镉诱导HEK293细胞凋亡及其线粒体凋亡途径

本课题研究了氯化镉(CdCl_2)诱导HEK293细胞(人胚胎肾细胞系)的凋亡,初步探讨了凋亡过程中Caspase-3、Bcl-2的变化和凋亡诱导因子(AIF)的转移以及它们的意义。MTT法检测CdCl_2对HEK293细胞增殖的抑制作用;通过倒置显微镜、电镜、琼脂糖凝胶电泳、流式细胞术、激光共聚焦观察细胞凋亡;应用Western blot法和荧光免疫法测定Caspase-3酶原、Bcl-2蛋白的变化以及检测AIF蛋白在细胞中的定位。结果显示:CdCl_2对HEK293细胞具有显著的生长抑制作用,并呈明显的剂量和时间依赖性。在琼脂糖凝胶电泳中,显示有凋亡细胞特有的DNA梯状条带,其中30μmol/L作用6-9h梯状条带最为清晰,时间过长或浓度过高则梯状条带逐渐模糊,表明镉浓度过高或处理时间过长,细胞有坏死。流式细胞仪检测也印证了这一结果。形态学观察可见明显的细胞凋亡特征。同时线粒体膜电位明显下降,发现Caspase-3酶原蛋白、Bcl-2蛋白含量减少,并具有时间依赖性;另外检测到线粒体AIF向细胞核转移。而Bcl-2转染后有一定的抑制凋亡作用。实验结果提示,CdCl_2能够诱导HEK293细胞凋亡,线粒体损伤导致AIF转移与细胞色素c释放,从而引发的非Caspases与Caspases凋亡途径可能在镉引发的细胞凋亡过程中起重要作用,而Caspase-3, Bcl-2起着重要的调控作用。     

斜生褐孔菌多糖诱导人肝癌HepG-2细胞凋亡的研究

研究了斜生褐孔菌多糖对人类肝癌HepG-2细胞凋亡的诱导作用。采用噻唑蓝法(MTT法)观察了斜生褐孔菌多糖对HepG-2细胞生长的影响,用透射电镜观察了细胞形态,用DNA Ladder检测了细胞凋亡,用流式细胞仪检测了细胞凋亡率;同时采用逆转录-聚合酶链反应法(RT-PCR法)研究了不同浓度斜生褐孔菌多糖作用后HepG-2细胞中Bax和Bcl-2基因mRNA转录水平的变化。结果表明斜生褐孔菌多糖能抑制HepG-2细胞增殖,并呈时间剂量依赖关系;电镜观察、DNALadder和流式细胞仪检测均证实了斜生褐孔菌多糖能够诱导HepG-2细胞凋亡;经斜生褐孔菌多糖处理后,HepG-2细胞中Bax基因mRNA转录水平增强,而Bcl-2基因mRNA无明显变化。证明了斜生褐孔菌多糖具有抑制HepG-2细胞生长及诱导HepG-2细胞凋亡的作用,这可能与调节Bcl-2和Bax基因表达水平有关。     

定点整合人Bcl-2基因的CHO/dhfr-细胞株的建立

构建重组载体质粒pMCEfrt—Bcl-2,利用FIp—In^TM定点重组系统,在CHO—dhfr^-细胞内定点整合人Bcl-2基因,通过Western印迹检测重组细胞Bcl-2蛋白的表达。通过流式细胞仪和DNA Ladder检测在高NH4C1条件下细胞的凋亡情况;用台盼蓝染色检测在无血清IMDM培养基中细胞的活细胞数目和活细胞比例。结果获得了稳定表达Bcl-2基因的细胞株CHO—Bcl-2,该细胞株能高水平表达Bcl-2蛋白。在无血清培养过程中,CHO—Bcl-2细胞比对照细胞保持高约15％的活细胞比例,细胞总数高25％。CHO-Bcl-2在高NH4^＋（50mmol／L）培养条件下具有较低的凋亡水平。建立了能够高表达Bcl-2基因并具有一定的抗凋亡能力的重组CHO／dhfr^-细胞株。     

c-myc表达对顺铂诱导人胶质瘤细胞系BT_(325)凋亡的影响

研究 c- m yc在化疗药物顺铂诱导肿瘤细胞凋亡中的作用。在原有已构建好 c- myc反义表达载体 pc DNA3- MYC并成功转染 BT32 5 细胞的基础上 ,用顺铂诱导细胞凋亡。采用 TUNEL技术并从光镜、电镜、荧光显微镜及激光共聚焦显微镜水平观察 BT32 5 细胞凋亡的形态学特征 ;流式细胞仪检测实验组 (即 pc DNA3- MYC转染的细胞 )及对照组 (包括未转染或仅转染空载体 pc DNA 3的细胞 )凋亡率的异同。结果显示 :与转染空载体 pc DNA3及未转染组的细胞相比 ,在转染 pc DNA 3-MYC的 BT32 5 细胞中 ,顺铂诱导的细胞凋亡作用明显受阻 ,结果表明 :肿瘤细胞内异常表达的 c- myc在顺铂诱导肿瘤细胞凋亡的过程中有重要作用。     

氧化修饰LDL诱导U937细胞凋亡及其机制探讨

用氧化修饰低密度脂蛋白（ox-LDL）诱导人髓系白血病细胞株U937细胞凋亡,并研究其作用机制.用脱氧核苷酸转移酶介导的dUTP切口末端标记技术(TUNEL法)、流式细胞仪和DNA断裂分析检测细胞凋亡;用免疫组化检测c-fos、c-jun和c-myc蛋白表达,RT-PCR显示c-fos、c-jun和c-myc mRNA表达水平.结果表明ox-LDL可致U937细胞凋亡,其作用具有浓度效应;ox-LDL可以上调c-fos、c-jun和c-myc基因表达,使c-fos、c-jun和c-myc蛋白合成增多,最终诱导U937细胞凋亡.     

维生素C诱导人宫颈癌Caski细胞凋亡及其分子机制的研究

为了研究维生素C对人宫颈癌Caski细胞体外抑制、诱导凋亡的作用及其分子机制,使用不同剂量维生素C处理人宫颈癌Caski细胞,采用噻唑蓝(MTT)法检测药物对细胞增殖的抑制作用;流式细胞仪检测Cas-ki细胞周期变化;琼脂糖电泳法观察凋亡细胞DNA Ladder现象;Western blot检测凋亡相关蛋白Bcl-2、Bax和E6的表达以及Caspase 3的激活;荧光染色观察细胞线粒体膜电位的改变.分析发现,维生素C可显著抑制人宫颈癌Caski细胞增殖,呈现明显的时间和剂量依赖性;将细胞阻滞于S期;诱导细胞凋亡,下调Bcl-2和E6、上调Bax蛋白表达,促进Caspase3活化,降低线粒体膜电位.表明维生素C在体外可有效抑制人宫颈癌Caski细胞增殖,诱导细胞凋亡.     

羊栖菜多糖诱导lovo细胞凋亡及其机理探讨

本课题研究羊栖菜多糖（Sargassum Fusforme Polysaccharides．SFPS）诱导人大肠癌lovo细胞凋亡及凋亡过程中Caspase-3的变化及其意义。MTT法检测SFPS对大肠癌细胞增殖的抑制率：通过电镜、琼脂糖凝胶电泳、流式细胞术鉴定细胞凋亡：应用Westernblot法测定Caspase-3酶原的变化：RT—PCR检测Caspase-3mRNA表达。结果显示：SFPS作用lovo细胞24,36,48和72h的IC50分别为375,355,178和60mg／L,表明对lovo细胞具有显著生长抑制作用。在电镜下,可见明显的细胞凋亡特征：细胞膜表面微绒毛减少、染色质固缩、边集,凋亡小体形成。在琼脂糖凝胶电泳中,药物浓度为5—300mg／L作用24h后,显示有凋亡细胞特有的DNA梯状条带：而500mg／L处理后梯状条带模糊,开始出现“涂片状”,表明在高药物浓度的作用下,细胞有坏死。流式细胞仪测得细胞凋亡率有剂量的依赖性;DNA直方图出现亚G1峰,但细胞周期时相的分布无明显改变。SFPS处理lovo细胞后,发现Caspase-3酶原蛋白表达降低,Caspase-3的mRNA高表达,并具有剂量和时间的依赖性。实验结果提示,SFPS在体外能够诱导lovo细胞凋亡,这可能是SFPS抑制肿瘤增殖的机制之一．而Caspase-3的活化参与了SFPS诱导lovo细胞凋亡的调控。     

SLE患者PBMC凋亡状态及相关基因表达的研究

探讨外周血单个核细胞(PBMC)凋亡及其基因调控在系统性红斑狼疮(systemic lupus erythematosus,SLE)发病机制中的作用.用流式细胞仪(FCM)检测PBMC凋亡百分率及T细胞亚群的凋亡状态;用RT-PCR检测PBMC bcl-2和bax的mRNA表达;用FCM检测凋亡相关基因bcl-2,bax,fas,p53和c-myc的蛋白表达.结果显示,SLE患者PBMC凋亡百分率明显高于正常人,且活动期患者高于非活动期患者.SLE活动期患者CD4+,CD8+T细胞数明显低于正常人;非活动期患者CD8+T细胞数明显低于正常人,而CD4+T细胞数与正常人比较无统计学差异;SLE患者PBMC bcl-2和bax mRNA表达与正常人比较无统计学差异;SLE患者PBMC bcl-2,bax和fas蛋白表达明显高于正常人,p53和c-myc蛋白表达在各组之间无统计学差异.SLE患者PBMC凋亡百分率增高、外周血T细胞亚群的异常及bcl-2,bax和fas蛋白表达增高,在SLE发病机制中可能起了一定的作用.     

原花青素诱导胃癌SGC-7901细胞凋亡及其机制的研究

为探讨原花青素对人胃癌SGC-7901细胞增殖及凋亡的影响及其可能的作用机制,以体外培养的SGC-7901细胞为研究对象,经一定浓度的原花青素作用后,用MTT法及流式细胞仪检测细胞增殖抑制及凋亡情况,Real-time PCR技术及免疫组化法检测Bcl-2、Bax mRNA和相关蛋白表达的含量。结果表明,不同浓度的原花青素不仅能有效抑制SGC-7901细胞增殖,还可诱导细胞凋亡,且抑制增殖及促进凋亡作用呈浓度和时间依耐性;Real-time PCR及免疫组化试验中显示,随着原花青素浓度的增加,Bcl-2mRNA及相应蛋白表达逐渐减少,Bax mRNA和相关蛋白表达逐渐增加。因此,原花青素对人胃癌SGC-7901细胞具有明显的抑制作用,其作用机制可能与上调Bcl-2蛋白和下调Bax蛋白水平有关。     

大肠杆菌诱导U937细胞凋亡过程中bcl-2和bax基因的表达

目的研究bcl-2和bax在大肠杆菌诱导U937细胞凋亡中的作用。方法U937细胞的凋亡用AnnexinV-FITC/PI染色流式细胞仪技术测定。Bcl-2和bax基因表达用RT-PCR法测定。结果当细胞与细菌浓度比分别为0,1:5,1:10,1:20,1:50及1:100时作用30min均可诱导U937细胞凋亡,凋亡率分别为3·16%±0·90%,9·46%±0·84%,17·90%±1·41%,35·59%±3·76%,38·35%±7·12%和55·07%±5·82%,呈浓度依赖性。在细胞凋亡过程中bcl-2和bax的表达均呈现趋势变化,bax表达逐渐增强,bcl-2表达逐渐减弱。结论E.coli可诱导U937细胞凋亡;其机制涉及bcl-2表达下调和bax表达上调。     

Expression of TRAIL receptors in human autoreactive and foreign antigen-specific T cells

Deletion of T cells due to apoptosis induction is a regulatory mechanism in the human immune system that may be impaired in autoimmune diseases such as multiple sclerosis (MS). Involvement of the apoptosis-mediating CD95/CD95 ligand system in MS has been demonstrated. Here, we report that (auto)antigen-specific human T cells are not killed in vitro by soluble TNF-related apoptosis-inducing ligand (TRAIL) although expressing death-inducing receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2. Apoptosis was assessed by caspase activation and DNA fragmentation, receptor expression was detected by RT - PCR and flow cytometry. The (auto)antigen-specific T cells were also resistant to specific TRAIL-R1/TRAIL-R2-directed induction of apoptosis, indicating that coexpression of the truncated TRAIL-R3 and TRAIL-R4 in these T cells is not responsible for the observed resistance. Upon stimulation, levels of death-inducing TRAIL receptors decreased whereas TRAIL was up-regulated on the cell surface. In contrast to CD95, the role of TRAIL receptors in MS might not involve regulation of T cell vulnerability.     

细胞凋亡过程中bcl-2基因的甲基化

为探讨凋亡过程中,ｂｃｌ－２基因下调与该基因甲基化状态的关系,用５－氟尿嘧啶（５－Ｆｕ）诱导小鼠成纤维细胞ＮＣ３Ｈ１０,ＴＣ３Ｈ１０及人乳腺癌细胞ＭＣＦ－７的凋亡,分别检测了这三种细胞凋亡过程中ｂｃｌ－２的表达变化,与其调控区及编码区的甲基化状况．我们曾观察到５－Ｆｕ作用２４～４８ｈ出现细胞存活率下降,ＤＮＡ梯状断裂及细胞周期凋亡峰显现等典型凋亡现象．Ｎｏｒｔｈｅｒｎ杂交显示,在５－Ｆｕ作用１２ｈ时ｂｃｌ－２ｍＲＮＡ水平已明显降低．由此,我们用小鼠ｂｃｌ－２（ｍｂｃｌ－２）及人ｂｃｌ－２（ｈｂｃｌ－２）基因调控区ＰＣＲ扩增片段及ｂｃｌ－２编码区（ｃＤＮＡ）片段作为探针,与５－Ｆｕ作用１２ｈ的细胞ＤＮＡ的ＭｓｐⅠ／ＨｐａⅡ酶切产物进行Ｓｏｕｔｈｅｒｎ杂交,以未作用的细胞ＤＮＡ同样酶切杂交为对照．通过杂交带谱的变化,分析ｂｃｌ－２基因的甲基化状况．结果显示：ｍｂｃｌ－２及ｈｂｃｌ－２在５－Ｆｕ作用１２ｈ后调控区甲基化水平增高,但其编码区甲基化状态皆未出现可检出的变化．上述结果提示：ｂｃｌ－２基因调控区甲基化水平升高可能与该基因下调有关     

Xanthohumol exhibits anti-myeloma activity in vitro through inhibition of cell proliferation,induction of apoptosis via the ERK and JNK-dependent mechanism,and suppression of sIL-6R and VEGF production

BackgroundXanthohumol (XN, a hop-derived prenylflavonoid) was found to exert anticancer effects on various cancer types. However, the mechanisms by which XN affects the survival of multiple myeloma cells (MM) are little known. Therefore, our study was undertaken to address this issue.MethodsAnti-proliferative activity of XN towards two phenotypically distinct MM cell lines U266 and RPMI8226 was evaluated with the MTT and BrdU assays. Cytotoxicity was determined with the LDH method, whereas apoptosis was assessed by flow cytometry and fluorescence staining. The expression of cell cycle- and apoptosis-related proteins and the activation status of signaling pathways were estimated by immunoblotting and ELISA assays.ResultsXN reduced the viability of RPMI8226 cells more potently than in U266 cells. It blocked cell cycle progression through downregulation of cyclin D1 and increased p21 expression. The marked apoptosis induction in the XN-treated RPMI8226 cells was related to initiation of mitochondrial and extrinsic pathways, as indicated by the altered p53, Bax, and Bcl-2 protein expression, cleavage of procaspase 8 and 9, and elevated caspase-3 activity. The apoptotic process was probably mediated via ROS overproduction and MAPK (ERK and JNK) activation as N-acetylcysteine, or specific inhibitors of these kinases prevented the XN-induced caspase-3 activity and, hence, apoptosis. Moreover, XN decreased sIL-6R and VEGF production in the studied cells.ConclusionsERK and JNK signaling pathways are involved in XN-induced cytotoxicity against MM cells.General Significance: The advanced understanding of the molecular mechanisms of XN action can be useful in developing therapeutic strategies to treat multiple myeloma.     

67kD层粘连蛋白受体的克隆、表达及其对肝癌细胞侵袭能力的影响

探讨细胞膜表面 6 7kD层粘连蛋白受体 (6 7kDlamininreceptor ,6 7LR)在肝癌细胞侵袭转移中的作用 ,从肝癌细胞中提取RNA ,通过RT PCR扩增 6 7LR的前体——— 37kD层粘连蛋白受体前体(37kDlamininreceptorprecursor,37LRP)基因并定向克隆到真核表达载体pcDNA3.1 myc His(- )A ,采用脂质体将重组质粒转染到HepG2肝癌细胞中 ,通过G4 1 8筛选和RT PCR、流式细胞术鉴定 ,获得了细胞膜表面 6 7LR高表达 (阳性率为 6 9.2 % )和低表达 (阳性率为 1 1 .7% )的细胞克隆 ,采用体外细胞侵袭实验测定不同细胞的侵袭能力 ,发现膜表面 6 7LR高表达的细胞侵袭能力明显高于低表达及不表达细胞 ,说明 6 7LR在肝癌细胞侵袭转移过程中可能具有重要意义     

可溶性人TRAIL分子的制备及其抗肿瘤活性

TRAIL(TNF relatedapoptosis inducingligand)是1 995年发现的一个新的TNF超家族成员.使人感兴趣的是该分子既可广泛介导多种组织来源的肿瘤细胞发生凋亡而基本不影响正常细胞的功能,也可引起许多对于FasL和TNF α有抗性的细胞凋亡[1 ,2 ] .因此,有可能成为一种新的抗肿瘤药物.     

Effect of nitrogen-containing derivatives of the plant triterpenes betulin and glycyrrhetic acid on the growth of MT-4, MOLT-4, CEM, and Hep G2 tumor cells

Derivatives of the available plant triterpenes glycyrrhetic acid and betulin (betulin succinates and amides of betulonic and 18beta-glycyrrhetic acids containing fragments of long-chain amino acids and a peptide) were synthesized. The inhibitory action of these compounds on the growth of MT-4, MOLT-4, CEM. and Hep G2 tumor cells and their effect on the apoptosis of these cells were studied. It was shown that betulonic acid amides are more effective inhibitors of the tumor cell growth than the corresponding amides of glycyrrhetic acid. It was also found that betulonic acid amides containing fragments of caprylic, pelargonic, and undecanoic acids are more effective inhibitors of tumor cell growth than betulinic acid. The 17-dipeptide derivative of betulonic acid N-{N-[3-oxo-20(29)-lupen-28-oyl]-9-aminononanoyl}-3-amino-3-phenylpropionic acid exhibited the maximum inhibitory activity toward the tumor cells studied. Data on the induction of apoptosis in tumor cells by betulin derivatives at a concentration of 10 microg/ml were obtained by flow cytometry. The amides of betulonic acid proved to be the most effective inducers of apoptosis.