蟾蜍灵诱导人肺腺癌细胞凋亡作用及其机制

目的 研究中药蟾酥有效成分蟾蜍灵(bufalin)对人肺腺癌细胞的作用及其机制。方法 MTT法检测蟾蜍灵对细胞的增殖抑制作用;瑞氏 吉姆萨染色法观察细胞形态学的变化;流式细胞术分析细胞凋亡和线粒体跨膜电位;Western blot法检测Bcl-2、Caspase-3蛋白的表达。结果 (1) 蟾蜍灵明显抑制A549细胞增殖,48h及72h的IC50分别为(56.14±6.72)nmol/L、(15.57±4.28)nmol/L。(2) 蟾蜍灵能诱导肺癌细胞凋亡,形态学表现为出现凋亡小体及流式细胞仪检测到的亚二倍体凋亡峰。(3) 蟾蜍灵可以明显降低细胞线粒体跨膜电位(ΔΨm)。(4) 蟾蜍灵诱导细胞凋亡过程中,下调Bcl-2蛋白表达(P<0.01),同时活化Caspase-3。结论 线粒体途径是蟾蜍灵诱导肺腺癌A549细胞凋亡的主要通路之一。     

RNA干扰GRP75表达改善人肺腺癌细胞对顺铂耐药性

背景与目的 GRP75(glucose regulated protein75)属于热休克蛋白(hot shock protein,HSP)家族,是一种主要位于线粒体的分子伴侣,在某些耐药的肿瘤细胞中高表达。本研究通过慢病毒介导的RNA干扰技术沉默GRP75基因的表达,观察下调GRP75的表达对肿瘤细胞耐药性的影响并探讨GRP75在肿瘤细胞耐药机制中的作用。方法以顺铂为诱导药物,人肺腺癌细胞系A549为诱导对象,采用逐步增加剂量与大剂量冲击相结合的方法,诱导建立耐顺铂细胞株A549/CDDP。分别将包裹GRP75-shRNA和不含干扰序列的慢病毒转染A549和A549/CDDP细胞,在荧光显微镜下观察各组细胞转染率,应用M比色法检测干扰前后各组细胞对顺铂的敏感性,应用Western blot检测干扰前后各组细胞GRP75、p53、bcl-2的表达。结果各组细胞感染效率均在90%以上,转染后A549/CDDP和A549细胞中GRP75的表达均明显下调(P<0.05)。转染前后A549/CDDP细胞对顺铂的耐药指数分别为21.52和4.14。转染后A549/CDDP细胞内p53的表达上调(P<0.05),bcl-2表达下调(P<0.05)。结论 GRP75是A549细胞对顺铂耐药机制的相关蛋白之一,其在耐药机制中的作用与其对p53和bcl-2的调控有关。     

高良姜素诱导肺癌A549细胞凋亡的研究

目的研究高良姜素诱导肺癌细胞系A549细胞凋亡效应。方法MTT法测定A549细胞生长抑制率,荧光显微镜观察细胞形态学的变化,流式细胞仪分析细胞周期和线粒体膜电位的变化。Western blot检测细胞凋亡相关蛋白的表达变化。结果随高良姜素浓度增高,A549细胞生长抑制率明显上升,IC50在30.15 mg/L。细胞凋亡可在10~80mg/L 高良姜素处理后24 h出现,呈浓度依赖性。高良姜素使线粒体膜电位降低。Caspases被激活,Bcl-2、Bcl-XL表达下调,p53、Bax、Bid表达呈浓度依赖性上调。结论高良姜素可能是通过线粒体途径诱导A549细胞发生凋亡。     

NDV-HN致人肺腺癌A549细胞凋亡的实验研究

摘 要：［目的］ 探讨NDV-HN诱导人肺腺癌A549细胞凋亡的相关机制。［方法］ （1）构建包含绿色荧光素蛋白（GFP）及NDV-HN的慢病毒sfGFP-HN载体,用293V细胞包装慢病毒Lv-sfGFP-HN,用293V细胞进行空载质粒转染组（空载组）慢病毒包装,命名为Lv-sfGFP;（2）以空载组A549-sfGFP细胞和空白组A549为对照,用慢病毒转染方法建立稳定表达NDV-HN蛋白的A549细胞株,即A549-sfGFP-HN细胞株,RT-PCR、Western blot检测A549细胞NDV-HN蛋白的表达;（3）分别在A549-sfGFP-HN和A549两组细胞中加入顺铂,流式细胞术检测细胞凋亡;（4）在基因水平和蛋白水平上分别用RT-PCR和Western blot检测各组细胞凋亡相关蛋白Bcl-2的表达。［结果］ （1）Lv-sfGFP-HN和Lv-sfGFP慢病毒分别转染A549细胞后,只在转染组A549-sfGFP-HN细胞检测到NDV-HN蛋白。（2）转染组A549-sfGFP-HN细胞凋亡率明显高于空白组A549细胞 (P＜0.01),转染组A549-sfGFP-HN细胞加入顺铂后,其细胞凋亡率明显增加。（3）转染组A549-sfGFP-HN细胞与空载质粒转染组A549细胞和空白组A549细胞相比,凋亡相关蛋白Bcl-2表达量明显下调(P＜0.01)。［结论］ 慢病毒转染NDV-HN到A549细胞后导致A549-sfGFP-HN细胞出现凋亡,且与Bcl-2下调有关。转染NDV-HN的肺癌细胞联合使用抗癌药物顺铂,增加了肺癌细胞凋亡率。     

双氢青蒿素和顺铂诱导人肺腺癌A549/CDDP 细胞凋亡

目的:观察双氢青蒿素和顺铂在体外对A549/CDDP细胞的作用,分析双氢青蒿素逆转耐药效果,从诱导细胞凋亡角度分析可能的作用机理。方法:A549/CDDP细胞分为双氢青蒿素作用组和顺铂对照组,顺铂对细胞增殖抑制实验采用MTT检测法,用annexin-V和PI双标记进行流式细胞检测分析细胞凋亡率。双氢青蒿素对细胞Bcl-2,Bax等蛋白的影响采用免疫组织化学法结合图像分析。结果:对人肺腺癌A549/CDDP细胞双氢青蒿素作用组和顺铂对照组IC50值分别为1.30μg/ml和5.58μg/ml,两组比较差异显著(P<0.01),逆转倍数4.29。对A549/CDDP细胞,双氢青蒿素作用组和对照组凋亡率分别为17.6%和1.6%两组比较差异显著(P<0.01)。双氢青蒿素作用于A549/CDDP细胞后,Bcl-2蛋白表达下降,Bax蛋白表达上升。结论:A549/CDDP细胞耐药作用与凋亡耐受有关,双氢青蒿素可使A549/CDDP细胞恢复对顺铂的敏感性,通过解除凋亡抑制从而逆转耐药。     

双氢青蒿素和顺铂诱导人肺腺癌A549/CDDP细胞凋亡

目的：观察双氢青蒿素和顺铂在体外对A549/CDDP细胞的作用,分析双氢青蒿素逆转耐药效果,从诱导细胞凋亡角度分析可能的作用机理。方法：A549/CDDP细胞分为双氢青蒿素作用组和顺铂对照组,顺铂对细胞增殖抑制实验采用MTT检测法,用annexin-V和PI双标记进行流式细胞检测分析细胞凋亡率。双氢青蒿素对细胞Bcl-2,Bax等蛋白的影响采用免疫组织化学法结合图像分析。结果：对人肺腺癌A549/CDDP细胞双氢青蒿素作用组和顺铂对照组IC50值分别为1.30μg/ml和5.58μg/ml,两组比较差异显著（P〈0.01）,逆转倍数4.29。对A549/CDDP细胞,双氢青蒿素作用组和对照组凋亡率分别为17.6%和1.6%两组比较差异显著（P〈0.01）。双氢青蒿素作用于A549/CDDP细胞后,Bcl-2蛋白表达下降,Bax蛋白表达上升。结论：A549/CDDP细胞耐药作用与凋亡耐受有关,双氢青蒿素可使A549/CDDP细胞恢复对顺铂的敏感性,通过解除凋亡抑制从而逆转耐药。     

siRNA干扰MT1H基因对A549/DDP细胞耐药性的逆转

目的：探讨siRNA干扰金属硫蛋白1H（metallothionein 1H,MT1H）基因逆转A549/DDP细胞耐药的可行性。方法：采用RT-PCR方法检测MT1H基因在A549和其顺铂耐药株A549/DDP细胞中的表达;将针对MT1H的siRNA导入A549/DDP细胞;用RT-PCR和斑点印迹方法分析MT1H基因表达情况;MTT法观察细胞顺铂耐药性;TUNEL、流式细胞术检测顺铂诱导细胞凋亡率;免疫细胞化学分析凋亡相关蛋白Bcl-2、Bax的表达。结果：MT1H在A549/DDP细胞中高表达但不在A549细胞中表达;A549/DDP细胞转染48 h后,与对照组比较,MT1HsiRNA转染组MT1H mRNA和蛋白表达均明显下调,细胞对DDP的药物敏感性明显提高,DDP诱导凋亡率明显增加,Bcl-2表达明显下降,Bax表达无变化。结论：MT1H基因沉默能降低Bcl-2表达,增强顺铂对A549/DDP细胞凋亡诱导作用,有效逆转A549/DDP细胞耐药。     

上调miRNA-506对肺癌耐药细胞株A549/DDP耐药性的逆转及其机制

目的:探讨微小核糖核酸（miRNA）-506对人非小细胞肺癌顺铂耐药株A549/DDP细胞耐药性的逆转及其可能机制。方法:构建miRNA-506 模拟物,应用脂质体法转染A549/DDP细胞。应用实时逆转录酶链聚合反应（qRT-PCR）法验证各组细胞中miRNA-506的表达情况,CCK8法检测顺铂对细胞的抑制作用。流式细胞术Annexin V／PI双染检测各组细胞的凋亡。Western blot检测MDR1、MRP1、Bcl-2、Bax的蛋白表达。结果:qRT-PCR结果显示,miRNA-506转染组miRNA-506的表达量明显高于对照组（P<0.05）。CCK8结果显示,上调miRNA-506 增强A549/DDP细胞对顺铂的敏感性。流式细胞术结果显示上调miRNA-506 促进顺铂诱导的A549/DDP细胞凋亡。上调miRNA-506可以使A549/DDP细胞MDR1、MRP1和Bcl-2蛋白的表达下降,使Bax蛋白的表达升高。结论:上调miRNA-506能逆转A549/DDP细胞对顺铂的耐药,这一过程可能通过miRNA-506调控多药耐药蛋白和凋亡相关蛋白实现。     

真核表达survivin基因对曲古菌素A诱导卵巢癌细胞凋亡作用的影响

目的　探讨survivin 基因对曲古菌素A( TSA) 诱导卵巢癌细胞凋亡作用的影响。方法　(1) 将本实验室已构建成功的survivin 正义全长真核表达质粒(pcDNA 3. 1-urvivin) ,经脂质体包裹转染人卵巢癌细胞A2780 ,以转染pcDNA 3. 1空载体的A2780 细胞为对照。(2) RT2PCR 和Western blot 方法分别检测survivin mRNA 和蛋白质的表达。(3) MTT 比色法和流式细胞仪(FACS) 分别检测TSA 对两组细胞存活率和凋亡率的影响。(4) Western blot 检测TSA 作用下A2780 细胞中survivin 蛋白的表达变化。结果　(1) RT-PCR和Western blot 检测提示转染pcDNA 3. 1-urvivin 组中survivin mRNA 和蛋白质表达明显高于空载体组。(2) MTT 比色法和FACS 检测提示转染pcDNA 3. 1-urvivin 组细胞存活率明显高于空载体组,细胞凋亡率明显低于空载体组,差异有统计学意义( P<0. 05) 。pcDNA 3. 1-urvivin转染后的2780 细胞对TSA 的敏感性明显降低。(3) Western blot 检测提示survivin 的表达水平随着TSA 作用时间的延长而下降。结论　曲古菌素A 诱导卵巢癌细胞的凋亡作用可能与survivin 基因表达有关。     

TSA对肺腺癌细胞株A549细胞凋亡的影响

目的：探讨组蛋白脱乙酰化酶抑制剂曲古抑菌素A（trichostatin A，TSA）对A549肺腺癌细胞凋亡的影响。方法：Annexin V和Hoechst染色法检测细胞凋亡；流式细胞仪分析细胞周期；Western blot检测凋亡信号通路中caspas-8、caspase-9活化及多聚ADP核糖聚合酶（PARP）裂解情况。结果：TSA可诱导细胞凋亡，主要使细胞积聚在G2／M期，且呈浓度依赖性。Western blot检测表明TSA诱导了A549肺腺癌细胞caspase-8、caspase-9裂解活化及PARP裂解，且随TSA作用时间延长而逐步升高。结论：TSA诱导A549细胞凋亡中caspase-8、caspase-9介导caspas-3的活化，TSA通过caspase级联反应诱导A549细胞凋亡。     

Aurora A激酶研究进展

Aurora A激酶是进化上保守的有丝分裂丝/苏氨酸激酶Aurora激酶家族成员之一,在细胞内随细胞周期的变化呈动态分布,它广泛的参与了细胞周期不同阶段的各种事件,并在人类多种恶性肿瘤的发生发展过程中起到了至关重要的作用,因而很有可能成为一个极具前途的恶性肿瘤的分子治疗靶点。     

A phase I trial of CGS 16949A. A new aromatase inhibitor

CGS 16949A is a new, nonsteroidal competitive inhibitor of the aromatase enzyme. In this Phase I trial, 16 heavily pretreated postmenopausal patients with metastatic breast cancer were treated with escalating doses of CGS 16949A from 0.6 to 16 mg total daily oral dose. No hematologic, biochemical, or significant clinical toxicity was encountered. Endocrinologic and pharmacologic data were available from 12 of these patients. Maximum inhibition of estrogen biosynthesis was observed at a dose of 2 mg CGS 16949A daily. At this dose, the inhibition of estrogen biosynthesis was equivalent to 1000 mg aminoglutethimide (AG). The fall in plasma and urinary estrogens without a concomitant drop in androgens confirmed the specific blockade of aromatase activity. At doses of 4 to 16 mg daily, CGS 16949A appeared to inhibit the C21-hydroxylase enzyme as well. The t1/2 of CGS 16949A in the circulation was 10.5 hours. Of 16 evaluable patients there were two partial responses and seven patients with stable disease.     

A gist of gastrointestinal stromal tumors: A review

Gastrointestinal stromal tumors (GISTs) have been recognized as a biologically distinctive tumor type, different from smooth muscle and neural tumors of the gastrointestinal tract (GIT). They constitute the majority of gastrointestinal mesenchymal tumors of the GIT and are known to be refractory to conventional chemotherapy or radiation. They are defined and diagnosed by the expression of a proto-oncogene protein detected by immunohistochemistry which serves as a crucial diagnostic and therapeutic target. The identification of these mutations has resulted in a better understanding of their oncogenic mechanisms. The remarkable antitumor effects of the molecular inhibitor imatinib have necessitated accurate diagnosis of GIST and their distinction from other gastrointestinal mes-enchymal tumors. Both traditional and minimally invasive surgery are used to remove these tumors with minimal morbidity and excellent perioperative outcomes. The revolutionary use of specific, molecularlytargeted therapies, such as imatinib mesylate, reduces the frequency of disease recurrence when used as an adjuvant following complete resection. Neoadjuvant treatment with these agents appears to stabilize disease in the majority of patients and may reduce the extent of surgical resection required for subsequent complete tumor removal. The important interplay between the molecular genetics of GIST and responses to targeted therapeutics serves as a model for the study of targeted therapies in other solid tumors. This review summarizes our current knowledge and recent advances regarding the histogenesis, pathology, molecular biology, the basis for the novel targeted cancer therapy and current evidence based management of these unique tumors.     

Expression of blood group A antigen during erythroid differentiation in A1 and A2 subjects

The expression of blood group A antigen on marrow and blood cells from A1 and A2 subjects was investigated by the binding of Helix pomatia and Dolichos biflorus lectins using immunofluorescence. These two lectins stained BFU-E-derived colonies from A subjects in the early days of culture before the expression of glycophorin. The erythroid origin of these cells was ascertained by the coexpression of two other very early erythroid markers. In bone marrow, the ultrastructural immunogold method revealed that the entire erythroid lineage including proerythroblasts was labeled by HPA, whereas no staining was observed on granulomonocytic cells including myeloblasts. Platelets from A subjects were HPA-labeled and so were platelets from an O subject preincubated in A plasma. Megakaryocytes obtained in CFU-MK-derived colonies were weakly and heterogeneously labeled by the HPA lectin. Cultures from A1 and A2 subjects were the reflection of the genetic differences only when investigations were performed on mature erythroblasts. In contrast, the great majority of immature erythroblasts both from A2 and A1 subjects were equally labeled by both lectins; during further erythroid maturation, binding of both lectins markedly diminished only on A2 erythroblasts. When marrow erythroblasts were investigated at electron microscopic level, heterogeneity of labeling among all stages of maturation was clearly observed in A2 subjects, with staining stronger on immature than on mature erythroblasts. Therefore, the genetic differences between A1 and A2 subjects are revealed during terminal erythroid differentiation.