人EGFR显性负性突变体对胃癌细胞体内成瘤及淋巴结转移的影响

为了研究人表皮生长因子显性负性突变体(dominant negative mutant of EGFR, dnEGFR)对胃癌细胞体内成瘤及淋巴结转移的影响,用目的质粒pEGFPN1 dnEGFR,空质粒载体pEGFP N1分别转染胃癌细胞NCI-N87.筛选出稳定转染株,实验共分3组：NCI-N87细胞未转染组（untreated NCI-N87,UN组）,NCI-N87细胞pEGFP-N1转染组（EN组）;NCI-N87细胞pEGFPN1-dnEGFR转染组（DN组）.将3组细胞接种于裸鼠右后足垫,6周后测量移植瘤大小及对应腹股沟转移淋巴结数目,HE染色验证,real-time PCR和Western 印迹检测3组细胞中AKT1、MAPK3 mRNA和蛋白的表达改变.结果发现,DN组移植瘤较UN、EN组明显缩小（P<0.05）,且右腹股沟转移淋巴结数目较UN、EN组减少（P<0.05）.DN组细胞中,AKT1、MAPK3 mRNA和蛋白水平较UN、EN组降低（P<0.05）.提示pEGFPN1-dnEGFR可抑制裸鼠体内胃癌细胞成瘤及淋巴结转移,AKT1及MAPK3信号通路可能参与其中.     

靶向survivin基因的siRNA对姜黄素诱导胃癌细胞凋亡的影响

目的:研究靶向survivin基因的siRNA对胃癌细胞,survivin表达的影响,抑制survivin基因表达对姜黄素诱导胃癌细胞凋亡的影响。方法:通过脂质体将survivinsiRNA导入胃癌细胞株BGC-803,用Real-timePCR和Western-blotting检测转染后细胞内survivin基因表达水平,流式细胞仪和Hochest染色检测细胞凋亡的改变。结果:姜黄素可抑制BGC-803细胞的生长,其生长抑制率和药物浓度与作用时间呈依赖关系;姜黄素作用BGC-803细胞后,survivin蛋白和mRNA表达降低;通过转染survivinsiRNA抑制BGC-803细胞survivin基因的表达能促进姜黄素诱导BGC-803细胞凋亡的作用。结论:靶向抑制survivin基因表达后姜黄素诱导胃癌细胞BGC-803凋亡的作用增强。     

优化胶粘贴法建立裸鼠胃癌原位种植模型

目的通过对两种胶粘贴法建立的胃癌原位种植动物模型的比较研究,为探讨胃癌的发病机制和实验治疗提供理想的动物模型。方法用OB胶和FS生物蛋白胶法分别建立胃癌原位种植动物模型,观察和比较两种方法所建立的模型肿瘤生长状况、转移情况和形态学变化。结果FS生物蛋白胶组未出现肿瘤大片坏死,腹水形成率为85.7%,幽门梗阻发生率为57.1%;而OB胶组肿瘤大片坏死发生率为100%,腹水形成率为14.3%,未出现幽门梗阻。FS生物蛋白胶组有三例出现了肺和脑转移。结论FS生物蛋白胶法建立的裸鼠胃癌原位种植动物模型能更好的模拟人胃癌患者的临床过程,为研究人胃癌转移机制和实验治疗提供理想的动物模型。     

靶向Survivin的反义寡核苷酸对肿瘤细胞增殖的抑制作用

 Survivin是新近克隆的一种凋亡抑制蛋白 (IAP)家族成员 ,在几乎所有肿瘤组织中特异性表达 ,而在正常成年终末分化组织中低表达甚至不表达 .采用四唑盐 (MTT)比色实验法比较 2 0条抗人survivin反义寡核苷酸对HeLa细胞增殖的抑制效果 ,并从中筛选效果显著的反义寡核苷酸 ,在体外水平进一步验证其抑制survivin表达的能力 .在用 4 0 0nmol L反义寡核苷酸转染HeLa细胞 4 8h后 ,有 4条反义寡核苷酸对细胞增殖的抑制率超过 4 0 %,其中 4 5号反义寡核苷酸的抑制率可达5 9%,而阳性对照序列ISIS2 372 2的抑制率仅达 30 %.Northern和Western印迹分析证明 :4 5号反义寡核苷酸可明显降低细胞中survivin基因的mRNA含量和蛋白水平 .4 5号反义寡核苷酸还可在较低浓度 (2 0 0nmol L)显著增强HeLa细胞对化疗药三尖杉酯碱的敏感性 .因此 ,4 5号反义寡核苷酸有望应用于survivin高表达肿瘤的辅助治疗之中     

应用siRNA干扰胃癌的研究进展

胃癌是消化系统最常见的恶性肿瘤,而我国是胃癌高发区,其发病率和死亡率均高于世界平均水平。在我国大多数患者明确诊断时已进入进展期,所以大多数患者再行手术切除后还需放化疗治疗。近来随着对胃癌的研究深入,可通过对胃癌肿瘤标本行分子检测给予患者药物靶向治疗,实现个体化治疗。RNA干涉(RNAi)技术被广泛用于基因功能的研究,并且在哺乳动物研究中得到飞速发展.si RNA是在RNAi中起中心作用,其可抑制特定m RNA,以调节不同蛋白在肿瘤发生时的异常表达。对si RNA的研究将为胃癌的基因治疗供更广阔的空间。     

两种人乳腺癌裸鼠移植模型的建立

目的建立简便的人乳腺癌裸鼠移植模型,并探讨其部分生物学特性。方法采用雌激素受体阴性的MDA-MB-231和SK-BR-3人乳腺癌细胞株,分别接种于10只裸鼠左侧腋窝皮下,移植细胞总数为1×107/只。观察肿块生长情况,第42天处死荷瘤鼠,切除肿块作病理切片。结果 MDA-MB-231接种后第5d在接种部位可见结节,成瘤率为90%（9/10）,接种42 d肿瘤体积426.6±333.8,瘤重0.417±0.276,病理学检查为浸润性导管癌;SK-BR-3接种后第11天在接种部位可见结节,成瘤率为80%（8/10）,接种42 d肿瘤体积357.5±246,瘤重0.325±0.167,病理学检查为浸润性导管癌。结论该方法建立的人乳腺癌裸鼠移植模型,皮下移植方法简单,易于操作,成功率较高,肿瘤可部分保持人乳腺癌生物学特性,为研究人乳腺癌提供了重要工具。     

人结肠癌SW480细胞裸鼠皮下移植瘤DcR3基因的RNA干扰及其作用

目的:观察DcR3基因小干扰RNA(siRNA)对人结肠癌SW480细胞裸鼠皮下移植瘤DcR3基因表达的影响。方法:建立结肠癌SW480细胞裸鼠皮下移植瘤模型,瘤体注射脂质体与DcR3siRNA混合物,转染DcR3siRNA,免疫组织化学及RT-PCR检测观察DcR3基因的表达。结果:建立了结肠癌SW480细胞裸鼠皮下移植瘤模型;治疗后,治疗组移植瘤明显减小,空白对照组、阴性对照组肿瘤体积显著大于治疗组(P<0.01);各组肿瘤组织中DcR3基因均有不同程度的表达,治疗组表达程度明显低于阴性对照组及空白对照组(RT-PCRP<0.05,免疫组化P<0.01)。结论:人结肠癌SW480细胞在裸鼠皮下有良好的成瘤性;脂质体与DcR3siRNA混合物可特异性抑制结肠癌裸鼠皮下移植瘤内DcR3基因的表达。     

An RGD-Modified MRI-Visible Polymeric Vector for Targeted siRNA Delivery to Hepatocellular Carcinoma in Nude Mice

RNA interference (RNAi) has significant therapeutic promise for the genetic treatment of hepatocellular carcinoma (HCC). Targeted vectors are able to deliver small interfering RNA (siRNA) into HCC cells with high transfection efficiency and stability. The tripeptide arginine glycine aspartic acid (RGD)-modified non-viral vector, polyethylene glycol-grafted polyethylenimine functionalized with superparamagnetic iron oxide nanoparticles (RGD-PEG-g-PEI-SPION), was constructed as a magnetic resonance imaging (MRI)-visible nanocarrier for the delivery of Survivin siRNA targeting the human HCC cell line Bel-7402. The biophysical characterization of the RGD-PEG-g-PEI-SPION was performed. The RGD-modified complexes exhibited a higher transfection efficiency in transferring Survivin siRNA into Bel-7402 cells compared with a non-targeted delivery system, which resulted in more significant gene suppression at both the Survivin mRNA and protein expression levels. Then, the level of caspase-3 activation was significantly elevated, and a remarkable level of tumor cell apoptosis was induced. As a result, the tumor growth in the nude mice Bel-7402 hepatoma model was significantly inhibited. The targeting ability of the RGD-PEG-g-PEI-SPION was successfully imaged by MRI scans performed in vitro and in vivo. Our results strongly indicated that the RGD-PEG-g-PEI-SPION can potentially be used as a targeted non-viral vector for altering gene expression in the treatment of hepatocellular carcinoma and for detecting the tumor in vivo as an effective MRI probe.     

胰腺癌裸鼠皮下异种移植动物模型建立研究

目的:用人体胰腺癌细胞株,建立小鼠胰腺癌细胞株(pGHAM-1)移植性胰腺癌模型,并研究其生物学特性。方法:将pGHAM-1细胞培养后配成1×107/ml,取0.2mL接种于小鼠皮下。于接种后20、30、40天观察肿瘤的生长、转移及腹水量。接种40天后处死动物,解剖取出移植瘤,用游标卡尺测量肿瘤大小,再进行HE染色的组织病理学检查,免疫组织化学检测血管内皮细胞生长因子(VEGF)及肿瘤转移相关蛋白(nm23-H1)的表达。结果:分别于20、30、40天测量肿瘤体积为84.1±21.9 mm3,413.7±208.4 mm3,2187.3±1882.8 mm3,后者与10 d前比较差异均具有统计学意义(P<0.01)。HE染色结果显示肿瘤组织呈条索状或小梁状排列,肿瘤组织与正常组织交界处有少量淋巴细胞浸润,肿瘤组织中血管生成罕见。免疫组织结果显示VEGF和nm23-H1蛋白在肿瘤组织中均呈阴性表达。结论:异位裸鼠人胰腺癌移植瘤模型易复制,时间短,成功率高,为胰腺癌体内研究提供了理想的动物模型。     

Survivin、Dnmt 和CD44 在胃溃疡及胃癌中表达的差异

胃溃疡(Gastric Ulcer GU)和胃癌(Gastrio Cancer Gc)均是我国乃至全世界人群中的常见病、多发病。近年来,虽然胃溃疡的发病率开始呈下降趋势,但仍属消化系统疾病中最常见的疾病之一,目前已被认为是癌前病变之一。据统计,5%左右的胃溃疡可发生癌变,甚至有统计最高达29.4%的胃癌来自胃溃疡[1]。在世界范围内恶性肿瘤中,胃癌位居第4,病死率位居第2,在我国则居第1位。胃癌发生的分子机制研究表明多基因变异是细胞发生癌变的内因[2]。各种癌基因、抑癌基因和错配修复基因、细胞信号传导通路的异常、细胞周期调控改变及相关产物均对胃癌的发生发展产生影响。如Survivin、DNA甲基化和CD44等均是近年来在胃癌组织中发现的并成为研究热点的基因。通过对Survivin、Dnmt和CD44三种基因在胃溃疡及胃癌中表达的差异的了解,有助于加深对胃癌发生、发展及转移机制的认识,更好的为临床应用中胃溃疡及胃癌的治疗提供理论依据和找到更好的治疗方法。     

Novel Immunocytokine IL12-SS1 (Fv) Inhibits Mesothelioma Tumor Growth in Nude Mice

Mesothelin is a glycosylphosphatidylinositol-anchored glycoprotein that is highly expressed on the cell surface of malignant mesothelioma. Monoclonal antibodies against mesothelin are being evaluated for the treatment of mesothelioma. Immunocytokines represent a novel class of armed antibodies. To provide an alternative approach to current mesothelin-targeted antibody therapies, we have developed a novel immunocytokine based on interleukin-12 (IL12) and the SS1 Fv specific for mesothelin. IL12 possesses potent anti-tumor activity in a wide variety of solid tumors. The newly-developed recombinant immunocytokine, IL12-SS1 (Fv), was produced in insect cells using a baculovirus-insect cell expression system. The SS1 single-chain Fv was fused to the C terminus of the p35 subunit of IL12 through a short linker (GSADGG). The single-chain IL12-SS1 (Fv) immunocytokine bound native mesothelin proteins on malignant mesothelioma (NCI-H226) and ovarian (OVCAR-3) cells as well as recombinant mesothelin on A431/H9 cells. The immunocytokine retained sufficient bioactivity of IL12 and significantly inhibited human malignant mesothelioma (NCI-H226) grown in the peritoneal cavity of nude mice and showed comparable anti-tumor activity to that of the SS1P immunotoxin. IL12-SS1 (Fv) is the first reported immunocytokine to mesothelin-positive tumors and may be an attractive addition to mesothelin-targeted cancer therapies.     

亚砷酸对裸鼠宫颈癌移植瘤模型的干预研究

目的建立宫颈癌移植瘤模型,研究亚砷酸的体内干预效果及机制。方法将Hela细胞注射于裸鼠皮下接种,成瘤后腹腔分别连续注射亚砷酸、卡铂及生理盐水14d,观察肿瘤大小和裸鼠精神状态,用流式细胞术（FCM）检测细胞凋亡和细胞周期。结果亚砷酸组小鼠精神状态良好。与对照组比较,亚砷酸组治疗7d后肿瘤生长速度减慢;治疗14d肿瘤重量显著性降低（P〈0．05）,抑瘤率达到35．8％,高于卡铂组的27．9％;治疗14d肿瘤细胞的凋亡率显著升高（P〈0．01）,增殖指数（PI）显著降低（P〈0．01）,处于G0／G1周期的细胞明显增多（P〈O．01）,处于G2/M周期的细胞明显减少（P〈0．05）。结论亚砷酸具有抑制宫颈癌移植瘤生长的作用,且未见明显毒副作用,其抑瘤的机理可能与诱导肿瘤细胞凋亡、干扰肿瘤细胞生长周期和抑制肿瘤细胞增殖有关。     

G6PD缺陷抑制人黑色素瘤细胞裸鼠移植瘤的生长

敲减葡糖6-磷酸脱氢酶(G6PD)表达的人黑色素瘤A375细胞(A375-G6PDΔ) 呈现生长增殖抑制和凋亡率升高. 为明确G6PD缺陷对裸鼠体内成瘤的影响及其可能机制,用A375-WT与A375-G6PDΔ细胞制作裸鼠荷瘤模型,观察体内瘤体生长,real-time PCR、免疫组织化学染色与紫外分光光度法分别检测瘤体组织G6PD mRNA、G6PD蛋白及酶活性,Western 印迹分析凋亡相关蛋白,分光光度法测定NADPH和GSH/GSSG水平. 结果显示,A375-G6PDΔ细胞注射组的裸鼠成瘤时间延长,瘤体生长明显减慢,瘤体的体积与质量显著低于A375 WT细胞注射组（P <0.01）;与A375-WT细胞注射组相比,A375 G6PDΔ细胞注射组的裸鼠瘤体组织中G6PD mRNA表达、G6PD阳性细胞数与G6PD活性分别降低了87.10%、77.20%与75.77%（P<0.01）,G6PD、p53和Bcl-2的表达分别降低了67.92%、65.54%和62.32%（P<0.01）,Fas升高了86.38%（P<0.01）,NADPH和GSH/GSSG分别降低了74.37%和86.02%（P<0.01）. 结果提示,G6PD缺陷可能通过减少核酸等合成的原料、改变细胞内氧化还原状态及凋亡相关蛋白表达抑制裸鼠瘤体生长与增殖,这为黑色素瘤发生和治疗研究提供了新的线索.     

抑制survivin表达对软骨多糖诱导乳腺癌细胞凋亡的增敏作用

目的:研究靶向抑制survivin表达对软骨多糖诱导乳腺癌MCF-7细胞凋亡的影响.方法:将survivin-siRNA转染乳腺癌MCF-7细胞.用定量PCR和Western-blotting检测转染后细胞内survivin基因表达水平,流式细胞仪和Hochest染色检测细胞凋亡的改变.结果:软骨多糖可抑制MCF-7细胞的生长,其生长抑制率与药物浓度和作用时间呈依赖关系;软骨多糖作用MCF-7细胞后,survivin表达降低;转染survivin-siRNA能促进软骨多糖诱导MCF-7细胞凋亡.结论:靶向抑制survivin表达对软骨多糖诱导乳腺癌细胞凋亡具有增敏作用.     

Knockdown of RAGE Inhibits Growth and Invasion of Gastric Cancer Cells

The receptor for advanced glycation end-products (RAGE) is an oncogenic trans-membranous receptor, which is overexpressed in multiple human cancers. However, the role of RAGE in gastric cancer is still elusive. In this study, we investigated the expression and molecular mechanisms of RAGE in gastric cancer cells. Forty cases of gastric cancer and corresponding adjacent non-cancerous tissues (ANCT) were collected, and the expression of RAGE was assessed using immunohistochemistry (IHC) in biopsy samples. Furthermore, RAGE signaling was blocked by constructed recombinant small hairpin RNA lentiviral vector (Lv-shRAGE) used to transfect into human gastric cancer SGC-7901 cells. The expression of AKT, proliferating cell nuclear antigen (PCNA) and matrix metallopeptidase-2 (MMP-2) was detected by Real-time PCR and Western blot assays. Cell proliferative activities and invasive capability were respectively determined by MTT and Transwell assays. Cell apoptosis and cycle distribution were analyzed by flow cytometry. As a consequence, RAGE was found highly expressed in cancer tissues compared with the ANCT (70.0% vs 45.0%, P=0.039), and correlated with lymph node metastases (P=0.026). Knockdown of RAGE reduced cell proliferation and invasion of gastric cancer with decreased expression of AKT, PCNA and MMP-2, and induced cell apoptosis and cycle arrest. Altogether, upregulation of RAGE expression is associated with lymph node metastases of gastric cancer, and blockade of RAGE signaling suppresses growth and invasion of gastric cancer cells through AKT pathway, suggesting that RAGE may represent a potential therapeutic target for this aggressive malignancy.Key words: RAGE, gastric cancer, growth, invasion     

Chemo-Immunotherapy with Oxaliplatin and Interleukin-7 Inhibits Colon Cancer Metastasis in Mice

Combination of immunotherapy and chemotherapy has shown promise for cancer. Interleukin-7 (IL-7) can potentially enhance immune responses against tumor, while oxaliplatin (OXP), a platinum-based drug, can promote a favorable immune microenvironment and stimulate anticancer immune responses. We evaluated the anti-tumor activity of IL-7 combining OXP against a murine colon carcinoma in vitro and in vivo and studied the tumor immune microenvironment to investigate whether the combined treatment affects on the local immune cell populations. Utilizing lung and abdomen metastasis models by inoculation of CT26 mice colon cancer cells, we evaluated the anti-tumor efficacy of combining IL-7 and OXP in mice models. Tumor immune microenvironment was evaluated by flow cytometric analysis and immunohistochemical staining. Our study showed that the in vivo administration of IL-7 combined with OXP markedly inhibited the growth of tumors in lung and abdomen metastasis models of colon cancer. IL-7 alone had no effect on tumor growth in mice and IL-7 did not alter cell sensitivity to OXP in culture. The antitumor effect of combining IL-7 and OXP correlated with a marked increase in the number of tumor-infiltrating activated CD8+ T cells and a marked decrease in the number of regulatory T (Treg) cells in spleen. Our data suggest that OXP plus IL-7 treatment inhibits tumor cell growth by immunoregulation rather than direct cytotoxicity. Our findings justify further evaluation of combining IL-7 and chemotherapy as a novel experimental cancer therapy.     

PKG II Inhibits EGF/EGFR-Induced Migration of Gastric Cancer Cells

Background

Our previous research results showed that Type II cGMP dependent protein kinase (PKG II) could block the activation of epidermal growth factor receptor (EGFR) and consequently inhibit the proliferation and the related MAPK/ERK-mediated signal transduction of gastric cancer cell line BGC-823, suggesting that PKG II might inhibit other EGFR-triggered signal transduction pathways and related biological activities of gastric cancer cells. This paper was designed to investigate the potential inhibition of PKG II on EGF/EGFR-induced migration activity and the related signal transduction pathways.

Methodology/Principal Findings

In gastric cancer cell line AGS, expression and activity of PKG II were increased by infecting the cells with adenoviral construct encoding PKG II cDNA (Ad-PKG II) and treating the cells with cGMP analogue 8-pCPT-cGMP. Phosphorylation of proteins was detected by Western Blotting and active small G protein Ras and Rac1 was measured by “Pull-down” method. Cell migration activity was detected with trans-well equipment. Binding between PKG II and EGFR was detected with Co-IP. The results showed EGF stimulated migration of AGS cell and the effect was related to PLCγ1 and ERK-mediated signal transduction pathways. PKG II inhibited EGF-induced migration activity and blocked EGF-initiated signal transduction of PLCγ1 and MAPK/ERK-mediated pathways through preventing EGF-induced Tyr 992 and Tyr 1068 phosphorylation of EGFR. PKG II bound with EGFR and caused threonine phosphorylation of it.

Conclusion/Significance

Our results systemically confirms the inhibition of PKG II on EGF-induced migration and related signal transduction of PLCγ1 and MAPK/ERK-mediated pathways, indicating that PKG II has a fargoing inhibition on EGF/EGFR related signal transduction and biological activities of gastric cancer cells through phosphorylating EGFR and blocking the activation of it.     

Silencing of Bcl-XL Expression in Human MGC-803 Gastric Cancer Cells by siRNA

To investigate the inhibitory effect of the Bcl-XL small interfering RNA(siRNA)on BcI-XLgene expression in the human gastric cancer cell line MGC-803,green fluorescent protein(GFP)siRNAwas constructed and transfected into MGC-803 ceils,together with GFP expression vector pTrace SV40.GFP expression levels were observed using fluorescence microscopy.Bcl-XL siRNA and negative siRNAwere then constructed and stably transfected into MGC-803 cells.RT-PCR and immunofluorescence wereused to detect the expression of Bcl-XL.Spontaneous apoptosis was detected by acridine orange(AO)andflow cytometry.Results were as follows:(1)48 h after GFP expression vector and GFP siRNA co-transfection,the expression level of GFP in the GFP siRNA group was much lower than the negative siRNA group,according to fluorescence microscopy results.The mRNA and protein levels of Bcl-XL in Bcl-XL siRNAstable transfectants were reduced to almost background level compared with negative siRNA transfectantsor untreated cells.(2)Changes in nucleus morphology was observed by AO staining nucleic and flowcytometry analysis,which showed that stable Bcl-XL siRNA transfectants have an increased spontaneousapoptosis (21.17%+1.26% vs.1.19%+0.18% and 1.56%+0.15% respectively,P<0.05 vs.negative siRNAor untreated control),siRNA targeting GFP or Bcl-XL genes can specifically suppress GFP or BcI-XLexpression in MGC-803 cells,and Bcl-XL siRNA can increase spontaneous apoptosis.Bcl-XL siRNA maybe a beneficial agent against human gastric adenocarcinoma.