生存素及其意义

生存素（Survivin）是凋亡抑制蛋白家族中的新成员，能抑制细胞凋亡，促使细胞增殖，调节细胞有丝分裂。生存素与肿瘤侵袭、放疗和化疗抵抗及预后不良有关。最新的研究表明，细胞核生存素表达是判断肿瘤预后的重要指标。抑制生存素表达能显著促进肿瘤细胞发生凋亡，而对正常组织无明显影响，有望成为胶质瘤治疗的新靶点。     

生存素在肿瘤中的研究进展

生存素(survivin)是凋亡抑制蛋白(inhibitor of apoptosis proteins, IAP)家族的成员之一,具有抑制细胞凋亡和调控细胞周期的生物学功能.生存素在大多数正常成人组织中检测不到,但在肿瘤组织中过量表达,可为恶性肿瘤的诊断、预后判断提供临床参考.通过对生存素的深入研究,可以进一步阐明细胞凋亡及肿瘤发生机制,也将为肿瘤开辟新的靶向治疗途径.该文就生存素的分子结构及生物学功能、生存素与肿瘤表达、生存素与癌基因、生存素与肿瘤治疗的研究进展作一综述.     

凋亡抑制因子存活素与脑胶质瘤

凋亡(apoptosis)是正常体细胞维持稳定的重要保护机制之一。细胞凋亡受抑制为基因改变的异常细胞提供生存之机,使细胞的转化突变得以保存、积蓄,最终导致肿瘤的发生和演进。凋亡蛋白抑制因子(inhibitorofapoptosis-protein,IAP)是一类抑制凋亡的调节分子,其成员存活素(survivin)是新发现的凋亡抑制基因,在众多人类恶性肿瘤中上调表达,并与肿瘤的凋亡、增殖、血管生成及其预后和耐药性的产生有密切的关系。     

生存素在大肠癌中的表达及其与血管生成的关系

目的研究生存素(survivin)在大肠癌组织中的表达及其与血管生成的关系。方法应用RT-PCR方法检测52例大肠癌组织,48例癌旁正常粘膜组织中生存素mRNA的表达,序列分析验证PCR扩增的正确性;用免疫组织化学法检测52例大肠癌组织中生存素蛋白、凋亡指数(AI)、增殖指数(LI)和微血管密度(MVD)。结果大肠癌组织中生存素mRNA阳性表达率为67.3%,而癌旁正常组织阳性表达率为25.0%(P<0.01);生存素mRNA表达与大肠癌患者性别、肿瘤大小、病理类型、淋巴结转移、远处转移及临床分期无明显相关关系。序列分析结果:所扩增生存素与人生存素序列具有99%的同源性。免疫组化检测显示大肠癌组织中生存素蛋白阳性表达率为51.9%(27/52)。生存素表达阳性组的凋亡指数为(0.67±0.18)%,显著低于生存素表达阴性组(1.14±0.42)%,(P<0.01);生存素表达阳性组的LI(51±22)%,MVD(21.4±8.2),显著高于生存素表达阴性组的(27±18)%,(P<0.01)和(14.2±5.4)(P<0.05)。结论(1)生存素表达与大肠癌患者性别、肿瘤大小、病理类型、淋巴结转移、远处转移及临床分期无明显相关关系。生存素抑制凋亡和促进增殖可能是参与大肠癌发生的重要机制。(2)生存素与大肠癌血管生成关系密切。     

宫颈癌组织中生存素基因表达及意义

宫颈癌是女性常见的恶性肿瘤,其发病率及病死率在我国呈上升趋势,其发生、发展是一个多基因、多阶段的演进过程.生存素(survivin)基因是近年新发现的凋亡抑制蛋白(inhibitor of apoptosis protein,IAP)家族成员之一,能抑制细胞凋亡、促进细胞增殖,与肿瘤的发生、发展有密切关系[1].本研究采用RT-PCR方法对宫颈癌组织中生存素基因进行检测,探讨生存素基因的表达规律及其与预后之间的关系.     

生存素在乳腺癌中的表达及其与细胞增殖的关系

为探讨乳腺癌组织中生存素表达的临床意义及其与癌细胞增殖的关系,采用免疫组织化学SP法检测生存素、Ki-67蛋白在96例乳腺癌组织中的表达和生存素在20例正常乳腺组织的表达,分析生存素表达与Ki-67增殖指数及各临床病理因素的关系。结果表明,生存素阳性表达乳腺癌的Ki-67增殖指数（35．32&#177;21．28％）明显高于生存素阴性者（20．42&#177;11．34％）,生存素表达与肿瘤细胞增殖呈正相关（P〈0．05）;生存素在乳腺癌组织中的表达率为70．83％（68／96）,正常乳腺组织未见生存素表达,二者差异有统计学意义（P〈0．01）;生存素蛋白的表达与临床分期、淋巴结转移呈正相关（P〈0．05）,与5年生存率呈负相关（P〈0．05）,与年龄、是否绝经、肿瘤大小和组织学分级均无关。结论：生存素不仅参与凋亡的调控,还促进了细胞增殖。生存素蛋白在乳腺癌中表达上调,提示其通过抑制凋亡在乳腺癌发生、发展中起重要作用,过度表达提示预后不良。     

宫颈鳞癌生存素与p53表达的相关性

生存素（survivin）是近年新发现的一种凋亡抑制基因,具有抑制凋亡效应蛋白酶Caspase活性、参与细胞周期调控及调节有丝分裂等多种生物学作用。我们应用免疫组织化学方法观察宫颈癌组织中生存素和p53蛋白的表达,着重探索生存素和p53在宫颈鳞癌发生发展中的相关性。     

木犀草素抑制PKM2继而促进自噬诱导肝癌细胞凋亡

目的：探究木犀草素对人肝癌HepG2细胞中PKM2表达的影响，继而挖掘木犀草素诱导肝癌细胞凋亡的机制。方法：通过数据库比较肝癌的癌旁组织和肿瘤组织中的PKM2表达差异，收集肝癌患者标本，检测癌和癌旁组织中PKM2 mRNA和蛋白的表达差异。木犀草素刺激肝癌细胞HepG2，用CCK8、流式凋亡及Western blot方法检测木犀草素对肝癌生存率和凋亡的影响，以及木犀草素作用于肝癌细胞后PKM2的变化。在肝癌细胞系中敲减或过表达PKM2，用木犀草素刺激肝癌细胞，探究PKM2对木犀草素诱导肝癌细胞增殖和凋亡的影响，同时检测自噬相关分子，探究PKM2及木犀草素对自噬的影响。结果：与癌旁组织相比，肿瘤组织中PKM2表达量升高；木犀草素以浓度依赖性和时间依赖性抑制HepG2细胞增殖，诱导细胞凋亡，并且随着木犀草素浓度的增高PKM2的表达逐渐降低；敲减PKM2可以显著抑制肝癌细胞增殖，促进肝癌细胞凋亡，而过表达PKM2可以削弱木犀草素对肝癌细胞的凋亡作用。木犀草素可以促进肝癌细胞自噬，敲减PKM2后可以抑制木犀草素诱导的自噬。结论：木犀草素可以通过抑制PKM2表达，诱导肝癌细胞发生自噬，促进细胞凋亡。     

Survivin在肿瘤早期诊断及治疗中的作用

Survivin是新近被克隆出的一种凋亡抑制蛋白，是凋亡抑制蛋白（inhibitor of apoptosis protein．IAP）家族中的一员。但其与IAP家族其它成员不同，Survivin分子几乎在正常组织中不表达，而特异性表达于人和鼠的胚胎发育组织以及多数人类肿瘤细胞。在正常成人组织的表达仅见于胸腺、睾丸和分泌期子宫内膜。这为肿瘤治疗提供了一个新靶点。Caspase-3是一种促凋亡因子，是Caspase系统引起细胞凋亡的最下游成分。Survivin通过抑制Caspase-3的活性而阻断凋亡的发生过程。现就Survivin的分子生物学特征和功能、机制及其在肿瘤的早期诊断和治疗预后方面的价值作一综述。     

Sunrivin及其与肿瘤耐药相关性的研究进展

Survivin是凋亡抑制蛋白家族的成员,是目前发现的最强的凋亡抑制因子,是一个既可以抑制凋亡,又可以调节细有丝分裂的双功能蛋白.Survivin高表达于几乎所有恶性肿瘤组织,而在分化成熟的正常组织中(胸腺和生殖腺除外)几乎不表达.大量研究发现,Survivin在肿瘤发生、发展以及化疗耐药过程中起着重要作用.本文主要就Survivin参与肿瘤耐药的机制及其在肿瘤治疗中的应用做一综述.     

Batimastat reduces Mycobacterium tuberculosis-induced apoptosis in macrophages

In this study, we report evidences that Mycobacterium tuberculosis (MTB)-induced apoptosis in macrophages is reduced by a broad-spectrum hydroxamic acid-based matrix metalloproteinase (MMP) inhibitor, Batimastat (BB-94). In particular, we show that BB-94 administration to MTB-infected macrophages inhibits apoptosis and the downmodulation of membrane CD14 expression. Moreover, the addition of broad spectrum matrix metalloproteinase inhibitor to cell culture, during MTB infection, decreases the release of soluble TNF-alpha and leads to a simultaneous increase of membrane TNF-alpha. These results show that MTB-induced apoptosis in macrophages is reduced by a MMP inhibitor and most probably is related to TNF-alpha release. This identifies BB-94 as a simultaneous anti-apoptotic and anti-inflammatory molecule during MTB infection.     

Possible involvement of oxidative stress in cisplatin-induced apoptosis in LLC-PK1 cells

Use of cisplatin, a chemotherapeutic agent, is associated with toxicity as a significant number of patients develop a decline in renal function. The mechanisms by which cisplatin produces renal injury are not well understood. It has been suggested that free radical-catalyzed lipid peroxidation can induce apoptosis or necrosis leading to renal injury. This study examined whether low concentrations of cisplatin induce apoptosis in LLC-PK1 cells and whether caspases 1, 2, 3, 8, and 9 are activated during this event. Our results show a dose- and time-dependent induction of apoptosis by micromolar concentrations of cisplatin. Expression of oncogenes c-myc and p53 was induced, and except for caspase 1, all the other caspases tested were activated. Z-VAD, the broad-spectrum inhibitor of caspases, prevented caspase activation and apoptosis, but not c-myc and p53 induction. On the other hand, N-acetylcysteine prevented cisplatin-induced apoptosis as well as c-myc induction but not p53 induction. The antioxidant trolox also prevented cisplatin-induced apoptosis. The results suggest that antioxidants and caspase inhibitors may alleviate cisplatin-associated nephrotoxicity.     

Baculoviruses and apoptosis: a diversity of genes and responses

Apoptosis is used by metazoan organisms to dispose of damaged or unnecessary cells during development, tissue homeostasis, and disease. One of the situations where apoptosis is important is in defense against microbial pathogens, especially viruses. The demonstration that apoptosis could be stimulated by baculovirus infection was one of the first examples of apoptosis associated with virus infection, and this system remains one of the most valuable for studying how apoptosis can be a defense against viruses. In addition, studying how baculoviruses regulate apoptosis has led to many important findings in the field of apoptosis research, such as the discovery of P35, a caspase inhibitor that is widely used in studies of apoptosis, and IAP (inhibitor of apoptosis) proteins, which have homologs in cellular genomes that play important roles in regulating apoptosis and cytokinesis. This review highlights the range of apoptotic responses observed between different baculoviruses and different lepidopteran insects, and the diverse baculovirus genes that have evolved to regulate apoptosis.     

纤溶酶系统在成肌纤维细胞凋亡、组织纤维化过程中的作用

成肌纤维细胞(myofibroblast,MF)是介于平滑肌细胞(smooth muscle)和成纤维细胞(fibroblast)之间的一种细胞。它被公认为在伤口愈合和各种组织纤维化的过程中起关键作用。该文从信号转导角度介绍了纤溶酶系统(plasminogensystem)与成肌纤维细胞细胞凋亡之间的联系,通过对纤溶酶系统的调节,可以影响到人体各处组织中MF的凋亡和分化,进而缓解甚至治疗相应的疾病。最新的研究结果表明,PAI-1的小分子抑制剂和他汀类药物可以通过纤溶酶系统来影响MF的凋亡,它们有望成为治疗组织纤维化的新药。     

Mechanisms of cyclosporine A-induced apoptosis in rat hepatocyte primary cultures

In rat hepatocytes and isolated liver mitochondrial fractions, Cyclosporine A (CsA) is often used as a specific inhibitor of mitochondrial Ca(2+) release and as a specific blocker of mitochondrial membrane potential and permeability transition (MPT), which are all processes involved in the inhibition of apoptosis. However, neither inhibition nor induction of apoptosis by CsA has yet been described in the rat hepatocyte primary culture during incubation for 4 and 20 h. It was the purpose of the present study to examine by means of morphological and biochemical criteria the effects of CsA on apoptosis and to characterize the underlying mechanisms. Rat hepatocytes were cultured for 4 or 20 h with CsA at concentrations of 0, 10, 25, and 50 microM. Chromatin condensation and fragmentation, DNA fragmentation (TUNEL), membrane phosphatidylserine distribution (Annexin V), caspase-1, -3, and -6 activity, mitochondrial membrane potential (Rhodamine 123), and cytochrome c release into the cytosol were investigated. Four hours after CsA treatment, chromatin condensation and fragmentation and the number of TUNEL- and Annexin V-positive cells increased dose-dependently without any observable enzyme leakage, which indicated the integrity of the outer cell membrane. After 20 h of CsA incubation apoptosis parameters were further increased and were accompanied by the increased activity of the cysteine protease, caspase-3 (CPP 32), and slightly increased caspase-6 (Mch 2), but not caspase-1 (ICE). The caspase-3 inhibitor, Ac-DEVD-CHO, inhibited caspase-3 activation and attenuated CsA-induced apoptosis and LDH leakage. The caspase-6 inhibitor, Ac-VEID-CHO, only marginally inhibited CsA-induced apoptosis. Decreased mitochondrial membrane potential and cytochrome c release went in parallel with ultrastructural mitochondrial changes and might be regarded as early events that trigger the apoptosis cascade. Transmission electron microscopy confirmed an increase in the number of necrotic cells after 20 h, but not after 4 h, compared with controls.     

姜黄素抗肿瘤作用机制的研究进展

多种恶性肿瘤细胞中表达细胞凋亡抑制蛋白（IAPs）,如：Survivin、NAIP、XIAP、Livin等,同样表达抗细胞凋亡Bcl-2家族蛋白。IAPS介导的凋亡抑制可能是肿瘤细胞耐药而存活的原因之一;Bcl-2家族蛋白在抗肿瘤凋亡及促其凋亡中发挥作用。姜黄素具有抗炎、抗氧化、抑制血管新生等,可以通过调控蛋白表达及相关信号通路促进细胞凋亡、抗肿瘤作用。     

Induction of apoptosis by esculetin in human leukemia U937 cells through activation of JNK and ERK

Esculetin is a phenolic compound that is found in various natural plant products and induces apoptosis in several types of human cancer cells. However, the underlying mechanisms of its action are not completely understood. In the present study, we used human leukemia cells to gain further insight into the mechanism of esculetin-induced anti-proliferative action and apoptosis. It was found that esculetin inhibits cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, DNA fragmentation, and the accumulation of cells in the sub-G1 phase. Esculetin-induced apoptosis was correlated with mitochondrial dysfunction, leading to the release of cytochrome c from the mitochondria to the cytosol, as well as the proteolytic activation of caspases. The z-DEVD-fmk caspase-3 inhibitor and the ectopic expression of anti-apoptotic Bcl-2 significantly inhibited esculetin-induced apoptosis, demonstrating the important role of caspase-3 and mitochondrial proteins in the observed cytotoxic effect. Furthermore, esculetin selectively increased the phosphorylation of extracellular-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but not that of other kinases such as Akt and p38 activation. In addition, an ERK-specific inhibitor, PD98059, and a JNK-specific inhibitor, SP600125, showed inhibited sub-G1 phase DNA content, DNA fragmentation, caspase activation, and mitochondrial dysfunction induced by esculetin treatment. These results indicated that the JNK and ERK pathways were key regulators of apoptosis in response to esculetin in human leukemia U937 cells.     

NS-398诱导肝癌细胞凋亡的实验研究

目的 :研究选择性环氧化酶 2 (COX 2 )抑制剂NS 398对人肝癌细胞HepG2 凋亡的影响 ,及其相关蛋白Bcl 2在细胞凋亡中的作用。方法 :通过体外细胞培养 ,应用荧光显微镜、透射电镜、流式细胞仪观察NS 398对HepG2 的凋亡诱导作用 ,应用免疫细胞化学法观察Bcl 2在人肝癌细胞HepG2 凋亡中的表达。结果 :NS 398处理HepG2 细胞后 ,电镜下可见到细胞核固缩、染色质凝集成新月型紧靠核膜周边 ,核碎裂、染色质片断化等典型的细胞凋亡形态变化。荧光显微镜及流式细胞检测则未见凋亡征象。免疫细胞化学分析显示 ,NS 398处理后的HepG2 细胞 ,其Bcl 2表达较对照组明显下降。结论 :COX 2选择性抑制剂NS 398对人肝癌HepG2 细胞有显著的凋亡诱导作用 ;抗凋亡基因Bcl 2在NS 398诱导的HepG2 细胞凋亡中有重要的调控作用。     

Antisense-mediated melanoma inhibitor of apoptosis protein downregulation sensitizes G361 melanoma cells to cisplatin

Malignant melanoma is an aggressive form of skin cancer that is highly resistant to conventional therapies. The melanoma inhibitor of apoptosis protein is a potent inhibitor of apoptosis and is overexpressed in melanoma cells, but undetectable in most normal tissues including melanocytes. We designed 20-mer phosphorothioate antisense oligonucleotides complementary to five putatively single-stranded sites on the melanoma inhibitor of apoptosis protein mRNA and investigated their ability to sensitize G361 melanoma cells to cisplatin. Inhibition of melanoma inhibitor of apoptosis protein mRNA and protein expression were measured by real-time polymerase chain reaction and immunoblotting. Cell viability and apoptosis were quantitated by colorimetric viability assays and by annexin V staining, respectively. Oligonucleotide M706 was identified as the most efficient antisense sequence which downregulated melanoma inhibitor of apoptosis protein mRNA and protein levels in G361 cells by 68 and 78%, respectively. The specificity of target downregulation was confirmed using scrambled sequence control oligonucleotides that only marginally decreased melanoma inhibitor of apoptosis protein expression. Whereas downregulation of melanoma inhibitor of apoptosis protein moderately inhibited cell growth by 26%, in combination with cisplatin, this resulted in a supra-additive effect with almost 57% reduction in G361 cell viability compared with cisplatin alone (17%) (P<0.05). Cell death was mainly due to apoptosis as demonstrated by a 3- to 4-fold increase in annexin V-positive cells and typical morphological changes compared with controls. In summary, we describe a new antisense oligonucleotide that efficiently downregulates melanoma inhibitor of apoptosis protein expression and sensitizes melanoma cells to cisplatin.     

Butyl paraben promotes apoptosis in human trophoblast cells through increased oxidative stress‐induced endoplasmic reticulum stress

Butyl paraben (BP) has antimicrobial effects and is widely used as a preservative in cosmetics, foods, and pharmaceuticals. It is also absorbed into various tissues of the human body. It is known that BP is measurable in maternal and fetal tissues during pregnancy, but the effects of BP on placental development, essential for maintaining normal pregnancy, are unclear. Therefore, we investigated the effect of BP on the proliferation, apoptosis, and invasiveness of human trophoblast cells, using an HTR8/SVneo cell line. BP inhibited cell proliferation and induced both apoptosis and endoplasmic reticulum stress. In addition, BP promoted the production of intracellular reactive oxygen species, increased Ca²⁺ concentration in HTR8/SVneo cells, and induced mitochondrial membrane depolarization. BP also inhibited the activation of PI3K/AKT pathways including AKT, ribosomal protein S6, P70 S6 kinase, and glycogen synthase kinase 3β. Furthermore, pretreatment of cells with LY294002 (an AKT inhibitor) and U0126 (ERK1/2 inhibitor) revealed that ERK1/2 activity is also involved in BP‐mediated signal transduction in HTR8/SVneo cells. We therefore suggest that exposing human trophoblast cells to BP diminishes normal physiological activity, leading to apoptosis and problems with early placental development.