力达霉素对人肝癌bel 7402细胞凋亡基因表达和细胞骨架的影响

背景与目的：力达霉素是我所分离的烯二块类抗肿瘤抗生素,因其独特的化学结构和对体内外肿瘤的强烈抑制作用,而倍受关注。除了断裂DNA外,力达霉素对细胞凋亡基因表达和细胞骨架的影响,可能与其高活性有关。本文通过观察力达霉素对人体肝癌bel-7402细胞多指标的影响,进一步阐明其分子机制。方法：用Northern blot印迹法和dot印迹法检测癌基因表达,间接免疫荧光法检测微丝和微管,线粒体特异染料Mitosensor^tm检测细胞凋亡。结果：低浓度的力达霉素（0.1nmol/L)处理人肝癌bel-7402细胞8h,明显促进c-myc、c-fos基因表达,而抑制N-ras表达。10nmol/L力达霉素处理细胞8h后,细胞伸展,微丝排列整齐,向非恶性细胞转变,但对微管没有影响。用线粒体特异凋亡染料Mitosensor^TM检测发现,力达霉素处理8h后的细胞未出现凋亡,说明力达霉素引起肿瘤凋亡首先需要诱导c-myc基因表达。结论：低浓度的力达霉素明显影响人肝癌bel-7402细胞的有关凋亡基因表达和细胞骨架的分布,这些结果有助于解释力达霉素高活性地作用肿瘤细胞的分子机制。     

Hsp90 Inhibitor Geldanamycin Enhances the Antitumor Efficacy of Enediyne Lidamycin in Association with Reduced DNA Damage Repair

Inhibition of heat shock protein 90 (Hsp90) leads to inappropriate processing of proteins involved in DNA damage repair pathways after DNA damage and may enhance tumor cell radio- and chemo-therapy sensitivity. To investigate the potentiation of antitumor efficacy of lidamycin (LDM), an enediyne agent by the Hsp90 inhibitorgeldanamycin (GDM), and possible mechanisms, we have determined effects on ovarian cancer SKOV-3, hepatoma Bel-7402 and HepG2 cells by MTT assay, apoptosis assay, and cell cycle analysis. DNA damagewas investigated with H2AX C-terminal phosphorylation (γH2AX) assays. We found that GDM synergistically sensitized SKOV-3 and Bel-7402 cells to the enediyne LDM, and this was accompanied by increased apoptosis. GDM pretreatment resulted in a greater LDM-induced DNA damage and reduced DNA repair as compared with LDM alone. However, in HepG2 cells GDM did not show significant sensitizing effects both in MTT assay and in DNA damage repair. Abrogation of LDM-induced G2/M arrest by GDM was found in SKOV-3 but not inHepG2 cells. Furthermore, the expression of ATM, related to DNA damage repair responses, was also decreased by GDM in SKOV-3 and Bel-7402 cells but not in HepG2 cells. These results demonstrate that Hsp90 inhibitors may potentiate the antitumor efficacy of LDM, possibly by reducing the repair of LDM-induced DNA damage.     

雷氏大疣蛛蛛毒对人肝癌BEL-7402 细胞增殖的抑制作用及其机制的研究

背景与目的蜘蛛毒素抗肿瘤的研究迄今还是未知领域。本研究探讨雷氏大疣蛛(Macrotheleraveni)蛛毒对BEL-7402细胞增殖的抑制作用,进一步探讨其作用机制。方法采用MTT法测定了雷氏大疣蛛蛛毒(10、20、40、80滋g/ml)对BEL-7402细胞增殖作用的影响;采用[3H]-TdR掺入法检测蛛毒加入前后BEL-7402细胞DNA的变化;利用流式细胞光度术(FCM)探讨雷氏大疣蛛蛛毒对BEL-7402细胞凋亡率和细胞周期的影响;利用Westernblot方法进一步检测雷氏大疣蛛蛛毒对细胞周期相关基因c-myc的变化。结果雷氏大疣蛛蛛毒对BEL-7402细胞增殖有较强的抑制作用(P<0.05),IC50为20滋g/ml,时效和量效关系良好。雷氏大疣蛛蛛毒可以抑制BEL-7402细胞DNA的合成。流式细胞仪检测发现经过雷氏大疣蛛蛛毒作用下的BEL-7402细胞凋亡率增加,细胞周期阻滞在G0/G1期。Westernblot方法进一步检测表明雷氏大疣蛛蛛毒作用于BEL-7402细胞72h后,c-myc基因表达减弱。结论雷氏大疣蛛蛛毒就可以抑制人肝癌BEL-7402细胞的增殖和DNA的合成。其药理作用机制可能是除了诱导凋亡外,主要是使细胞周期相关基因c-myc表达减弱,导致细胞周期的变化。     

Preliminary investigation of the inhibitory effects of the tyroservaltide (YSV) tripeptide on human hepatocarcinoma BEL-7402

This study aimed to investigate the inhibitory effect of tyroservaltide (YSV) on the human hepatocarcinoma BEL-7402 transplanted into nude mice and to explore its possible anti-tumor mechanism. Nude mice bearing xenografts of the human BEL-7402 hepatoma were given daily i.p. injections of YSV or saline (as a control) after the tumor were transplanted. Calculating tumor volume and measuring tumor weight determined the extent of inhibition of xenografts. The ultrastructure of tumor cells was observed by electron microscopy. Proliferating cell nuclear antigen (PCNA) expression in tissues of the YSV-treated group was observed by immunohistochemistry. Apoptosis of tumor tissue cells was assayed by the terminal transferase uridyl nick end labeling (TUNEL) method. At doses of 80 microg/kg/d and 160 microg/kg/d, YSV could significantly inhibit growth of tumors transplanted into nude mice, with inhibition rates of 60% and 64%, respectively, compared with that of the controls (P < 0.05). Moreover, YSV changed the ultrastructure of tumor cells, resulting in necrosis and apoptosis of the tumor cells. Compared with the saline group, the expression of PCNA in tumor tissue decreased and the count of apoptotic cell increased. Therefore, YSV can significantly inhibit the growth of human hepatocarcinoma BEL-7402 in nude mice, decrease the expression of PCNA in tumor tissue, and induce tumor cell apoptosis.     

Growth arrest and apoptosis of the human hepatocellular carcinoma cell line BEL-7402 induced by melittin

OBJECTIVE: The aim of this study was to investigate the cellular effects of melittin on the growth and apoptosis of human hepatocellular carcinoma (HCC) cells and to provide the molecular mechanism for potential application of a recombinant adenovirus carrying the melittin gene (Ad-rAFP-Mel) in the treatment of liver cancer. METHODS: Human HCC cells (BEL-7402) were infected with Ad-rAFPMel at different times. In vitro cell growth was determined by MTT assay. Cellular apoptosis was evaluated quantitatively and qualitatively by phase-contrast microscopy, transmission electron microscopy, DNA ladder electrophoresis, TUNEL staining and flow cytometry. RESULTS: Ad-rAFP-Mel infection had an inhibitory effect on the proliferation of BEL-7402 cells. The morphological changes of apoptosis were confirmed by microscopy and DNA electrophoresis. The ultrastructural characteristics of apoptotic cells, such as chromatin condensation and nuclear fragmentation, were also observed by electron microscopy in the Ad-rAFP-Mel-infected cells. Ad-rAFPMel infection markedly induced cellular apoptosis, and Fas expression on Bel-7402 cells infected by Ad-rAFPMel was up-regulated. CONCLUSION: The fact that melittin can induce apoptosis of the HCC cell line BEL-7402 leads us to consider adenovirus-mediated delivery of melittin as a promising approach for the treatment of HCC. However, the underlying mechanism needs to be further investigated.     

复方苦参注射液对SGC-7901，HepG2和BEL-7402肿瘤细胞作用的实验研究

 目的 通过观察复方苦参注射液（岩舒注射液）对SGC-7901，HepG2和BEL-7402肿瘤细胞的作用，探讨其在恶性肿瘤治疗中的作用机制。方法 本实验选用SGC-7901、HepG2和BEL-7402细胞，采用MTT法检测岩舒注射液对于各肿瘤细胞的体外杀伤率，流式细胞仪检测岩舒注射液作用后的肿瘤细胞的细胞周期、凋亡率及bcl-2、CD44V6和nm23基因表达的变化。结果 岩舒注射液浓度达到150 μl／ml时HepG2，SGC-7901和BEL-7402细胞存活率最低。岩舒注射液终浓度100 μl／ml作用后的HepG2细胞G0／G1期、G2／M期明显增高，S期的细胞数量明显减少，凋亡率（2.8 %）明显高于对照组（0.2 %）；SGC7901细胞G2／M期细胞明显增多，S期细胞明显减少，凋亡率（4.6 %）明显高于对照组（0.8 %）；100 μl／ml岩舒注射液浓度作用后的nm23为97.85 %，明显高于对照组（41.01 %），CD44V6为10.29 %明显低于对照组（12.26 %）。结论 岩舒注射液对于SGC-7901，HepG2和BEL-7402细胞具有明显的体外杀伤作用，并影响SGC-7901、HepG2的细胞周期，促进其凋亡；同时能够明显的抑制BEL7402细胞体内CD44V6的表达，促进抑转移因子nm23的表达，具有明显的抑制肿瘤转移的作用。     

PDGF-D对人肝癌细胞增殖及VEGF表达影响研究*

目的:研究血小板源性生长因子D（PDGF-D）对人肝癌细胞株BEL-7402增殖及其血管内皮生长因子（VEGF）表达的影响。方法:体外培养肝癌细胞株BEL-7402和肝癌旁非瘤性细胞株QSG-7701,采用RT-PCR 方法检测PDGF-D 与PDGFR βmRNA 在BEL-7402和QSG-7701的表达情况;将浓度分别为0（对照）、5、10、20、50、100、200 μ g/mL 的人重组PDGF-DD蛋白加入BEL-7402中,采用四甲基偶氮唑蓝比色法检测肝癌细胞的生长曲线;流式细胞仪检测细胞周期变化;半定量RT-PCR 检测VEGF及PDGFR β mRNA 表达情况,ELISA 检测PDGF-DD干预细胞后培养上清中VEGF蛋白的表达情况。结果:PDGF-D 及PDGFR βmRNA 在BEL-7402中高表达,与QSG-7701相比差异有统计学意义（P<0.05）。 PDGF-DD干预细胞后,可促进人BEL-7402增殖,浓度为100 μ g/mL 时达最高峰;细胞周期分布变化,G0/G1 期细胞数减少,S 期细胞数增加,与对照组相比差异有统计学意义;RT-PCR 结果显示,VEGF 及PDGFR β RI 值,实验组（除5 μ g/mL 组外）与对照组相比差异有统计学意义;ELISA 结果显示,加入PDGF-DD各浓度组VEGF蛋白浓度较对照组增高,差异有统计学意义,并呈量效依赖性关系。结论:PDGF-DD能促进BEL-7402的增殖,上调PDGFR β 及VEGF的表达。PDGF-D 及其信号传导系统在肝癌的发生、发展中可能发挥重要的作用,可作为肝癌预后预测指标和治疗靶点。      

Sorafenib联合紫杉醇不同给药顺序作用于人肝癌细胞BEL-7402的效应

背景与目的：Sorafenib是一种多靶点的抗肿瘤药物,其治疗原发性肝癌的疗效已经初步得到证实。本研究应用Sorafenib与紫杉醇（paclitaxel,TAX）联合．观察两药不同的给药顺序作用于人肝癌细胞BEL-7402的不同效应,初步探讨产生这种差异的机制。方法：采用MTY法检测Sorafenib与紫杉醇单药作用于BEL-7402细胞的IC50流式细胞术检测Sorafenib与紫杉醇不同给药顺序作用后,BEL-7402细胞周期和凋亡率的变化。Western blot检测不同给药顺序作用后的BEL-7402细胞Bcl-2的表达情况。结果：Sorafenib和紫杉醇单药作用于BEL．7402细胞48h的IC50分别为（2.43±0.32） μg/mL、（1.89±0.72） μg/mL。分析Sorafenib、紫杉醇单药,先用紫杉醇再加入Sorafenib,先用Sorafenib再加入紫杉醇及紫杉醇与Sorafenib同时作用后BEL-7402细胞周期及凋亡率的变化,结果显示：①Sorafenib主要将细胞阻滞在S期,而紫杉醇主要将细胞阻滞在G2-M期。②先用紫杉醇再给予Sorafenib组细胞S期及G2-M期均有延长,且较其他组获得较高的凋亡率（36.43±2.29）％（P〈0．01）。Western blot显示先用紫杉醇再给予Sorafenib组BEL-7402细胞的Bcl-2表达的水平最低。结论：Sorafenib联合紫杉醇不同给药顺序作用于BEL-7402细胞,先应用紫杉醇诱导再序贯给予Sorafenib时细胞凋亡率更高：产生这种不同效应的可能机制为两种药物作用于不同的细胞周期,以及不同给药方法后的Bcl-2的表达水平不同。     

miR-16对人肝癌细胞BEL-7402增殖与凋亡的影响

背景与目的：miR-16和miR-15a基因复合体位于人13q14区域的DLEU2基因内含子内,是目前公认的抑癌基因之一。该基因区域的缺失与多种实体肿瘤有关,miR-16同时促进肿瘤细胞的凋亡。该研究旨在探讨miR-16对BEL-7402肝癌细胞增殖与凋亡的影响。方法：人肝癌细胞BEL-7402分为miR-16感染组(加入LV-hsamiR-16-1慢病毒)和阴性对照组(加入阴性对照病毒),采用倒置荧光显微镜观察细胞绿色荧光的强度;采用细胞计数试剂盒(cell counting kit-8,CCK-8)检测miR-16对BEL-7402肝癌细胞增殖的影响;采用流式细胞术分析miR-16对人肝癌细胞BEL-7402的细胞周期与凋亡的影响。结果：CCK-8检测结果显示,感染组细胞增殖能力明显降低(P<0.05);流式细胞术检测结果显示,阴性对照组BEL-7402细胞周期中G₁期细胞百分率数值明显下降,但S及G₂/M期细胞的百分率均明显上升(P<0.05)。miR-16促进BEL-7402肝癌细胞凋亡。结论：miR-16抑制BEL-7402肝癌细胞的增殖并促进其凋亡,miR-16有望成为临床肝癌靶向治疗的新靶点。     

人肝癌细胞BEL-7402非常规照射模式生物效应探讨

目的 探讨不同照射模式对人肝癌细胞株BEL-7402生物效应变化影响及其与人肝细胞株QSG-7701放射敏感度差异。方法 6MV X线两种模式照射BEL-7402细胞(包括0、1、2、3、5、7、9、10Gy共8个吸收剂量点,剂量率3Gy/min)：(1)急速照射组,照射完成时间0~4min;(2)模拟三维适形照射组：照射完成时间：12~15min。成克隆分析法计算存活分数,多靶单击数学模型拟合曲线,求出SF2、D0、Dq等参数值;6MV X线单次5Gy照射体外培养的BEL-7402、QSG-7701 细胞, 采用MTT 比色法、流式细胞术测定细胞受照后不同时间存活率、凋亡率、细胞周期。结果 BEL-7402细胞模拟急速照射组和三维适形照射组D0、Dq、SF2值分别为1.78和1.69、1.45和1.54、0.625和0.654;QSG-7701 细胞照后24 h 凋亡率最高(18 %),而BEL-7402细胞照后12h凋亡率最高(32 %),存活率最低(65%),两株细胞照后12 h 凋亡率和存活率差异最大（P<0.01）。结论 三维适形照射模式下分次照射时间延长,生物效应下降;BEL-7402及QSG-7701两株细胞在照后存在放射敏感度差异。     

Egr-1对低氧应激下肝癌细胞BEL-7402黏附和迁移能力的影响

目的探讨显性负性突变（dominant negative）抑制即刻早期蛋白Egr-1转录因子活性对低氧应激下肝癌BEL-7402细胞黏附和迁移能力的影响。方法构建显性负性突变Egr-1腺病毒,感染BEL-7402细胞,同时以空载体和空白细胞做对照。“划痕”实验检测细胞迁移能力的变化;细胞与基质黏附实验,免疫荧光检测Egr-1对黏附能力的影响;Westernblot检测相关蛋白的改变。结果成功构建获得Egr-1转录功能竞争抑制型稳定腺病毒,并感染BEL-7402细胞。与BEL-7402细胞比较,低氧状态下Ad-dnEgr-1/BEL-7402组细胞,迁移,黏附能力显著降低（P<0.01）,细胞中与迁移、粘附相关的微丝所形成的伪足结构明显减少,FAK蛋白磷酸化水平降低。结论抑制Egr-1转录因子功能可以抑制肝癌BEL-7402细胞的迁移和黏附。     

切割MDR1 RNA的核酶(Ribozyme)对肝癌多药耐药细胞株BEL-7402/DOX化疗耐药性的逆转作用

为逆转肿瘤多药耐药基因(MDR1)产物P-gp蛋白所介导的肿瘤细胞对多种化疗药物的耐受性,设计合成了一种能切割MDR1 mRNA第196密码子GUC序列的锤头状核酶(Ribozlyme)并定向克隆于转录病毒载体pDOR-neo的BamH Ⅰ位点.经病毒包装细胞PA317包装后感染人肝癌多药耐药细胞株BEL-7402/DOX细胞,经G418筛选得到稳定的转化细胞株.Northem Blot杂交证实包装细胞PA317及转化的BEL-7402/DOX细胞中均有病毒的高表达,RT-PCR证实转化细胞中MDR1 mRNA与未转化细胞相比明显减少甚至不能扩增出来,流式细胞技术检测转化细胞P-gp的表达与非转化细胞的93.4～97.5%相比下降至8.2～14.6%.MTT法检测证实转化细胞对多种化疗药物重新产生较高的敏感性.结果表明,表达Ribozyme的逆转录病毒载体转化肝癌多药耐药细胞BEL-7402/DOX后能有效抑制MDR1的表达和翻译,使已产生耐药的肿瘤细胞的多药耐药表型发生逆转.     

Characterization and Resistance Mechanisms of A 5-fluorouracilresistant Hepatocellular Carcinoma Cell Line

Purpose: The chemoresistance of human hepatocellular carcinoma (HCC) to cytotoxic drugs, especiallyintrinsic or acquired multidrug resistance (MDR), still remains a major challenge in the management of HCC.In the present study, possible mechanisms involved in MDR of HCC were identified using a 5-fluorouracil (5-FU)-resistant human HCC cell line. Methods: BEL-7402/5-FU cells were established through continuous culturingparental BEL-7402 cells, imitating the pattern of chemotherapy clinically. Growth curves and chemosensitivityto cytotoxic drugs were determined by MTT assay. Doubling times, colony formation and adherence rates werecalculated after cell counting. Morphological alteration, karyotype morphology, and untrastructure were assessedunder optical and electron microscopes. The distribution in the cell cycle and drug efflux pump activity weremeasured by flow cytometry. Furthermore, expression of potential genes involved in MDR of BEL-7402/5-FUcells were detected by immunocytochemistry. Results: Compared to its parental cells, BEL-7402/5-FU cells hada prolonged doubling time, a lower mitotic index, colony efficiency and adhesive ability, and a decreased drugefflux pump activity. The resistant cells tended to grow in clusters and apparent changes of ultrastructuresoccurred. BEL-7402/5-FU cells presented with an increased proportion in S and G2/M phases with a concomitantdecrease in G0/G1 phase. The MDR phenotype of BEL-7402/5-FU might be partly attributed to increaseddrug efflux pump activity via multidrug resistance protein 1 (MRP1), overexpression of thymidylate synthase(TS), resistance to apoptosis by augmentation of the Bcl-xl/Bax ratio, and intracellular adhesion medicated byE-cadherin (E-cad). P-glycoprotein (P-gp) might play a limited role in the MDR of BEL-7402/5-FU. Conclusion:Increased activity or expression of MRP1, Bcl-xl, TS, and E-cad appear to be involved in the MDR mechanismof BEL-7402/5-FU.     

卵圆细胞标志分子在肝癌细胞株ＢＥＬ-７４０２中的表达及其意义

目的　探讨肝癌细胞株ＢＥＬ-７４０２的发生与卵圆细胞之间的分子关联及诱导分化前后的变化特征。方法　应用免疫细胞化学和酶细胞化学技术检测卵圆细胞的多种标志分子ＣＫ７、ＣＫ８、ＣＫ１８、ＣＫ１９、ＡＦＰ及ＧＧＴ在人肝癌细胞株ＢＥＬ-７４０２中的表达状态,并观察ＢＥＬ-７４０２诱导分化前后各种标志分子的表达变化特征。结果　ＢＥＬ ７４０２中ＣＫ７、ＣＫ８、ＣＫ１８、ＡＦＰ及ＧＧＴ表达阳性,ＣＫ１９表达阴性,与卵圆细胞向肝细胞分化早期阶段的分子表达谱相似。ＢＥＬ ７４０２诱导分化前后各分子标记物及ＧＧＴ酶活性的表达无明显改变。结论　ＢＥＬ ７４０２与卵圆细胞在分子表达谱上有高度相似性,提示肝细胞癌的发生与卵圆细胞之间存在重要关联。在诱导分化过程中,ＢＥＬ-７４０２标志分子表达水平的变化要晚于其在细胞周期方面的变化。     

免疫杀手细胞的体外扩增方法及其对肝癌细胞BEL-7402的杀伤作用

目的:探讨免疫杀手细胞(immune-killer cells,IKCs)的体外扩增方法及其对人肝癌细胞BEL-7402的杀伤作用。方法:改良自然杀伤细胞培养扩增法扩增IKCs细胞,流式细胞仪分析IKCs表型,台盼蓝染色计数法观察细胞增殖状况,AlamarBlue法观察IKCs细胞对BEL-7402细胞的杀伤作用,用BALB/c裸鼠模型检测IKCs细胞对肝癌动物模型的治疗作用。结果:IKCs细胞培养14 d的细胞总数扩增300倍以上,主要由CD3~+CD56~+、CD3~-CD56~+和CD8~+细胞亚群组成,CD3~+CD56~+和CD3~-CD56~+比例达85%以上,CD8~+比例达到77%以上。IKCs细胞对肝癌BEL-7402细胞的杀伤实验显示,当效靶比为25:1时和100:1时,其杀伤活性分别为66.5%和97.8%(P<0.01)。裸鼠肝瘤模型治疗实验显示,IKCs细胞对早期和晚期人肝癌BEL-7402细胞裸鼠模型均有显著的治疗作用,与对照组比较,其抑瘤率达69%以上(P<0.01)。结论:本实验建立的肿瘤免疫杀手细胞IKCs的培养扩增方法是可行的、有效的,有望成为一种新的肿瘤免疫细胞治疗方法。     

Anti-hepatoma cells function of luteolin through inducing apoptosis and cell cycle arrest

The aim of this study is to explore the apoptotic induction and cell cycle arrest function of luteolin on the liver cancer cells and the related mechanism. The liver cancer cell line SMMC-7721, BEL-7402, and normal liver cells HL-7702 were treated with different concentrations of luteolin. Cell proliferation ability was tested. Morphological changes of the apoptotic cells were observed under inverted fluorescence microscope after Hoechst33342 staining. We investigated the effect of luteolin on cell cycling and apoptosis with flow cytometry. The mitochondrial membrane potential changes were analyzed after JC-1 staining. Caspases-3 and Bcl-2 family proteins expression were analyzed by real-time PCR. Cell proliferation of SMMC-7721 and BEL-7402 were inhibited by luteolin, and the inhibition was dose–time-dependent. Luteolin could arrest the cells at G1/S stage, reduce mitochondrial membrane potential, and induce higher apoptosis rate and the typical apoptotic morphological changes of the liver carcinoma cells. Q-RT-PCR results also showed that luteolin increased Bax and caspase-3 expression significantly and upregulated Bcl-2 expression in a dose-dependent manner in liver carcinoma cells. However, the normal liver cells HL-7702 was almost not affected by luteolin treatment. Luteolin can inhibit SMMC-7721 and BEL-7402 cell proliferation in a time- and dose-dependent manner. And the mechanism maybe through arresting cell cycle at phase G1/S, enhancing Bax level, reducing anti-apoptotic protein Bcl-2 level, resulting in activating caspase-3 enzyme and decrease of mitochondrial membrane potential, and finally leading to cell apoptosis.     

CD80 transfected human hepatocellular carcinoma cells activate cytotoxic T lymphocytes to target HCC cells with shared tumor antigens

Human HCC cell lines (BEL-7402, SMMC-7721 and QGY-7703) do not express CD80 molecules, although they express MHC class I molecules and ICAM-1. HCC's poor immunogenicity may therefore be due to lack of CD80 molecules. This study first investigated whether CD80 molecules could provide minimal co-stimulatory signal for establishing an efficient anti-tumor immunity in HCC and second, whether the transfection of CD80 into the BEL-7402 cell line could induce T cell activation for targeting other HCC cell lines expressing shared common antigens. The transfection of cDNA encoding CD80 into ICAM-1+ HCC BEL-7402 cells was confirmed by flow cytometrical analysis. The CD80-transfected cells could enhance the immunogenicity of BEL-7402 cells as detected by T cell proliferation assay, and also activated the T cells at a higher proliferation rate comparing with the BEL-7402 cells transfected with vector only. The CD80-transfected cell line was also found able to activate T cells which subsequently induced cell lysis of SMMC-7721, QGY-7703 and parent BEL-7402 cell lines as detected by cytotoxicity assay. It can be concluded that the cytotoxicity was due to MHC class I restricted CD8+ cytotoxic T lymphocytes, but not natural killer (NK) cells, since this cytotoxic effect could be blocked by anti-MHC class I antibody and the cytotoxicity was shown very low in NK-cell-sensitive K562 cell line. Electroporation of CD80 cDNA into human HCC cells could increase the expression of the functional CD80 molecules and enhance the immunogenicity of the genetically-modified HCC cells to activate T cells for targeting 3 HCC cell lines in an HLA-restricted manner.     

靶向表皮生长因子受体的寡肽与力达霉素强化融合蛋白的构建及其抗肿瘤活性

背景与目的：表皮生长因子受体（epidermal growth factor receptor,EGFR）在多种肿瘤细胞表面异常表达。力达霉素是从链霉菌中分离得到的具有强抗肿瘤作用的烯二炔类抗生素。本研究的目的是制备一种特异性靶向EGFR的寡肽配体与力达霉素的强化融合蛋白（Ec—LDP-AE）,并初步探讨其抗肿瘤活性。方法：制备融合蛋白（Ec-LDP）,并分离纯化,用高效液相色谱法检测Ec-LDP的纯度,ELISA、流式细胞技术以及细胞免疫荧光方法分析纯化的Ec-LDP蛋白对不同肿瘤细胞的免疫结合活性。将纯化的Ec-LDP蛋白与力达霉素发色团进行组装,构建Ec-LDP-AE,用高效液相色谱法检测350nm处的吸收峰。MTY法检测Ec—LDP-AE的体外抗肿瘤活性。结果：成功构建并表达了Ec-LDP蛋白,目的蛋白分泌至大肠杆菌周质腔中,产量为每升发酵液18mg活性蛋白,其纯度为95．3％。ELISA和细胞流式检测结果均显示Ec-LDP蛋白对EGFR高表达的肿瘤细胞系A431和MCF-7都有很强的免疫结合活性．而对不表达EGFR的NIH3T3细胞则无结合活性。免疫荧光实验也证实Ec—LDP蛋白可与A431细胞膜受体结合。Ec-LDP-AE蛋白在350nm波长处出现特定吸收峰,表明其构建成功。MTT法检测结果显示Ee-LDP—AE对体外培养的肿瘤细胞有强烈的杀伤作用,对MCF-7和A431细胞的IC。值分别为3．06×10^11mol/L和9．38×10^-13mol／L。结论：本研究制备的强化融合蛋白Ec—LDP—AE对表皮生长因子受体有靶向作用,并且保留了力达霉素的强烈细胞毒作用。