肝癌细胞CD80表达与MHC-Ⅰ分子的关系

目的：研究共刺激分子CD80在肝癌细胞中的表达与MHC－I（Majorhistocompatibilitycomplex）分子相互关系,以探讨在肿瘤细胞所诱发的免疫排斥反应中共刺激分子对抗原提呈机制的影响。方法：通过逆转录病毒载体介导,将CD80基因转入肝癌细胞系HHCC,以流式细胞仪检测其表面MHC－I分子的表达情况。同时检测LAK细胞对转染前后的细胞的杀伤效果。结果：表达CD80的肝癌细胞其表面MHC－I分子表达明显增高（P＜0.01）,而γ－INF刺激对细胞表面MHG-I分子的表达情况并无影响（P＞0.05）。LAK细胞对转染后细胞的杀伤作用远远大于未转染组（P＜0．01）,而γ-INF刺激前后的细胞毒活性几乎无改变（P＞0．05）。结论：转染CD80后肝癌细胞高表达MHC-I分子,增强抗原提呈作用的同时又表达第二信号—共刺激分子CD80,从而可诱发更强的免疫排斥反应。     

转导B7-1基因消除IFN-γ对黑色素瘤转移潜力的增强作用

γ干扰素(IFN-γ)可通过增加MHCⅠ类分子或其它机制增强多种肿瘤的转移能力,而将T细胞共刺激分子B7基因导入肿瘤细胞能增强机体免疫系统对肿瘤的攻击。本文以Lipofectamine转染法将小鼠B7-1(mB7-1)基因导入B16黑色素瘤低转移株,导入空载体(只含neo基因)的B16细胞作对照。亲本B16细胞和基因转导细胞(B16-B7-1和B16-neo)经100U/ml IFN-γ预处理36小时后进行实验性肺转移试验,同时流式细胞分析细胞表面MHCⅠ类和Ⅱ类分子的表达。结果发现,IFN-γ预处理明显增强B16和B16-neo细胞的肺转移能力,而经IFN-γ预处理的B16-B7-1细胞转移能力并不增强,其实验性肺转移结节数与未经处理的对照组无差别。流式细胞分析显示IFN-γ预处理使B16、B16-neo和B16-B7-1三种细胞的MHCⅠ类(H-2K~b和H-2D~b)分子均明显增高,但IFN-γ增加B16-B7-1细胞MHCⅡ类分子I-A~b表达程度显著高于其它两种细胞。结果表明,转导B7-1基因可降低IFN-γ诱导的B16细胞转移能力,MHCⅡ类分子表达增高可能在其中起一定作用。     

顺氨氯铂,阿霉素增强人抗CD3单克隆抗体活化杀伤细胞的杀瘤效应

应用抗CD3单克隆抗体和基因重组人IL-2共同诱导人外周血单个核细胞，制备抗CD3单克隆抗体活化的杀伤细胞（CD3AK）。利用LDH释放法，观察顺氨氯铂（CDDP）和阿霉素（ADM）预处理人肝癌细胞系H－7402，对CD3AK杀伤该靶细胞的调节作用。ABC－ELISA法检测CDDP和ADM对H-7402细胞表达细胞间粘附分子-1（ICAM-1）、HLA－ABC、HLA－DR抗原的影响。结果表明：经CDDP（2．0μg／ml）、ADM（O．1μg／ml）预处理12h的H－7402细胞对CD3AK的杀伤敏感性显著提高（P＜0.05）；CDDP能够明显促进H－7402细胞表达ICAM-1、HLA－ABC分子（P＜0.05）；ADM预处理的肿瘤细胞表面三种分子的表达均未发生明显的变化。CDDP促进人肝癌细胞对CD3AK的杀伤敏感性可能与其上调了肿瘤细胞表面的ICAM-1分子有关。     

pIRES-IL-24对Bel-7402肝癌细胞抑制的实验研究

目的:观察白细胞介素-24(IL24)基因对肝癌细胞系Bel-7402生长的抑制作用,为肝癌的基因治疗提供理论基础.方法:将真核分泌表达载体pIRES-IL-24转染肝癌细胞系Bel-7402.RT-PCR检测IL-24基因的表达,蛋白质印迹法及ELlSA检测IL-24蛋白的表达,MTT法检测IL-24对肝癌细胞的生长抑制和杀伤作用,流式细胞仪检测细胞的凋亡和细胞周期.结果:pIRES-IL-24能够在Bel-7402中高效表达.细胞培养上清液中IL-24蛋白表达浓度为124.1 ng/mL.IL-24能明显抑制Bel-7402肝癌细胞的生长,转染后第4天抑制率为46.3%,与对照组比较,P＜0.05.IL-24促进肝癌细胞的凋亡,凋亡率41.0%,与对照组比较,P＜0.05.细胞周期分析显示,IL-24阻滞肝癌细胞在G2/M期.结论:重组表达载体pIRES-IL-24介导IL-24基因在人肝癌细胞中高效表达,可杀伤肝癌细胞Bel-7402,促进细胞增殖阻滞及诱导肿瘤细胞凋亡.     

肿瘤生物治疗新方法的研究

本文简述“九五”攻关项目间“肿瘤生物治疗新方法”且经协作攻关主要完成的研究工作有：重组人TNF、IL－2及B7重组腺病毒表达载体的构建及其包装体系的建立：腺病毒介导的人TNF－α基因转染对人肝癌细胞凋亡和MHC－Ⅰ类分子表达的影响;瘤体内／瘤周注射TNF－α重组腺病毒和（或）IL－2T重组腺病毒对肝癌小鼠的治疗作用及其免疫机理研究。粘附LAK细胞的制备、体外扩增、冻存及复苏;转染B7、IL－2、TNF－α基因重组腺病毒的肿瘤细胞及A－LAK的生物学特性研究;人肝癌组织中MAG基因的表达及MAGE基因修饰树突状细胞体外抗肿瘤作用;转基因瘤苗临床应用安全性的初步性的初步检测,这些研究工作的完成为肿瘤基因治疗的临床应用打下基础。     

反义IGF-I寡核苷酸转染抑制人肝癌细胞生长的实验观察

胰岛素样生长因子-Ⅰ(Insulin like growth factor Ⅰ,IGF-Ⅰ)是一种多效的生长因子,在肿瘤的生长、分化和转移过程中起重要作用[1].肿瘤细胞通过自分泌方式过度产生IGF-Ⅰ,激活IGF-Ⅰ受体,使自身不断生长,因此IGF-Ⅰ成为反义核酸治疗的良好靶分子.利用反义寡核苷酸(ASON)技术人工合成IGF-Ⅰ寡核苷酸片段,脂质体包裹并转染人肝癌细胞系BEL-7402细胞,可以抑制肿瘤细胞IGF-Ⅰ的过度表达,为IGF-Ⅰ反义核苷酸治疗肝细胞癌提供依据.     

RT-PCR克隆人IL-6、IL-10、IL-13和SCF等四种细胞因子膜外区cDNA

在逆转录病毒介导下将TNF基因转染入小鼠LAK细胞中．结果发现．转染TNF基因的LAK细胞比正常LAK细胞和转染对照基因的LAK细胞分泌更高水平的TNF．其体外生长能力和杀伤活性均显著升高．抗TNF单抗可显著抑制其体外杀伤活性．表明其杀伤活性升高是由基因转染后所表达的TNF介导的。将较低数量的TNF基因转染的LAK细胞与IL-2联合腹腔内注射后，对腹水型肝癌小鼠有显著的治疗效果．     

MHCI类样分子(MICA)在部分肿瘤组织和肿瘤细胞系中的表达及临床意义

目的:探讨MHC Ⅰ类样分子(MICA)在肿瘤组织和肿瘤细胞系中的表达及其临床意义.方法:分别采用半定量RT-PCR和免疫组织化学技术检测肿瘤组织和肿瘤细胞系MICA表达,MTT法测定NK细胞细胞毒活性.结果:人红白血病细胞K562、喉癌细胞系Hep2、宫颈癌细胞系Hela、肝癌细胞系HepG2和结直肠癌细胞系HT29均有MICA mRNA和蛋白表达,而人Burkitt淋巴瘤Raji和高转移肺癌PG不表达MICA.MICA表达阳性的肿瘤细胞对NK杀伤敏感性明显高于MICA阴性者.多数肿瘤组织存在MICA mRNA和蛋白表达,但并非在所有肿瘤均有表达,癌旁组织均无MICA表达.结论:肿瘤细胞表达MICA可激发NK细胞对肿瘤的杀伤,NKG2D及其配体的相互作用在肿瘤免疫监视中起着非常重要的作用,肿瘤细胞分泌sMICA分子为肿瘤发生免疫逃逸的机制之一.     

B7-1基因转染小鼠EL-4淋巴瘤诱导带瘤宿主抗瘤效应的体内研究

本文研究了IL-2、IL-4、IL-6基因转染后B16黑色素瘤细胞表面MHCⅠ类抗原及ICAM-1的表达水平,并探讨了其在CTL诱导过程中的作用.结果表明,IL-2、IL-4、IL-6基因转染的B16黑色素瘤细胞表面MHCⅠ类抗原及ICAM-1表达均高于野生型B16黑色素瘤细胞及转染对照质粒的B16黑色素瘤细胞.体内接种后,小鼠脾脏CTL活性明显增强,CTL培养体系中IFN-γ、TNF-α的分泌水平也增高.在CTL诱导体系中加入抗ICAM-1单抗可以抑制CTL的活化,加入抗MHCⅠ类分子单抗后可使CTL的活化完全阻断.这提示细胞因子基因转染可能通过使肿瘤细胞表面MHCⅠ类抗原、ICAM-1的表达增加,从而增强瘤苗的免疫原性.     

反义IGF-Ⅰ寡核苷酸转染抑制人肝癌细胞生长的实验观察

胰岛素样生长因子-Ⅰ(Insulinlikegrowthfac鄄torⅠ,IGF-Ⅰ)是一种多效的生长因子,在肿瘤的生长、分化和转移过程中起重要作用[1]。肿瘤细胞通过自分泌方式过度产生IGF-Ⅰ,激活IGF-Ⅰ受体,使自身不断生长,因此IGF-Ⅰ成为反义核酸治疗的良好靶分子。利用反义寡核苷酸(ASON)技术人工合成IGF-Ⅰ寡核苷酸片段,脂质体包裹并转染人肝癌细胞系BEL-7402细胞,可以抑制肿瘤细胞IGF-Ⅰ的过度表达,为IGF-Ⅰ反义核苷酸治疗肝细胞癌提供依据。1材料与方法1.1材料脂质体Lipofectin(GIBCO公司);正、反义IGF-Ⅰ寡核苷酸片段(上海博亚生物技术…     

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.     

Recombinant gamma interferon provokes resistance of human breast cancer cells to spontaneous and IL-2 activated non-MHC restricted cytotoxicity

Natural and lymphokine activated killer cells (NK and LAK) are believed to play an important role in the control of tumour progression and metastasis. Their specific receptors on tumours cells are still unknown. Several studies suggest that these cells recognise and eliminate abnormal cells with deleted or reduced expression of MHC class I molecules. Previous reports suggest that interferons (IFN), by increasing MHC class I expression on target cells, induce resistance to killing by NK cells. We investigated the role of MHC molecule expression by two human breast cancer cell lines T47D and ZR75-1 in their susceptibility to NK and LAK cells. These two cell lines spontaneously express low levels of HLA class I antigens but no HLA class II molecules. After IFN-gamma treatment they both overexpressed MHC class I and de novo expressed class II molecules as detected by flow cytometry, quantified by a radioimmunoassay and analysed by two-dimensional gel electrophoresis. Opposed to untreated cells these IFN-gamma treated cells were resistant to NK and LAK lysis. Furthermore, preincubation of IFN-gamma treated breast cancer cells with F(ab')2 fragments of monoclonal antibodies to HLA class I and HLA class II molecules was unable to restore lysis. In contrast, several complete monoclonal antibodies including anti-HLA class I and HLA class II induced the lysis of target cells whether or not they had been treated by IFN-gamma. The therapeutic use of monoclonal antibodies directed against antigens expressed on tumour cells (ADCC) in conjunction with interferon therapy should be discussed in lymphokine-based strategies for treatment of cancer patients.     

Retaliation against tumor cells showing aberrant HLA expression using lymphokine activated killer-derived T cells.

Lymphokine activated killer (LAK) cells represent mixtures of natural killer (NK) and non-MHC-restricted CTLs that have the capacity to lyse a variety of tumor cells and MHC class I-negative target cells. Although it is clear that NK cells are negatively regulated by interactions with MHC class Ia or class Ib molecules, the regulation of LAK-derived T cells has not been clarified to date. In the studies presented here, we demonstrate that IFN-gamma treatment of tumor cells can induce their resistance to LAK-derived T cells in a manner similar to that seen for NK cells. The IFN-gamma-mediated suppression of LAK activity correlates with increased MHC class I expression by the tumor cells, and the inhibition of LAK-mediated cytotoxicity can be reversed in the presence of class I-specific antibody. Furthermore, the expression of MHC class Ia or class Ib molecules in class I-negative cell lines can reduce their susceptibility to LAK-mediated cytotoxicity. This principle of negative regulation by MHC class I molecules applies to LAK-derived T cells generated from peripheral blood lymphocytes of renal cell carcinoma patients and healthy, control donors. Although LAK-derived T cells can be inhibited in their lytic activity through interactions with MHC class Ia and class Ib molecules, they do not express the known inhibitory receptors specific for these ligands that are found on NK cells. Apparently, LAK-derived T cells are negatively regulated by as yet undefined inhibitory receptors.     

IL—4基因转染人胃癌细胞的实验研究

目的：评价ＩＬ－４基因转染人胃癌细胞株分泌ＩＬ－４的可行性。方法：用脂质体转染法将ＩＬ－４基因转入ＳＧＣ－７９０１人胃癌细胞株，并检测细胞分泌的ＩＬ－４和对ＬＡＫ细胞杀伤肿瘤细胞作用的影响。结果：ＩＬ－４基因可以转染入人胃癌细胞，并表达有活性ＩＬ－４，基因转染可以明显增强ＩＬ－２激活的ＬＡＫ细胞的肿瘤杀伤作用，用大剂量的γ射线照射后，转染细胞仍可以持续分泌ＩＬ－４３～４周期。结论：ＩＬ－４基因转染不改变胃癌细胞的体外生长特性，但可以明显增强抗肿瘤免疫反应     

Lack and restoration of sensitivity of lung cancer cells to cellular attack with special reference to expression of human leukocyte antigen class I and/or major histocompatibility complex class I chain related molecules A/B

Both cytotoxic T lymphocytes (CTL) and natural killer (NK) cells may play major roles in the host defense against cancer. However, their relationship against the same tumor remains to be elucidated. Among 26 human lung cancer cell lines established in our laboratory, 10 (38%) exhibited human leukocyte antigen (HLA)-class I haplotype loss and three (12%) lost HLA-class I expression totally by flow cytometry analysis. The two cell lines (E522L and C831L) that lost their expression of HLA-class I in vitro and in vivo were applied for further evaluations. Genetic abnormalities of β2-microglobulin gene were observed in both E522L (loss of mRNA) and C831L (point mutation). Transduction of the wild-type β2-microglobulin gene rendered them positive for HLA-class I expression. The CTL were induced from autologous peripheral blood mononuclear cells or regional lymph node lymphocytes by stimulation with wild-type β2-microglobulin transduced-E522L or -C831L, and they showed tumor-specific cytotoxicity against wild-type β2-microglobulin-transductant, but not parental cells. In NK cell cytotoxicity, E522L showed high sensitivity to NK cells; however, C831L showed resistance despite loss of HLA-class I expression. E522L expressed MHC class I chain related molecules A/B, but C831L did not. The transduction of the MHC class I chain related molecule A gene from E522L rendered C831L positive for expression and sensitive to NK cell cytotoxicity. Reconstruction of HLA-class I and MHC class I chain related molecules A expression could abrogate evasion from cellular attack by CTL and NK cells, and it may lead to a breakthrough in the development of cancer immunotherapy. ( Cancer Sci 2007; 98: 1795–1802)     

反义IGF—I基因转染人肝癌细胞分泌CEA和AFP水平的研究

本研究利用基因治疗方法中的反义RNA技术，通过脂质体包裹反义胰岛素样生长因子－I（IGF－I）基因导入人HepG2肝癌细胞株，NorthernBlot分析显示反义IGF－IRNA表达阳性。研究反义IGF－I基因转染的HePG2细胞分泌CEA和AFP的水平，放射性同位素的测定结果表明细胞培养上清中的CEA的水平显著地低于亲本细胞（P＜0．05），而分泌AFP的水平更显著地低于亲本细胞（P＜0．01）。预示着阳性克隆细胞的恶性程度低于亲本细胞，细胞内原有的生物学过程发生改变。     

The expression of MHC class I, TAP1/2, and LMP2/7 gene in human gastric cancer cell lines

Intracellular antigens are presented to CD8+ T cells through major histocompatibility complex (MHC) class I molecule. For stable MHC class I expression, several molecules as well as the MHC molecule itself have to express simultaneously and function well. To determine a gene associated with MHC class I surface expression, the expressions of LMP2/7 and TAP1/2 including MHC I gene were analyzed in ten human gastric cancer cell lines, using RT-PCR and Northern blot analysis. Although LMP2, TAP1/2, and MHC class I gene expression were reduced in some cells, this was not significantly associated with MHC class I surface expression. By comparison, the expression of LMP7 was significantly reduced in three of ten cell lines, which also showed low levels of MHC class I surface expression, and increased in four of ten cell lines, which also showed high levels of MHC class I surface expression. These results suggest that the level of MHC class I surface expression is associated, in most cases, with the expression of the LMP7 gene regardless of the LMP2, TAP1, TAP2, or MHC class I genes.     

Turning tumor cells in situ into T-helper cell-stimulating, MHC class II tumor epitope-presenters: immuno-curing and immuno-consolidation

Immunological control or cure of tumors depends on initiating a robust T helper cell response to MHC class II epitopes of tumor-associated antigens. T helper cells regulate the potency of cytotoxic T lymphocyte and antibody responses. We have developed a novel approach to stimulate T helper cells by converting tumor cells into MHC class II molecule-positive, antigen presenting cells. Furthermore, using antisense methods, we suppress expression of the Ii protein, that normally blocks the antigenic peptide binding site of MHC class II molecules during synthesis in the endoplasmic reticulum. In such gene-engineered tumor cells, the MHC class II molecules pick up antigenic peptides, which have been transported into the endoplasmic reticulum for binding to MHC class I molecules. All nucleated cells create such "surveys of self" to detect viral or malignant transformation. Our method extends that survey of self to MHC class II endogenous tumor-associated antigens. Simultaneous presentation of tumor antigens by both MHC class I and II generates a robust and long-lasting antitumor immune response. Injecting murine tumors with genes, which induce MHC class II molecules and suppress Ii protein, cures a significant number of animals with renal and prostate tumors. We have developed analogous human gene vectors that are suitable for most patients and cancers, because they are monomorphic and active in all HLA-DR alleles. We review our findings, and analyze remaining issues for preclinical study and the design of clinical trials.     

Intensity of class I antigen expression on human tumour cell lines and its relevance to the efficiency of non-MHC-restricted killing.

A modified tetrazolium reduction assay (MTT) was used to assess the relation between HLA class I antigen expression on tumour cells and their susceptibility as a target for non-MHC restricted LAK/NK cytotoxicity using interleukin-2 activated peripheral blood mononuclear cells (MNC) from normal individuals. At 20/1 effector/target ratio this ranged from no killing to 77%. The efficiency of killing was dependent on duration of effector cell culture with IL-2, peaking at day 10 and declining thereafter. This killing could be enhanced by addition of other cytokines including interferons alpha, beta and gamma. Study of a panel of 15 tumour cell lines using a single effector showed that there was no statistically significant inverse correlation (using Spearman rank test) between the degree of tumour class I expression and LAK/NK killing at 20/1 (r = 0.23 P = 0.39) and 10/1 (r = 0.30, P = 0.27) and at 5/1 E/T ratio r = 0.47, P = 0.08) respectively. Lack of inverse correlation between these two parameters came from study of one bladder tumour line (FEN), whose absent class I antigens had been corrected by transfection with beta 2 microglobulin gene. At high E/T ratio (20/1) there was an increase in the susceptibility of target cells to lysis (36% parent cell, 45% transfected cell), whilst at lower E/T ratios (1/1) there was significantly more killing of the non-transfected cells (10% vs 31%). The addition of anti-class I antibody W6/32 increased killing by 18% but this was non-specific as the same increase occurred with a class II antibody. These data suggest that overall there was not an inverse correlation between class I expression and LAK/NK killing at high E/T ratios, whilst at low (5/1 or lower) E/T ratios this correlation nearly reached statistical significance suggesting that the conflicting literature reports may be due to a threshold levels of effector cells above which the masking effects of MHC antigens disappears.