凋亡的诱导作用。方法设计合成特异性靶向survivin ASODN。胃癌细胞株SGC7901分为4组:空白对照组(Sham)、单纯脂质体对照组(Lip)、正义链转染对照组(Lip-SODN)、ASODN转染组(Lip-ASODN)。作用12、24、48 h后收获各组细胞。Western blot法检测各组细胞survivin表达情况,倒置显微镜观察细胞生长形态变化,流式细胞仪检测各组细胞凋亡率,免疫组化SP法检测细胞中Ki67表达。结果脂质体介导survivin ASODN转染后的胃癌细胞出现survivin蛋白表达明显下降;形态学上表现为细胞膜起泡、染色质固缩、凋亡小体形成;细胞凋亡率明显高于各对照组(P<0.05);细胞中Ki67表达水平明显降低。结论survivin反义寡核苷酸转染胃癌细胞能下调survivin蛋白表达,诱导胃癌细胞凋亡,抑制细胞增殖,具有明显的抗癌作用。