肿瘤诱导的树突状细胞功能缺陷及其机制

机体的免疫监视功能是防止肿瘤发生的重要机制.除了由NK细胞和NKT细胞等免疫细胞所介导的天然免疫监视外,机体可以通过获得性免疫监视功能防止肿瘤细胞的扩增和转移[1].转化的肿瘤细胞可以释放细胞因子和热休克蛋白等信号以活化机体的"哨兵"--专职抗原递呈细胞(APC);一旦活化后,APC可以识别并且递呈肿瘤相关抗原(TAA),如黑色素瘤抗原1(MAGE1)和T细胞识别的黑色素瘤抗原1(MART1);然后APC迁移入次级淋巴器官(淋巴结和脾脏)启动获得性免疫反应,产生抗原特异的效应性T淋巴细胞和B淋巴细胞,并且最终由CTL裂解肿瘤[1-2].     

髓系来源免疫抑制性细胞在胃腺癌组织及癌旁组织中的表达

目的探讨髓系来源免疫抑制性细胞(MDSC)在胃腺癌组织及癌旁组织中的表达情况。方法采集50例胃腺癌患者和30例健康体检者的外周血标本,分别作为观察组和对照组,取29例观察组患者胃腺癌组织和癌旁组织的标本,流式细胞仪检测两组受试者外周血和观察组患者胃腺癌组织和癌旁组织中,MDSC粒细胞来源(G-MDSC)和单核细胞来源(M-MDSC)两个表型的相对表达量。结果观察组患者外周血G-MDSC的相对表达量高于对照组受试者,观察组患者胃腺癌组织中G-MDSC的相对表达量为高于癌旁组织,差异均有统计学意义(P﹤0.05)。但两组患者外周血M-MDSC相对表达量,及观察组患者胃腺癌组织和癌旁组织中M-MDSC相对表达量的比较,差异均无统计学意义(P﹥0.05)。结论 G-MDSC在胃腺癌患者外周血及肿瘤组织中相对表达量均升高,可能参与胃腺癌细胞的免疫逃逸过程。     

Survivin基因特异性siRNA腺病毒介导的肿瘤放射增敏作用

T细胞的失能在肿瘤免疫逃逸过程中起重要作用,而髓样抑制细胞(MSCs)是引起T细胞的失能的关键因素之一。目前认为MSCs诱导的肿瘤免疫逃逸主要是通过抑制T细胞功能实现的,其中精氨酸代谢起关键性作用。研究表明肿瘤浸润部位的MSCs产生的精氨酸酶Ⅰ可消耗T细胞周围的精氨酸,抑制T细胞CD3ζ表达,从而抑制其功能。但是肿瘤浸润部位的MSCs的精氨酸酶I产生机制未知。以往研究证实Th2型细胞因子IL-4、IL-13可诱导精氨酸酶I的表达。本研究中作者首先发现在3LL肿瘤细胞,浸润淋巴细胞均不表达IL-4,IL-13的mRNA。利用Prkdcscid小鼠模型发…     

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.     

胃癌患者外周血和肿瘤组织中高表达CD14+ DRlow/-髓源抑制性细胞

目的:探讨胃癌患者外周血和肿瘤组织中CD14+DRlow/-髓源抑制性细胞(myeloid-derived suppressor cells,MDSCs)的表达及其与肿瘤病理特征的关系。方法:选取2009年3月至2010年10月安徽医科大学第三附属医院胃癌患者43例(Ⅰ期9例、Ⅱ期13例、Ⅲ期14例、Ⅳ期7例),另采集26例正常健康者作为对照组。流式细胞术检测外周血、瘤组织中CD14+DRlow/-MDSCs的表达水平,分析MDSCs表达水平与肿瘤病理特征的相关性。结果:胃癌患者肿瘤组织中CD14+DRlow/-MD-SCs的表达显著高于自身外周和健康对照者外周血的表达水平[2.87±1.93)%vs(2.37±1.7)%,(0.89±0.47)%,P<0.05和P<0.01],后两者间差异也有统计学意义(P<0.01)。CD14+DRlow/-MDSCs的表达与胃癌的恶性程度呈正相关,晚期胃癌组织内CD14+DRlow/-MDSCs表达明显增加(Ⅰ∶Ⅱ∶Ⅲ∶Ⅳ=(1.15±0.78)%∶(1.71±0.92)%∶(2.25±1.24)%∶(4.85±2.37)%,P<0.05)。同时,肿瘤浸润组织与非浸润组织的CD14+DRlow/-MDSCs表达也有明显差异[3.90±1.67)%vs(2.62±1.53)%,P<0.05]。结论:CD14+DRlow/-MDSCs在胃癌患者外周血和肿瘤组织中均高表达,与胃癌的发生、发展密切相关。     

外源人gp96基因在肿瘤细胞中的高效表达

背景与目的：从肿瘤细胞中分离出的热休克蛋白gp96制备物免疫小鼠可产生抗相应肿瘤的特异性保护性细胞毒性T细胞免疫应答,为肿瘤免疫治疗开辟了一条新的可行性途径,但gp96害细胞中的表达水平较低,从有限的细胞或组织中获得的gp96制备物难以满足研究的需要。因此,本研究拟为制备高质量和充足的gp96而建立高表达gp96的单克隆细胞株。方法：构建人gp96cDNA的重组表达质粒pcDNA-hgp96并将其转染HeLa细胞,G418筛选稳定转染的阳性细胞克隆,然后用Western印迹分析单克隆细胞株的gp96表达时。结果：成功构建了人gp96的重组表达质粒,建立了稳定转染的单克隆细胞株,并筛选出一株高表达gp96的单克隆细胞。结论：成功建立了高表达gp96的单克隆细胞株,为gp96抗肿瘤免疫的研究奠定了基础。     

胃癌患者外周血和肿瘤组织中高表达CD14~+DR~(low/-)髓源抑制性细胞

目的:探讨胃癌患者外周血和肿瘤组织中CD14+DRlow/-髓源抑制性细胞(myeloid-derived suppressor cells,MDSCs)的表达及其与肿瘤病理特征的关系。方法:选取2009年3月至2010年10月安徽医科大学第三附属医院胃癌患者43例(Ⅰ期9例、Ⅱ期13例、Ⅲ期14例、Ⅳ期7例),另采集26例正常健康者作为对照组。流式细胞术检测外周血、瘤组织中CD14+DRlow/-MDSCs的表达水平,分析MDSCs表达水平与肿瘤病理特征的相关性。结果:胃癌患者肿瘤组织中CD14+DRlow/-MD-SCs的表达显著高于自身外周和健康对照者外周血的表达水平[2.87±1.93)%vs(2.37±1.7)%,(0.89±0.47)%,P<0.05和P<0.01],后两者间差异也有统计学意义(P<0.01)。CD14+DRlow/-MDSCs的表达与胃癌的恶性程度呈正相关,晚期胃癌组织内CD14+DRlow/-MDSCs表达明显增加(Ⅰ∶Ⅱ∶Ⅲ∶Ⅳ=(1.15±0.78)%∶(1.71±0.92)%∶(2.25±1.24)%∶(4.85±2.37)%,P<0.05)。同时,肿瘤浸润组织与非浸润组...     

肿瘤的免疫逃逸

肿瘤在人体免疫监视功能作用下仍能发生、发展、转移，表明肿瘤具有逃避机体免疫监视的功能。肿瘤自身释放的抑制因子起到重要作用。肿瘤细胞本身会释放VEGF、IL10、TGFβ、PEG2、IL6、趋化因子、NO等抑制因子使DC分子表面MHC分子或共刺激分子CD80/86表达改变；或是肿瘤细胞表面的标志物Fas、CD44、TAA、MHC分子、B7分子、MCRP在肿瘤表面表达改变，影响DC的抗原提呈过程，致使肿瘤无法被正常识别和杀伤。另外，T细胞应答能力的下降，在肿瘤细胞数量极少时造成漏逸，以及血清中封闭因子的存在，也会造成机体在抗肿瘤方面受到抑制。     

Mcl-1蛋白在宫颈病变中的表达及意义

目的：髓样细胞白血病-1（myeloid cell leukemia-1，Mcl-1）蛋白是bcl-2家族成员，它在调控肿瘤细胞的凋亡、增殖、分化等过程中起一定作用。本研究拟检测子宫颈病变组织中Mcl-1蛋白的表达，探讨该蛋白在宫颈癌形成和演进进程中的意义。方法：采用免疫组织化学SP法检测83例石蜡包埋的子宫颈组织中Mcl-1的表达情况，并结合临床病理分型分析其表达的意义。结果：Mcl-1蛋白在慢性宫颈炎、宫颈上皮内瘤样病变（cervical intraepithelial neoplasia，CIN）和宫颈癌组织中的阳性率分别为4．0％，33．3％和74．2％，3组样本中Mcl-1的阳性率差异有统计学意义（P〈0．05），宫颈癌病理学分级G1及G2期与G3相比，差异有统计学意义（P〈0．05）。Mcl-1蛋白表达阳性率与CIN的分级、与宫颈癌临床分期、组织学分型和淋巴结转移无关（P〉0．05）。结论：Mcl-1蛋白在宫颈癌组织中表达升高，可能在宫颈癌的发生发展过程中起重要作用。     

核因子-κB在人脑肿瘤中的表达及意义

目的 :探讨核因子 κB(nuclearfactorkappaB ,NF κB)在人脑肿瘤组织中的表达及意义。方法 :应用免疫组织化学方法检测NF κBP65在 1 0 6例人脑肿瘤中的表达 ,其中星形细胞肿瘤 64例、髓母细胞瘤 2 2例、脑膜瘤 2 0例。 1 0例正常大脑组织作为对照。结果 :星形细胞肿瘤、髓母细胞瘤及脑膜瘤中NF κBP65蛋白阳性表达率分别为54 7% (35 64)、36 4% (8 2 2 )和 5 0 % (1 2 0 ) ;1 0例正常脑组织中NF κBP65无 1例阳性表达。NF κBP65蛋白的表达在星形细胞瘤与脑膜瘤、髓母细胞瘤与脑膜瘤之间差异显著 (P <0 0 5)。结论 :NF κB组成性活化与脑恶性肿瘤的发生相关 ,NF κBP65是一种与人脑肿瘤相关的新的癌蛋白     

肿瘤特异单链抗体库的构建及肿瘤血管特异性结合抗体的体内筛选

目的:研究化疗药物依托泊苷对腺病毒载体介导的外源基因在肿瘤细胞内表达水平的影响。方法:携带外源基因增强型绿色荧光蛋白(EGFP)的复制缺陷型腺病毒Ad5-CMV-EGFP(MOI为1或10)单独或联合终质量浓度为0.2、2、20、40、80、100和200μg/ml的依托泊苷感染体外培养的肿瘤细胞NCI-H446(人非小细胞肺癌细胞株)、A549(人肺腺癌细胞株)、SMMC-7721(人肝癌细胞株)、SGC7901(人胃癌细胞株)、SKBR-3(人乳腺癌细胞株)和BTT(小鼠膀胱移行上皮癌细胞株)后不同时间,流式细胞仪分析肿瘤细胞EGFP阳性率和平均荧光强度,Western blotting检测EGFP蛋白表达,RT-PCR和实时荧光定量PCR检测肿瘤细胞内EGFP的mRNA表达量和DNA拷贝数。结果:不同剂量的依托泊苷可不同程度地提高Ad5-CMV-EGFP在7种肿瘤细胞内的表达水平,但对EGFP阳性率无明显提高。10MOI的Ad5-CMV-EGFP联合40μg/ml依托泊苷分别感染肿瘤细胞NCI-H446、NCI-H460、A549、SMMC-7721、SGC7901、SKBR-3和BTT24h后,细胞内EGFP的荧光强度分别是单独感染的3.3、3.5、3.1、6.2、7.0、5.4和3.4倍。Ad5-CMV-EGFP联合应用依托泊苷后肿瘤细胞内EGFP蛋白表达增加2~5倍,EGFP mRNA表达量提高,但DNA拷贝数未见明显改变。结论:依托泊苷可提高腺病毒载体介导的外源基因在肿瘤细胞内的表达水平,该作用可能是在转录水平上发挥作用的。     

重组复制缺陷型腺病毒Ad p53AIP1的抗肿瘤效应及其作用机制

目的:探讨外源性p53AIP1（p53regulated apoptosisinducing protein 1）基因抗肿瘤效应及其作用机制，以评估p53AIP1基因在肿瘤基因治疗中应用的可行性。方法：构建携带p53AIP1基因的重组复制缺陷型腺病毒Adp53AIP1，感染人肝癌细胞HepG2，应用MTT比色法、Western blotting、流式细胞术、罗丹明染色以及电镜等观察外源性p53AIP1基因表达对肿瘤细胞的作用及其相关机制。小鼠皮下接种感染Adp53AIP1的小鼠乳腺癌4T1细胞，观察Adp53AIP1对肿瘤细胞体内成瘤性的影响;建立4T1细胞皮下移植瘤小鼠模型, 直接瘤内多点注射重组腺病毒，观察Adp53AIP1的抗肿瘤疗效。结果：感染Adp53AIP1的HepG2细胞能够高效表达P53AIP1蛋白。MTT检测显示Adp53AIP1对人肝癌细胞HepG2的生长抑制率达50％以上；流式细胞术分析证实p53AIP1使肿瘤细胞周期阻滞于G2/M期；罗丹明染色、电镜观察以及凋亡相关蛋白PARP表达的检测均证实p53AIP1 能诱导肿瘤细胞发生明显凋亡。感染Adp53AIP1的肿瘤细胞体内成瘤受到非常明显的抑制（P<001）, Adp53AIP1瘤体注射对移植瘤生长也有明显的抑制作用（P<0.05）。Western blotting以及RTPCR检测证实Adp53AIP1对p53mRNA表达无影响，能下调mdm2 基因的表达；p53AIP1能上调P53蛋白的表达、下调MDM2蛋白的表达水平，同时还影响P21等细胞周期相关蛋白和凋亡相关蛋白的表达。结论：p53AIP1有明显的体内外抗肿瘤作用，其作用机制与其反向调控P53蛋白、调控多种细胞周期和细胞凋亡相关蛋白、诱导细胞周期阻滞和细胞凋亡有关，该基因在肿瘤基因治疗中具有潜在的应用前景。     

Systemic vector leakage and transgene expression by intratumorally injected recombinant adenovirus vectors.

Interleukin 12 is a heterodimeric cytokine that exhibits potent immunostimulatory effects. It has shown some promise in preclinical and clinical studies but was accompanied by serious systemic toxicity such as flu-like syndromes, a rapid transient leukopenia, elevated liver transaminases, gastrointestinal toxicity, and/or liver dysfunction. Gene therapy with intratumorally injected recombinant adenoviral vectors offers the potential to restrict therapeutic gene expression in the tumor. Here we show that a substantial amount of adenoviral vectors disseminates into the systemic circulation and infects parenchymal organs. We further show that this results in high systemic levels of potentially toxic transgene products. To reduce potential toxicity, we tested an inducible promoter based on the heat shock proteins (hsp70B) and present evidence that high intratumoral levels of a therapeutic transgene can be obtained while systemic expression is reduced to a minimum, increasing the safety of adenovirus-based tumor gene therapy.     

Coxsackievirus-adenovirus receptor expression in ovarian cancer cell lines is associated with increased adenovirus transduction efficiency and transgene expression

The expression of coxsackievirus-adenovirus receptor (CAR) and the integrins alpha(v)beta3 and alpha(v)beta5 was analyzed quantitatively (flow cytometry) and qualitatively (immunocytochemistry) in five human ovarian cancer cell lines (PEO1, PEO4, PEO14, SKOV-3, and OVCAR-3) and three control cell lines (293, HeLa, and CHO-K1). The transduction efficiencies were evaluated by adv/rsv-beta-Gal transduction followed by X-gal staining. The effects of 17beta-estradiol on cell growth, CAR and integrins alpha(v)beta3/5 expression, adenovirus transduction efficiency, and cell-killing efficacy of adv/rsv-tk plus ganciclovir were determined. The levels of CAR, integrin alpha(v)beta3, and integrin alpha(v)beta5 showed great variation between the cell lines. Whereas the expression of CAR appeared to be essential for and positively correlated with adenovirus transduction efficiency, the integrins alpha(v)beta3 and alpha(v)beta5 were not absolutely necessary for adenovirus transduction even though their presence may facilitate transduction. In PEO4 and PEO1 cells, proliferation was stimulated by 17beta-estradiol in a dose-dependent manner. In PEO4 cells, and much less pronounced in PEO1 cells, this was accompanied by an increase in CAR expression. The stimulation of CAR expression was paralleled by an increased transduction efficiency resulting in an increased cell-killing efficacy. Our data suggest that the expression of CAR is one of the most important prerequisites for successful adenovirus-mediated gene therapy of ovarian cancer.     

The histone deacetylase inhibitor FK228 preferentially enhances adenovirus transgene expression in malignant cells.

PURPOSE: Efficient adenovirus infection requires coxsackie-adenovirus receptor (CAR) and alpha(v) integrin. Whereas many malignant cells express these proteins poorly, normal tissues, especially liver, express high levels and are susceptible to adenovirus infection. Our previous studies showed that treatment of cancer cell lines with low concentrations of the histone deacetylase inhibitor FK228 (FR901228, depsipeptide), a drug in Phase II clinical trials, before infection was associated with an increase in adenovirus transgene expression. The purpose of these studies was to analyze the effects of FK228 on cultured normal human cells before initiating animal studies. EXPERIMENTAL DESIGN: Cancer and normal cells from the corresponding tissue were treated with FK228 and analyzed for the proteins needed for infection and the infection efficiency. RESULTS: Treatment of cancer cell lines with 1 ng/ml FK228 increased CAR RNA, alpha(v) integrin RNA, and histone H3 acetylation levels, and was associated with a 4-10-fold increase in the number of infected cells expressing the transgene. Similar treatment of normal human mammary epithelial cells, renal proximal tubule epithelial cells, and hepatocytes had little effect. The insensitivity of cultured normal cells may be explained, in part, by expression of the drug efflux pump P-glycoprotein, because addition of the P-glycoprotein inhibitor XR9576 (tariquidar) with FK228 resulted in increased histone acetylation and CAR expression. CONCLUSION: These studies suggest that low concentrations of FK228 preferentially increase the efficiency of adenoviral transgene expression in cancer cells compared with cultured normal cells from the corresponding tissue and may increase the efficiency of adenovirus therapies in vivo.     

Polycations and cationic lipids enhance adenovirus transduction and transgene expression in tumor cells.

Replication-deficient adenovirus vectors are efficient vehicles for delivering therapeutic genes into mammalian cells. However, the high doses required to produce effective gene transfer in vivo can also cause unwanted cellular toxicity. To improve replication-deficient adenovirus transgene expression while minimizing adverse reactions, we have tested polycationic compounds for their ability to enhance adenovirus adsorption. We demonstrate increased transgene expression after mixing adenovirus preparations with polycations, cationic lipids, and CaCl2 prior to transduction in vitro. An E1-deleted adenovirus vector was admixed with various polycations, and beta-galactosidase (beta-gal) activity was evaluated. The optimal polycation concentrations for augmenting adenovirus-mediated gene transfer were 5-10 microg/mL polybrene, 400 microg/mL protamine sulfate, 10 microg/mL N-(1-[2,3-dioleoyloxy]propyl)-N,N,N-trimethylammonium methylsulfate (DOTAP), 2.5 microg/mL Lipofectamine, and 62.5 mM CaCl2. Polycations enhanced beta-gal expression in three of six established cell lines. Similar results were obtained using primary tumor cell cultures, where beta-gal expression was increased 1.5- to 10.7-fold (mean = 3.6) by polybrene, 1.8- to 7.5-fold (mean = 3.4) by DOTAP, and 2.3- to 10.4-fold (mean = 4.8) by protamine sulfate. Adenovirus transduction efficiency in two primary leukemia isolates was improved by 3- and 4.5-fold. We were unable to demonstrate any benefit when adenovirus was admixed with protamine sulfate prior to intratumoral injection in a xenogeneic severe combined immunodeficient mouse melanoma tumor model. Further studies will determine whether polycations can improve intratumoral gene transfer.     

Suppression of c-myc and c-myb expression in myeloid cell lines treated with recombinant tumor necrosis factor-alpha

Proto-oncogenes are thought to be involved in cellular differentiation and proliferation. Tumor necrosis factors (TNFs) are specific cytokines that have cytostatic and cytotoxic effects in vitro against a wide range of human tumor cells. We have previously demonstrated that recombinant TNFs (rTNFs) have an antiproliferative effect on certain human leukemic cell lines (HL-60, KBM3, KBM5) and no effect on others (K562). To study the possible role of the c-myc and c-myb oncogenes in this antiproliferative effect of TNF, we examined their expression in cell lines HL-60, KBM3, KBM5, and K562 before and after incubation with rTNF-alpha. Expression of c-myc and c-myb was elevated in all cell lines prior to incubation with rTNF-alpha. In the sensitive cell lines HL-60, KBM5, and KBM3 expression of c-myc and c-myb decreased rapidly 8-, 16-, and 4-fold, respectively, by 24 hr. K562 cells, insensitive to rTNF-alpha, exhibited no change in c-myc or c-myb expression over 24 hr. These studies demonstrated that down-regulation of c-myc and c-myb expression were associated with antiproliferative effects of rTNF-alpha on these cell lines.     

Halofuginone enhances the radiation sensitivity of human tumor cell lines

Transforming growth factor beta (TGF-β) is implicated in radiation-induced fibrosis of normal tissues in patients receiving radiotherapy. Inhibiting the TGF-β signaling pathway by various means has been shown to reduce radiation-induced fibrosis in pre-clinical studies. The present study evaluated the effects of interfering with the TGF-β signaling pathway on the radiosensitivity of selected human tumor cell lines using the plant-derived alkaloid, halofuginone. Halofuginone treatment inhibited cell growth, halted cell cycle progression, decreased radiation-induced DNA damage repair, and decreased TGF-β receptor II protein levels, leading to increased cellular radiosensitization. These data further support the goal of manipulating the TGF-β pathway to achieve a positive increase in the therapeutic gain in clinical radiotherapy.