重组人p53腺病毒联合奥沙利铂对胃癌细胞BGC-823的生长抑制作用

目的观察重组人p53腺病毒(rAd-p53)联合奥沙利铂对胃癌细胞BGC-823的生长抑制作用。方法用rAd-p53注射液(A组)及奥沙利铂(B组)及两者联合(C组)作用于胃癌细胞株BGC-823不同时间后,MTT法检测其对体外培养细胞的抑制率,免疫组织化学SP法检测p53蛋白表达,流式细胞术分析其细胞凋亡蛋白半胱天冬氨酸蛋白酶3(Caspase-3)表达;结果与对照组(D组)比较。结果在A组、B组中,随药物浓度及作用时间的增加,细胞的生长抑制率逐渐增高;C组作用24h,在较低浓度时细胞生长抑制率即明显增高(P<0.05)。C组与D组比较,胃癌细胞Caspase-3蛋白的含量升高(P<0.05),但p53蛋白无明显升高(P>0.05)。结论 rAd-p53有增强奥沙利铂化疗敏感性的作用;其机制可能与其通过线粒体途径激活下游的Caspase-3诱导细胞凋亡有关。     

SHIP2通过上调Bim表达增强胃癌细胞BGC-823对紫杉醇的敏感性

目的探讨SHIP2(SH2 domain containing inositol 5-phosphatase 2)基因转染人胃癌细胞BGC-823后对紫杉醇敏感性的影响。方法流式细胞仪PI单染法检测细胞凋亡率。应用免疫蛋白印迹法(Western blot)检测各组细胞蛋白表达情况。实时荧光定量PCR(real-time quantitative PCR,qRT-PCR)分析mRNA的变化水平。将pCMV6-SHIP2质粒在脂质体介导下转染人胃癌BGC-823细胞,同时以转染空载体和未转染细胞作为对照组。将GV112-Puromycin空载体和GV112-Puromycin-Bim(Bcl-2 interacting mediator of cell death)慢病毒颗粒分别感染BGC-823细胞,建立稳定细胞株,再将pCMV6-SHIP2质粒分别转染空载体和稳定干扰Bim表达细胞株。结果与SGC-7901细胞相比,BGC-823细胞对紫杉醇诱导的凋亡相对不敏感,0.3μmol·L-1紫杉醇诱导BGC-823 48 h后细胞凋亡率仅为(25.6±1.6)%,在紫杉醇作用不同时间点Bim蛋白和mRNA表达均无明显变化;与对照组相比,转染SHIP2基因能明显增加Bim的表达,紫杉醇作用48 h后,细胞凋亡率上升到(50.8±0.9)%;GV112-Puromycin-Bim慢病毒颗粒感染的BGC-823细胞,Bim的表达明显被抑制,在GV112-Puromycin-Bim慢病毒颗粒感染的稳定BGC-823细胞中转入pCMV6-SHIP2,紫杉醇作用48 h后,凋亡率为(27.6±1.6)%。结论转染外源性SHIP2基因能有效提高BGC-823细胞内Bim的表达,诱导BGC-823细胞凋亡,明显增加BGC-823细胞对紫杉醇的敏感性。     

血管生成素1基因转染对胃癌细胞侵袭能力的影响

目的 探讨人血管生成素1(Ang-1)对人胃癌细胞BGC-823基质会属蛋白酶2(MMP-2)表达情况的影响.方法 利用腺病毒作为载体将已构建成功的含Ang-1基因的重组腺病毒(Ad-Ang-1)瞬时转染人胃癌细胞BGC-823为实验组,转染编码绿色荧光蛋白的复制缺陷型腺病毒重组体(Ad-GFP)为阴性对照组,未转染的正常细胞为对照组.应用RT-PCR和Western blot印迹检测三组细胞中MMP-2在mRNA和蛋白表达的情况.结果 MMP-2在实验组中表达明显高于阴性对照组和空白对照组(P<0.05).结论 Ang-1能显著提高人胃癌细胞BGC-823的MMP-2的表达,提示Ang-1可能具有促进肿瘤细胞侵袭的作用.     

葫芦素B对人胃癌BGC-823细胞增殖及凋亡的影响

目的探讨葫芦素B对人胃癌BGC-823细胞增殖及凋亡的影响及其作用的分子机制。方法体外培养BGC-823细胞,MTT法观察葫芦素B对细胞增殖的影响,采用流式细胞术检测细胞凋亡率,采用分光光度法检测Caspase-3、Caspase-9的活性,采用Western blot方法检测葫芦素B对Bcl-2、Bax蛋白表达的影响。结果葫芦素B对BGC-823细胞的增殖有抑制作用,且此作用呈剂量和时间依赖性;流式细胞仪检测结果显示,葫芦素B诱导BGC-823细胞凋亡,呈剂量依赖性。葫芦素B处理后Caspase-3、Caspase-9活性升高,细胞抗凋亡蛋白Bcl-2表达减少,促凋亡蛋白Bak的表达增加。结论葫芦素B可以抑制人胃癌BGC-823细胞的增殖并诱导细胞凋亡。     

紫杉醇诱导胃癌BGC-823和SGC-7901细胞凋亡作用的比较

目的研究胃癌BGC-823细胞和SGC-7901细胞对紫杉醇诱导凋亡的敏感性。方法用0．1～0．5μmol·L^-1紫杉醇作用于BGC-823和SGC-7901细胞,再用0．3μmol·L^-1紫杉醇对BGC-823和SGC-7901细胞分别作用0、6、12、24、36、48h,通过形态学观察及流式细胞术检测细胞凋亡率的变化。结果（1）紫杉醇对两种胃癌细胞均有明显诱导凋亡作用,且均呈时间依赖性及剂量依赖性;（2）中分化的SGC-7901细胞株对紫杉醇的敏感性明显高于低分化的BGC-823细胞株。结论不同分化程度的胃癌细胞株对紫杉醇的敏感性不同。     

低氧环境下转染Ang-1对胃癌细胞凋亡的影响

目的探讨在低氧环境下将促血管生成素1(Ang-1)转染到人胃癌细胞BGC-823中,检测其对人胃癌细胞凋亡的影响。方法利用腺病毒作为载体将已构建成功的Ang-1基因的重组腺病毒瞬时转染人胃癌细胞株BGC-823。实验分为对照组(未转染Ang-1的正常胃癌细胞)、低氧组(仅以低氧诱导剂氯化钴进行低氧干预)、转染组(仅以Ang-1转染)和低氧转染组(低氧干预加Ang-1转染)。通过流式细胞术检测转染各组凋亡率的改变,再分别使用半定量RT-PCR和Western blot方法检测上述各组Bcl-2和Bax mRNA和蛋白表达水平。结果与对照组、低氧组和转染组比较,低氧转染组胃癌细胞凋亡率明显下降(P<0.01);Bcl-2 mRNA和蛋白表达水平明显增加,BaxmRNA和蛋白水平明显减少(P<0.05)。结论低氧环境下转染Ang-1能够明显上调人胃癌细胞Bcl-2的表达,下调Bax的表达。这可能是其抑制细胞凋亡的机制之一。     

选择性COX-2抑制剂NS-398对人胃腺癌细胞增殖和凋亡的影响

目的 研究环氧化酶2(COX-2)抑制剂NS-398对胃癌培养细胞系BGC-823增殖及凋亡的影响.方法 应用MTT法检测NS-398对胃癌细胞BGC-823细胞增殖的影响;应用流式细胞术、逆转录聚合酶链反应(RT-PCR)和Western blot法检测NS-398对胃癌细胞BGC-823细胞凋亡的影响.结果 NS-398随剂量的增加及作用时间延长对胃癌细胞呈抑制作用;体外NS-398能减少BGC-823细胞株COX-2的表达,对BGC-823有细胞毒作用,可增加细胞凋亡率.结论 NS-398可抑制胃癌BGC-823细胞的增殖,促进胃癌BGC-823细胞的凋亡.其可能机制是与抑制COX-2表达有关.     

冬凌草甲素诱导胃癌BGC-823细胞凋亡及G2／M细胞周期阻滞作用研究

目的研究冬凌草甲素体外诱导胃癌BGC-823细胞凋亡和细胞周期阻滞的作用，阐明其作用机理，为临床应用提供科学依据。方法用MTT方法测定冬凌草甲素体外抑制BGC-823细胞生长的作用。用共聚焦荧光显微镜和流式细胞仪分别观察诱导凋亡的情况。线粒体膜电位和细胞内钙离子浓度分别用荧光探针标记后流式细胞仪测定。凋亡和细胞周期相关蛋白的表达用Westem blotting进行测定。结果冬凌草甲素对BGC-823细胞的半数生长抑制浓度IC50值为22．21μmol.L^-1，并诱导细胞凋亡，呈现浓度依赖性。此外，能够降低线粒体膜电位，升高细胞内钙离子浓度，激活caspase-3前体。同时，冬凌草甲素能够使得BGC-823细胞阻滞在细胞周期的G2／M期，伴随有cyclin A蛋白的表达下降。在发生凋亡和细胞阻滞之前，观察到p53蛋白的表达增加。结论冬凌草甲素能够诱导BGC-823细胞产生凋亡，并使细胞周期阻滞在G2／M期。其凋亡机理与caspase-3的激活，p53蛋白表达上调及cyclin A表达下调相关。     

重组人p53腺病毒注射液逆转人耐药胃癌MGC-803细胞耐药性的体外试验研究

目的:研究重组人p53腺病毒注射液(rAd-p53)对体外人耐药胃癌MGC-803细胞的逆转作用及其可能的机制。方法:通过紫杉醇由低到高剂量诱导人胃癌MGC-803细胞内多耐药基因表达;不同剂量rAd-p53作用于人耐药胃癌MGC-803细胞不同时间后,MTT法检测细胞增殖抑制率,并计算半数有效抑制浓度(IC50),流式细胞仪检测细胞周期及凋亡情况,免疫组织化学法和蛋白质印迹法测定多药耐药基因mdr1表达蛋白P糖蛋白(MDR1-Pgp)的表达。结果:rAd-p53可明显抑制人耐药胃癌MGC-803细胞增殖,呈时间-剂量依赖关系,作用24、48、72h的IC50分别为1889.85、998.44、354.91MOI;rAd-p53可阻滞人耐药胃癌MGC-803细胞周期于G2/M期并诱导其凋亡,可下调MDR1-Pgp蛋白表达。结论:人耐药胃癌MGC-803细胞的耐药性可能与MDR1-Pgp的高表达有关;rAd-p53可显著抑制人耐药胃癌MGC-803细胞的增殖并诱导耐药细胞凋亡,且呈剂量和时间依赖关系。     

Effect of Oct-4 on chemosensitivity of cisplatin against gastric cancer cells

目的:建立胃癌BGC-823顺铂耐药细胞株,研究Oct-4基因在胃癌顺铂耐药中的作用.方法:使用顺铂逐步增加剂量法诱导胃癌BGC-823细胞,以建立其多药耐药细胞株BGC-823/DDP; MTT细胞毒实验检测顺铂对肿瘤细胞的细胞毒作用;半定量RT-PCR检测Oct-4基因的表达;基因转染干扰Oct-4表达;Western blot实验检测Oct-4蛋白的表达改变.结果:经过30～34周的诱导我们建立了胃癌BGC-823顺铂耐药细胞株;MTT细胞毒实验结果显示顺铂对BGC-823和BGC-823/DDP细胞的IC50值分别为(2.33±0.12)和(21.46±0.97)μmol/L(P＜0.01),与BGC-823细胞比较,BGC-823/DDP细胞对顺铂耐药是其9.21倍;半定量RT-PCR检测显示胃癌耐药株BGC-823/DDP高表达Oct-4基因;Western blot结果显示化学合成的siRNA可以靶向下调Oct-4蛋白的表达;siRNA干扰BGC-823/DDP细胞Oct-4基因的表达后,BGC-823/DDP细胞对顺铂的的IC50值从(22.04±1.84) μmol/L减小到(6.15±0.53)μmol/L,二者差异具有统计学意义(P＜0.01).结论:研究结果表明,Oct-4基因的高表达在胃癌顺铂的耐药中起着重要的作用.     

Topoisomerase I inhibitor (camptothecin)-induced apoptosis in human gastric cancer cells and the role of wild-type p53 in the enhancement of its cytotoxicity

Camptothecin (CPT), a human topoisomerase I inhibitor, blocks DNA replication in human cancer cells. It represents a promising new class of chemotherapeutic agents with broad anti-tumor activity. However, its effect on gastric cancer cells remains unknown. We examined cell growth, apoptosis and cell cycle phase distribution in gastric cancer cells by exposing these cells to CPT for up to 72 h. Cell viability was determined by the Trypan blue exclusion assay. Cell cycle phase distribution and apoptosis were measured using flow cytometry, fluorescence microscopy and DNA ladder assay. Exposure of exponentially growing gastric AGS cancer cells to CPT induced time-dependent apoptosis and growth inhibition. Serum starvation-synchronized AGS cells (about 60% cells in G0/G1 phase) showed similar cellular responses. Analysis of cell cycle phase distribution of AGS cells treated with CPT for up to 72 h showed no obvious differences compared to untreated control cells. Although the induction of apoptosis was noticed in gastric cancer cell lines both with and without p53, cells lacking p53 showed less apoptosis compared to those cell lines possessing p53. Our data show that CPT is capable of inducing gastric cancer cell growth inhibition and apoptosis. Wild-type p53 may enhance the cytotoxicity of CPT against gastric carcinoma.     

腺病毒介导的p53转移对顺铂诱导KB细胞凋亡的影响

目的　探讨野生型 p5 3基因对顺铂诱导肿瘤细胞凋亡的影响。方法　用重组p5 3腺病毒 (Ad p5 3)和重组luc腺病毒 (Ad luc)分别感染 p5 3缺失的口腔癌细胞KB ,观察外源p5 3基因对顺铂诱导肿瘤细胞凋亡的影响。 结果　流式细胞术和原位末端标记显示用Ad luc与顺铂联合处理KB细胞不能诱导凋亡发生 ,用Ad p5 3与顺铂联合处理则诱导出较明显的细胞凋亡 ,表明p5 3可增强KB细胞对顺铂的敏感性 ;Northernblot显示 p5 3可下调bcl 2基因表达及上调bax基因的表达。结论　p5 3可能通过调节凋亡相关基因的表达水平而在顺铂诱导的肿瘤细胞凋亡中发挥重要作用 ,重组p5 3腺病毒与顺铂联合应用有助于克服 p5 3失活肿瘤细胞的耐药性。     

Differential apoptosis by indomethacin in gastric epithelial cells through the constitutive expression of wild-type p53 and/or up-regulation of c-myc.

Nonsteroidal anti-inflammatory drug (NSAID)-induced apoptosis is considered to be an important mechanism in the antineoplastic effects and damage produced by the drugs in the gastrointestinal tract. In this study, two different gastric cancer cell lines, MKN28 (mutant-type p53) and AGS (wild-type p53), were compared as to growth inhibition, apoptosis, and cell cycle and apoptosis-related gene expression in response to indomethacin treatment. Cell growth was measured by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Apoptosis was characterized by acridine orange staining and DNA fragmentation, and cell cycle kinetics by flow cytometry. The mRNA and protein levels of p53, p21waf1/cip1, and c-myc were determined by Northern and Western blotting. The results showed that indomethacin initiated growth inhibition and apoptosis in both cell lines without cell cycle shifting. AGS cells were more sensitive to growth inhibitory activity and apoptosis of indomethacin than MKN28 cells. In MKN28 cells, the levels of p53, p21waf1/cip1, and c-myc mRNA remained unchanged over the 24-hr treatment with indomethacin, but the p53 protein level was elevated after 4 hr. There was no change in the p21waf1/cip1 and c-myc protein levels in the MKN28 cells. In AGS cells, a progressive increase in c-myc mRNA and protein levels was noted, while p53 and p21waf1/cip1 remained unchanged. It can be concluded that wild-type p53 and/or up-regulation of c-myc is associated with indomethacin-mediated differential apoptosis in gastric epithelial cells.     

Interferon-alpha enhances sensitivity of human osteosarcoma U2OS cells to doxorubicin by p53-dependent apoptosis

Aim： To determine whether interferon-or （IFNα） can enhance doxorubicin sensitivity in osteosarcoma cells and its molecular mechanism. Methods： Cell viability was evaluated using 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay. Apoptosis was studied using Flow cytometry analysis, Hoechst33258 staining, DNA fragmentation assay, as well as the activation of caspase-3 and poly （ADP-ribose） polymerase. Protein expression was detected by Western blotting. The dependence of p53 was determined using p53-siRNA transfection. Results： IFNα increased doxorubicin-induced cytotoxicity to a much greater degree through apoptosis in human osteosarcoma p53-wild U2OS cells, but not p53-mutant MG63 cells. IFNα markedly upregulated p53, Bax, Mdm2, and p21, downregulated Bcl-2, and activated caspase-3 and PARP cleavage in response to doxorubicin in U2OS cells. Moreover, the siRNA-mediated silencing of p53 significantly reduced the IFNα/doxorubicin combination-induced cytotoxicity and PARP cleavage. Conclusion： IFNα enhances the sensitivity of human osteosarcoma U2OS cells to doxorubicin by p53-dependent apoptosis. The proper combination with IFNα and conventional chemotherapeutic agents may be a rational strategy for improving the treatment of osteosarcoma with functional p53.     

AICAR inhibits proliferation and induced S-phase arrest, and promotes apoptosis in CaSki cells

Aim： The aim of the present study was to determine the effect of 5-aminoimidazole- 4-carboxamide-ribonucleoside （A/CAR） on proliferation, cell cycle, and apoptosis in the human epithelial cervical cancer cell line CaSki cells. Methods： Cell count and 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay were used to determine cell proliferation and viability. Hoechst 33258 staining was con- ducted to distinguish the apoptotic cells. Cell cycle and Annexin-V/propidium iodide staining were analyzed by fluorescence-activated cell sorting （FACS）. A Western blot assay was used to evaluate the expression of AKT （also known as protein kinase B）, mammalian target of rapamycin （mTOR）, p53, and extracellular signal-regulated kinase （ERK）. Results： A/CAR （500 pmol/L） significantly inhibi- ted the proliferation of CaSki cells treated for 24, 48, and 72 h as determined by cell count. The cells at the Gl and G2 phases were dramatically decreased while cells at the S phase were increased in response to A/CAR treatment for 24, 48, and 72 h, The MTF assay showed less viable cells and Hoechst fluorescent staining showed more apoptotic cells upon AICAR stimulation. The results of the Annexin-V staining demonstrated a time-dependent increase of apoptosis in cells treated with A/CAR for 24, 36, and 48 h. Furthermore, AICAR activated caspase-3 in a time-dependent manner. It was also found that AICAR inhibited the phosphory- lation of AKT and mTOR, which are important kinases regulating cell growth and survival. AICAR stimulation obviously increased the expression of the tumor suppressor p53 and the phosphorylation of ERK. Conclusion： A/CAR inhibited proliferation and induced S phase arrest and promoted apoptosis in CaSki cells, which might be mediated by the dowrtregulation of the AKT/mTOR pathway and the upregulation of the p53/ERK pathway.     

维生素C体外抑制宫颈癌H eLa细胞株生长及其机制的研究

目的探讨维生素C对人宫颈癌HeLa细胞生长和凋亡的影响,并初步探讨其机制。方法用MTT比色法检测细胞生长抑制作用,流式细胞术测定各组细胞周期分布和凋亡率,以间接免疫荧光法流式细胞术检测相关蛋白的表达,以TRAP-PCR-ELISA法测定端粒酶活性。结果维生素C能以浓度依赖和时间依赖方式阻滞HeLa细胞于G0/G1期,抑制其生长并诱导凋亡。同时HPV18 E6、Bc l-2蛋白表达下调,wtp53、Bax蛋白表达上调,端粒酶活性降低。结论维生素C可抑制HeLa细胞生长,使其细胞周期阻滞于G0/G1期,并诱导其凋亡;其原因在于病毒癌基因E6表达的降低,以及由此而引起的端粒酶活性的降低和细胞内蛋白表达水平的改变,包括HPV18 E6、Bc l-2蛋白表达的下调,wtp53、Bax蛋白表达的上调。