人IL-4基因修饰诱导肝母细胞瘤细胞凋亡及分化的研究

目的　研究人白细胞介素 4(IL 4)基因修饰对肝母细胞瘤细胞凋亡及分化的影响及可能机制。方法　以逆转录病毒为载体将人IL 4基因导入人肝母细胞瘤细胞系 (HepG2 )细胞。台盼蓝拒染、瑞氏染色、放射免疫测定、流式细胞仪细胞周期分析、原位杂交等方法检测人IL 4基因修饰后细胞形态、甲胎蛋白合成以及原癌基因c fos、c jun、c myc表达的变化。流式细胞仪AnnexinⅤ /PI双染色法及间接免疫荧光染色法检测凋亡细胞及凋亡调控基因p5 3、bcl 2的蛋白表达。结果　 (1)人IL 4基因修饰较空载体修饰及野生型HepG2细胞的细胞周期发生G0 /G1期阻滞 ,甲胎蛋白分泌量及原癌基因c fos、c jun、c myc表达降低 (P <0 .0 0 1)。细胞在形态及功能上趋向正常肝细胞转化 ;(2 )较空载体修饰及野生型HepG2细胞 ,IL 4基因修饰后部分细胞形态上出现核固缩等典型凋亡细胞的特征 ,流式细胞仪亦检测到 18.5 %± 4.7%的凋亡细胞 ;(3)人IL 4基因修饰增加p5 3而抑制bcl 2表达 (P <0 .0 5 )。结论　人IL 4基因修饰可诱导肝母细胞的凋亡及分化 ,诱导凋亡细胞可能与上调p5 3蛋白及抑制bcl 2蛋白表达有关。     

Mutations of the E1beta subunit gene (PDHB) in four families with pyruvate dehydrogenase deficiency

Pyruvate dehydrogenase complex (PDC) deficiencies are a major cause of primary lactic acidosis. Most cases result from mutations of the gene for the pyruvate dehydrogenase E1α subunit (PDHA1), with fewer cases resulting from mutations in genes for E3, E3-binding protein, E2, and the E1β subunit (PDHB). We have found four cases of PDHB mutations among 83 analyzed cases of PDC deficiency. In this series, PDHB mutations were found to be about 10% as frequent as PDHA1 mutations. All cases were diagnosed by low PDC activity, with normal E2 and E3 activities. These included a 6.5-year-old male (consanguineous, homozygous R36C); a neonatal female who died soon after birth, (compound heterozygous C306R/D319V), a 26-year-old female (heterozygous I142M/W165S), and a 13 month old female (consanguineous, homozygous Y132C) who is a sibling of a previously published case. Their ethnic background is diverse (Caucasian, Arab, and African American descent). All cases had lactic acidosis and developmental delay. Three cases had agenesis of the corpus callosum, seizures, and hypotonia; one died within the first year of life. These clinical findings are similar to those of PDHA1 deficiency, except that ataxia was more frequent in PDHA1 cases and consanguinity was found only in PDHB families. PDC activity in lymphocytes from six parents is normal, who all are heterozygous carriers for the respective mutations. Immunoreactivity of E1β was markedly reduced in one case and showed a slightly larger form of E1β in one case. Computer analysis predicts that: R36C affects the interaction of several amino acids resulting in conformational change, C306R affects interaction of the two β subunits, D319 is in the interface of E1 and E2, I142M affects conformation around a K ion affecting stability of the β subunit, W165S affects hydrophobic interaction between the β subunits, and Y132C affects interaction between the β subunits. All of these residues are conserved in E1β across species, and Y132 is also conserved in other TPP-requiring enzymes. These observations support the conclusion that these are pathogenic mutations.     

Sulindac对人肝癌细胞HepG2增殖及β-catenin表达的影响

目的　观察Sulindac对人肝癌细胞HepG2增殖、凋亡及β-catenin蛋白表达的影响,探讨Sulindac抗肝癌的可能机制。 方法　不同浓度的Sulindac作用HepG2细胞后,采用MTT实验检测细胞增殖抑制作用;采用Hoechst33258染色法检测Sulindac对HepG2细胞凋亡的影响;利用RT-PCR及Western blotting检测HepG2细胞在Sulindac作用后Wint通路中β-catenin的表达变化。 结果　Sulindac对人肝癌细胞HepG2有增殖抑制作用,且呈剂量时间依赖关系;Hoechst33258结果显示,Sulindac作用24 h后HepG2细胞凋亡数目明显增多;随着Sulindac浓度的增加,β-catenin mRNA及蛋白表达量逐渐下降。 结论　Sulindac能够抑制人肝癌细胞HepG2增殖,通过阻断Wnt信号传导通路,降低β-catenin表达,诱导人肝癌细胞HepG2的凋亡。     

Nodosin通过Apaf-1和caspase-3诱导HepG2细胞凋亡

目的:研究传统中药提取物nodosin对人肝细胞癌Hep G2细胞凋亡的影响,并探讨其作用机制。方法:将nodosin设置为1. 25μmol/L、2. 5μmol/L、5μmol/L、10μmol/L和20μmol/L不同浓度组,作用于Hep G2细胞24 h后,用Hoechst 33258染色和电镜观察不同浓度的药物对细胞形态学的影响,用流式细胞术检测细胞凋亡率,用RT-qPCR检测凋亡蛋白酶激活因子1 (Apaf-1) mRNA的表达,用Western blot检测caspase-3及其前体和活化体的蛋白水平。结果:形态学结果显示,随着用药剂量的增加,细胞皱缩和细胞核偏移越明显,凋亡小体在5μmol/L、10μmol/L和20μmol/L剂量组明显增多。Apaf-1 mRNA的表达增加,caspase-3及其前体的表达和cleaved caspase-3的蛋白水平随着用药剂量的增加逐渐增加(P 0. 01)。结论:Nodosin能够诱导Hep G2细胞凋亡。该作用可能是通过增加Apaf-1 mRNA的表达继之激活caspase-3实现的。     

Arginine 302 mutations in the pyruvate dehydrogenase E1α subunit gene: Identification of further patients and in vitro demonstration of pathogenicity

Three further patients with mutations in the codon for arginine 302 of the E1α subunit of the pyruvate dehydrogenase complex have been identified. Mutations in this codon have now been found in nine patients with pyruvate dehydrogenase deficiency in seven unrelated families, in sharp contrast to the great majority of other PDH E1α mutations which have been described in single individuals only. Because of the relatively high frequency of this mutation and because very few PDH E1α mutations have been demonstrated to be causative, we have established a system for analysing the consequences of defined mutations using transfection of normal and mutant PDH E1α cDNA into transformed human fibroblasts which have no endogenous E1α mRNA or protein. Using this test system, we have demonstrated that the R302C mutation results in the production of PDH E1α protein which is devoid of enzymic activity. Hum Mutat 12:114–121, 1998. © 1998 Wiley-Liss, Inc.     

miRNA-7介导Bax和Bcl-2表达对人鼻咽癌CNE-1细胞凋亡的影响

 目的:研究过表达微小RNA-7(microRNA-7,miRNA-7)诱导人鼻咽癌(nasopharyngeal carcinoma,NPC)CNE-1细胞凋亡及其与Bax和Bcl-2表达之间的关联情况。方法:体外利用脂质体Lipofectamine 2000将miRNA-7模拟物转染到人鼻咽癌CNE-1细胞中;采用real-time PCR法检测转染后各实验组细胞中miRNA-7的相对表达情况;CCK-8法检测各组细胞活力的改变;在荧光显微镜下利用Hoechst 33258荧光染色法观察转染后细胞的凋亡;real-time PCR法检测Bax和Bcl-2的mRNA表达水平;Western blot法检测Bax和Bcl-2蛋白表达水平。结果:Real-time PCR结果表明,转染miRNA-7模拟物的CNE-1细胞中其miRNA-7的相对表达水平明显高于无关序列组和空白对照组(P<0.01);转染miRNA-7模拟物后,CNE-1细胞的活力明显下降(P<0.01);Hoechst 33258染色检测可发现典型的凋亡细胞核形态学变化;real-time PCR及Western blot结果显示,转染miRNA-7模拟物的CNE-1细胞中Bax的mRNA及蛋白显著上调(P<0.01),而Bcl-2的mRNA及蛋白则显著下调(P<0.01)。结论:过表达miRNA-7可以通过调节Bax/Bcl-2之间的比例关系来抑制鼻咽癌CNE-1细胞的恶性生长,并促进细胞凋亡。     

Liposome-mediated gene transfer of K1-5 suppresses tumor development and improves the prognosis of hepatocellular carcinoma in mice

It has been reported that kringle 1-5 (K1-5) has a potent and specific antiangiogenic activity. In the present study, we investigated the antitumor effect of gene transfer of K1-5 for hepatocellular carcinoma in mice. Inhibitory effect by the media of Cos-1 cells containing K1-5 on bovine capillary endothelial (BCE) cell proliferation was evaluated by a tetrazolium-based assay. For tumor growth, intrahepatic metastasis, and survival studies, intravenous injection of liposome–K1-5 cDNA complexes was performed to nude mice implanted with three hepatoma cell lines into the liver. Production of K1-5 was investigated by immunohistochemistry and Western blotting. The number of vessels in the tumor was counted in 0.125 mm² fields. Expression of vascular endothelial growth factor (VEGF) and angiopoietin (Ang)-1 and -2 in tumors was investigated by Western blotting. Serum ALT levels and body weight of the mice were measured. Proliferation of BCE cells was inhibited by 44% in the media containing K1-5. Gene transfer of K1-5 suppressed tumor growth of the three hepatoma cell lines, respectively. In the K1-5-treated group, survival period was prolonged and the number of intrahepatic metastases was reduced. Expression of K1-5 protein was detected on hepatoma cells and hepatocytes. The number of vessels in tumor tissues was decreased by K1-5 transfection. Expression of angiopoietin-2 in tumor tissues was suppressed by K1-5 transfection. Serum ALT levels and body weight of mice were not influenced by K1-5 transfection. These findings suggest that antiangiogenic gene therapy with K1-5 cDNA will be a safe and effective strategy to suppress the growth of hepatocellular carcinoma.     

黄连素抑制人卵巢癌SKOV3细胞增殖并诱导凋亡

黄连素(berberine)对多种肿瘤有抑制增殖和诱导凋亡的作用[1-2],但在卵巢癌中的作用尚未见报道.本研究以人卵巢癌SKOV3细胞为研究对象,观察黄连素对SKOV3细胞增殖抑制作用及凋亡诱导效应.     

沉默JAG1基因对人乳腺癌MDA-MB-231细胞增殖和凋亡的影响

 目的:探究沉默Jagged 1 (JAG1)基因对人乳腺癌MDA-MB-231细胞增殖和凋亡的影响及其分子生物学机制。方法:
用已构建的pRS-JAG1重组质粒转染人乳腺癌MDA-MB-231细胞, 采用Western blotting方法检测重组质粒对JAG1蛋白表达的影响;MTT比色法测定沉默JAG1对细胞生长的抑制情况;流式细胞术检测细胞周期和细胞凋亡;蛋白印记分析细胞周期蛋白1(cyclin D1)、p21CIP1/WAF1、p27KIP1、p-Rb、Bcl-2、Bax、Bcl-xL和cleaved caspase-3蛋白水平的变化。结果:Western blotting结果证实重组质粒可在72h内有效抑制JAG1蛋白表达;人乳腺癌MDA-MB-231细胞JAG1被沉默后,细胞的生长速度明显减慢,细胞明显阻滞于G 0/G 1期,细胞凋亡率显著升高(P<0.05),cyclin D1、p-Rb、Bcl-2和Bcl-xL蛋白水平被下调(P<0.05),而p21CIP1/WAF1、p27KIP1、Bax和cleaved caspase-3的蛋白水平显著升高(P<0.05)。结论:沉默JAG1可有效抑制人乳腺癌MDA-MB-231细胞增殖,并诱导其凋亡。本研究为以JAG1为分子靶点的三阴乳腺癌治疗提供实验依据。     

白藜芦醇对Hela细胞凋亡及Bcl-2和Fax基因表达的影响

目的观察白藜芦醇对人宫颈癌Hela细胞凋亡及Bcl-2、Fax基因表达的影响。方法实验设白藜芦醇用药组和空白对照组,应用流式细胞术检测药物作用24h后细胞凋亡和细胞周期进程情况;应用免疫组化法检测Heal细胞Bcl-2、Fax基因的表达情况。结果经不同浓度的白藜芦醇处理Heal细胞后,镜下可见到凋亡细胞,各组的凋亡率明显高于对照组(P0.01)。PCM分析发现各实验组S期细胞比例增高,G2/M期细胞比例减少,并呈剂量依赖性(P0.01);各实验组Heal细胞Bcl-2的表达均低于对照组。而Fax的表达均高于对照组(P0.01)。结论白藜芦醇对人宫颈癌Hela细胞有明显的抑制生长和促凋亡作用,凋亡途径可能与Fas表达上调、Bel-2表达下调有关。     

CD3-mediated apoptosis of human medullary thymocytes and activated peripheral T cells: Respective roles of interleukin-1, interleukin-2, interferon-γ and accessory cells

Clonal deletion represents an important mechanism for the establishment of tolerance, by the elimination of autoreactive T cells. Deletion is accomplished by programmed cell death, termed apoptosis, induced by mobilization of the T cell receptor (TCR) on both thymocytes and mature T cells. The mechanism which drives T cells towards cell death or cell proliferation after TCR mobilization remains unclear. We show here that the mobilization of the CD3/TCR complex of both CD4⁺ and CD8⁺ single-positive medullary human thymocytes and human mature activated T cells, in the absence of accessory cells, leads to an activation-induced cell death process by apoptosis. In both cases, apoptosis was associated with interferon (IFN)-γ gene expression and secretion in the absence of interleukin (IL)-2 gene expression; and the addition of anti-IFN-γ antibody prevented cell death. Apoptosis could also be prevented by cyclosporin A (CsA) treatment and could be re-induced by the addition of IFN-γ to CsA-treated cells. Addition of IL-2 had two different effects, it prevented apoptosis and also allowed proliferation in response to CD3 monoclonal antibody. Addition of IL-1, which induces IL-2 gene expression and secretion or addition of accessory cells, had the same preventive effect. These results suggest that the uncoupling of IFN-γ and IL-2 gene expression following CD3/TCR mobilization initiates apoptosis of human T cells at several different stages during development and activation. We propose that co-signals provided by accessory cells allow a coupling of IL-2 gene and IFN-γ gene expression, and that an essential role for IL-2 secretion in T cell activation involves the inhibition of a death program induced by IFN-γ secretion.     

碱性成纤维细胞生长因子对人卵巢癌CAOV3细胞凋亡及葡萄糖调节蛋白78表达的影响

目的： 研究碱性成纤维细胞生长因子（bFGF）与人卵巢癌CAOV3细胞凋亡的关系及葡萄糖调节蛋白78（GRP78）表达的变化,探讨bFGF促进人卵巢癌CAOV3细胞增殖,抑制凋亡的信号机制。方法：利用无血清饥饿诱导卵巢癌CAOV3细胞凋亡。分为对照组、bFGF组、PKB抑制剂组。应用流式细胞术、Annexin V/PI双荧光染色法观察bFGF对CAOV3细胞增殖及凋亡的影响。利用Western blotting、RT-PCR检测bFGF对PKB、GRP78表达的影响。结果：bFGF呈剂量依赖性激活PKB信号通路,呈时间依赖性促进GRP78 mRNA及蛋白表达（P＜0.01）。与对照组相比,bFGF可加速CAOV3细胞的细胞周期进程,促进细胞增殖,抑制无血清培养诱导的细胞凋亡。PKB特异性抑制剂wortmannin可阻断bFGF的上述作用。结论：bFGF可能通过PKB信号通路上调GRP78的表达,促进细胞增殖,抑制饥饿诱导的卵巢癌CAOV3细胞凋亡。     

Stat5b/Survivin信号转导通路调控结肠癌细胞凋亡的机制

目的: 探讨Stat5b/Survivin信号转导通路调控结肠癌细胞凋亡的作用机制。方法: 用阳离子脂质体介导Stat5反义寡核苷酸转染人结肠癌HT29细胞，MTT法检测细胞增殖状态；流式细胞术检测细胞周期与凋亡；EMSA检测Stat5活性；Western blotting检测Stat5、p-Stat5、cyclin D1、Survivin与Bcl-2凋亡家族成员Bcl-2和Bcl-x_L的表达。结果: 转染Stat5反义寡核苷酸后HT29细胞增殖受抑制，凋亡细胞增多，Stat5、p-Stat5与Survivin表达下降，Bcl-2与Bcl-x_L变化不明显。结论: 阻断Stat5通路可以抑制靶基因Survivin表达并诱导结肠癌细胞凋亡。     

Overexpression of the death-promoting gene bax-α sensitizes human BL-41 Burkitt lymphoma cells for surface IgM-mediated apoptosis

Major regulators of programmed cell death, or apoptosis, are the members of the bcl-2 gene family. Recently, we reported that surface(s) IgM triggering of the human B lymphoma cell line BL-41 led to strong induction of bax-α, a death-promoting member of the bcl-2 family, and subsequently to induction of apoptosis, suggesting a potential regulatory role of bax-α in sIgM-mediated cell death. In contrast, apoptosis-resistant subclones of this cell line showed only weak bax-α expression, which was not inducible by sIgM cross-linking. In this study, we were able to demonstrate the functional significance of this observation. We stably transfected bax-α into a BL-41 subline resistant against sIgM-mediated apoptosis. Several bax-α overexpressing clones could be selected, which all showed enhanced sensitivity for sIgM-mediated apoptosis. In contrast, no sensitive clone could be identified in a large number of mock controls. This clearly indicates that induction of bax-α is a critical regulatory step, which sensitizes B cells for sIgM-mediated apoptosis.     

人肿瘤转移抑制基因1转染对人乳腺癌细胞MDA-MB-231体外生物学行为的影响

目的研究人肿瘤转移抑制基因1（TMSG-1）转染引起人乳腺癌细胞MDA-MB-231体外生物学行为的改变及对肿瘤转移表型的影响。方法构建TMSG-1全长编码序列真核表达载体,稳定转染人乳腺癌MDA-MB-231细胞系,G418筛选挑取TMSG-1过表达阳性克隆。通过MTT比色实验、软琼脂集落形成实验检测体外细胞生长能力;Matrige1穿膜实验检测肿瘤细胞体外侵袭能力。TMSG-1瞬时转染24、48h,分别用Annexin-V碘化丙啶（PI）双标流式细胞术检测肿瘤细胞凋亡情况。结果从稳定转染TMSG-1的MDA-MB-231细胞中挑取3个TMSG-1-FLAG融合蛋白表达量较高的阳性克隆株用于下游生物学行为实验。M1Tr比色实验及软琼脂集落形成实验结果显示,TMSG-1正义转染各组（S1、S2、S3）细胞增殖速度及克隆形成数与未转染组及转染空载体组相比均明显减低（P〈0．05）;Matrigel穿膜实验显示,正义转染各组的穿膜细胞数[（72．3±8．1）个、（85．0±4．2）个、（73．5±7．8）个]与未转染组[（187．5±2．1）个]和转染空载体组[（162。3±6．8）个]相比均明显减少（P〈0．01）。TMSG．1瞬时转染MDA．MB-231细胞,转染24和48h均可引起细胞凋亡率的增加（P〈0．05）。结论TMSG．1表达上调可使人乳腺癌细胞MDA-MB-231体外生长速度、锚着不依赖性生长能力及侵袭能力明显降低,细胞凋亡增加。该实验为TMSG-1是一个新发现的肿瘤转移抑制基因提供了证据。     

RNAi-mediated silencing of the Skp-2 gene causes inhibition of growth and induction of apoptosis in human renal carcinoma cells

Renal cancer ranks one of the most frequent causes of cancer death in the world. S-phase kinase-associated protein 2 (SKP 2) is overexpressed in human tumors and has prognostic value in many cancers including renal cancer, indicating its potential as a therapeutic target. In this study, we investigated the therapeutic potential of Skp-2 in renal cancer using the technique of RNA silencing via short hairpin RNA (shRNA). Synthetic shRNA duplexes against Skp-2 were introduced to down-regulate the expression of Skp-2 in a highly malignant renal carcinoma cell line, ACHN. The results indicated that siRNA targeting of Skp-2 could lead to an efficient and specific inhibition of endogenous Skp-2 activity. Furthermore, we found that depletion of Skp-2 caused a dramatic cell cycle arrest, followed by massive apoptotic cell death, and eventually resulted in a significant decrease in growth, viability and tumor formation in renal cancer cell lines studied.     

TPX2对人肺癌细胞增殖、凋亡及cleavedcaspase-3表达的影响

目的 探讨Xklp2靶蛋白(TPX2)对人肺癌细胞增殖、凋亡及活化的半胱氨酸天冬氨酸蛋白酶3(cleaved caspase-3)表达影响。方法 培养人肺癌细胞A549,分为Control组(不进行细胞转染)、siRNA-NC组(细胞转染TPX2 siRNA control)、TPX2 siRNA组(细胞转染TPX2 siRNA),采用实时荧光定量PCR (qPCR)和Western blot检测TPX2 siRNA的转染效果。取转染后各组细胞,采用噻唑蓝检测细胞增殖情况,流式细胞术检测细胞凋亡情况,Western blot检测cleaved caspase-3蛋白表达情况。结果 TPX2 siRNA组中,TPX2 mRNA、蛋白水平和细胞光密度(OD)值均明显低于Control组和siRNA-NC组,细胞凋亡率、细胞中cleaved caspase-3蛋白表达水平均明显高于Control组和siRNA-NC组,差异均有统计学意义(P值均<0.05);而siRNA-NC组中,TPX2 mRNA、蛋白水平及细胞OD值、细胞凋亡率、细胞中cleaved caspase-3与Control组比较,差异均无统计学意义(P值均＞0.05)。结论TPX2 siRNA能够干扰人肺癌细胞A549中TPX2的表达。下调TPX2的表达能够抑制人肺癌细胞A549增殖,促进caspase-3活化,促进人肺癌细胞A549的凋亡。