Reorganization of mitotic apparatus in the etoposide-treated CHO-K1 cells precedes apoptotic death

In a culture of CHO-K1 cells, etoposide (1 h, 25 μM) has been shown to produce interphase arrest, after which the cells resume mitotic division and, after some time, are submitted to apoptotic death. Accumulation of apoptotic cells in the culture follows a gradual increase in the number of multipolar mitoses. Our findings provide the first evidence for differences in the pattern of immunofluorescent staining of multipolar mitotic spindle microtubules with antibodies to α-tubulin, acetylated α-tubulin, and tyrosinated α-tubulin in mitotic cells dividing in the period preceding apoptosis. Moreover, some parts of the multipolar mitotic spindle can differ by the presence of antigenic determinants accessible to anti-tyrosinated α-tubulin antibodies. These abnormalities of the mitotic apparatus are aggravated immediately before the increase in the number of cells submitted to apoptosis. Our data have also shown that some cells pass through at least two mitotic cycles prior to a sharp increase in the number of apoptotic cells in the cell culture.     

Doxorubicin induces cell death in breast cancer cells regardless of Survivin and XIAP expression levels

Breast cancer is the leading cause of deaths in women around the world. Resistance to therapy is the main cause of treatment failure and still little is known about predictive biomarkers for response to systemic therapy. Increasing evidence show that Survivin and XIAP overexpression is closely associated with chemoresistance and poor prognosis in breast cancer. However, their impact on resistance to doxorubicin (dox), a chemotherapeutic agent widely used to treat breast cancer, is poorly understood. Here, we demonstrated that dox inhibited cell viability and induced DNA fragmentation and activation of caspases-3, -7 and -9 in the breast cancer-derived cell lines MCF7 and MDA-MB-231, regardless of different p53 status. Dox exposure resulted in reduction of Survivin and XIAP mRNA and protein levels. However, when we transfected cells with a Survivin-encoding plasmid, we did not observe a cell death-resistant phenotype. XIAP and Survivin silencing, either alone or in combination, had no effect on breast cancer cells sensitivity towards dox. Altogether, we demonstrated that breast cancer cells are sensitive to the chemotherapeutic agent dox irrespective of Survivin and XIAP expression levels. Also, our findings suggest that dox-mediated modulation of Survivin and XIAP might sensitize cells to taxanes when used in a sequential regimen.     

Design,synthesis and biological studies of Survivin Dimerization Modulators that prolong mitotic cycle

Survivin, a member of the inhibitor of apoptosis protein (IAP) family proteins, has essential roles in cell division and inhibition of apoptosis. Several clinical studies in cancer patients have shown that the elevated levels of survivin correlate with aggressiveness of the disease and resistance to radiation and chemotherapeutic treatments. Survivin is an integral component of chromosomal passenger complex (CPC) where it binds to borealin and INCENP through its dimerization interface. Thus, disruption of functional survivin along its dimer interface with a small molecule is hypothesized to inhibit the proliferation of cancer cells and sensitize them to therapeutic agents and radiation. Recently, a small molecule (Abbott8) was reported to bind at the dimerization interface of survivin. Further development of this compound was accomplished by computational modeling of the molecular interactions along the dimerization interface, which has led to the design of promising survivin dimerization modulators. Two of the most potent survivin modulators, LLP3 and LLP9 at concentrations between 50 and 100 nM, caused delay in mitotic progression and major mitotic defects in proliferating human umbilical vein endothelial cells (HUVEC) and prostate cancer cells (PC3).     

Survivin 及Anx-A1 在肝癌组织中的表达及其临床意义

目的:探讨Survivin及Anx-A1在肝癌组织中的表达及其临床意义。方法:收集原发性肝癌病例45例,采用免疫组织化染色法检测Survivin及Anx-A1在肝癌组织及癌旁正常组织中的表达,分析Survivin及Anx-A1的表达与肝癌临床病理特征的关系。结果:Survivin在肝癌组织中的阳性表达率为86.67%,在癌旁正常组织中的阳性表达率为17.78%;Anx-A1在肝癌组织中的阳性表达率为46.67%,在癌旁正常组织中的阳性表达率为8.89%;Survivin及Anx-A1在肝癌组织中的阳性表达率均显著高于癌旁正常组织,差异具有统计学意义(P0.05);不同肿瘤分级患者肝癌组织中Survivin与Anx-A1的表达水平存在显著差异(P0.01),肿瘤分级越高,Survivin与Anx-A1表达水平越高。结论:Survivin及Anx-A1的表达与肝癌的发生发展密切相关,可用于肝癌的辅助诊断。     

Survivin基因在肺癌中的作用

Survivin是凋亡蛋白抑制因子(inihibitor of apoptosis protein,IAP)家族中的一员,发挥强大的抑制凋亡功能,同时也参与细胞周期调控,使该基因在肿瘤的发生发展过程中起重要作用。Survivin基因特异性的表达于大多数常见的恶性肿瘤(如肺癌、乳腺癌、肝癌、胃癌等),而在正常成人组织中不表达或低表达。大量的研究涉及Survivin基因与肺癌的关系,目前的研究认为,Survivin基因可能成为一个提示预后不良的肿瘤标志物,可为肺癌的诊断提供新的方法。而且很多研究已经进入临床试验阶段,使得Survivin基因在肺癌治疗方面的应用前景广泛。随着研究的不断深入,Survivin有望成为肺癌治疗的理想靶点。本文对Survivin基因在肺癌中作用的研究进展作如下简要综述。     

Organization of mitotic apparatus poles in etoposide-treated CHO-K1 cells

Analyzed in this study is the organization of mitotic spindle poles in CHO-K1 cells dividing after treatment with etoposide (1 h, 25 μM). At various periods after the treatment, we studied the following: (1) the distribution of γ-tubulin in mitotic cells by immunofluorescent staining, (2) the level of post-translational modification of α-tubulin in spindle microtubules by immunoelectron microscopy, and (3) the ultrastructure of mitotic apparatus poles by standard electron microscopy. 48 h after the addition of etoposide, disturbances in the ultrastructure of mitotic spindle poles were observed in etoposide-treated CHO-K1 cells with both bipolar and with multipolar mitotic apparatuses. The increased number of centrioles was unevenly distributed between the mitotic spindle poles; some centrioles did not take an obvious part in the mitotic spindle organization and differed in their number of outgrowing microtubules. Most centrioles were without fibrillar halos. Immunoelectron microscopy showed the differences in the staining of the poles of a multipolar spindle within one cell with antibodies to tyrosinated α-tubulin, whereas the staining of cells with antibodies to acetylated α-tubulin did not reveal such differences. Immunofluorescence staining for γ-tubulin also indicated differing organizations of poles in the same spindle. Our data findings provided the first evidence that the pattern of immunostaining and ultrastructure of mitotic apparatus poles can differ in cells dividing at various time periods after the action of etoposide.     

Preferential Fas-mediated apoptotic execution at G1 phase: the resistance of mitotic cells to the cell death

Apoptosis is induced by various stresses generated from the extracellular and intracellular environments. The fidelity of the cell cycle is monitored by surveillance mechanisms that arrest its further progression if any crucial process has not been completed or damages are sustained, and then the cells with problems undergo apoptosis. Although the molecular mechanisms involved in the regulation of the cell cycle and that of apoptosis have been elucidated, the links between them are not clear, especially that between cell cycle and death receptor-mediated apoptosis. By using the HeLa.S-Fucci (fluorescent ubiquitination-based cell cycle indicator) cells, we investigated the relationship between the cell cycle progression and apoptotic execution. To monitor apoptotic execution during cell cycle progression, we observed the cells after induction of apoptosis with time-lapse fluorescent microscopy. About 70% of Fas-mediated apoptotic cells were present at G₁ phase and about 20% of cells died immediately after cytokinesis, whereas more than 60% of etoposide-induced apoptotic cells were at S/G₂ phases in random culture of the cells. These results were confirmed by using synchronized culture of the cells. Furthermore, mitotic cells showed the resistance to Fas-mediated apoptosis. In conclusion, these findings suggest that apoptotic execution is dependent on cell cycle phase and Fas-mediated apoptosis preferentially occurs at G₁ phase.     

Effects of Survivin on cell proliferation and apoptosis in MG-63 cells in vitro

Osteosarcoma is the most frequent primary malignant tumor of the skeleton and occurs mainly in children and adolescent. The prognosis of osteosarcoma is very poor due to its aggressive and no effective treatment. This study is the first to investigate the anti-cancer effects of antisense pEGFP-C1-Survivin on human osteosarcoma cells. It was shown in our results that Survivin blockaded could significantly induce apoptosis and inhibit the invasive of osteosarcoma cells line MG-63. The effects were probably produced by the decreased expression of Survivin induced by antisense pEGFP-C1-Survivin which was examined by RT-PCR and western blotting. All these suggested that Survivin should be very important in the development of osteosarcoma and Survivin blockaded by using antisense pEGFP-C1-Survivin could markedly inhibit the proliferation and invasion of osteosarcoma cells line MG-63, partially reversed their malignant phenotype. Targeting Survivin might be a promising option in the treatment of osteosarcoma.     

Borealin: a novel chromosomal passenger required for stability of the bipolar mitotic spindle

The chromosomal passenger complex of Aurora B kinase, INCENP, and Survivin has essential regulatory roles at centromeres and the central spindle in mitosis. Here, we describe Borealin, a novel member of the complex. Approximately half of Aurora B in mitotic cells is complexed with INCENP, Borealin, and Survivin; and Borealin binds Survivin and INCENP in vitro. A second complex contains Aurora B and INCENP, but no Borealin or Survivin. Depletion of Borealin by RNA interference delays mitotic progression and results in kinetochore-spindle misattachments and an increase in bipolar spindles associated with ectopic asters. The extra poles, which apparently form after chromosomes achieve a bipolar orientation, severely disrupt the partitioning of chromosomes in anaphase. Borealin depletion has little effect on histone H3 serine10 phosphorylation. These results implicate the chromosomal passenger holocomplex in the maintenance of spindle integrity and suggest that histone H3 serine10 phosphorylation is performed by an Aurora B-INCENP subcomplex.     

应用组织芯片技术研究Survivin基因蛋白在前列腺肿瘤组织中的表达及其意义

目的:应用组织芯片技术分析Survivin基因蛋白在人类前列腺癌组织、前列腺正常组织及前列腺良性痛变组织中的表达情况.方法:采用兔抗人survivin单克隆抗体的免疫组织化学ABC法,研究Survivin在不同前列腺组织的表达,并分析Survivin在不同前列腺组织中的表达差异.结果:免疫组化结果显示,前列腺癌组织与前列腺良性病变组织及正常前列腺组织中Survivin的表达相比呈显著性差异(P<0.05).结论:Survivin在前列腺癌组织中呈高表达,提示其可能对前列腺癌的发生或发展有重要作用.     

针对Oct-4和Survivin基因的双靶向shRNA腺病毒载体的构建及其对肝癌细胞的抑制作用

转录因子Oct-4和Survivin是细胞增殖的关键调控因子,构建针对Oct-4和Survivin基因的双靶向shRNA腺病毒载体Ad5-Dual-shRNA,并研究其对肝癌细胞及移植瘤的生长抑制作用。合成Oct-4和Survivin基因的shRNA序列,插入腺病毒穿梭载体pDC312,含有shRNA的穿梭载体与腺病毒骨架载体pBHGloxdeltaE13Cre共转染HEK293细胞,经Cre/LoxP位点特异性重组获得重组腺病毒Ad5-Dual-shRNA;腺病毒Ad5-Dual-shRNA感染肝癌细胞系EHBH-H1,经Western blotting检测Oct-4和Survivin基因的表达情况,用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐染色法(MTT实验)和裸鼠荷瘤实验检测对肿瘤细胞生长的影响。研究结果显示,双靶向重组腺病毒Ad5-Dual-shRNA感染肝癌细胞系EHBH-H1能够有效沉默Oct-4与Survivin基因的表达,并且在MTT实验和裸鼠荷瘤试验中都显示出较单一靶向的shRNA腺病毒载体Ad5-Surv-shRNA、Ad5-Oct4-shRNA具有更为明显的肿瘤细胞生长抑制作用。实验结果表明,特异性双靶向shRNA腺病毒载体Ad5-Dual-shRNA是一种更为高效的靶向肿瘤基因治疗载体。     

Survivin基因在系统性红斑狼疮患者中的异常表达

目的:检测Survivin基因在系统性红斑狼疮(SLE)患者中的表达变化,探讨Survivin基因在SLE发病过程中的作用机制。方法:抽取32例正常健康对照人群和26例SLE患者的外周血,分离单个核细胞,提取总RNA。半定量RT-PCR法检测Survivin基因的表达,以GAPDH基因为内对照,结果以Survivin基因与GAPDH基因的RT-PCR产物的灰度比值表示。同时分析Survivin基因与SLE患者病情活动度的三个实验室指标dsDNA、补体C3和C4的相关性。结果:半定量RT-PCR显示Survivin基因mR- NA表达在SLE患者组为0.83±0.61,正常对照组为0.49±0.59,SLE患者的Survivin基因mRNA的表达明显高于正常对照组(P<0.05)。SLE患者的抗dsDNA抗体水平与Survivin基因表达呈正相关(R=0.62,P<0.01),C3水平则与Survivin基因表达呈负相关(R=-0.41,P<0.05),而C4水平则与Survivin基因表达无显著相关(R=-0.28,P>0.05)。结论:Survivin基因在SLE患者外周血中异常高表达,可能在SLE的发病机制中起着一定的作用,且其高表达与SLE患者的病情活动度有关。     

Survivin的表达和功能研究

目的 探讨Survivin基因在各种组织中的表达及其功能研究。结论 利用RT-PCR方法确认了Survivin在多种胚胎和肿瘤组织中的表达;利用分子克隆方法构建表达了重组Survivin蛋白,体外检测到该重组蛋白与RhSmac具有良好的结合活性;经脂质体转染重组Survivin蛋白的L929细胞与对照相比具有更好的存活率。     

肿瘤中与survivin有关的信号通路及分子以及靶向survivin的治疗前景

Survivin在细胞内环境稳定和肿瘤的形成中起重要的作用,在肿瘤的治疗中,survivivin的靶向治疗调节与一些典型的信号通路和一系列生长因子有关。众所周知,survivin是一个小的凋亡蛋白抑制因子,也是一个主要的抗癌靶标,与细胞分裂和凋亡抑制有关,它在大部分正常组织中缺失但在大部分癌组织中过表达。Survivin是一个与众多细胞信号通路有关的节点蛋白,这些通路协调各种细胞因子、转录网络和修饰基因,通过调节癌细胞内环境稳定直接或间接促进细胞增殖。临床前研究数据表明,survivin的抑制可以降低细胞增殖促进凋亡,增加细胞对细胞毒药物和放疗的敏感性,其过表达与不良预后和治疗耐受有关。因此对于癌症治疗,survivin是一个潜在的靶标。     

凋亡抑制因子Survivin的克隆、高效表达与纯化

Survivin蛋白抑制细胞的凋亡并参与调控细胞的分裂,在绝大多数肿瘤细胞中均有过量表达。本实验以人肝癌细胞系MHCC-97L总RNA为模板,应用RT-PCR的方法得到survivin cDNA,并构建了重组原核表达载体pET-21b(+)-survivin,导入BL21（DE3）菌株进行表达,表达产物以包涵体形式存在,表达量超过总蛋白的60%。Western blot结果表明表达产物与抗人survivin抗体发生特异性反应,经凝胶过滤层析后纯度达到95%以上,为进一步研究靶向Survivin的诊断试剂与抑制剂奠定了基础。     

Survivin在细胞分裂中的作用

Survivin是凋亡蛋白抑制因子家族的一个新成员,它主要在细胞周期G2/M期表达,并有两种不同的亚细胞定位。Survivin与有丝分裂细胞周期的启动有关,并在有丝分裂中的中心体装配、纺锤体检验点的监控、胞质分裂等过程中发挥作用。Survivin在减数分裂中也有一定的作用,目前研究甚少。Survivin发挥功能的首要前提是通过主要的有丝分裂激酶p34cdc2-cyclinB1使Thr34磷酸化,其表达水平受很多因素的调节。     

Survivin和COX-2的表达及与胰腺癌预后的关系

目的:评价Survivin和COX-2在胰腺癌中的表达与预后的关系.方法:采用免疫组化二步法检测63例手术切除的原发性胰腺癌组织及11例癌旁非肿瘤胰腺组织中Survivin和COX-2的表达情况.应用spearman相关分析Survivin与COX-2表达的相关性.用Kaplan-Meier法分析生存曲线,多变量Cox比例风险回归模型筛选影响患者生存的独立预后因素.结果:Survivin、COX-2蛋白在胰腺腺癌中的表达呈正相关(r=0.613,P=0.000).Survivin阻性表达患者中位生存时间(9个月)明显小于阴性表达者中位生存时间(21个月),P=0.000; COX-2阳性表达患者中位生存时间(10个月)也明显小于阴性表达者生存时间(大于36个月),P=0.000; Survivin阴性/COX-2阴性组患者(9例)中位生存时间(大于36个月)及1年累计生存率为88.9％,均明显高于单一阳性表达或均阳性表达组.多因素分析(Cox模型)显示分化程度(P=0.002)、临床分期(P=0.000)及Survivin过表达(P=0.005)为影响胰腺癌预后的独立因素.结论:Survivin、COX-2蛋白在胰腺癌组织中表达上调且呈正相关,二者在胰腺癌的发生发展中可能具有协同作用,有望作为靶点用于胰腺癌的靶向治疗.患者的分化程度、临床分期及Survivin的表达水平是胰腺癌患者手术后生存的独立危险因素.     

Survivin与VEGF在良、恶性胃溃疡组织中的表达及研究

目的:研究凋亡基因生存素(Survivin)及血管内皮生长因子(VEGF)在良、恶性胃溃疡中的表达及二者在溃疡型胃癌中的表达与临床病理特征之间的关系,分析二者在胃癌发生发展中的作用和在胃癌中表达的相关性。方法:应用免疫组化S-P染色检测Survivin及VEGF在良性胃溃疡,胃溃疡伴中-重度不典型增生和溃疡性胃癌中的表达,结合临床病理特征进行相关分析。结果:Survivin及VEGF在良性胃溃疡中的表达率分别为16.2%、24.3%,在胃溃疡伴中-重度不典型中的表达率分别为52.3%、45.5%,在溃疡型胃癌中的表达率分别为71.4%、55.4%,差异具有显著性(P0.01);Survivin和VEGF的表达与溃疡型胃癌的浸润深度、淋巴结转移、TNM分期具有相关性。Survivin和VEGF的表达亦呈正相关。结论:Survivin基因在溃疡型胃癌组织中的表达显著增高,是胃癌演变进程中的重要步骤,过表达Survivin可能提示预后不良。Survivin对胃癌的诊断及预后有潜在的应用价值。Survivin和VEGF在溃疡型胃癌的发生发展中起协同作用,动态随访二者对胃溃疡的演变可能有一定的价值,可作为判断肿瘤进程和浸润转移的生物学指标。Survivin及VEGF的联合检测可能对胃癌的综合治疗提供理论依据,对其进行深入研究有望为胃癌的诊疗开辟新的天地。     

Survivin小分子抑制剂的研究进展

Survivin是凋亡抑制蛋白家族的一员,在抑制细胞凋亡、调控细胞周期、参与血管形成等方面发挥重要的生物学功能。Survivin在多种肿瘤组织中过量表达,与肿瘤不良预后和耐药性密切相关。Survivin作为一种潜在的肿瘤治疗靶点,其小分子抑制剂用于肿瘤治疗的研究为人们所关注。概述了Survivin的结构、功能及其在肿瘤组织中的特异性表达,综述了目前靶向Survivin的小分子抑制剂的研究进展。     

靶向survivin基因的siRNA对姜黄素诱导胃癌细胞凋亡的影响

目的:研究靶向survivin基因的siRNA对胃癌细胞,survivin表达的影响,抑制survivin基因表达对姜黄素诱导胃癌细胞凋亡的影响。方法:通过脂质体将survivinsiRNA导入胃癌细胞株BGC-803,用Real-timePCR和Western-blotting检测转染后细胞内survivin基因表达水平,流式细胞仪和Hochest染色检测细胞凋亡的改变。结果:姜黄素可抑制BGC-803细胞的生长,其生长抑制率和药物浓度与作用时间呈依赖关系;姜黄素作用BGC-803细胞后,survivin蛋白和mRNA表达降低;通过转染survivinsiRNA抑制BGC-803细胞survivin基因的表达能促进姜黄素诱导BGC-803细胞凋亡的作用。结论:靶向抑制survivin基因表达后姜黄素诱导胃癌细胞BGC-803凋亡的作用增强。