人白细胞介素18在毕氏酵母细胞中的分泌表达

目的 在酵母细胞中表达IL-18。方法 用Sac I 将pPIC9K-IL18线性化后,电转化毕氏酵母GS115,筛选后得到His Mut 转化子,在BMGY和BMMY培养基中进行诱导表达,表达产物进行SDS-PAGE和Western blot 分析。结果 SDS-PAGE和Western blot印迹杂交结果证实表达蛋白的相对分子量为21 000,与预期的分子量一致。结论 在毕氏酵母中成功的表达了IL-18。     

人重组白细胞介素-13在毕氏酵母中的表达及其体外诱导DC分化作用的研究

目的：在毕氏酵母中表达重组人IL-13并探讨其对DC的诱导作用。方法：用基因工程的方法人工合成IL-13的全长片段，并转化至毕氏酵母菌株GS115中，筛选后获得表达量相对较高且分泌稳定的rhIL-l3基因工程菌株，用rhIL-l3来替代IL-4体外诱导DC。结果：得到表达量达25mg/L且分泌稳定的rhIL-l3基因工程菌株；rhIL-l3具有rhIL-4同样的体外诱导外周血单核细胞向比增殖分化的作用,MHCII、CDlα、CD80、CD80、CD86等DC表型分析和混合淋巴细胞反应刺激T细胞增殖的作用与IL-4诱导得到的成熟DC并无显著差别，其所诱导的末成熟DC具有很强的摄取抗原能力。结论：获得表达量相对较高且分泌稳定的rhIL-l3基因工程菌株，rhIL-l3在体外可有效地诱导外周血单核细胞向DC分化。     

可溶性CD14在酵母细胞中的分泌表达与LPS结合活性分析

目的在酵母系统中实现可溶性CD14基因的分泌表达,并进行LPS结合活性分析。方法将可溶性CD14基因克隆入表达载体pPIC9K,用SacI将重组质粒线形化,电转化PichiapastorisGS115细胞,筛选阳性整合子并进行甲醇诱导表达。结果经过诱导表达条件的优化,sCD14在pH6.5培养基BMMY中实现了分泌表达。免疫印迹和酶联免疫检测结果显示,重组产物可以结合其特异抗体。经流式细胞仪检测,重组产物具有结合细菌内毒素(LPS)的生物学活性。结论具有良好LPS结合活性的重组可溶性CD14分子可以用于进一步的结构与功能研究。     

食管癌相关基因1在甲醇酵母中的表达与纯化

目的为获得食管癌相关基因1(ECRG1)编码的活性蛋白,利用甲醇酵母系统表达ECRG1。方法将本研究室构建的PCDNA6-HA-ECRG1重组到分泌表达载体pPIC9k中,然后转入酵母GS115,通过G418筛选,在甲醇的诱导下,获得表达的蛋白。结果成功构建了分泌表达重组体pPIC9k-ECRG1,并转入了GS115,筛到抗2.5mg/ml G418的重组菌株,在甲醇的诱导下,ECRG1蛋白得到了分泌表达,发酵培养获得的融合蛋白经镍离子亲和层析,得到纯度80%左右的蛋白。结论用酵母表达系统得到了活性蛋白,可用于进一步的生物功能及作用机理的研究,也为今后研究基因-蛋白的功能与结构,提供了分离和纯化蛋白的重要方法。     

人可溶性TRAIL基因的克隆及表达

为了利用大肠杆菌表达人可溶性肿瘤坏死因子相关性凋亡诱导配体 (TRAIL )蛋白 ,应用RT PCR技术从激活的人外周血淋巴细胞总RNA中扩增人可溶性TRAIL蛋白cDNA ,克隆入PCR2 1 载体 ,测序验证后用基因重组法分别构建了人可溶性TRAIL蛋白的真核与原核表达质粒载体。将重组质粒分别转入COS 7和大肠杆菌M1 5中表达。用流式细胞仪检测人可溶性TRAIL蛋白在COS 7细胞中的瞬时表达 ,用SDS PAGE电泳和Westernblot鉴定大肠杆菌中的表达产物。所表达融合蛋白为人可溶性TRAIL蛋白分子 ,相对分子质量为 2 1 0 0 0 ,表达量约为 2mg/ml。所表达的人可溶性TRAIL蛋白具有诱导HL 60细胞凋亡的作用。上述结果提示大肠杆菌可良好表达具有生物活性的人可溶性TRAIL蛋白 ,为深入研究TRAIL分子在肿瘤与自身免疫性疾病中的可能应用提供了材料。     

嗜甲醇酵母表达系统研究进展

以毕赤酵母 (P.pastoris)为代表的嗜甲醇酵母 ,作为一种新的外源蛋白表达系统 ,正在基因工程领域中得到日益广泛的应用。该系统具有操作技术简单、可进行高水平的分泌型表达、可对表达产物进行类似真核细胞的翻译后修饰与加工等显著优点。本文从表达载体 (包括新的启动子 ,选择标志 )、宿主菌株、发酵培养、表达产物的翻译后修饰等方面介绍了嗜甲醇酵母表达系统的最新进展     

人源TRAIL胞外段基因的克隆、表达与功能的初步检测

目的 获得人源TRAIL胞外段结构域在大肠杆菌中可溶性表达，并初步鉴定其功能。方法 RT-PCR法从人外周血单个核细胞中扩增TRAIL胞外段基因，克隆入pGEM-T-Easy载体，DNA序列测定鉴定正确性。为了便于纯化目的蛋白，将其克隆入原核表达载体pET-30a，并在其氨基端加上组氨酸标签。采用E．coliBL21（DE3）表达，Ni亲和柱分离纯化目的蛋白。SDS-PAGE和Westernblot鉴定原核表达产物。MTT法、PI染色法及瑞氏．姬姆萨染色法观察TRAILHis蛋白的生物学活性。结果 所表达目的蛋白相对分子质量（Mr）与预期蛋白Mc相一致，该蛋白分别可以与抗TRAIL多克隆抗体及抗组氨酸标签抗体反应，并可抑制人淋巴瘤细胞系Jurkat细胞的增殖和诱导Jurkat细胞凋亡。结论 获得了具有生物学活性的TRAIL蛋白，为对其生物学功能及肿瘤治疗的进一步研究奠定了基础。     

TRAIL受体在肿瘤细胞系上的表达及意义

目的 检测TNF相关凋亡诱导配体（TRAIL）的受体，在来源于血液系统、肝脏、肺脏和大肠的8个肿瘤细胞系中的表达，并探讨其意义。方法 采用半定量RT－PCR，对TRAIL受体的表达进行半定量检测。结果 TRAIL凋亡通路中，能够诱导凋亡反应的死亡受体DR4和DR5，在所检测的肿瘤细胞系中都有表达，其中DR5在所有肿瘤细胞系中的表达水平均显著高于DR4（P＜0．05）。而能够竞争性与TRAIL诱导的凋亡反应的诱骗受体DcR1和DcR2，在所有的肿瘤细胞中都呈低水平表达或不表达。结论 DR5可能在TRAIL诱导凋亡的通路中发挥最重要的作用。TRAIL死亡受体和诱骗受体在肿瘤细胞系中的表达具有差异性，这种差异性可在一定程度上解释不同细胞对TRAIL诱导凋亡的敏感度。     

重组人白介素18在毕赤酵母中的高效分泌表达

目的:构建人白介素18(hIL-18)真核表达载体, 在毕赤酵母中高效分泌表达hIL-18.方法:通过PCR法扩增得到hIL-18基因, 构建其真核表达载体pPICZaC/hIL-18, 电转化毕氏酵母X-33, PCR、 SDS-PAGE、 Western blot等方法筛选获得高效表达rhIL-18的工程菌株, 疏水层析和阴离子交换层析纯化表达产物, 并初步测定其生物学活性.结果:rhIL-18经甲醇诱导后其表达产量约为202 mg/L.Western blot检测了rhIL-18的特异性结合活性; rhIl-18纯化后纯度达95%左右, 并证明rhIL-18能够协同IL-2诱导PBMC分泌IFN-γ.结论:构建了重组hIL-18的基因工程菌, 并在毕赤酵母中实现了高效分泌表达, 为进一步研究其活性和功能奠定了基础.     

EGF在毕赤酵母中的表达及活性测定

目的高效表达和纯化有活性的EGF蛋白。方法将含有表皮生长因子(EGF)基因的质粒pAO815通过LiAc法转入毕赤酵母细胞中,筛选在MM平板上生长缓慢的Muts型酵母工程菌,甲醇诱导基因表达产生EGF,柱纯化后利用SDS-PAGE检测到EGF的生成,MTT法及新生小鼠皮下法分别检测活性。结果 SDS-PAGE电泳检测EGF成功表达和纯化,MTT法测定EGF生物活性约为2.8×106IU/mL。结论本研究构建的工程菌株能高效表达EGF,且纯化的EGF具有与天然EGF同样的体外和体内活性。     

膜结合配体依赖的TRAIL抗肿瘤细胞旁观者效应

目的：研究TRAIL基因抗肿瘤作用旁观者效应的发生机制。方法：腺病毒Ad/Lac-Z转染肿瘤细胞后作为标记的旁观者细胞，腺病毒Ad/g-TRAIL 转染肿瘤细胞作为效应细胞，在6孔Transwell培养板上同一孔内应用隔离或混合培养旁观者细胞和效应细胞的方法，通过检测旁观者细胞Lac-Z酶的活性，以明确TRAIL基因旁观者效应的发生机制。结果：检测了不同来源的肿瘤细胞株，包括大肠癌细胞株DLD1和Lovo、肺癌细胞株A549、肝癌细胞株HepG2、乳腺癌细胞株MDA-MB231、卵巢癌细胞株DOV13。各株肿瘤细胞转染Ad/g-TRAIL后ELISA方法均未检测出培养液中出现可溶性TRAIL（s-TRAIL）；隔离培养效应细胞与旁观者细胞，旁观者细胞的Lac-Z活性与PBS及腺病毒Ad/CMV-GFP对照组无明显差异，而混合培养组其活性明显低于对照组（P<0.05）；混合培养效应细胞与旁观者细胞（1∶1），发现高密度细胞生长组其旁观者效应明显大于低密度生长组（P<0.05 ）；FACS检测Sub G0/G1 发现DOV13细胞在高密度生长组显著高于低密度生长组（P<0.05）；荧光及相差显微镜下观察发现TRAIL转染细胞可诱导周围旁观者细胞发生凋亡而自己并不首先发生凋亡。结论：腺病毒介导的TRAIL基因的旁观者效应是通过TRIAL蛋白表达并定位于细胞膜上，通过细胞接触结合于邻近肿瘤细胞膜上的TRAIL受体而诱导旁观者肿瘤细胞的凋亡，而不是通过水解膜配体形成s-TRAIL而发生旁观者效应，这种作用是细胞接触依赖的。     

Expression of TRAIL (TNF-related apoptosis-inducing ligand) and its receptors in normal colonic mucosa,adenomas, and carcinomas

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in tumour cell lines. Four membrane-bound receptors for TRAIL have been identified, two apoptosis-mediating receptors, DR4 and DR5, and two apoptosis-inhibiting receptors, DcR1 and DcR2. The aim of this study was to examine the role of TRAIL and its receptors in colorectal cancer development. The immunohistochemical expression and localization of TRAIL and its receptors were investigated in normal mucosa (n=10), adenomas (n=19), and carcinomas (n=21). Correlations between the expression of TRAIL and its receptors and the degree of apoptosis (assessed by M30 expression) and histopathological characteristics were explored. TRAIL and its receptors were expressed in normal mucosal epithelium. Expression of the receptors was seen in adenomas and carcinomas. TRAIL expression was lost in a subset of colorectal tumours, more frequently in carcinomas than in adenomas (p<0.05). DR4 and DR5 staining was stronger in neoplastic cells than in normal cells and was accompanied by a higher degree of apoptosis. No differences were found between tumour and normal cells regarding DcR1 and DcR2 expression. No correlations were found between TRAIL or TRAIL receptor expression and histopathological characteristics. In conclusion, marked changes were seen in the course of the adenoma-carcinoma sequence with respect to the expression of TRAIL and TRAIL receptors DR4 and DR5. The stronger expression of DR4 and DR5 in neoplastic cells than in normal cells, together with a higher degree of apoptosis, suggests a possible functional role for these receptors in apoptosis induction in neoplastic colorectal cells.     

Doxorubicin-loaded human serum albumin nanoparticles surface-modified with TNF-related apoptosis-inducing ligand and transferrin for targeting multiple tumor types

Human serum albumin (HSA) nanoparticles (NPs) surface modified with tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and transferrin, and containing doxorubicin were designed and prepared. Surface amines of HSA were reversibly protected with dimethylmaleic anhydride (DMMA), and HSA-NPs were prepared using a desolvation technique. Furthermore, the surfaces of HSA-NPs were modified with thiolated TRAIL or transferrin using sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC). The prepared TRAIL/transferrin plus doxorubicin HSA-NPs were characterized by TEM, FE-SEM, and particle size analysis, and their cytotoxic and apoptotic activities were evaluated in several cancer cell lines, namely, HCT 116, doxorubicin-resistant MCF-7, and CAPAN-1. In addition, the tumor-targeting abilities of NPs were assessed using an infrared imaging system in HCT 116-xenografted nu/nu mice. Results showed that the TRAIL/transferrin/doxorubicin HSA-NPs had remarkable cytotoxic and apoptotic activities in all cancer cells examined with a general or a drug-resistant character, and that these NPs had obvious synergistic cytotoxic effects particularly on CAPAN-1 cells. Moreover, these HSA-NPs were effectively localized to tumors in a HCT 116-xenografted nu/nu mouse over 32 h. The findings of this study suggest that the described TRAIL/transferrin/doxorubicin HSA-NPs are a useful targeting agent capable of killing different types of tumor cells in various tissue organs.     

TNF相关的凋亡诱导配体与肿瘤

TNF相关的凋亡诱导配体（TNF-related apoptosis-inducing ligand, TRAIL），属于TNF 超家族成员，又称为Apo-2L，TRAIL能诱导多种肿瘤细胞的凋亡，而正常的细胞却对其不敏感，TRAIL主要通过与其受体结合激活caspase-8，启动非线粒体和线粒体依赖途径导致细胞凋亡。部分肿瘤细胞对TRAIL的敏感性较差，其原因与TRAIL的受体、信号转导途径激酶以及相关蛋白存在密切联系。     

Hydrogen peroxide upregulates TNF-related apoptosis-inducing ligand (TRAIL) expression in human astroglial cells, and augments apoptosis of T cells

The brain is particularly vulnerable to oxygen free radicals, and these radicals have been implicated in the pathology of several neurological disorders. In this study, the modulation of TNF-related apoptosis-inducing ligand (TRAIL) expression by oxidative stress was shown in LN215 cells, an astroglioma cell line. Hydrogen peroxide (H2O2) treatment increased TRAIL expression in LN215 cells and H2O2-induced TRAIL augmented apoptosis in Peer cells, a cell line sensitive to TRAIL- mediated cell death. Our findings suggest that the upregulation of TRAIL in astroglial cells may abrogate immune cell effector functions.     

TNF-related apoptosis-inducing ligand cooperates with NSAIDs via activated Wnt signalling in (pre)malignant colon cells

Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a viral interleukin 6 (vIL-6) that mimics many activities of human IL-6 (hIL-6). Both vIL-6 and hIL-6 play important roles in stimulating the proliferation of tumours caused by KSHV. Here, we provide evidence that a miRNA pathway is involved in regulation of vIL-6 and hIL-6 expression through binding sites in their open reading frames (ORFs). We show a direct repression of vIL-6 by hsa-miR-1293 and hIL-6 by hsa-miR-608. The repression of vIL-6 by miR-1293 was reversed by disruption of the vIL-6 miR-1293 seed match through the introduction of point mutations. In addition, expression of vIL-6 or hIL-6 in KSHV-infected cells could be enhanced by transfection of the respective miRNA inhibitors. In situ hybridization of human lymph node sections revealed that miR-1293 is primarily expressed in the germinal centre but is deficient in the mantle zone of lymph nodes, where the expression of vIL-6 is often found in patients with KSHV-associated multicentric Castleman's disease, providing evidence of an anatomical correlation. Taking these factors together, our study indicates that IL-6 expression can be regulated by miRNA interactions in its ORF and provides evidence for the role of these interactions in the pathogenesis of KSHV-associated diseases.     

重组人可溶性TRAIL分子诱导白血病细胞株凋亡的研究

比较重组人可溶性TRAIL(rhsTRAIL)诱导Jurkat细胞株、K562细胞株以及HL-60细胞株凋亡之间的差异,探讨这些差异与细胞表面TRAIL受体(DR4、DR5、DcR1和DcR2)表达量的关系。不同浓度的rhsTRAIL分别处理Jurkat细胞、K562细胞和HL-60细胞12 h、24 h和48 h后,用流式细胞仪检测经碘化丙啶(PI)染色后的细胞凋亡情况;用RT-PCR方法检测细胞表面受体DR4、DR5、DcR1、DcR2的表达。培养12 h、24 h、48 h后,不同浓度rhsTRAIL诱导Jurkat细胞株的凋亡率均明显高于对照组,且具有剂量依赖性和时间依赖性;但K562细胞株和HL-60细胞株未见明显的凋亡发生。RT-PCR结果显示,培养12 h、24 h、48 h后,Jurkat细胞株表面DR4的表达随时间的延长和rhsTRAIL浓度的升高而升高,而DR5、DcR1和DcR2的表达未检出;K562和HL-60细胞株表面DR4的表达没有明显变化,而且DR5、DcR1和DcR2的表达也未检出。rhsTRAIL诱导Jurkat细胞株的凋亡具有剂量依赖性和时间依赖性,且与其细胞表面DR4的表达呈正相关;在一定的浓度条件下,rhsTRAIL未能诱导K 562和HL-60细胞株发生明显凋亡,且其细胞表面DR4的表达也未见明显变化。这些结果提示,应用TRAIL治疗不同种类白血病时,应注意它的使用剂量和适应范围。     

Involvement of tumor necrosis factor-related apoptosis-inducing ligand and tumor necrosis factor-related apoptosis-inducing ligand receptors in viral hepatic diseases

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in tumor cells, but not in most normal cells. The role of TRAIL in hepatic cell death and hepatic diseases is not well understood. The present study investigated the expression of TRAIL and TRAIL receptors (TRAIL-Rs) in patients with hepatitis C virus infection using immunohistochemistry and examined physiological roles under viral infection in the HepG2 cell line. Staining of TRAIL or TRAIL-Rs was prominent in the cytoplasm and membrane of hepatocytes in the periportal area. Some liver-infiltrating lymphocytes also displayed positive staining for TRAIL. Staining intensity was significantly increased with disease progression, particularly in the periportal area. AdCMVLacZ (Q-BIOgene, Carisbad, Calif) infection was also found to induce apoptosis in HepG2 cells and significantly augment TRAIL-induced apoptosis. Anti-TRAIL antibody significantly inhibited apoptosis induced by AdCMVLacZ infection. Flow cytometry analysis revealed that both TRAIL-R2 and TRAIL were up-regulated on the cell surface of HepG2 cells with AdCMVLacZ infection. Transforming growth factor-beta1 also enhanced TRAIL expression in HepG2 cells. These results indicate that TRAIL/TRAIL-R apoptotic pathways play important roles in the hepatic cell death during viral infection.     

Comprehensive expression analysis of TNF-related apoptosis-inducing ligand and its receptors in colorectal cancer: Correlation with MAPK alterations and clinicopathological associations

TNF-related, apoptosis-inducing ligand (TRAIL) apoptotic pathway constitutes a promising therapeutic target due to high selectivity and low toxicity of TRAIL targeting agents when administered in combination therapies. 106 colorectal cancers were examined for: relative mRNA expression of TRAIL pathway genes, decoy receptors TRAIL-R3 and TRAIL-R4 promoter methylation and the presence of KRAS, NRAS, BRAF mutations. Elevated mRNA levels were observed in 26%, 15%, 13%, 12% and 10% of the cases for TRAIL-R4, TRAIL-R3, TRAIL-R2, TRAIL-R1 and TRAIL genes respectively. Reduced mRNA levels were detected in 77%, 65%, 64%, 60% and 37% of the cases for TRAIL, TRAIL-R2, TRAIL-R3, TRAIL-R1 and TRAIL-R4 genes respectively. TRAIL-R3 and TRAIL-R4 promoter methylation was detected in 55% and 16% of the analysed samples respectively. TRAIL-R1, TRAIL-R2 elevated relative mRNA levels inversely correlated with tumor stage (p?=?.036, p?=?.048). Strong linear correlations of TRAIL receptors’ mRNA levels were found: TRAIL-R1/TRAIL-R2 (R?=?0.653, p?<?.001), TRAIL-R2/TRAIL-R3 (R?=?0.573, p?<?.001). Finally, relative expression of TRAIL was correlated with KRAS, BRAF and NRAS mutation status, defining an inverse correlation between increased TRAIL expression and the absence of mutations in Mitogen-activated protein kinase (MAPK) pathway.In conclusion, simultaneous analysis of TRAIL pathway membrane components, pointed towards a significant deregulation of mRNA expression in colorectal tumours. Death receptor overexpression was an indicator of a less aggressive phenotype. The multiple expression patterns of TRAIL pathway components in colorectal tumours underscore the importance of patient selection in order to achieve maximum efficiency with TRAIL targeted therapy.