蛋白酶体抑制剂硼替佐米对K562细胞株NF-κB活性及ICAM-1表达的影响

为了研究蛋白酶体抑制剂硼替佐米对急性白血病K562细胞株核因子κB(NF-κB)及细胞间黏附分子(ICAM-1)表达的影响,用含10%小牛血清的RPMI1640培养液体外培养K562细胞,用0、10、20、30、50、100nmol/L的硼替佐米干预K562细胞6小时后收集细胞。用SP免疫组织化学法测各组细胞NF-κB活性,并以反转录聚合酶链反应(RT-PCR)分析K562细胞ICAM-1表达的变化。结果表明:各药物处理组K562细胞NF-κB的活性和ICAM-1的表达均明显受抑制,与对照组相比,存在显著性差异(p<0.05),且各组NF-κB活性与ICAM-1表达成正相关。结论:蛋白酶体抑制剂硼替佐米可能通过抑制NF-κB活性下调细胞间黏附分子ICAM-1的表达,这为白血病靶向治疗提供了一个新的途径。     

硼替佐米对K562细胞株粘附分子ICAM-1表达的影响

目的:探讨蛋白酶体抑制剂硼替佐米(万珂,Valcade)对白血病K562细胞株细胞问粘附分子(ICAM-1)表达的影响。方法:用含10?S的RPMI1640培养液体外培养K562细胞,分别用0、10、20、30、50、100 nmol/L的硼替佐米干预K562细胞6h后收集,用反转录聚合酶链反应(RT-PCR)分析K562细胞ICAM-1表达的变化。并用20 nmol/L浓度硼替佐米作用K562细胞株不同时间(0,6,12,24,48h)分析K562细胞ICAM-1表达的变化。结果:硼替佐米明显抑制K562细胞ICAM-1的表达(P<0.05),在硼替佐米浓度为0～20 nmol/L时成正比关系,当浓度>20 nmol/L各组差异无显著性。以20 nmol/L浓度作用K562细胞株不同时间后,ICAM-1的表达较作用前明显下降.并且这种效应持续存在。结论:K562细胞株ICAM-1基因表达异常增高,硼替佐米可抑制其表达量。     

硼替佐米体外诱导K562细胞凋亡的作用不受骨髓间充质干细胞的影响

本研究探讨蛋白酶体抑制剂硼替佐米在有或无骨髓间充质干细胞(mesenchymal stem cells)条件下对白血病细胞株K562促凋亡作用,以及对MSC和K562细胞的黏附分子VCAM-1表达的影响.建立MSC和K562细胞的共培养体系,以终浓度为50 mnol/L的绷替佐米处理K562细胞4-24小时,应用Annexin-V/PI双染法检测K562细胞凋亡,半定量RT-PCR检测VCAM-1 mRNA的表达.结果显示,硼替佐米可诱导K562细胞凋亡,并呈现时间依赖性;共培养组调亡细胞比例与单独培养组相比无显著差异;K562细胞与MSC共培养可诱导K562细胞表达VCAM-1,MSC在共培养前后表达VCAM-1无明显变化.硼替佐米作用24小时后,K562细胞表达VCAM-1消失,MSS表达VCAM-1明显下降.结论:硼替佐米在MSC存在的情况下依然可诱导白血病细胞凋亡,提示硼替佐米可拮抗MSC对白血病细胞的保护作用.     

硼替佐米治疗淋巴瘤新进展

硼替佐米作为第一个应用于临床的蛋白酶体抑制剂,通过影响多种细胞周期调控蛋白及NF-κB活性,发挥抗肿瘤作用.硼替佐米在多发性骨髓瘤(MM)的治疗中取得了令人鼓舞的疗效,是近年来MM药物治疗最重要的进展之一.淋巴瘤细胞中普遍存在NF-κB的组成性高表达,因此,硼替佐米可望成为治疗淋巴瘤一种新的选择.     

不同浓度硼替佐米对柔红霉素诱导的K562耐药细胞株ERK、JNK及P38表达的影响

本研究旨在观察蛋白酶体抑制剂硼替佐米(bortezomib,PS-341)对柔红霉素(daunorubicin,DNR)诱导的K562白血病耐药细胞株ERK、JNK及P38表达的影响,探讨硼替佐米逆转耐药的分子机制。用四甲基偶氮唑盐微量酶反应比色法(MTT法)进行耐药细胞株和硼替佐米细胞毒性的判定。以100nmol/L DNR单用或联合应用1及10nmol/L PS-341作用于K562耐药细胞株36小时,检测各组ERK、JNK及P38的表达情况,检测各组细胞凋亡率。结果表明:与DNR组相比,PS-341联合DNR可抑制ERK和P38的表达,增加JNK的表达(p<0.05)。结论 :PS-341可显著抑制K562耐药细胞株ERK和P38的表达,增加JNK的表达;PS-341通过MAPK途径逆转细胞耐药,促进细胞凋亡。     

硼替佐米诱导Burkitt淋巴瘤Raji细胞凋亡的研究

本研究探讨硼替佐米对Burkitt淋巴瘤Raji细胞是否具有凋亡诱导作用及其机制。以硼替佐米处理Raji细胞,观察细胞增殖抑制作用的时间效应和剂量效应,在光学显微镜下观察药物作用前后细胞的形态变化,用流式细胞术检测药物孵育前后细胞凋亡率（AP）,用RT—PCR法检测药物孵育前后NF—κB和p53基因的表达水平。结果表明,在一定剂量和时间范围内硼替佐米能抑制Raji细胞生长;硼替佐米能诱导Raji细胞凋亡并显示时间和剂量效应;在硼替佐米诱导Raji细胞凋亡过程中,NF-κB及p53基因的袁达水平下调。结论：硼替佐米能诱导Raji细胞凋亡,NF—κB基因和p53基因很可能参与了硼替佐米诱导Raji细胞凋亡的调控。     

CXCR4抑制剂AMD3100联合硼替佐米对人淋巴瘤细胞株Ramos增殖、凋亡的影响

目的探讨CXCR4抑制剂AMD3100、硼替佐米对人淋巴瘤细胞株Ramos协同诱导凋亡作用。方法 1检测淋巴瘤患者骨髓单个核细胞中CXCR4及核因子κB(NF-κB)表达水平;2AMD3100、硼替佐米单用以及联合用药分别处理Ramos细胞,利用CCK-8法检测细胞增殖;利用流式细胞术检测细胞凋亡;Wester blot检测NF-κB、Bcl-2、Bcl-xl、c-IAP1及Caspase-3表达水平。结果 1淋巴瘤患者骨髓单个核细胞中CXCR4、NF-κB表达增高;2AMD3100、硼替佐米作用Ramos细胞后,随着药物浓度的增加,对细胞增殖的抑制作用逐渐增强、凋亡增加,两药具有协同作用(P0.05);3AMD3100、硼替佐米单药组NF-κB、Bcl-2、Bcl-xl及c-IAP1表达降低,Caspase-3表达升高,联合用药组作用增强。结论 AMD3100、硼替佐米对Ramos细胞的增殖抑制、凋亡促进具有协同作用,其作用机制可能是通过抑制NF-κB、Bcl-2、Bcl-xl、c-IAP1及增强Caspase-3表达。     

Bmi-1介导的K562/ADR细胞多药耐药机制

目的:观察Bmi-1基因沉默对白血病耐药细胞株K562/ADR耐药性的影响并初步探讨其机制。方法:将2种序列的Bmi-1小干扰RNA SiRNA转染到耐药细胞K562/ADR,检测Bmi-1基因m RNA和蛋白的表达以确定转染效果。检测Bmi-1基因沉默后耐药蛋白P-gp及其编码基因MDR1的表达情况,并采用流式细胞术检测细胞内阿霉素蓄积情况。检测Bmi-1基因沉默后NF-κB蛋白的表达变化;应用NF-κB抑制剂PDTC处理K562/ADR细胞抑制NF-κB活性后,检测P-gp蛋白的表达及其功能的变化。检测Bmi-1基因沉默后PTEN、AKT和p-AKT蛋白表达的变化。应用PI3K/AKT通路抑制剂LY294002处理K562/ADR细胞抑制p-AKT表达后,检测NF-κB和P-gp蛋白的表达。应用PTEN抑制剂BPV(phen)处理Bmi-1基因沉默后的细胞,检测AKT、p-AKT、NF-κB和P-gp蛋白的表达。以上mRNA表达用RT-PCR法检测,蛋白表达用Western blot法检测。结果:在mRNA水平和蛋白水平2种序列的小干扰RNA均使K562/ADR细胞Bmi-1基因表达降低。MDR1/P-gp在Bmi-1 siRNA干扰细胞中的表达明显低于在K562/ADR细胞的表达(P0.05);干扰后细胞内阿霉素蓄积增多。Bmi-1基因沉默后,细胞NF-κB活性降低;NF-κB抑制剂抑制NF-κB活性后,K562/ADR细胞P-gp蛋白表达及药物泵出功能被抑制。Bmi-1基因沉默后PTEN蛋白表达增高,而p-AKT蛋白表达明显降低(P0.05)。PI3K/AKT通路抑制剂LY294002抑制p-AKT表达后,NF-κB活性和P-gp蛋白表达明显下降(P0.05)。PTEN抑制剂BPV(phen)处理Bmi-1基因沉默细胞后,NF-κB活性和P-gp蛋白表达得到重塑。结论:Bmi-1在MDR1/P-gp介导的K562/ADR细胞多药耐药中起关键作用,这种作用可能是通过激活PTEN/AKT途径调控NF-κB完成。     

硼替佐米联合5-氮杂胞苷对K562细胞凋亡和SHIP基因表达的影响

本研究旨在探讨硼替佐米联合5-氮杂胞苷对K562细胞凋亡和SHIP mRNA表达的影响.用不同浓度硼替佐米和5-氮杂胞苷处理K562细胞24 h,采用MTT比色法检测细胞增殖活性,流式细胞术检测细胞凋亡,RTPCR法检测SHIP基因mRNA的表达.结果表明：5-20 nmol/L硼替佐米对K562细胞增殖均有一定抑制作用,并随着浓度增加抑制作用逐渐增强.硼替佐米和5-氮杂胞苷联合处理组对细胞的抑制作用比同剂量两药单用时都显著增强（P＜0.05）.硼替佐米能促使K562细胞凋亡,且随浓度增加而凋亡增多,联合处理组对细胞的凋亡作用比同剂量单药作用时显著增强（P＜0.01）.硼替佐米能下调K562细胞SHIP mRNA的表达,且随着药物浓度增加,表达逐渐降低,联合处理组与同剂量单药组相比更显著下调SHIP mRNA表达（P＜0.05）.结论：硼替佐米或5-氮杂胞可以下调K562细胞中SHIP mRNA的表达,并可能通过此机制诱导K562细胞凋亡,两药具有协同作用.     

三氧化二砷诱导白血病细胞凋亡与核因子-κB活化的关系

为了研究三氧化二砷（As2O3）诱导白血病细胞凋亡与核因子-κB（NF-κB）活化以及血管内皮生长因子（VEGF）、基质金属蛋白酶-9（MMP9）表达的关系,应用流式细胞仪Annexin V FITC法检测白血病细胞系K562-n凋亡;采用免疫组织化学方法半定量分析K562-n细胞NF-κB、VEGF、MMP9表达的动态变化.结果显示：As2O3在诱导K562-n细胞凋亡的过程中可活化NF-κB,而VEGF、MMP9的表达也随之增强.地塞米松（DXM）1μmol/L能显著增加As2O3诱导K562-n细胞凋亡的作用和抑制K562-n细胞NF-κB活化,细胞凋亡增加率为43.04%,（P＜0.05）,NF-κB活化抑制率为31.15%（P＜0.05）,VEGF、MMP9变化与NF-κB一致.结论：As2O3诱导K562-n细胞凋亡的过程中可使NF-κB活化,VEGF、MMP9表达亦随之增强;DXM可通过抑制NF-κB活化增强其诱导K562-n细胞凋亡的作用,VEGF、MMP9的表达也随之下降.     

硼替佐米对K562细胞增殖、凋亡及其对XIAP表达的影响

目的 研究蛋白酶体抑制剂硼替佐米(bortezomi)对白血病细胞株K562细胞的增殖、凋亡及X连锁凋亡抑制蛋白(XIAP)表达的影响.方法 将不同浓度的硼替佐米作用于K562细胞,采用WST-1法测定细胞增殖活性,瑞特-吉姆萨染色观察细胞形态学变化,用流式细胞术、原位末端转移酶标记(TUNEL)法检测细胞凋亡,RT-PCR法检测XIAP mRNA表达,SP免疫组化法检测XIAP蛋白的表达.结果 5、10、30、50、100 nmol/L硼替佐米作用于K562细胞24 h,细胞增殖抑制率分别为(13.6±0.2)%、(28.7±0.5)%、(55.4±1.1)%、(68.1±1.1)%、(81.4±0.1)%,空白对照组为(1.2±0.0)%(P＜0.05),24 h IC50值为24.6 nmol/L.30 nmoL/L硼替佐米作用于K562细胞12、24、36、48 h,细胞增殖抑制率分别为(29.1±0.9)%、(55.4±1.1)%、(57.8±0.8)%、(59.8±1.2)%,12 h组与24 h组比较,差异有统计学意义(P＜0.05),但24 h组与36、48 h组比较差异有统计学意义(P＞0.05);30 nmol/L硼替佐米作用于K562细胞24 h,镜下可见细胞核固缩、核边集、核碎裂,胞质中见大量空泡及凋亡小体,对照组细胞形态正常.TUNEL检测法显示凋亡细胞阳性率为49.0%,空白对照组阳性率2.3%(P＜0.05).10、30、100 nmoL/L硼替佐米作用于K562细胞24 h,AnnexinⅤ-FTTC/PI双标法显示其凋亡率分别为(32.2±1.2)%、(53.9±1.3)%和(81.3±2.8)%,均高于对照组(0.3±0.6)%(P＜0.05).RT-PCR法检测结果显示随硼替佐米浓度增高,XIAP mRNA表达下调明显.免疫组化结果显示硼替佐米组XIAP蛋白表达下调,与空白对照组比较差异有统计学意义(P＜0.05).结论 硼替佐米呈时间、浓度依赖性抑制K562细胞增殖,并可能通过下调XIAP的表达诱导细胞凋亡.

Abstract：

Objective To investigate the effect of proteasome inhibitor bortezomib on proliferation,apoptosis of K562 cells and the expression of XIAP. Methods K562 cells were treated with bortezomib at different concentration. Cell proliferation was analyzed by WST-1 assay, cell apoptosis by flow cytometry and TUNEL, XIAP mRNA expression from 5 - 100 nmol/L by RT-PCR, and XIAP protein expression by SP immunohistochemistry. Results K562 cells were treated with bortezomib at different concentrations for 24 h respectively, the cells growth was significantly inhibited with inhibition rates from( 13.6 ±0.2)% to (81.4 ±0. 1 ) %, respectively, being markedly higher than that of control ( 1.2 ± 0. 1 ) % ( P ＜ 0. 05 ). IC50 was 24.6 nmol/L of bortezomib treated for 24 h. When K562 cells were treated with 30 nmol/L of bortezomib for 12 - 48 h, the inhibition rates were (29.1 ± 0. 9) % to (59.8 ± 1.2 ) %, respectively, the differences being statistically significant( P ＜0.05 ) between 12 h group and 24 h group, while there was no statistical difference between 24 h, 36 h and 48 h groups. K562 cells treated with 30 nmol/L bortezomib for 24 h showed nuclear condensation, nuclear margination, nuclear fragmentation, cytoplasmic vacuoles and a large number of apoptotic body formation. The apoptotic cells rate was 83.67% in bortezomib treated group, and 2.33% in untreated group (P ＜ 0.05 ). The expression of XIAP mRNA was decreased in a dose-dependent manner, and the expression of its protein was down-regulated. Conclusion Bortezomib can inhibit the proliferation of K562 cells, and induce apoptosis by down-regulating the expression of XIAP, providing the laboratory evidence for the targeted therapy in acute leukemia.     

Epidermal growth factor receptor inhibition sensitizes renal cell carcinoma cells to the cytotoxic effects of bortezomib

In renal cell carcinoma (RCC) models, maximal cytotoxicity of the proteasome inhibitor bortezomib is dependent on efficient blockade of constitutive nuclear factor kappaB (NF-kappaB) activity. Signaling through the epidermal growth factor receptor (EGFR) has been shown to result in NF-kappaB activation. Thus, we sought to investigate whether inhibition of the EGFR sensitizes RCC cells to the cytotoxic effects of bortezomib. We first established that constitutive NF-kappaB activity is dependent on signaling through the EGFR in RCC cells. Indeed, blockade of EGFR signaling with an EGFR tyrosine kinase inhibitor (TKI) resulted in inhibition of NF-kappaB activity. Using pharmacologic and genetic approaches, we also showed that EGFR-mediated NF-kappaB activation occurs through the phosphotidylinositol-3-OH kinase/AKT pathway. Combinations of the EGFR-TKI and bortezomib resulted in synergistic cytotoxic effects when RCC cells were pretreated with the EGFR-TKI, but an antagonistic interaction was observed with bortezomib pretreatment. Evaluation of the effects of drug sequencing on inhibition of NF-kappaB activity revealed that EGFR-TKI pretreatment markedly augmented the NF-kappaB inhibitory effect of bortezomib, whereas bortezomib preexposure resulted in suboptimal NF-kappaB blockade and thus provides a biochemical explanation for the drug interaction results. We conclude that the constitutive NF-kappaB activity observed in RCC cells is mediated, at least in part, through an EGFR/phosphotidylinositol-3-OH kinase/AKT signaling cascade. Pretreatment with an EGFR-TKI sensitizes to bortezomib-mediated cytotoxicity by inhibiting constitutive NF-kappaB activity. The combination of bortezomib and a currently approved EGFR inhibitor warrants clinical investigation.     

Maximal apoptosis of renal cell carcinoma by the proteasome inhibitor bortezomib is nuclear factor-kappaB dependent

Advanced renal cell carcinoma (RCC) is resistant to cytotoxic chemotherapy, and immunotherapy has modest activity. Proteasome inhibitors represent a novel class of anticancer agents that have activity across a wide spectrum of tumor types. We investigated the efficacy of the proteasome inhibitor bortezomib (VELCADE, formerly known as PS-341) in RCC and found that bortezomib potently induces apoptosis of RCC cell lines. Blockade of the nuclear factor-kappaB (NF-kappaB) pathway is considered a crucial effect in bortezomib-induced apoptosis, but the dependence on NF-kappaB inhibition for bortezomib-mediated death has not been formally demonstrated. Thus, we also studied the contribution of NF-kappaB inhibition as a mechanism of bortezomib-induced apoptosis in RCC cells, which display constitutive NF-kappaB activation. Ectopic expression of the NF-kappaB family members, p65 (Rel A) and p50 (NF-kappaB1), markedly reduced bortezomib-induced apoptosis. However, when we used selective genetic and chemical inhibitors of NF-kappaB, we found that NF-kappaB blockade was not sufficient to induce apoptosis of RCC cells. Thus, we conclude that maximal bortezomib-induced apoptosis is dependent on its NF-kappaB inhibitory effect, but NF-kappaB-independent effects also play a critical role in the induction of apoptosis by bortezomib. This represents the first report to formally demonstrate that bortezomib-induced NF-kappaB blockade is required to achieve the maximum degree of apoptosis by this drug.     

硼替佐米对K562细胞增殖、凋亡及SHIP基因表达的影响

本研究旨在探讨蛋白酶体抑制剂硼替佐米(bortezomib)对K562细胞的增殖、凋亡及SHIP基因表达的影响。将不同浓度的硼替佐米作用于K562细胞,采用MTT法测定细胞增殖活性,用流式细胞术检测细胞凋亡,RT-PCR方法检测SHIP mRNA表达。结果表明,硼替佐米10、20、50和100 nmol/L作用于K562细胞24 h,细胞增殖抑制率分别为(5.76±1.47)%、(10.55±1.59)%、(17.14±2.05)%和(27.69±3.57)%,空白对照组为(1.30±0.10)%;20nmol/L硼替佐米作用于K562细胞24、48、72 h,细胞增殖抑制率分别为(10.55±1.59)%、(16.33±2.53)%、(19.78±1.56)%,24 h组与48 h组比较,差异具有统计学意义(P<0.05),10、20、50、100 nmol/L硼替佐米作用于K562细胞24h,Annexin V-FITC/PI双标法显示其凋亡率分别为(12.7±0.6)%、(26.9±0.9)%、(32.6±1.2)%、(72.5±1.5)%,均高于对照组(1.0±0.5)%(P<0.05)。RT-PCR法检测结果显示应用硼替佐米作用后SHIP mRNA表达上调明显,与空白对照组比较差异有统计学意义。结论:硼替佐米呈时间、浓度依赖性抑制K562细胞增殖,并能通过上调SHIP基因的表达诱导细胞凋亡。     

Effect of tetrandrine in combination with droloxifen on the expression of NF-kappaB protein in K562 and K562/A02 cell lines

OBJECTIVE: To study the effect of tetrandrine (Tet) in combination with droloxifen (DRL) on the expression of nuclear factor kappa B (NF-kappaB) in K562 and K562/A02 cell lines and its reversal mechanism. METHODS: The activation of NF-kappaB in K562 and K562/A02 cell lines and the effect of Tet or DRL alone or in combination on NF-kappaB protein expression were determined with immunocytochemistry and Western blotting respectively. RESULTS: (1) K562/A02 cells displayed higher level of NF-kappaB protein expression than K562 cells. (2) The application of Tet or DRL alone or in combination had no effect on NF-kappaB expression in K562 cells at 6 h and 12 h (P > 0.05). (3) Tet and DRL alone or in combination could significantly down-regulate NF-kappaB protein expression in nuclei of K562/A02 cells. The effect was more significant in combination than either alone. This effect was more significant at 12 h than at 6 h. CONCLUSIONS: (1) Activation of NF-kappaB may be involved in the mechanism of MDR of K562/A02 cell line. (2)Inhibition of NF-kappaB activation may be involved in the reversal of multidrug resistance in K562/A02 cells by Tet and DRL.