miR-24对肺癌A549细胞化疗敏感性的影响

目的:探究微小RNA(miR)-24对肺癌细胞A549化疗敏感性的影响及可能的作用机制。方法:Real-time PCR实验检测肺腺癌细胞系A549及肺腺癌耐药细胞株A549/DDP中miR-24的表达情况。转染miR-24抑制序列(miR-24 inhibitor)下调A549/DDP细胞中的miR-24后,采用CCK-8法检测细胞活力,流式细胞术检测细胞凋亡,Western blot检测Bcl-2、Bax、cleaved caspase-3、cleaved caspase-9、细胞色素C(Cyt C)、磷酸化细胞外信号调节激酶(p-ERK)和P53的蛋白水平。双荧光素酶报告基因实验预测及验证miR-24可能的靶基因。结果:耐药细胞株A549/DDP中miR-24的表达水平明显高于A549细胞(P0.05)。miR-24 inhibitor可诱导肺腺癌耐药细胞株A549/DDP的凋亡,增加细胞对顺铂的敏感性;此外还可下调Bcl-2/Bax比值,同时上调P53、p-ERK、cleaved caspase-9、cleaved caspase-3及Cyt C的蛋白水平。而应用ERK特异性抑制剂U0126可部分恢复miR-24 inhibitor转染的细胞活力。生物信息学分析显示p53是miR-24的可能作用靶点基因,在A549/DDP细胞中共转染miR-24 inhibitor和P53 siRNA可部分逆转miR-24 inhibitor对细胞活力的影响。结论:下调肺腺癌耐药细胞株A549/DDP中miR-24的表达可增加细胞对顺铂的敏感性,其机制可能与靶向p53基因同时激活ERK/P53信号通路后促进细胞经线粒体途径的凋亡有关。     

miR-29b通过调控Bax基因抑制LPS诱导的肺泡上皮细胞系A549凋亡

目的探讨miR-29b对脂多糖(LPS)诱导的肺泡上皮细胞系A549凋亡的影响及其机制。方法将体外培养的A549细胞分为对照组、LPS组(给予10 mg/L的LPS处理)、LPS+miR-NC组(转染miR-29b mimics阴性对照后给予LPS处理)、LPS+miR-29b组(转染miR-29b mimics后给予LPS处理);用RT-qPCR检测细胞中miR-29b的表达水平;MTT法检测细胞存活率;流式细胞仪检测细胞凋亡率;Western blot检测Bcl-2、Bax和cleaved caspase-3蛋白的表达;双荧光素酶报告基因实验检测Bax和miR-29b的靶向关系。结果与对照组相比,LPS组、LPS+miR-NC组和LPS+miR-29b组细胞中miR-29b、Bcl-2蛋白的表达水平和细胞存活率均明显降低,而细胞凋亡率和Bax、cleaved caspase-3蛋白的表达水平均明显升高(P<0.05);与LPS组相比,LPS+miR-29b组细胞中miR-29b、Bcl-2蛋白的表达水平和细胞存活率均明显升高,而细胞凋亡率和Bax、cleaved caspase-3蛋白的表达水平均明显降低(P<0.05)。双荧光素酶报告基因实验证实Bax是miR-29b的潜在靶基因。结论miR-29b可抑制LPS诱导的A549细胞凋亡,其作用机制可能与靶向调控Bax表达有关。     

抗菌肽merecidin诱导人肺腺癌细胞系A549凋亡

目的探讨抗菌肽merecidin对人肺癌细胞系A549的作用及其机制。方法实验分为对照组(Ctrl)、顺铂干预组(cisplatin 40μmol/L)、merecidin干预组(merecidin 25/35μmol/L)、caspase抑制剂组(z-VAD-fmk)、caspase抑制剂+merecidin干预组(z-VAD-fmk+merecidin 25/35μmol/L)。MTT法检测细胞增殖,annexin V/PI双染法检测细胞凋亡,Western blot检测caspase-3、8、9、激活型caspase-3、Bcl-2和Bax蛋白表达。结果抗菌肽merecidin明显抑制A549细胞增殖(P0.05),merecidin处理24 h后的IC_(50)值为34.8μmol/L。与Ctrl组相比,merecidin干预组的凋亡率显著升高(P0.05);与merecidin干预组相比,caspase抑制剂+merecidin干预组的凋亡率并没有下降。caspase-3、8、9蛋白表达无显著变化且未检测到激活型caspase-3蛋白表达。Bcl-2蛋白表达下调(P0.05)及Bax蛋白表达增多(P0.05)。结论抗菌肽merecidin可以抑制人肺腺癌细胞A549的增殖并诱导其凋亡。     

miR-137对喉癌Hep-2细胞增殖、侵袭与凋亡的影响及可能机制

目的探讨miR-137对喉癌Hep-2细胞增殖及迁移能力的影响及可能机制。方法采用miR-137模拟物转染喉癌Hep-2细胞,实验分为空白对照组组(未进行转染)、miR-137阴性对照组(转染无关序列)、miR-137模拟物转染组(进行miR-137模拟物转染)。real-time PCR法验证转染效率,采用CCK8法检测miR-137对喉癌Hep-2细胞增殖的影响,采用Transwell实验检测转染后Hep-2细胞的侵袭能力变化,采用流式细胞术检测miR-137对Hep-2细胞凋亡的影响;Western blot检测转染后Hep-2细胞凋亡相关蛋白Bcl-2、Bax、caspase-3以及侵袭相关蛋白T细胞因子-4(TCF-4)蛋白表达的变化。结果与空白对照组或阴性对照组相比,miR-137模拟物转染组Hep-2细胞miR-137的表达水平显著高于对照组(P0.01),喉癌Hep-2细胞的增殖与侵袭能力显著降低,细胞凋亡率明显升高,凋亡相关蛋白Bcl-2表达水平降低,而Bax与caspase-3蛋白表达升高,侵袭相关蛋白TCF-4表达降低。结论过表达miR-137抑制Hep-2细胞增殖与侵袭、诱导细胞凋亡,与上调Bax、caspase-3蛋白表达和下调Bcl-2、TCF-4表达相关。     

过表达Rip2对人胰腺癌细胞Panc-1凋亡的影响

目的:观察受体相互作用蛋白2(Rip2)对人胰腺癌细胞Panc-1凋亡的影响。方法:采用Jet PRIME试剂分别将pEGFP-C2和pEGFP-Rip2质粒转染入Panc-1细胞,实验分为对照组、pEGFP-C2组和pEGFP-Rip2组。转染后培养细胞48 h,采用流式细胞术检测细胞凋亡率;Western blot检测细胞Rip2水平及凋亡相关蛋白Bax、胞浆细胞色素c(Cyt-c)和Bcl-2蛋白表达;比色法检测细胞caspase-3的活性。结果:转染pEGFP-Rip2细胞Rip2蛋白表达明显增加。流式细胞术检测表明,p EGFP-Rip2组的细胞凋亡率明显高于对照组和pEGFP-C2组。与对照组和pEGFP-C2组相比,pEGFP-Rip2组的Bax和胞浆Cyt-c蛋白表达明显升高,而Bcl-2蛋白水平则显著降低。并且,pEGFP-Rip2组细胞caspase-3活性明显高于对照组和pEGFP-C2组。结论:过表达Rip2能诱导Panc-1细胞凋亡,其作用机制可能与Rip2上调Bax以及胞浆Cyt-c蛋白表达,下调Bcl-2蛋白水平,增加caspase-3活性,从而激活内源性凋亡途径有关。     

芹菜素对人肺癌A549细胞凋亡及相关蛋白Bax、Bcl-2表达的影响

目的研究芹菜素对人肺癌 A549细胞增殖抑制和凋亡诱导作用与 Bax、Bcl-2蛋白表达的影响。方法10~80μmol/L 不同浓度芹菜素作用 A549细胞,采用 MTT 法检测芹菜素对 A549细胞增殖抑制作用;Hoechst 33258细胞核染色法观察芹菜素诱导细胞凋亡形态学的变化;流式细胞仪 AnnexinV- FITC/PI 双染色法检测细胞凋亡率;Western blot 法检测凋亡相关蛋白 Bax 和 Bcl-2表达的变化。结果 MTT 法显示,芹菜素对 A549细胞有显著的增殖抑制作用（P <0.01）,且具浓度和时间依赖性;荧光显微镜下观察到芹菜素处理组细胞出现典型的凋亡形态学改变：细胞核固缩、染色质凝集和核碎片化等;流式细胞仪分析结果显示,芹菜素呈浓度依赖性诱导 A549细胞凋亡;Western blot结果显示,促凋亡蛋白 Bax 随着芹菜素浓度升高表达增加,抗凋亡蛋白 Bcl-2随着芹菜素浓度升高表达减少。结论芹菜素具有抑制人肺癌 A549细胞增殖,诱导其凋亡的作用,其机制可能与上调 Bax 蛋白表达和下调 Bcl-2蛋白表达有关。     

盐霉素抑制人肺腺癌耐顺铂细胞株A549/DDP增殖及诱导凋亡的机制

目的: 探讨盐霉素对人肺腺癌耐药细胞株A549/DDP增殖的抑制作用及其可能机制。方法: 采用MTT法检测盐霉素对A549/DDP细胞生长的抑制作用;流式细胞术检测盐霉素对A549/DDP细胞凋亡及线粒体膜电位(ΔΨ_m)的影响;比色法检测caspase-3、8和9活性;Western blotting分析细胞色素C、Bcl-2、Bax、β-catenin和磷酸化低密度脂蛋白受体相关蛋白6(p-LRP6)蛋白水平。结果: 盐霉素对A549/DDP细胞生长具有剂量依赖性抑制作用。0.2 μmol/L盐霉素作用于A549/DDP细胞,ΔΨ_m显著下降,而细胞内活性氧和Ca²⁺浓度在短期显著升高,胞浆细胞色素C蛋白水平、caspase-3、8和9酶活性均显著增加,与对照组比较差异均有统计学意义(P<0.01);Bcl- 2 的表达下调,Bax 的表达明显增加,Bcl-2/Bax 比值显著降低。48 h时增殖抑制率为(34.61±1.97)%,细胞凋亡率为(18.74±2.08)%。盐霉素也减少A549/DDP细胞内β-catenin和p-LRP6蛋白水平。结论: 盐霉素通过抑制Wnt信号通路抑制A549/DDP细胞增殖,通过Bcl-2/Bax途径和线粒体凋亡途径诱导人肺腺癌耐药细胞株A549/DDP凋亡。     

叶黄素抑制叔丁基过氧化氢诱导的视网膜神经节细胞凋亡

目的:观察叶黄素(lutein)对叔丁基过氧化氢(t-BHP)处理的视网膜神经节细胞(RGC-5细胞系)的保护效应并探讨其作用机制。方法:用免疫荧光染色检测视网膜神经节特异性蛋白Brn-3和神经微管结合蛋白MAP-2的表达来鉴定RGC-5细胞;将RGC-5细胞随机分为对照组、t-BHP处理组、t-BHP和lutein共同处理组、lutein处理组,培养24 h,MTT实验检测细胞活力;Annexin V-FITC/PI双染流式细胞术检测细胞凋亡;免疫细胞化学技术检测caspase-3蛋白的活化情况;Western blot检测Bcl-2/Bax、cleaved caspase-3、JNK和c-Jun蛋白的变化。结果:MTT实验和流式细胞检测结果显示,lutein能提高t-BHP处理的RGC-5细胞的活力,并降低t-BHP诱导的RGC-5细胞凋亡;免疫荧光结果显示lutein能抑制t-BHP诱导的caspase-3的活化;与对照组比较,t-BHP处理后RGC-5细胞抗凋亡蛋白Bcl-2表达下调(P0.05),Bax/Bcl-2比率升高,cleaved caspase-3表达上调(P0.05),JNK和c-Jun蛋白的磷酸化水平增加(P0.05),t-BHP的上述作用可被lutein部分逆转。结论:Lutein能够降低t-BHP诱导的RGC-5细胞凋亡,其机制与其上调Bcl-2的表达、抑制caspase-3的活化并降低JNK和c-Jun蛋白的磷酸化有关。     

藻蓝蛋白诱导喉癌HEP-2细胞凋亡的实验研究

目的:探讨藻蓝蛋白对人喉癌HEP-2细胞凋亡的影响,并初步探讨其机制。方法:不同浓度藻蓝蛋白处理HEP-2细胞,分别以MTT、倒置显微镜、扫描电镜、透射电镜、流式细胞术检测藻蓝蛋白对HEP-2细胞活力及凋亡的影响;DCFH-DA标记的流式细胞术检测细胞内的活性氧水平;分光光度法检测细胞内caspase-3、-8、-9的活性;RT-PCR、Western blot检测细胞凋亡相关基因的表达。结果:MTT结果显示藻蓝蛋白能够抑制喉癌HEP-2的细胞活力,且呈时间和剂量依赖性;倒置显微镜、电镜、流式细胞术的一系列定性化和定量化实验证实藻蓝蛋白可显著诱导HEP-2细胞的凋亡;藻蓝蛋白处理后细胞内ROS水平升高,caspase-3、-8、-9被激活;RT-PCR结果表明,藻蓝蛋白作用后Bax、Fas、P53、caspase-3和caspase-9表达显著上调(P0.05),Bcl-2表达显著下调(P0.05);Western blot结果和RT-PCR结果一致。结论:藻蓝蛋白能够诱导HEP-2细胞的凋亡,其机制可能与细胞内ROS水平升高,上调Bax、Fas和P53 mRNA,下调Bcl-2 mRNA的表达,从而促进凋亡信号的转导最终导致细胞凋亡有关。     

低剂量电离辐射诱导小鼠睾丸生精细胞凋亡及P53基因和蛋白表达

目的:研究低剂量电离辐射对小鼠睾丸生精细胞凋亡及 P53 基因和蛋白表达的影响。方法:应用密度梯度离心法分离不同种类生精细胞, 流式细胞术检测其细胞凋亡, 免疫组化法观察生精细胞P53蛋白表达, 原位杂交法观察其 P53 mRNA水平。结果:0.025-0.2 Gy X射线全身照射后, 生精细胞凋亡具有明显的细胞种类规律性。在较低剂量照射(0.025和0.05 Gy)时, 以精原细胞凋亡为主, 随照射剂量增加(0.075-0.2 Gy)逐渐累及精母细胞, 并且前者凋亡率明显高于后者, 很少累及精子细胞和精子。P53蛋白表达主要见于精原细胞和精母细胞, 并且前者阳性率高于后者, 随照射剂量增加, 其阳性率逐渐升高, 而精子细胞和精子阳性率较低; P53 mRNA表达在较低剂量照射(0.025 Gy)时, 主要以精母细胞和精子细胞为主, 随剂量增加(0.05-0.2 Gy)逐渐累及精原细胞。精原细胞和精母细胞 P53 mRNA表达呈明显的剂量依赖性关系, 但精子细胞表现不明显。结论:低剂量电离辐射可选择性诱导小鼠睾丸生精细胞凋亡, 具有明显的剂量和时程效应关系。提示, 这种选择性诱导凋亡调控机制可能与 P53 基因和蛋白表达相关联。     

雷公藤甲素抗肿瘤血管新生的研究进展（英文）

雷公藤甲素(triptolide,TPL)是从中草药雷公藤中提取的一种有效活性物质,已被用来治疗多种疾病,包括系统性红斑狼疮,类风湿性关节炎,肾病综合征等,TPL甚至有很强的抑制肿瘤的活性。近些年的研究显示,TPL具有抗血管新生的能力,TPL不仅可以抑制肿瘤的增殖,诱导细胞的凋亡,还可以抑制肿瘤的转移,可以增加其它化疗药物的抗肿瘤活性。本综述将讨论TPL在抗肿瘤血管新生方面的研究进展,以及初步探讨其潜在的作用机制。     

Changes in activity of neutral proteases in tissues of ground squirrels in the dynamics of hibernation

Total activities of neutral proteases in the cerebral, hepatic, and myocardial tissues of ground squirrel vary during hibernation: in autumn (before hibernation) activities of the enzymes in the brain and myocardium start increasing, while in the liver they do not change. A common feature for all tissues is minimum activity of active neutral proteases in the middle of hibernation month 1 bout, while the maximum activity is recorded before awakening. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 9, pp. 278–280, September, 2008     

Kinetics of decline of maternal measles virus-neutralizing antibodies in sera of infants in France in 2006

The optimal age for measles vaccination is an important health issue, since maternal antibodies may neutralize the vaccine antigen before a specific immune response develops, while delaying vaccination may increase the risk of complicated diseases in infants. However, measles vaccination impacts the duration of protection afforded by transplacental transfer of maternal antibodies: vaccination-induced maternal antibodies disappear faster than disease-induced antibodies. In order to maintain protection against measles in infants, it is important to monitor the dynamics of this phenomenon in vaccinated populations. To assess the current situation in France, a multicenter, prospective seroepidemiological study was conducted in seven French hospitals between October 2005 and January 2007. Maternal measles antibody concentrations from 348 infants 0 to 15 months old were measured using the plaque reduction neutralization assay. Geometric mean concentrations and the percentage of infants with maternal measles antibody concentrations above the protection threshold (≥120 mIU/ml) were assessed according to age. Results show that after more than 20 years of routine measles vaccination in France, maternal measles-neutralizing antibodies decrease dramatically in French infants by 6 months of age, from 1,740 mIU/ml for infants 0 to 1 month old to 223 mIU/ml for infants 5 to 6 months old, and that 90% of infants are not protected against measles after 6 months of age. Infant protection against measles could be optimized both by increasing herd immunity through an increased vaccine coverage and by lowering the age of routine vaccination from 12 to 9 months.     

Effect of vitamin C in reducing the toxicity of endosulfan in liver in rabbits

In this study, the effect of endosulfan, an organochlorine pesticide, and the ameliorating effect of vitamin C on the livers of New Zealand white rabbits were studied. Livers of the rabbits were examined grossly and histopathologically, and caspase-3 activity was detected by immunohistochemical methods. A total of twenty-four rabbits were divided into four groups (n=6). Rabbits in Group I (END) were daily given a sublethal dose of endosulfan (1 mg/kg bw) in corn oil by oral gavage for 6 weeks. Group II (END+C) received the same dose of endosulfan and additionally Vit C (20 mg/kg bw) every other day during this period. Group III (OIL+C) received corn oil daily by oral gavage and vitamin C every other day for 6 weeks. Group IV (OIL), the control group, received only corn oil daily, by oral gavage throughout the experiment. The concentration of α-endosulfan in the END group was higher in livers (0.102±0.012 ppb) than the β-endosulfan (0.072±0.001 ppb). Decreased accumulation of α and β endosulfan was observed in the END+C group (0.025±0.003 and 0.016±0.002 ppb, respectively) (p<0.0001). The most prominent gross findings at the necropsy were seen in the END group, in which swollen and pale livers were commonly observed. Hemorrhages, degenerations, necrosis, and in some rabbits bile duct hyperplasia were the marked histopathological findings of the END group. Caspase-3 positive reaction was more severe in this group than in the others. An ameliorating effect of Vit C on gross, histopathological and immunohistochemical findings was observed in the END+C group. The results revealed that endosulfan is highly toxic for rabbit livers. However, toxicity was decreased by Vit C treatment, which reduced the accumulation of endosulfan in livers four-fold.