吲哚美辛与埃罗替尼对胰腺癌细胞生长的协同抑制作用

背景：目前胰腺癌药物化疗疗效不佳。既往研究提示环氧合酶（COX）-2和表皮生长因子受体（EGFR）信号途径均参与了胰腺癌的发生、发展，COX-2抑制剂和EGFR抑制剂联用对胰腺癌的生长可能具有协同抑制作用。目的：观察COX-2抑制剂吲哚美辛与EGFR酪氨酸激酶抑制剂埃罗替尼对胰腺癌细胞生长的协同抑制作用。方法：以甲基噻唑基四唑（MTT）比色法检测胰腺癌细胞株BxPC-3的增殖情况，以流式细胞分析和原位末端标记（TUNEL）法观察用药前后细胞凋亡和细胞周期的变化，以逆转录聚合酶链反应（RT—PCR）观察用药前后细胞中COX-2、EGFR以及凋亡相关基因Bcl-2、Bax、Bcl-xL、Bak mRNA表达的变化。结果：BxPC-3细胞中可观察到COX-2和EGFRmRNA表达．吲哚美辛和埃罗替尼单用均可下调COX-2和EGFRmRNA的表达，两者联用时下调作用更明显。吲哚美辛和埃罗替尼单用均可抑制BxPC-3细胞增殖，促进细胞凋亡，诱导细胞周期阻滞于G0／G1期，减少抗凋亡基因Bcl-2、Bcl-xL的表达，轻微上调促凋亡基因Bax的表达，两者联用对细胞生长的抑制作用增强。结论：吲哚美辛和埃罗替尼均可抑制COX-2和EGFR的表达，下调Bcl-2／Bax比值，两者联用对胰腺癌细胞生长具有协同抑制作用。     

蟾毒灵介导JNK信号通路诱导人胰腺癌细胞的凋亡

目的:研究蟾毒灵诱导人胰腺癌细胞凋亡以及凋亡相关基因表达的JNK信号转导通路,揭示其抗胰腺癌的部分机制.方法:MTT法观察蟾毒灵对人胰腺癌BxPC-3细胞的生长抑制作用;0.16、0.32、0.64mg/L蟾毒灵分别作用人胰腺癌BxPC-3细胞48h后,流式细胞仪(flow cytometry,FCM)检测细胞周期和细胞凋亡;Western印迹法检测蟾毒灵作用BxPC-3细胞后SAPK/JNK信号通路的激活情况,荧光定量PCR检测Survivin基因mRNA的表达水平;并比较阻断JNK信号通路后丹参酮ⅡA对胰腺癌细胞凋亡Survivin基因mRNA的表达.结果:MTT法测得蟾毒灵对人胰腺癌BxPC-3细胞具有显著的抑制作用,其作用效果与剂量和作用时间成正相关;0.16、0.32、0.64mg/L浓度蟾毒灵作用人胰腺癌细胞后的细胞凋亡率分别为19.36%±0.39%、40.69%±0.44%、59.63%±1.14%,与对照组2.24%±0.37%比较均有显著性差异(P<0.01);蟾毒灵作用人胰腺癌细胞1h后JNK信号通路被激活,2h达峰值;阻断JNK信号通路后,凋亡率明显降低(P<0.01);0.32mg/L蟾毒灵作用人胰腺癌细胞48h后Survivin mRNA的表达明显下降;阻断JNK信号通路后,蟾毒灵作用人胰腺癌细胞的Survivin mRNA的表达明显上升.结论:蟾毒灵通过JNK信号转导通路下调人胰腺癌BxPC-3细胞Survivin mRNA的表达,可能是其诱导胰腺癌细胞凋亡的机制.     

EGCG对鼻咽癌细胞株CNE-1生长及其survivin表达的影响

目的探讨表没食子儿茶素没食子酸酯（EGCG）对鼻咽癌细胞株CNE-1的生长抑制作用及其机制。方法不同浓度EGCG作用于鼻咽癌CNE-1细胞,用MTT法检测不同时间点的细胞生长抑制率,同时用RT-PCR法检测其survivin mRNA。结果EGCG作用后CNE-1细胞的生长抑制率升高,同时伴survivin mRNA表达下调,呈浓度和时间依赖性。结论EGCG可明显抑制鼻咽癌细胞株CNE-1的生长,其机制是下调该细胞survivin mRNA的表达。     

吲哚美辛对胰腺癌细胞BxPC-3生长的抑制作用及机制

目的探讨环氧合酶抑制剂吲哚美辛体内外对胰腺癌细胞BxPC-3细胞生长的影响及其作用机制。方法用MTT法检测吲哚美辛作用后BxPC-3细胞的增殖情况;用流式细胞分析、透射电镜和原位末端标记(TUNEL)法观察细胞凋亡和细胞周期的变化;建立裸鼠胰腺癌BxPC-3细胞移植瘤模型,用吲哚美辛给荷瘤裸鼠灌胃(3 mg.kg-1.d-1,共4周),观察其对种植瘤生长曲线的影响,TUNEL法检测裸鼠移植瘤组织细胞凋亡。结果吲哚美辛呈剂量和时间依赖性抑制BxPC-3细胞生长。TUNEL、流式细胞仪检测显示药物处理后细胞凋亡增加,细胞阻止于G0/G1。透射电镜可见细胞呈现明显凋亡形态。随着用药时间的增加,吲哚美辛对裸鼠移植瘤的生长抑制作用增加,移植瘤组织凋亡细胞增多。结论吲哚美辛体内外可抑制胰腺癌细胞BxPC-3的生长,其机制可能与促进细胞凋亡,阻滞细胞周期有关。     

血管内皮生长因子-A siRNA对人肝癌HepG2细胞凋亡的影响及机制

目的通过RNA干扰技术特异性地使人肝癌细胞株Hep G2中血管内皮生长因子(VEGF)-A表达下调,检测细胞凋亡率变化及pAkt、生成素、caspase-3表达。方法采用脂质体介导将针对靶基因VEGF-A的小片段RNA导入人Hep G2细胞内,用Western印迹和RT-PCR技术检测人Hep G2细胞内VEGF-A、p-Akt、生成素、caspase-3的表达,用膜联蛋白(Annexin-V)/碘化丙啶(PI)双标记流式细胞术检测细胞凋亡。结果细胞转染成功后,VEGF-A siRNA组VEGF-A mRNA表达量显著降低,较RNA干扰组下降80.88%(0.26±0.07 vs 1.36±0.05,P0.01),VEGF-A蛋白表达量显著降低,较RNA干扰组下降75.34%(0.18±0.02 vs 0.73±0.06,P0.01);细胞凋亡率增加,VEGF-A siRNA组较RNA干扰组增高21.96%(28.21%±1.75%vs 6.25%±0.82%,P0.01)。伴随p-Akt和生存素蛋白水平降低和caspase-3表达上调(P0.01)。结论通过RNA干扰技术特异性地使人肝癌细胞株Hep G2中VEGF-A表达下调,可以诱导Hep G2细胞发生凋亡,这可能是通过PI3K/p-Akt/生存素信号转导通路实现的。     

三氧化二砷诱导人肝癌SMMC-7721细胞凋亡及对OPN表达的影响

目的探讨三氧化二砷（As2O3）治疗肝癌的可行性及机制。方法将一定浓度梯度的As2O3与人肝癌细胞株SMMC-7721孵育后,采用MTT法、荧光显微镜及流式细胞仪检测细胞增殖与凋亡变化,逆转录聚合酶链反应（RT-PCR）检测肝癌细胞株中骨桥蛋白基因（OPN mRNA）表达水平。结果As2O3作用后SMMC-7721细胞生长明显受抑,且呈时间-浓度依赖性;荧光显微镜下细胞呈典型的凋亡形态学改变;在流式细胞仪上可见“凋亡峰”,细胞周期阻滞于G2／M期;细胞OPN mRNA表达阳性,OPN mRNA表达水平明显下调。结论As2O3体外能有效抑制肝癌细胞株生长;其机制可能为诱导细胞凋亡、下调OPN mRNA表达。     

NSAID对胰腺癌中COX-2的表达及其生长活力的影响

目的 :检测胰腺癌中COX 2表达 ,探讨COX 2抑制剂非甾体类消炎药 (NSAID)的抑癌机制。方法 :胰腺癌组织和细胞株中的COX 2检测分别采用免疫组化和细胞免疫化学分析 ,并使用MTT法及流式细胞仪检测细胞株生长活力和凋亡。结果 :胰腺癌组织中COX 2的表达增强 ,阳性率 73.3% (P <0 .0 5 )。SW 1 990和Capan 2细胞株均有COX 2表达 ,前者高表达 ,后者低表达。两种NSAID(NS398及ASA)均可抑制两种细胞株的生长 ,诱导细胞凋亡率显著升高 ,并与细胞株COX 2表达强度有关 ;对SW 1 990细胞株的作用强于Capan 2 ,NS398的抑制作用又强于ASA。结论 :COX 2在胰腺癌组织和细胞株中表达增强 ,NSAID抗胰腺癌机制可能是通过抑制COX 2活性 ,诱导胰腺癌细胞凋亡     

维生素D衍生物EB1089对胰腺癌细胞系BxPC-3生长的抑制作用

目的观察维生素D衍生物EB1089对人胰腺癌细胞系BxPC-3的生长抑制作用及其可能机制.方法应用MTT比色法、流式细胞术、Western blot法免疫印记电泳进行检测.结果EB1089抑制人胰腺癌细胞系BxPC-3的生长,抑制50%细胞生长的药物浓度(IC50)为10-7mmol/L.癌细胞在EB1089作用下,G0/G1期细胞比例增加23%,S期细胞比例下降12%.胰腺癌细胞系BxPC-3的p21蛋白的表达随EB1089的作用时间和药物浓度的提高而增强.结论EB1089对胰腺癌细胞系BxPC-3具有生长抑制作用,其作用机制可能与p21表达上调有关.     

维生素D衍生物EB1089对胰腺癌细胞系BxPC-3生长的抑制作用

目的：观察维生素D衍生物EB1089对人胰腺癌细胞系BxPC-3的生长抑制作用及其可能机制。方法：应用MTT比色法、流式细胞术、Western blot法免疫印记电泳进行检测。结果：EB1089抑制人胰腺癌细胞系BxPC-3的生长，抑制50％细胞生长的药物浓度(IC50)为10^-7mmol／L。癌细胞在EB1089作用下，G0／G1期细胞比例增加23％，S期细胞比例下降12％。胰腺癌细胞系BxPC-3的p21蛋白的表达随EB1089的作用时间和药物浓度的提高而增强。结论：EB1089对胰腺癌细胞系：BxPC-3具有生长抑制作用，其作用机制可能与p21表达上调有关。     

KAI1基因转染对乏氧培养下胰腺癌MiaPaCa-2细胞增殖、迁移及VEGF表达的影响

目的 观察转染KAI1基因的人胰腺癌MiaPaCa-2细胞在乏氧条件下培养后细胞增殖、迁移、侵袭能力的变化,探讨其可能机制.方法 应用KAl1基因过表达质粒转染乏氧条件培养后的人胰腺癌MiaPaCa-2细胞,采用蛋白质印迹法检测转染细胞KAI1、VEGF-C、VEGF-A蛋白的表达,四甲基偶氮唑蓝（MTT）法检测转染细胞的增殖,细胞划痕及Transwell小室实验观察转染细胞的迁移及侵袭能力,酶联免疫吸附测定法检测培养上清液中人VEGF-C、VEGF-A含量.结果 转染KAI1基因后的MiaPaCa-2-K细胞的KAI1蛋白表达量较未转染细胞显著增加[（0.549 ±0.021）比0].乏氧条件培养后转染细胞的增殖无明显变化,但它的迁移距离明显缩短,穿膜细胞数显著减少[（14.0±5.8）比（43.0±14.4）个,P＜0.05];细胞的VEGF-C表达显著降低[（0.218±0.043）比（0.745±0.069）.P＜0.05],但VEGF-A表达变化不显著;细胞培养上清液中VEGF-C含量显著减少[（1236±247）比（2045±221） pg/ml,P＜0.01].结论 转染KAl1基因的MiaPaCa-2细胞在乏氧条件下培养后的细胞迁移、侵袭能力减弱,其机制可能是通过下调VEGF-C的表达来抑制胰腺癌淋巴转移的.     

Retinal endothelial angiogenic activity: effects of hypoxia and glial (Müller) cells

OBJECTIVE: To explore the impact of retinal glial (Müller) cells on survival and neovascularization-related activities of cultured retinal endothelial cells under normoxic and hypoxic conditions. METHODS: Bovine retinal endothelial cells (BRECs) were cultured under normoxia or hypoxia (0.5% O2) either alone, together with the human Müller cell line MIO-M1, or in normoxia- or hypoxia-conditioned media of MIO-M1 cells. Cell number, proliferation, apoptotic cell death, and migration of BRECs were determined. RESULTS: Exposure of BRECs to hypoxia for 24 h decreased the number of adherent cells and the proliferation rate, but increased apoptosis and cell migration. Increased apoptosis and decreased proliferation of the BRECs occurred also in the presence of conditioned media of MIO-M1 cells. Under normoxic conditions, co-culture with MIO-M1 cells resulted in increased proliferation, but decreased apoptosis and migration rates of BRECs. Under hypoxic conditions, the Müller cells released elevated amounts of VEGF but their presence decreased proliferation, apoptosis and the migration rates of BRECs. CONCLUSIONS: Hypoxia inhibits the proliferation of retinal endothelial cells. Müller cells release soluble mediators that enhance this hypoxia-mediated effect but, under certain conditions (i.e., in co-culture), may protect retinal endothelial cells from apoptosis, thus supporting their survival. Altogether the findings indicate that the key signal necessary to trigger retinal endothelial proliferation under hypoxia remains to be determined.     

Melatonin antagonizes hypoxia‐mediated glioblastoma cell migration and invasion via inhibition of HIF‐1α

Hypoxia is a crucial factor in tumor aggressiveness and resistance to therapy, especially in glioblastoma. Our previous results have shown that melatonin exerts antimigratory and anti‐invasive action in glioblastoma cells under normoxia. However, the effect of melatonin on migration and invasion of glioblastoma cells under hypoxic condition remains poorly understood. Here, we show that melatonin strongly reduced hypoxia‐mediated invasion and migration of U251 and U87 glioblastoma cells. In addition, we found that melatonin significantly blocked HIF‐1α protein expression and suppressed the expression of downstream target genes, matrix metalloproteinase 2 (MMP‐2) and vascular endothelial growth factor (VEGF). Furthermore, melatonin destabilized hypoxia‐induced HIF‐1α protein via its antioxidant activity against ROS produced by glioblastoma cells in response to hypoxia. Along with this, HIF‐1α silencing by small interfering RNA markedly inhibited glioblastoma cell migration and invasion, and this appeared to be associated with MMP‐2 and VEGF under hypoxia. Taken together, our findings suggest that melatonin suppresses hypoxia‐induced glioblastoma cell migration and invasion via inhibition of HIF‐1α. Considering the fact that overexpression of the HIF‐1α protein is often detected in glioblastoma multiforme, melatonin may prove to be a potent therapeutic agent for this tumor.     

Mechanisms of regulation of PFKFB expression in pancreatic and gastric cancer cells

Enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 and -4 (PFKFB-3 and PFKFB-4) play a significant role in the regulation of glycolysis in cancer cells as well as its proliferation and survival. The expression of these mRNAs is increased in malignant tumors and strongly induced in different cancer cell lines by hypoxia inducible factor (HIF) through active HIF binding sites in promoter region of PFKFB-4 and PFKFB-3 genes. Moreover, the expression and hypoxia responsibility of PFKFB-4 and PFKFB-3 was also shown for pancreatic (Panc1, PSN-1, and MIA PaCa-2) as well as gastric (MKN45 and NUGC3) cancer cells. At the same time, their basal expression level and hypoxia responsiveness vary in the different cells studied: the highest level of PFKFB-4 protein expression was found in NUGC3 gastric cancer cell line and lowest in Panc1 cells, with a stronger response to hypoxia in the pancreatic cancer cell line. Overexpression of different PFKFB in pancreatic and gastric cancer cells under hypoxic condition is correlated with enhanced expression of vascular endothelial growth factor (VEGF) and Glut1 mRNA as well as with increased level of HIF-1α protein. Increased expression of different PFKFB genes was also demonstrated in gastric, lung, breast, and colon cancers as compared to corresponding non-malignant tissue counterparts from the same patients, being more robust in the breast and lung tumors. Moreover, induction of PFKFB-4 mRNA expression in the breast and lung cancers is stronger than PFKFB-3 mRNA. The levels of both PFKFB-4 and PFKFB-3 proteins in non-malignant gastric and colon tissues were more pronounced than in the non-malignant breast and lung tissues. It is interesting to note that Panc1 and PSN-1 cells transfected with dominant/negative PFKFB-3 (dnPFKFB-3) showed a lower level of endogenous PFKFB-3, PFKFB-4, and VEGF mRNA expressions as well as a decreased proliferation rate of these cells. Moreover, a similar effect had dnPFKFB-4. In conclusion, there is strong evidence that PFKFB-4 and PFKFB-3 isoenzymes are induced under hypoxia in pancreatic and other cancer cell lines, are overexpressed in gastric, colon, lung, and breast malignant tumors and undergo changes in their metabolism that contribute to the proliferation and survival of cancer cells. Thus, targeting these PFKFB may therefore present new therapeutic opportunities.     

LY294002对人胃腺癌细胞株BGC-823糖酵解水平的影响及其机制探讨

背景:有氧糖酵解是肿瘤细胞的特征性表型之一,靶向糖酵解有望成为一种有效的肿瘤治疗策略。M2型丙酮酸激酶(PKM2)在肿瘤组织中呈高表达,参与肿瘤细胞的有氧糖酵解。缺氧诱导因子-1α(HIF-1α)是调控肿瘤细胞糖酵解相关基因表达的重要转录因子,而PI3K信号在肿瘤细胞中可上调HIF-1α表达。目的:探讨PI3K特异性抑制剂LY294002对人胃腺癌细胞增殖和糖酵解水平的影响及其可能机制。方法:以不同浓度LY294002(10～100μmol/L)在不同条件下(常氧或缺氧)处理人胃腺癌细胞株BGC-823,CCK-8实验和流式细胞分析检测细胞增殖和细胞凋亡,蛋白质印迹法检测p-Akt、p-mTOR、HIF-1α、PKM2表达,比色法检测反映糖酵解水平的胞内乳酸脱氢酶活性和胞外乳酸浓度。结果:LY294002可呈浓度和时间依赖性地抑制BGC-823细胞增殖,在较高浓度时可诱导细胞早期凋亡。LY294002可呈浓度依赖性地抑制p-Akt、p-mTOR、HIF-1α表达,在较高浓度时可抑制PKM2表达,同时降低糖酵解水平。缺氧诱导可消除LY294002对HIF-1α、PKM2表达和糖酵解水平的抑制作用。结论:LY294002可通过阻断PI3K/Akt/mTOR信号通路抑制人胃腺癌细胞增殖及其糖酵解水平,而HIF-1α介导了糖酵解的抑制过程。     

NF-κB基因对胰腺癌细胞侵袭作用的影响及机制

目的探讨NF-κB基因对胰腺癌细胞侵袭的影响及机制。方法应用NF-κB基因小于扰RNA（siRNA）转染处理人胰腺癌PANC-1细胞,采用Westernblot方法检测NF-KB蛋白水平,采用Boyden小室模型试验检测癌细胞侵袭能力。收集转染48h的癌细胞,采用包含有96个转移相关基因的芯片检测基因表达情况;根据基因芯片结果,随机抽取3个表达明湿变化的基因采用荧光实时定量PCR（RT—PCR）验证基因芯片结果。结果转染组癌细胞NF-κB蛋白水平下调（P〈0．05）,且与时间和浓度相关。与对照组比较,转染组细胞的穿膜细胞数减少（P〈0．05）,且呈浓度依赖关系。基因芯片检测发现,96个基因中有11个基因表达出现明显变化,其中9个基因明显下调,包括基质金属蛋白酶2（MMP-2）、MMP-7和血管内皮生长因子（VEGF）,有2个基因出现明显上调。采用荧光RT—PCR方法检测MMP-2、MMP-7、VEGF基因表达,结果也发现这3个基因表达下调,且下调幅度与基因芯片结果一致。结论NF-κB基因siRNA转染可明昆抑制胰腺癌细胞的锚着不依赖性增殖和恶性侵袭,其机制可能与下调MMP-2、MMP-7和VEGF有关。     

CTRP9抑制低氧环境下肺微血管内皮细胞IL-6和TNF-α表达的研究

目的 研究低氧环境下C1q肿瘤坏死因子相关蛋白9（C1q/TNF-related protein 9,CTRP9）对肺微血管内皮细胞（Pulmonary microvascular endothelial cell,PMVEC）中白介素（IL）-6、肿瘤坏死因子（TNF）-α表达的影响。 方法 将雄性SD大鼠随机分为常氧组、低氧组,采用低压低氧法建立大鼠低氧性肺动脉高压（Hypoxic pulmonary hypertension,HPH）模型,28 d后检测各组大鼠血流动力学、右心室肥厚指标和组织病理学改变;用RT-PCR检测HPH大鼠肺组织中IL-6、TNF-α mRNA表达水平;用ELISA法检测二者在血清中的变化。分离培养健康雄性SD大鼠的PMVEC,分别在常氧（210 ml/L O₂、50 ml/L CO₂）、低氧（50 ml/L O₂、50 ml/L CO₂）、或者低氧+CTRP9（5 μg/ml）环境中孵育48 h。 结果 与常氧组相比,低氧组大鼠右心室收缩压和右心室肥厚指标增加（P<0.05）,肺小动脉管壁增厚,显示造模成功;肺组织中IL-6、TNF-α mRNA水平上调（P<0.05）,两种炎症因子在血清中的含量增加（P<0.05）。与常氧组相比,低氧处理使两种炎症因子IL-6、TNF-α在PMVEC中mRNA水平及在细胞培养上清中的含量均增加（P<0.05）;在低氧的同时给予CTRP9孵育时,与单纯低氧组相比,两种炎症因子在PMVEC中mRNA水平及在细胞培养上清中的含量均降低（P<0.05）。 结论 大鼠发生HPH时,炎症因子IL-6、TNF-α表达升高。而CTRP9对低氧条件下PMVEC表达和分泌IL-6及TNF-α具有抑制作用,进而有望预防或延缓HPH的发生发展。