泛素蛋白酶体与心肌细胞凋亡研究进展

细胞凋亡可导致细胞缺失,进而促使心血管疾病的发生.泛素蛋白酶体途径作为细胞内蛋白质选择性降解途径之一,可通过死亡受体调节通路、线粒体凋亡通路、细胞周期调节通路和抗凋亡调节通路等多种通路参与调控细胞凋亡.以泛素蛋白酶体系统为靶点防治心血管疾病具有较好的前景.     

泛素表达和蛋白酶体活性在胃癌及癌旁组织中的研究

目的研究26S蛋白酶体水解活性及泛素在胃癌、癌旁组织与正常胃黏膜组织中的差异。方法对75例胃癌患者分别在胃癌、癌旁及远端正常黏膜组织取样进行研究。采用免疫印迹方法分析泛素表达,免疫荧光方法分析26S蛋白酶体活性。结果泛素表达及26S蛋白酶体活性在胃癌及癌旁组织中增强,均高于正常胃黏膜组织。胃癌中泛素水平(4.24vs3.27)及26S蛋白酶体活性(628.3vs431.8)均高于癌旁组织,差异有统计学意义。结论胃癌中泛素-蛋白酶体系统被异常活化,与胃癌的发生与进展有关。     

泛素-蛋白酶体与足细胞损伤

泛素-蛋白酶体系统(UPS)是细胞内调控蛋白质降解的重要系统,参与细胞内80%以上蛋白质的降解,对维持细胞稳态和功能具有重要的作用。近年来,UPS与足细胞功能开始受到广泛关注。本文就目前UPS与足细胞损伤的研究进展作一综述。     

泛素-蛋白酶体系统与呼吸系统疾病

蛋白是细胞功能的主要执行者,蛋白的质量和数量与细胞功能和疾病有着密切的联系。蛋白的降解系统控制着蛋白的数量,泛素一蛋白酶体系统是细胞内蛋白的主要降解系统,负责细胞内大部分蛋白的降解。对于泛素一蛋白酶体与心血管、肿瘤和神经系统的关系目前研究的比较多,一些新的I艋床药物也应运到临床为患者带来福音。而该系统与呼吸系统疾病关系的研究并不多,了解泛素一蛋白酶体系统在呼吸系统疾病中的作用对于呼吸系统疾病的防治有重要的意义。     

泛素-蛋白酶体通路在心血管疾病中作用的研究进展

泛素蛋白酶体通路(UPS)除了介导细胞内蛋白质的降解外,还在细胞周期、基因转录及表达、信号转导、凋亡、抗原提呈和炎症等方面发挥重要的作用。近年来的研究发现,该通路还在心肌病、心力衰竭、缺血再灌注损伤、动脉粥样硬化、血管的再狭窄等心血管疾病方面,起着重要的病理生理作用。本文就近期UPS在心血管疾病方面的进展进行综述如下。     

泛素-蛋白酶体系统与帕金森病

目前帕金森病(PD)的病因和发病机制尚不完全清楚,可能是遗传和环境因素相互作用的结果.泛素-蛋白酶体系统(UPS)在许多与细胞周期性增殖和凋亡相关的蛋白质的降解中起重要作用.UPS可清除真核细胞内突变、损伤及异常折叠的蛋白质,起到调控蛋白质和维持细胞内环境稳定的作用.在一些家族性PD中发现α-synuclein、parkin和UCH-L1发生基因突变,突变后的三种蛋白质与UPS的功能损害密切相关.尸检研究表明在散发PD患者的黑质中也存在UPS功能的降低.这提示UPS功能受损可能是不同病因作用的共同途径.本文就UPS与PD间关系的研究进展做一综述.     

泛素-蛋白酶体系统功能异常与心脏疾病

<正>泛素(Ub)-蛋白酶体系统(UPS)是真核细胞内大多数蛋白质的降解通路,其调控异常与多种疾病发生有关,对生命活动具有重要的调控意义。UPS功能异常与心血管疾病,如心肌病、心肌缺血、心肌纤维化等有着密切的关系。本文对UPS与心脏疾病的关系进行综述。1 UPS概述1.1 UPS结构UPS由Ub、Ub活化酶(E1)、Ub结合酶(E2)、Ub连接酶(E3)、蛋白酶体构成。Ub是一种由76个氨基酸残     

泛素-蛋白酶体系统与动脉粥样硬化性疾病的发生

泛素-蛋白酶体系统(ubiqutin proteasome system,UPS)广泛存在于真核细胞中,在维持细胞的生理功能方面,UPS起着非常重要的作用。它除了降解损伤的蛋白质,还与炎症、增殖和细胞凋亡相关,其在动脉粥样硬化性疾病中的作用涉及了动脉粥样硬化斑块发展的各个阶段。本文综述了UPS与动脉粥样硬化的关系以及蛋白酶体抑制剂在动脉粥样硬化疾病中的治疗前景。     

泛素-蛋白酶体系统与动脉粥样硬化性疾病的发生

泛素-蛋白酶体系统(ubiqutin proteasome system,UPS)广泛存在于真核细胞中,在维持细胞的生理功能方面,UPS起着非常重要的作用.它除了降解损伤的蛋白质,还与炎症、增殖和细胞凋亡相关,其在动脉粥样硬化性疾病中的作用涉及了动脉粥样硬化斑块发展的各个阶段.本文综述了UPS与动脉粥样硬化的关系以及蛋白酶体抑制剂在动脉粥样硬化疾病中的治疗前景.     

泛素-蛋白酶体系统的研究进展

几乎所有生命活动均需蛋白质的参与,其在机体中的代谢对生物体具有重要影响。正常细胞蛋白质代谢是一个持续降解和再合成的动态过程。真核细胞内主要存在两种蛋白降解系统：一种是溶酶体,主要降解经胞吞进入细胞中的胞外蛋白质;另一种是泛素一蛋白酶体系统（ubiquitinpro—teasomesystem,UPS）。UPS是细胞内ATP依赖的蛋白质选择性降解的主要途径,是真核细胞内重要的蛋白质质控系统,主要降解细胞内80％-90％泛素化的蛋白质,并调节炎症、细胞增生与分化、信号转导、细胞周期进程、转录调控、抗原提呈、免疫应答、细胞凋亡和DNA修复等各种细胞生物学功能。     

反义端粒酶基因与顺铂诱导原代胃癌细胞凋亡作用的研究

目的　探讨端粒酶反义寡核苷酸 (PS- ASODN)与顺铂 (DDP)联合应用对原代胃癌细胞凋亡作用的影响。方法　常规组织块培养法进行胃癌细胞原代纯化培养 ,取第 3代对数生长期细胞分六组进行实验。其中四组在培养 2 4小时及 4 8小时分别加入相同剂量的培养液 ,终浓度为 PS- ASODN3μM,N- ASODN3μM,DDP2 .0μg/ ml。作用 2 4小时后分别在 PS- ASODN组及 N- ASODN组加入终浓度为 2 .0 μg/ ml的 DDP;分别于培养后 2 4、4 8、72及 96小时收集各组细胞。以台盼蓝拒染法计算各组细胞生长抑制率 ,观察 PS- ASODN联合 DDP对原代胃癌细胞生长的影响 ;流式细胞学观察细胞凋亡率及细胞周期变化。结果　终浓度为 3μM的 PS- ASODN作用于原代胃癌细胞 2 4小时后加入 DDP 2 .0μg/ m l,能明显抑制胃癌细胞增殖 ,流式细胞学可检测到凋亡峰 ,细胞受阻于G0 / G1 期 ,作用 4 8及 72小时的凋亡细胞百分率 (35 .1%、4 5 .7% )明显高于 N- ASODN组、PS- ASODN组、DDP组及 N- ASODN+DDP组 ,差异有显著性 (P<0 .0 5 )。其作用呈时间依赖性及序列特异性。结论　以端粒酶 RNA模板区为靶点的 PS- ASODN可促进 DDP诱导的胃癌细胞凋亡 ,对胃癌具有治疗价值     

Blocking effects of genistein on cell proliferation and possible mechanism in human gastric carcinoma

AIM: To study the blocking effects of genistein on cell proliferation cycle in human gastric carcinoma cells (SGC-7901) and the possible mechanism. METHODS: MTT assay was applied in the detection of the inhibitory effects of genistein on cell proliferation. Flow cytometry was used to analyze the cell cycle distribution. Immunocytochemical technique and Western blotting were performed to detect the protein expression of cyclin D_1, cyclin B_1 and p21~(waf1/cip1). RESULTS: Genistein significantly inhibited the growth and proliferation of human gastric carcinoma cells (SGC-7901). Seven days after treatment with different concentrations of genistein (2.5, 5.0, 10.0, 20.0 μg/mL), the growth inhibitory rates were 11.2%, 28.8%, 55.3%, 84.7% respectively and cell cycles were arrested at the G(2)/ M phase. Genistein decreased cyclin D_1 protein expression and enhanced cyclin B_1 and p21~(waf1/cip1) protein expression in a concentration-dependent manner. CONCLUSION: The growth and proliferation of SGC-7901 cells can be inhibited by genistein via blocking the cell cycle, with reduced expression of cyclin D_1 and enhanced expression of cyclin B_1 and p21~(waf1/cip1) protein in the concentration range of 0-20 μg/mL.     

Cell cycle arrest and apoptotic cell death in cultured human gastric carcinoma cells mediated by arsenic trioxide

AIM: To investigate the effect of arsenic trioxide on human gastric cancer cell line MKN45 with respect to both cytotoxicity and induction of apoptosis in vitro. METHODS: MKN45 cells were treated with arsenic trioxide (As2O3) at the concentration of 1, 5, and 10 μmol/L, respectively, for three successive days. Cell growth and proliferation were observed by cell counting and trypan blue exclusion. Cytotoxicity of As2O3 was determined by MTT assay. Morphologic changes were studied with light microscopy. Flow cytometry was used to assay cell DNA distribution and apoptotic cells were confirmed with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and DNA electrophoresis. RESULTS: The growth of MKN45 cells was significantly inhibited by As2O3 which was confirmed by colony-forming assay. After 7 d of culture with various concentrations of As2O3, colony-forming capacity of MKN45 cells decreased with As2O3 increment in comparison with that of control group. The inhibitory rate of colony-formation was 38.5%, 99.1%, and 99.5% when the concentration of As2O3 was 1, 5, and 10 μmol/L in culture medium, respectively. The cell number of a single colony in drug treatment groups was less than that of control group. The cell-killing rate of As2O3 to MKN45 cells was both dose- and time-dependent with an IC50 of (11.05±0.25) μmol/L After incubation in 10 μmol/L As2O3 for 24 h, the cell-killing rate was 27.1%, and it was close to 50% after 48 h. The results showed that As2O3 induced time- and dose-dependent apoptosis in MKN45 cells, blocked at G2/M phase. The apoptotic peak (sub-G1 phase) appeared and cell apoptotic rate in MKN45 cells was 18.3-32.5% after treatment by 10 umol/L As2O3 for 48 h. The percentage of G2/M cell of the experimental groups was 2.0-5.0 times than that of the control group. Gel electrophoresis of DNA from cells treated with each concentration of As2O3 for 48 h revealed a "ladder" pattern, indicating preferential DNA degradation at the internucleosomal, linker DNA sections. TUNEL also demonstrated strand breaks in DNA of MKN45 cells treated with As2O3, while control cells showed negative labeling. CONCLUSION: As2O3 can induce apoptosis of human gastric carcinoma cells MKN45, which is the basis of its effectiveness. It shows great potential in the treatment of gastric carcinoma.     

Guggulsterone induces apoptosis of human hepatocellular carcinoma cells through intrinsic mitochondrial pathway

AIM: To investigate the effects of guggulsterone on the proliferation and apoptosis of human hepatoma Hep G2 cells in vitro and relevant mechanisms.METHODS: Human hepatocellular carcinoma Hep G2 cells and normal human liver L-02 cells were treated with different concentrations of guggulsterone(5-100 μmol/L) for 24-72 h. Cell proliferation was tested by MTT assay. Cell cycle and apoptosis were investigated using flow cytometry(FACS). Bcl-2 and Bax m RNA and protein expression was detected by real-time PCR and Western blot, respectively. TGF-β1, TNF-α, and VEGF contents were determined by ELISA.RESULTS: Guggulsterone significantly inhibited Hep G2 cell proliferation in a dose- and time-dependent manner. FACS showed that guggulsterone arrested Hep G2 cell cycle at G0/G1 phase. Guggulsterone induced apoptosis was also observed in Hep G2 cells, with 24.91% ± 2.41% and 53.03% ± 2.28% of apoptotic cells in response to the treatment with 50 μmol/L and 75 μmol/L guggulsterone, respectively. Bax m RNA and protein expression was significantly increased and Bcl-2 m RNA and protein expression was decreased. ELISA analysis showed that the concentrations of TGF-β1 and VEGF were significantly decreased and TNF-α concentration was increased.CONCLUSION: Guggulsterone exerts its anticancer effects by inhibiting cell proliferation and inducing apoptosis in Hep G2 cells. Guggulsterone induces apoptosis by activation of the intrinsic mitochondrial pathway.     

胃癌组织中EphA2基因的表达及其与细胞凋亡、增殖的关系

目的 探讨EphA2基因在胃癌组织中表达的生物学意义及与细胞凋亡、增殖的关系.方法 利用免疫组织化学法(immunohisochemistory,IHC)检测82例胃癌手术切除标本的癌组织、癌旁组织及正常胃黏膜中EphA2的表达,采用逆转录聚合酶链反应(RT-PCR)及Western印迹技术对其中随机选取的30例标本进行EphA2 mRNA及其蛋白的定量检测,分析其表达与临床病理参数的关系.采用流式细胞术(FCM)检测82例癌组织中细胞凋亡率及增殖指数(PI),分析EphA2表达与细胞凋亡、增殖的关系.结果 IHC结果显示EphA2在癌组织中的表达显著高于癌旁组织及正常胃黏膜(P<0.01),且随胃癌分化程度降低、浸润深度增加及淋巴结转移而升高(P<0.05),但与肿瘤大小、患者年龄无关(P>0.05);RT-PCR结果显示EphA2 mRNA在各组中的表达水平无显著性差异(P>0.05);Western印迹与IHC结果一致,显示EphA2蛋白在癌组织中异常高表达(P<0.01).FCM结果显示EphA2高表达组细胞凋亡率显著低于低表达组(P=0.018),而其PI显著高于低表达组(P=0.002).结论 EphA2在胃癌组织中表达明显上调,可抑制细胞凋亡,促进细胞增殖,在胃癌的发生发展中发挥重要作用,其机制与EphA2 mRNA的转录异常无关,而可能是其翻译水平上调或蛋白质稳定性增高所致.     

Inhibitory effect of Polo-like kinase 1 depletion on mitosis and apoptosis of gastric cancer cells

AIM:Polo-like kinase 1 (PLK1) serine/threonine kinaseplays a vital role in multiple phases of mitosis in gastriccancer cells.To investigate the effect of PLK1 depletionon mitosis and apoptosis of gastric cancer cells.METHODS:PLK1 expression was blocked by smallRNA interference(siRNA).The expression levels ofPLK1,cdc2,cyclin B and caspase 3 were detected byWestern blotting.Then,PLK1 depletion,cdc2 activity,cell proliferation,cell cycle phase distribution,mitoticspindle structure,and the rate of apoptosis of the PLK1knockdown cells were observed.RESULTS:PLK1 gene knockdown was associated withincreased cyclin B expression,increased cdc2 activity (butnot with the expression levels),accumulation of gastriccancer cells at G2/M,improper mitotic spindle formation,delayed chromosome separation and delayed or arrestedcytokinesis.Moreover,PLK1 depletion in gastric cancercells was associated with decreased proliferation,attenuated pro-caspase 3 levels and increased apoptosis.CONCLUSION:Blockage of PLK1 expression may leadto decreased mitosis or even apoptosis in gastric cancercells,indicating that PLK1 may be a valuable therapeutictarget for gastric cancer.     

In vitro effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 cells

AIM: To investigate the effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 in vitro and the possible mechanisms involved. METHODS: Chitosan nanoparticles were characterized by particle size, zeta potential, and morphology. After treatment with various concentrations of chitosan nanoparticles (25, 50, 75, 100 μg/mL) at various time intervals, cell proliferation, ultrastructural changes, DNA fragmentation, mitochondrial membrane potential (MMP), cell cycle phase distribution and apoptotic peaks of MGC803 cells were analyzed by MTT assay, electron microscopy, DNA agarose gel electrophoresis, and flow cytometry. RESULTS: Chitosan nanoparticles exhibited a small particle size as 65 nm and a high surface charge as 52 mV. Chitosan nanoparticles markedly inhibited cell proliferation of MGC803 cells with an IC50, value of 5.3 μ/mL 48 h after treatment. After treatment with chitosan nanoparticles, the typical necrotic cell morphology was observed by electron microscopy, a typical DNA degradation associated with necrosis was determined by DNA agarose electrophoresis. Flow cytometry showed the loss of MMP and occurrence of apoptosis in chitosan nanoparticles-treated cells. CONCLUSION: Chitosan nanoparticles effectively inhibit the proliferation of human gastric carcinoma cell line MGC803 in vitro through multiple mechanisms, and may be a beneficial agent against human carcinoma.