Triptolide-induced apoptosis by inactivating nuclear factor-kappa B apoptotic pathway in multiple myeloma <Emphasis Type="Italic">in vitro</Emphasis>

The effect of triptolide on proliferation and apoptosis of human multiple myeloma RPMI-8226 cells in vitro,as well as the roles of nuclear factor-kappa B(NF-κB) and IκBα was investigated.The effect of tritptolide on the growth of RPMI-8226 cells was studied by MTT assay.Apoptosis was detected by Hoechest 33258 staining and Annexin V/PI double staining assay.The expression of NF-κB and IκBα was observed by Western blot and confocal microscopy.The results showed that triptolide inactivated NF-κB apoptotic pathway in human multiple myeloma RPMI-8226 cells.Triptolide at nM range induced proliferation inhibition in a dose-and time-dependent manner and apoptosis in a dose-dependent fashion in RPMI-8226 cells.Besides,we observed the inhibition of NF-κB /p65 in the nuclear fraction was correlated with the increase in the protein expression of IκBα in the cytosol.These results suggested that triptolide might exhibit its strong anti-tumor effects via inactivation of NF-κB/p65 and IκBα.     

Inhibition of NF-κB by mutant IκBα enhances TNF-α-induced apoptosis in HL-60 cells by controlling bcl-xL expression

Backgound The aim of this study was to explore whether the inhibition of nuclear factor-κB (NF-κB)activation by mutant IκBα (S32,36→A) can enhance TNF-α-induced apoptosis of leukemia cells and to investigate the possible mechanism. Methods The mutant IκBα gene was transfected into HL-60 cells by liposome-mediated techniques. G418 resistant clones stably expressing mutant IκBα were obtained by the limiting dilution method. TNF-α-induced NF-κB activation was measured by electrophoretic mobility shift assay (EMSA). The expression of bcl-xL was detected by RT-PCR and Western blot after 4 hours exposure of parental HL-60 and transfected HL-60 cells to a variety of concentrations of TNF-α. The percentage of apoptotic leukemia cells was evaluated by flow cytometry (FCM). Results Mutant IκBα protein was confirmed to exist by Western blot. The results of EMSA showed that NF-κB activation by TNF-α in HL-60 cells was induced in a dose-dependent manner, but was almost completely inhibited by mutant IκBα repressor in transfected cells. The levels of bcl-xL mRNA and protein in HL-60 cells increased after exposure to TNF-α, but changed very little in transfected HL-60 cells. The inhibition of NF-κB activation by mutant IκBα enhanced TNF-α-induced apoptosis. Thecytotoxic effects of TNF-α were amplified in a time- and dose-dependent manner. Conclusions NF-κB activation plays an important role in the resistance to TNF-α-induced apoptosis. The inhibition of NF-κB by mutant IκBα could provide a new approach that may enhance the antileukemia effects of TNF-α or even of other cytotoxic agents.     

Activation of NF-κB in bronchial epithelial cells from children with asthma

Objectives To determine whether nuclear factor-κB (NF-κB) is activated in epithelial cells from children with asthma and to understand the role of NF-κB in airway inflammation in asthma. Methods Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-κB expression in epithelial cells were detected by immunohistochemical examination, and NF-κB-DNA binding was measured by electrophoretic mobility shift assay (EMSA). Results Nuclear expression of NF-κB in epithelial cells was observed in the 9 asthmatic children. NF-κB-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-κB-DNA binding were absent in the 6 control subjects. Conclusion These results indicated that NF-κB is activated in epithelial cells from asthmatic children and the NF-κB activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.     

Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein （CRP）-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B （NF-κB） was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 （control group）, 25, 50 and 100 μg/mL （CRP groups） for 24 h. In PDTC （a specific NF-κB inhibitor） group, the cells were pre-treated with PDTC at 10 μmol/L and then with 100 μg/mL CRP. The conditioned media （CM） and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-κB inhibitor α （IκB-α） and NF-κB p65 was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IiB-α expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-κB p65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 μmol/L, the decrease in IκB-α expression and the increase in NF-κB p65 expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-κB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-κB activation.     

Inhibitory Activity of Nuclear Factor-κB Potentiates Cisplatin-induced Apoptosis in A549 Cells

Whether inhibiting the activity of nuclear factor (NF)-κB potentiates cisplatin-induced apoptosis in non-small cell lung cell line A549 cells was investigated. The recombinant plasmid pcDNA3.1( )/IκBα expressing IκBα was constructed. The in vitro cultured A549 cells were trans-fected with pcDNA3.1( )/IκBα alone, or pcDNA3.1( )/IκBα combined with cisplatin. The mitochondrial membrane potential (△ψm) was determined by rhodamine 123, the activity of caspase-3 was tested by colorimetric assay, and cell apoptosis was detected by flow cytometry with the annexin V/propidium iodide assay. The results showed that the activity of NF-κB in A549 cells was inhibited by transfecting pcDNA3.1( )/IκBα. Transfection of pcDNA3.1( )/IκBα alone did not promote apoptosis. Treatment of cisplatin alone had a little effect on cell apoptosis. Transfection of pcDNA3.1( )/IκBα combined with cisplatin treatment significantly induced apoptosis of A549 cells. It was concluded that inhibiting the activity of NF-κB potentiated cisplatin-induced apoptosis of A549 cells.     

The Role of IκBα in TNF-α-induced Apoptosis in Hepatic Stellate Cell Line HSC-T6

To investigate the role of NF-κB in TNF-α induced apoptosis in HSC-T6, a mutant IκBα was transfected into HSC-T6 cells by lipofectin transfection technique and its transient effect was examined 48 h after the transfection. The activation of NF-κB was detected by immune fluorescence cytochemistry and Western blotting with anti-p65 antibody. The apoptosis and the rate of inhibition by TNF-α in both transfected and untransfected HSC-T6 cells were measured respectively by FAC-Scan side scatter analysis and MTF methods. Our results showed that TNF-α could activate NF-κB in untransfected cells but not in transfected HSC-T6 cells. The percentage of apoptosis in transfected cells were significantly higher than that in the untransfected ones （P〈0.01） and it was also true of the inhibition rate （P〈0.01）. It is concluded that the resistance of HSC-T6 towards apoptosis induced by TNF-α can be mediated by NF-κB activation. The inhibition of NF-κB activation by mutant IκBα can attenuate the resistance of HSC-T6 cells and increase its sensitivity to TNF-α.     

Inhibitory Activity of Nuclear Factor-κB Potentiates Cisplatin-induced Apoptosis in A549 Cells

Whether inhibiting the activity of nuclear factor(NF)-κB potentiates cisplatin-induced apoptosis in non-small cell lung cell line A549 cells was investigated.The recombinant plasmid pcDNA3.1( )/IκBα expressing IκBα was constructed.The in vitro cultured A549 cells were transfected with pcDNA3.1( )/IκBα alone,or pcDNA3.1( )/IκBα combined with cisplatin.The mito-chondrial membrane potential(?ψm) was determined by rhodamine 123,the activity of caspase-3 was tested by colorimetric assay,and cell apoptosis was detected by flow cytometry with the annexin Ⅴ/propidium iodide assay.The results showed that the activity of NF-κΒ in A549 cells was inhibited by transfecting pcDNA3.1( )/IκΒα.Transfection of pcDNA3.1( )/IκΒα alone did not promote apoptosis.Treatment of cisplatin alone had a little effect on cell apoptosis.Transfection of pcDNA3.1( )/IκΒα combined with cisplatin treatment significantly induced apoptosis of A549 cells.It was concluded that inhibiting the activity of NF-κB potentiated cisplatin-induced apoptosis of A549 cells.     

Expression of Nuclear Factor-κB in Mouse Uterus during Peri-implantation

To investigate the expression of the subunit p65 of NF-κB and inhibitor kappa B alpha (IκBα) in mouse uterus during peri-implantation, thereby investigating whether transient activation of nuclear factor-κB (NF-κB) takes place during embryo implantation in mice. Immunohistochemical technique was used to examine the expression and localization of p65 in endometrium or deciduas, and Western blot analysis was employed to detect the levels of IκBα protein in mouse endometrium or deciduas. P65 protein was detected in stromal cells, epithelial cells of endometrium as well as in myometrium. Staining was predominately seen in the cytoplasm of the cells. Staining intensity for p65 was stronger in the epithelial compartment than the stromal compartment and myometrium. Staining intensity increased slightly during pregnancy, and it reached a high level on pregnancy day 5 and day 8. In contrast to p65, the level of IκBα protein was lowest on pregnancy day 5 in all groups. Our results suggested that NF-κB may regulate embryo implantation by its transient activation in mice.     

Inhibitory activity of nuclear factor-κB potentiates cisplatin-induced apoptosis in A549 cells

Whether inhibiting the activity of nuclear factor （NF）-κB potentiates cisplatin-induced apoptosis in non-small cell lung cell line A549 cells was investigated. The recombinant plasmid pcDNA3.1（＋）/IκBα expressing IκBα was constructed. The in vitro cultured A549 cells were transfected with pcDNA3.1 （＋）/IκBα alone, or pcDNA3.1（＋）/IκBα combined with cisplatin. The mitochondrial membrane potential （△ψm） was determined by rhodamine 123, the activity of caspase-3 was tested by colorimetric assay, and cell apoptosis was detected by flow cytometry with the annexin V/propidium iodide assay. The results showed that the activity of NF-κB in A549 cells was inhibited by transfecting pcDNA3.1（＋）/IκBα. Transfection of pcDNA3.1（＋）/IκBα alone did not promote apoptosis. Treatment of cisplatin alone had a little effect on cell apoptosis. Transfection of pcDNA3.1（＋）/IκBα combined with cisplatin treatment significantly induced apoptosis of A549 ceils. It was concluded that inhibiting the activity of NF-κB potentiated cisplatin-induced apoptosis of A549 cells.     

Adenovirus-mediated overexpression of novel mutated IκBα inhibits nuclear factor κB activation in endothelial cells

Nuclear factor κB （NF-κB） overactivation, requiring phosphorylation and degradation of its inhibitor IκBα, is the basis for chronicity of airway inflammation in asthma. Based on our previous plasmid pShuttle-IκBα, carrying an IκBα gene from human placenta, we optimized a novel IκBα mutant （IκBα） gene, constructed and characterized its replication-deficient recombinant adenovirus （AdIκBαM）, and tested whether AdIκBαM-mediated overexpression of IκBαM could inhibit the NF-κB activation in endothelial cells.     

人肝癌细胞株中FOXM1及NF-κB的表达及意义

目的 探讨不同肝癌细胞株中转录因子FOXM1（Forkhead Box M1）及核转录因子NF-κB（Nuclear factor kappa B）的表达强度及意义.方法采用Western blot、RT-PCR法,检测不同肝癌细胞株（QGY-7703、BEL-7402、SMMC-7721）中FOXM1及NF-κB在蛋白及mRNA水平的表达情况.结果 在3株肝癌细胞中FOXM1及NF-κB的表达无论是mRNA水平还是蛋白水平差异均有统计学意义,细胞株（QGY-7703、BEL-7402）中FOXM1及NF-κB的表达同时都明显高表达于细胞株SMMC-7721.结论 肝癌细胞株中FOXM1蛋白及mRNA表达与NF-κB表达趋势一致,提示FOXM的表达可能与NF-κB的活化有关.     

siRNA介导的NF-κB P65沉默诱导肝癌细胞SMMC7721凋亡

目的 研究siRNA介导的NF-κBP65沉默诱导肝癌细胞凋亡相关机制。方法实验以肝癌SMMC772l细胞株为材料,分为空白对照（Con）、脂质体对照（LP）以及siRNA干扰实验（siRNA）3组。以体外转录法合成dsRNA,并用脂质体转染SMMC7721细胞株;Westernblotting检测NF．KBP65表达水平,MTT检测细胞增殖情况,Annexin V-PI法检测细胞凋亡,免疫组化检测Bcl-2和Bax表达。结果与Con和LP组相比,siRNA具有抑制SMMC7721细胞NF-κBP65表达的作用,NF-κBP65表达抑制率分别达到64．74％和34．52％。siRNA明显抑制SMMC．7721细胞的增殖,并诱导细胞凋亡,晚期凋亡细胞分别是Con组和LP组的8倍和7倍。siRNA引起Bcl-2表达下调,而Bax表达上调。结论siRNA可以有效抑制NF-κBP65蛋白表达,并通过调节Bcl-2和Bax诱导SMMC7721细胞的凋亡。     

siRNA介导的新趋化因子VCC-1沉默对人SMMC7721肝癌细胞生长的影响

 目的 探讨siRNA靶向抑制VCC-1表达对人肝癌细胞株SMMC27721生长的影响。方法 采用脂质体法将siRNA质粒导入SMMC7721细胞,建立VEGF相关的趋化因子1（(VEGF correlated chemokine 1,VCC-1）)VCC-1基因表达沉默的肝癌细胞系,用Western blot检测细胞中VCC-1的表达水平,用MTT法、软琼脂克隆形成实验等研究siRNA靶向抑制VCC-1表达对SMMC7721细胞生长的影响。结果 Western blot 结果显示RNA干扰组（shVCC1-1组）细胞VCC-1蛋白表达水平明显低于对照组（P<0.01）; ,MTT法结果显示shVCC1-1组细胞增殖速度、克隆形成率均低于对照组（P<0.05）。结论 siRNA靶向抑制 VCC-1表达可以抑制人SMMC7721肝癌细胞增殖能力及克隆形成能力。     

NF-κB信号通路阻断对肝癌细胞SMMC7721增殖的影响

目的研究NF-κB信号通路阻断对肝癌细胞SMMC7721生长增殖的影响。方法常规培养SMMC7721细胞,采用SN50（36μmol/L）阻断NF-κB信号通路,Western blot检测核内p65蛋白水平,MTT比色法检测细胞生长增殖,计算肿瘤细胞生长抑制率,PI染色、流式细胞仪分析细胞周期与凋亡,观察NF-κB信号通路阻断对肝癌细胞SMMC7721细胞周期及凋亡的影响。结果肝细胞癌SMMC7721细胞核内存在较高水平的p65蛋白。经SN50阻断后,MTT测定显示细胞的增殖受到明显抑制,并随时间的延长而愈渐明显,24、48、72h后细胞增殖抑制率分别为22.77%、33.33%和38.89%,与阻断前相比,差异有统计学意义（P〈0.05）。流式细胞仪检测发现实验组G1期细胞比例高于对照组差异有统计学意义（69.5% vs 56.5%,P〈0.05）,S期细胞比例明显降低,与阻断前相比差异有统计学意义（11.1% vs 28.6%,P〈0.05）,而细胞凋亡率在实验组为38.3%,对照组仅为23.2%,差异有统计学意义（P〈0.05）。结论NF-κB信号通路阻断诱导细胞周期于G1期停滞和细胞凋亡,从而抑制了SMMC7721细胞生长与增殖,提示NF-κB信号通路组成性激活参与了肝细胞癌的生长增殖与发展,以NF-κB信号通路作为治疗的靶点可能给肝细胞癌带来新的治疗选择。     

汉防己甲素对白血病耐药细胞株K562/A02核因子κB表达的影响

目的：通过研究汉防己甲素（tetrandrine，Tet）对白血病细胞株K562及其耐药细胞株K562／A02核因子kB（nuclear factor-kaPPaB，NF-kB）表达的影响，探讨Tet逆转多药耐药的作用机制。方法：采用免疫细胞化学及蛋白印迹法分别检测1umol／L Tet作用K562和K562／A02细胞6h和12h舌，细胞NF-kB核转位水平和胞核NF—kB蛋白表达的变化。结果：Tet作用6h和12h后，对K562细胞的NF-kB核转位水平及胞核NF—kB蛋白表达均无明显影响（P〉0．05）；K562／A02细胞NF—kB核转位水平及胞核NF—kB蛋白表达明显高于K562细胞对照组（P〈0．01）；Tet作用6h和12h后，可明显降低K562／A02细胞NF-kB蛋白核转位（P〈0．05）和胞核NF—kB蛋白表达水平（P〈0．01）。作用12h较作用6h效果更显著（P〈0．05）。结论：1umol／L Tet可能通过抑制NF—kB活化逆转K562／A02细胞多药耐药性。     

Caveolin-1 RNA干扰慢病毒载体的构建及其对肝癌细胞株SMMC7721侵袭的影响

目的 构建人Caveolin-1 RNA干扰慢病毒载体,探讨慢病毒介导的Caveolin-1 RNA干扰对人肝癌细胞株SMMC7721侵袭能力的影响.方法 应用pGCSIL-GFP-Caveolin-1 RNA干扰慢病毒载体感染SMMC7721,检测其转导效率、mRNA和蛋白水平的敲除效率,并检测对SMMC7721侵袭能力的影响.结果 pGCSIL-GFP-Caveolin-1 RNA干扰慢病毒载体感染SMMC7721的转导效率为(96.0±1.2)%;Caveolin-1 mRNA水平的敲除率约90%;Western blot显示感染后Caveolin-1蛋白水平显著下降;感染后SMMC7721的侵袭能力显著下降.结论 慢病毒载体构建的Caveolin-1 RNA干扰能有效敲除SMMC7721中Caveolin-1的表达,显著降低SMMC7721侵袭能力.     

沉默CRAF基因表达对肝癌细胞侵袭和迁移的影响

目的：探讨肝癌细胞中原癌基因丝氨酸/苏氨酸蛋白激酶（CRAF）高表达对肝细胞癌（HCC）侵袭和转移的影响,并阐明其机制。方法：以CRAF高表达的SMMC-7721细胞作为研究对象,采用shRNA技术下调CRAF表达。将SMMC7721细胞分为对照组和沉默组（shCRAF#1转染组和shCRAF#2转染组）。细胞划痕法观察各组SMMC7721细胞创口愈合指数,Transwell实验检测各组SMMC-7721细胞的穿膜细胞数,Western blotting法检测各组SMMC7721细胞中基质金属蛋白酶2（MMP-2）和基质金属蛋白酶9（MMP-9）的表达水平。结果：细胞划痕实验,与对照组比较,沉默组SMMC7721细胞的创口愈合指数明显降低（P<0.05）。Transwell实验,与对照组比较,沉默组SMMC7721细胞的穿膜细胞数降低（P<0.05）。Western blotting法检测,沉默组细胞中MMP-2和MMP-9表达水平明显低于对照组（P<0.05）。结论：下调CRAF可以通过抑制MMP-2和MMP-9表达抑制肝癌SMMC7721细胞的侵袭和迁移。     

沉默热休克蛋白5可增敏青蒿琥酯诱导肝癌细胞铁死亡

目的: 探讨热休克蛋白5(heat shock protein family A member 5,HSPA5)对青蒿琥酯诱导人肝癌SMMC 7721细胞株化疗敏感性的影响。方法: 用不同浓度青蒿琥酯处理SMMC-7721细胞,CCK-8法检测细胞活性,筛选最佳实验浓度。将SMMC-7721细胞按以下分组处理：对照组、青蒿琥酯组、青蒿琥酯+去铁胺组,用流式细胞术检测细胞内脂质来源活性氧水平;试剂盒检测细胞内丙二醛水平。用包装HSPA5干扰或过表达质粒的慢病毒感染SMMC 7721细胞,qRT PCR和蛋白质印迹法分别测定转染后HSPA5 mRNA和蛋白表达;CCK-8法检测细胞活性,试剂盒检测细胞内丙二醛水平。结果： 青蒿琥酯浓度为20 μmol/L时,SMMC-7721细胞达到半数致死量,为最佳实验浓度;流式细胞术结果显示,青蒿琥酯处理的细胞内脂质来源活性氧水平、丙二醛水平明显升高,去铁胺可抑制青蒿琥酯导致的细胞内脂质来源活性氧和丙二醛升高(均P<0.05);经过青蒿琥酯处理的HSPA5干扰组细胞活性水平明显低于未干扰组,丙二醛水平明显高于未干扰组(均P<0.05)。结论： 干扰HSPA5可能增强人肝癌SMMC-7721细胞株对青蒿琥酯的化疗敏感性。