siRNA腺病毒载体沉默MEKK3基因促进TRAIL诱导肝癌HCC-9204细胞凋亡

目的研究抑制丝裂原活化蛋白激酶/细胞外信号调节激酶-激酶3（MEKK3）基因表达促进TRAIL诱导人肝癌HCC-9204细胞凋亡的作用。方法构建人MEKK3基因的siRNA重组腺病毒载体,转导人肝癌HCC-9204细胞,以RTPCR和印迹法检测MEKK3 mRNA和蛋白的表达,筛选并建立稳定沉默MEKK3基因表达的人肝癌HCC-9204细胞株,以流式细胞仪检测TRAIL诱导细胞凋亡的情况。结果①成功构建并鉴定表达人MEKK3基因的siRNA重组腺病毒载体。②建立MEKK3基因有效且稳定沉默的人肝癌HCC-9204细胞株。③500 g/LTRAIL处理MEKK3基因沉默的HCC-9204细胞株,细胞凋亡率较野生HCC-9204细胞株显著提高。结论本研究成功建立有效且稳定沉默MEKK3基因表达的人肝癌HCC-9204细胞株模型,初步证实MEKK3基因表达与TRAIL诱导肝癌细胞凋亡的敏感性相关。     

肝素和阿霉素对人鼻咽癌CNE2细胞增殖与凋亡的协同作用

目的:观察肝素联合阿霉素对人鼻咽癌细胞的=增殖与凋亡的影响及其可能的分子机制.方法:用MTT法、流式细胞术观察肝素联合阿霉素对人鼻咽癌细胞增殖及细胞周期的影响;而用TUNEL、琼脂糖凝胶电泳、Westem blot等方法观察肝素与阿霉素联合应用对人鼻咽癌细胞凋亡的作用.结果:肝素与阿霉素联合应用后对鼻咽癌细胞的生长抑制及其凋亡具有显著增强作用,同阿霉素单独应用于诱导细胞凋亡相比,低剂量的肝素与阿霉素联合应用后发现:TUNEL阳性细胞从12.6％±1.1％增加到65.7％±1.3％;G_0/G_1期细胞阻止,S期细胞明显减少,DNA“梯形”变化更加明显;Bax/Bcl-2的比率及p~(53)和p~(21)基因的表达明显升高.结论:肝素与阿霉素对人鼻咽癌细胞在抗增殖及促凋亡方面有协同作用,这可能与Bax/Bcx-2比率的升高及p~(53)和p~(21)的表达上调有关.     

RNA干扰靶向cyclin D1基因对K562细胞化疗增敏的研究

目的 cyclin D1基因在细胞周期调控中起关键性作用.研究表明其过表达与肿瘤的发生、发展及预后密切相关;并且与肿瘤细胞对化疗药物抗拒性有关.抑制Cyclin D1蛋白表达可达到化疗增敏作用.本研究利用RNA干扰(RNAi)技术体外观测其对K562细胞cyclin D1基因的沉默效应及增强阿霉素(ADM)对K562细胞毒性作用.方法 体外构建靶向cyclin D1基因的小发夹RNA(shRNA)表达质粒,通过壳聚糖介导转染K562细胞,Western blot分析检测转染前后Cyclin DI蛋白表达变化,流式细胞仪检测细胞周期分布及凋亡率的影响以及MTT法检测K562细胞对ADM敏感性的变化.结果 构建靶向cyclin D1基因的shRNA表达质粒(pshRNA-419和pshRNA-575)经壳聚糖转染后,能显著抑制cyclin D1基因表达;影响K562细胞周期分布,诱导细胞凋亡,并降低ADM半数抑制浓度,提高了化疗敏感性.而设计一碱基突变的序列所构建的质粒并无上述生物学效应.结论 沉默K562细胞cyclin D1基因表达可达到有效的化疗增敏目的.     

甲基莲心碱对MCF-7细胞体外化疗增敏作用

目的探讨甲基莲心碱(Neferine,Nef)的体外化疗增敏作用.方法以人乳腺癌细胞MCF-7为研究对象,MTT法测定药物的细胞生长抑制率,流式细胞仪(Flowcytometry,FCM)检测细胞凋亡.结果Nef(5umol*L-1、10umol*L-1)分别与阿霉素(ADM)、5-氟尿嘧啶(5-FU)、顺铂(CDDP)合用,可增加它们对MCF-7细胞的生长抑制率,q＞1.Nef(10umol*L-1可增强10umol*L-1ADM诱导MCF-7细胞凋亡的作用.结论Nef具有化疗增敏作用.     

灯盏花素促进阿霉素诱导的K562细胞凋亡

目的观察灯盏花素对淋巴细胞增殖和阿霉素致肿瘤细胞死亡的影响。方法MTT法检测细胞增殖,Western blot检测p53/bcl-2表达,Histone/DNA ELISA和流式细胞仪检测细胞凋亡,ELISA检测细胞色素C释放,分光光度法检测caspase-8和caspase-3激活。结果灯盏花素能增强小鼠淋巴细胞对阿霉素的抵抗,但促进阿霉素引起的K562细胞生长抑制、细胞色素C释放、caspase-8和caspase-3激活,上调其p53/bcl-2表达比率,增加细胞凋亡。结论灯盏花素有增强阿霉素抗肿瘤作用,激活肿瘤细胞凋亡通路可能是其化疗增敏的主要机制。     

复方丹参注射液对H2O2诱导的PC12细胞凋亡的保护作用

目的:探讨复方丹参注射液(ISM)对H2O2诱导的PC12细胞凋亡保护作用的机制.方法:在H2O2诱导PC12细胞凋亡模型的基础上,采用MTT比色分析测细胞存活率,Hoechst-PI荧光染色和流式细胞仪检测分析细胞凋亡情况,RT-PGR检测par-4和NF-gB P 65基因mRNA表达,Western b1ot检测Par-4和NF-κB P 65蛋白表达.结果:不同剂量ISM预处理1 h可提高PC12细胞的存活率,降低par-4和NF-κB P 65的mRNA表达以及蛋白表达.结论:ISM可剂量依赖性地对抗H2O2的神经毒性作用,其机制可能与降低凋亡基因par-4的表达有关.     

靶向NBS1的RNA干扰对鼻咽癌CNE-2细胞放射增敏作用的研究

目的:研究靶向NBS1的RNA干扰对鼻咽癌CNE-2细胞的放射增敏作用。方法:靶向NBS1的小干扰RNA转染鼻咽癌CNE-2细胞48小时后,4Gy剂量X射线照射。照射后24小时,流式细胞仪分析鼻咽癌细胞凋亡率。结果:X线照射+RNAi-NBS1组的细胞凋亡率显著高于单独X线照射组和X线照射+RNAi-阴性对照组(P<0.01)。结论:靶向NBS1的RNA干扰在鼻咽癌CNE-2细胞中有显著的放射增敏作用,诱导细胞凋亡是其放射增敏的重要机制之一。     

金喜素诱导肺癌细胞凋亡与抑制Bcl-2和PKC活性的关系

目的　研究金喜素诱导人肺癌SPC -A - 1细胞凋亡的作用及可能的机制。方法　体外培养肺癌细胞 ,以 2 0mg·L-1金喜素处理后 ,TUNEL法观察肺癌细胞凋亡形态学特征 ;流式细胞仪检测肺癌细胞凋亡率和肺癌细胞Bcl- 2蛋白的表达 ;放射性同位素法检测肺癌细胞蛋白激酶C(PKC)活性。结果　金喜素处理细胞 2 4h后 ,TUNEL法观察到典型的凋亡细胞形态学特征 ,流式细胞仪检测肺癌细胞凋亡率为 11 5 %± 2 8%,显著高于对照组细胞 (P<0 .0 1) ;Bcl- 2蛋白阳性表达细胞率为 7 8%± 1 1%,较对照组显著降低 (P <0 .0 1) ;肺癌细胞膜PKC活性较对照组显著降低 (P <0 0 1)。结论　金喜素可诱导肺癌细胞凋亡而发挥抗瘤作用 ,其作用机制可能为抑制凋亡蛋白Bcl- 2表达及PKC活性。     

甲基莲心碱对Saos-2细胞体外增敏作用的研究

目的探讨甲基莲心碱(Neferine ,Nef)对骨肉瘤细胞(Saos-2 cells)的体外化疗增敏作用.方法以人骨肉瘤细胞株(Saos-2 cells)为研究对象,MTT法测定药物的细胞生长抑制率,流式细胞仪(Flow Cytometry , FCM)检测细胞凋亡.结果 Nef(5,10μmol·L-1)分别为与阿霉素(ADM),5-氟尿嘧啶(5-Fu),顺铂(CDDP),鬼臼乙叉苷(VP16)合用,可增加它对Saos-2细胞的生长抑制率,q＞1.Nef(10μmol·L-1)可增强不同浓度ADM诱导Saos-2细胞凋亡.结论 Nef 对Saos-2细胞有化疗增敏作用.     

SUMO-1基因siRNA抑制肝癌细胞SMMC-7721生长的研究

目的:研究SUMO-1基因siRNA沉默人肝癌细胞SMMC-7721中SUMO-1基因表达的效果及对SMMC-7721生长的影响.方法:将人工合成的针对SUMO-1基因的siRNA片段转染体外培养的人肝癌细胞SMMC-7721,采用RT-PCR、Western blot方法在mRNA及蛋白水平检测siRNA沉默肝癌细胞中SUMO-1基因的效果.通过MTT、流式细胞仪及TUNEL试验检测SUMO-1基因沉默后对肝癌细胞生长的影响.结果:人工合成的针对SUMO-1基因的siRNA片段能显著地抑制SMMC-7721 中SUMO-1基因的表达,48 h抑制率可达73.43%.MTT结果显示肝癌细胞SMMC-7721转染SUMO-1 siRNA后生长明显受到抑制,流式细胞仪检测G_2期细胞明显增加,但TUNEL试验未发现凋亡细胞.结论:SUMO-1 siRNA沉默肝癌细胞SMMC-7721 中SUMO-1基因效果良好,SUMO-1基因控制SMMC-7721的生长,SUMO-1基因是肝癌生长的一个重要的调控因素.     

氧化型低密度脂蛋白对PC12细胞的毒性作用

目的 :探讨氧化型低密度脂蛋白 (oxLDL)对PC1 2细胞的毒性作用。方法 :通过HE染色、透射电镜、MTT实验、LDH释放实验、TUNEL实验及Caspase 3测定来观察oxLDL对PC1 2细胞形态、存活率、细胞膜通透性、细胞核及Caspase 3活性的影响。结果 :透射电镜及光镜下oxLDL作用的PC1 2细胞以坏死为主并伴少量凋亡细胞。细胞存活率随着ox LDL浓度及作用时间增加而下降 ;LDH释放率、TUNEL阳性细胞数及Caspase 3活性随着浓度增高而增高 ;LDL对上述各项指标无影响。结论 :oxLDL通过Caspase 3途径致PC1 2细胞的毒性作用主要以坏死细胞为主并伴少量凋亡细胞 ,并呈量效与时效关系 ;而LDL无细胞毒性作用     

吉西他滨诱导神经胶质瘤细胞凋亡及其对促凋亡因子Bax/Bak的影响

目的:研究抗癌药物吉西他滨(Gemcitabine, Gem)对人神经胶质瘤U87细胞的凋亡以及其对促凋亡因子Bax/Bak的影响。方法:MTT法检测0(对照组)、0.5,1,5,10μmol·L^-1的Gem对U87细胞增殖的影响以及5μmol·L^-1 Gem处理U87细胞12,24,36,48 h后的细胞活性。细胞核特异性染料DAPI核染后共聚焦显微镜下观察Gem处理的U87细胞核型的变化。流式细胞仪结合染色和免疫荧光技术检测细胞的凋亡情况、细胞周期分布以及Bax/Bak活化情况。Western blot检测shRNA基因沉默前后Gem引起的细胞内Bax/Bak蛋白的表达情况。MTT法检测沉默Bax/Bak后Gem对U87细胞活力的影响。结果:Gem对U87细胞活性的影响具有显著的浓度和时间依赖性。5μmol·L^-1的Gem处理细胞12,24,36,48 h后细胞活力分别(79±3.2)%、(41.2±2.6)%、(27.9±3.1)%、(20.4±1.7)%。Gem处理U87细胞后细胞核明显固缩并形成凋亡小体。Gem引起细胞凋亡,5μmol·L^-1Gem处理的细胞凋亡率为(45.9±2.6)%,显著高于对照组的(3.1±1.8)%。Gem能够显著将细胞阻滞在Sub-G1和S期(P<0.01),并明显引起细胞内Bak的活化而没有引起Bax的活化(P<0.01)。与对照组相比,5μmol·L^-1的Gem处理U87细胞后,沉默Bak基因很好的抑制了Bak蛋白的表达而没有抑制Bax蛋白的表达。最后发现,沉默Bak明显抑制了Gem对U87细胞的毒性(P<0.01),而沉默Bax相比Gem单独用药组没有明显变化。结论:Gem能够抑制U87细胞的增殖并引起细胞凋亡,在凋亡通路中引起细胞Sub-G1和S期的阻滞,并且导致细胞内Bak而非Bax的活化而促进凋亡。     

S型与R型人参皂苷Rh2诱导人肺腺癌A549细胞凋亡的体外研究

目的探讨人参皂苷Rh2(S型与R型)能够诱导人肺腺癌A549细胞凋亡。方法采用MTT实验测定细胞增殖能力;台肦蓝染色法检测细胞存活率;碘化丙啶(PI)单染流式细胞仪分析细胞周期中各时期的细胞百分数;电镜观察细胞凋亡。结果 30μg/mL的S型和R型人参皂苷Rh2作用于A549细胞48h后,死亡率均明显高于正常组细胞(P<0.05);20(S)-Rh2能阻滞细胞周期于G1期,并且2(S)-Rh2型的抗肿瘤活性明显强于20(R)-Rh2;电镜结果显示染色质浓集、断裂,核固缩并出现凋亡小体。结论 S型和R型人参皂苷Rh2均具有促进A549细胞凋亡的生物学功能。     

三氧化二砷(As_2O_3)诱导人胃腺癌SGC7901细胞程序化死亡并降低c-myc基因的表达

目的：探讨Ａｓ２Ｏ３对胃腺癌ＳＧＣ７９０１细胞系的生物学效应及机制。方法：通过ＭＴＴ还原法检测Ａｓ２Ｏ３对该细胞系存活率的影响,从光学显微镜形态观察,流式细胞仪分析,ＤＮＡ凝胶电泳,细胞凋亡原位检测（ＴＵＮＥＬ）进行细胞凋亡的检测。半定量ＲＴＰＣＲ检测基因表达。结果：Ａｓ２Ｏ３处理ＳＧＣ７９０１细胞后,细胞的存活率明显降低,光学显微镜下可见到明显的凋亡细胞,流式细胞仪测定细胞周期的Ｇ１期前有亚２倍体的凋亡峰,ＤＮＡ凝胶电泳显示出典型的凋亡特征：ＤＮＡ有规律断裂形成的梯状图谱,细胞凋亡原位检测发现ＤＮＡ的断裂,并降低细胞ｃｍｙｃ基因的表达。结论：Ａｓ２Ｏ３能诱导人胃腺癌ＳＧＣ７９０１细胞程序化死亡并可能通过降低ｃｍｙｃ基因的表达。     

Dihydroartemisinin is an inhibitor of ovarian cancer cell growth

Aim： To investigate the anticancer activity of dihydroartemisinin （DHA）, a derivative of antimalaria drug artemisinin in a panel of human ovarian cancer cell lines. Methods： Cell growth was determined by the MTT viability assay. Apoptosis and cell cycle progression were evaluated by a DNA fragmentation gel electro-phoresis, flow cytometry assay, and TUNEL assay; protein and mRNA expression were analyzed by Western blotting and RT-PCR assay. Results： Artemisinin and its derivatives, including artesunate, arteether, artemether, arteannuin, and DHA, exhibit anticancer growth activities in human ovarian cancer cells. Among them, DHA is the most effective in inhibiting cell growth. Ovarian cancer cell lines are more sensitive （5-10-fold） to DHA treatment compared to normal ovarian cell lines. DHA at micromolar dose levels exhibits a dose- and time-dependent cytotoxicity in ovarian cancer cell lines. Furthermore, DHA induced apoptosis and G2 cell cycle arrest, accompanied by a decrease of Bcl-XL and Bcl-2 and an increase of Bax and Bad. Conclusion： The promising results show for the first time that DHA inhibits the growth of human ovarian cancer cells. The selective inhibition of ovarian cancer cell growth, apoptosis induction, and G2 arrest provide in vitro evidence for further studies of DHA as a possible anticancer drug in the clinical treatment of ovarian cancer.     

Nitric Oxide-Induced Autophagy in MC3T3-E1 Cells is Associated with Cytoprotection via AMPK Activation

Nitric oxide (NO) is important in the regulation of bone remodeling, whereas high concentration of NO promotes cell death of osteoblast. However, it is not clear yet whether NO-induced autophagy is implicated in cell death or survival of osteoblast. The present study is aimed to examine the role of NO-induced autophagy in the MC3T3-E1 cells and their underlying molecular mechanism. The effect of sodium nitroprusside (SNP), an NO donor, on the cytotoxicity of the MC3T3-E1 cells was determined by MTT assay and expression of apoptosis or autophagy associated molecules was evaluated by western blot analysis. The morphological observation of autophagy and apoptosis by acridine orange stain and TUNEL assay were performed, respectively. Treatment of SNP decreased the cell viability of the MC3T3-E1 cells in dose- and time-dependent manner. SNP increased expression levels of p62, ATG7, Beclin-1 and LC3-II, as typical autophagic markers and augmented acidic autophagolysosomal vacuoles, detected by acridine orange staining. However, pretreatment with 3-methyladenine (3MA), the specific inhibitor for autophagy, decreased cell viability, whereas increased the cleavage of PARP and caspase-3 in the SNP-treated MC3T3-E1 cells. AMP-activated protein kinase (AMPK), a major autophagy regulatory kinase, was activated in SNP-treated MC3T3-E1 cells. In addition, pretreatment with compound C, an inhibitor of AMPK, decreased cell viability, whereas increased the number of apoptotic cells, cleaved PARP and caspase-3 levels compared to those of SNP-treated MC3T3-E1 cells. Taken together, it is speculated that NO-induced autophagy functions as a survival mechanism via AMPK activation against apoptosis in the MC3T3-E1 cells.     

Effects and mechanisms of emodin on cell death in human lung squamous cell carcinoma

1. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is an active component from the root and rhizome of Rheum palmatum that has been reported to exhibit antitumour effects, but the mechanism is not known. The study investigated the effects and mechanisms of emodin-induced cell death in human lung squamous carcinoma cell line CH27. 2. Emodin (50 microM)-induced CH27 cell apoptosis was confirmed by cell morphological change, sub-G1 formation in flow cytometry analysis, viability assay and degradation of focal adhesion kinase in this study. 3. Emodin-induced apoptosis of CH27 cells does not involve modulation of endogenous Bcl-X(L) protein expression, but appears to be associated with the increased expression of cellular Bak and Bax proteins. This study also demonstrated the translocation of Bak and Bax from cytosolic to particulate fractions. 4. This study has shown that emodin-treated CH27 cells revealed the increases in the relative abundance of cytochrome c for the indicated time intervals in cytosolic fraction. 5. This study demonstrates that the activation of caspase-3, caspase-9 and caspase-8 is an important determinant of apoptotic death induced by emodin. 6. These results suggested that emodin induces CH27 cell death by Bax death pathway and Fas pathway.