槲皮素对U937细胞系抑制增殖和诱导凋亡作用的研究

目的 探讨黄酮类化合物槲皮素（Que）对人类单核细胞白血病U937细胞系的抑制增殖和诱导凋亡的作用。方法 应用MTT法检测不同浓度槲皮素对U937细胞的增殖抑制作用；AO／PI荧光染色后倒置荧光显微镜下观察细胞形态学变化；琼脂糖凝胶电泳测定细胞DNA的片段化；应用流式细胞仪检测细胞凋亡率及细胞周期分布。结果槲皮素能明显抑制U937细胞增殖，并存在剂量-效应关系和时间-效应关系；诱导U937细胞出现凋亡所具有的形态学和生化特征；随着槲皮素浓度升高，凋亡细胞和坏死细胞比例增加；将细胞特异性地阻滞在S期，出现凋亡峰。结论 槲皮素能抑制U937细胞增殖，诱导细胞凋亡，并具有细胞周期特异性。     

唑来膦酸抑制U937细胞增殖及诱导凋亡

目的:研究唑来膦酸(ZOL)对人类急性髓系白血病细胞U937的增殖抑制及促凋亡作用。方法:CCK-8法检测不同时间ZOL对U937细胞的生长抑制率;流式细胞术检测ZOL对U937细胞周期的影响;Annexin V-PI法及Hoechst 33342法检测ZOL作用前后细胞凋亡情况变化,JC-1检测ZOL对U937细胞线粒体膜电位变化的影响;克隆形成实验检测U937细胞克隆形成能力;Western blot法检测ZOL对U937细胞周期和凋亡相关蛋白的变化。结果:CCK-8结果显示ZOL可以抑制U937细胞的活力,并呈时间-剂量依赖性;Annexin V-PI及Hoechst33342结果显示ZOL可以促进U937细胞凋亡,且呈时间-剂量依赖性;JC-1结果显示ZOL可以明显降低U937细胞线粒体膜电位;PI法证实ZOL将U937细胞周期阻滞在S期,克隆形成实验证实0.2 mmol/L ZOL可以完全抑制U937细胞的克隆形成能力;Western blot结果显示ZOL作用于U937细胞48 h后细胞周期相关蛋白p21表达显著增强,促凋亡蛋白Bax表达增强,抑凋亡蛋白Bcl-2表达明显减弱。结论:ZOL抑制U937细胞的增殖和克隆形成主要是由于抑制了细胞周期相关蛋白表达,同时ZOL可以促进U937细胞凋亡,这种作用主要是通过调节线粒体凋亡途径相关蛋白来实现的。     

替米沙坦抑制U937细胞增殖及诱导凋亡

目的:探讨替米沙坦对U937细胞株的生长抑制及凋亡诱导作用。方法:分别以不同浓度的替米沙坦处理人类急性髓系白血病细胞U937;以CCK-8法检测不同浓度替米沙坦对U937细胞的生长抑制作用;以集落形成实验观察不同浓度替米沙坦对U937细胞集落形成能力的影响;以Annexin V-PI双染法及Hoechst 33342染色法检测不同浓度替米沙坦作用前后U937细胞凋亡程度的变化;以流式细胞术检测U937细胞表面抗原CD11b的阳性表达率,瑞氏染色后倒置显微镜进行细胞形态学观察,了解U937细胞的分化情况;以Western blot法检测不同浓度替米沙坦作用U937细胞后凋亡相关蛋白表达量的改变。结果:CCK-8实验结果证实替米沙坦呈时间和剂量依赖性抑制U937细胞的生长;集落形成实验显示低剂量替米沙坦可以完全抑制U937细胞的集落形成能力;Annexin V-PI双染法及Hoechst 33342法结果证实替米沙坦可以诱导U937细胞凋亡;细胞表面抗原流式检测术及瑞氏染色结果证实替米沙坦可以促进部分U937细胞分化;Western blot实验结果证实替米沙坦作用于U937细胞72 h后,促凋亡相关蛋白cleaved PARP及cleaved caspase-3蛋白的水平明显增高。结论:替米沙坦可以抑制细胞增殖以及诱导U937细胞部分分化,并通过caspase依赖的凋亡途径触发U937细胞凋亡。     

线粒体凋亡途径在槲皮素诱导U937 细胞凋亡中的作用研究

目的:观察槲皮素对人急性髓系白血病U937 细胞增殖、凋亡、线粒体膜电位(Δφm),、人B 细胞淋巴瘤因子- 2、人Bcl-2 相关X 蛋白、细胞色素c 表达及半胱氨酸蛋白酶鄄3、半胱氨酸蛋白酶鄄9 活性的影响,探讨线粒体凋亡途径在槲皮素 诱导U937 细胞凋亡中的作用。方法:体外培养U937 细胞,分别以0、10、20、40、80、160μmol/ L 浓度的槲皮素处理24、48 和 72 h,采用细胞计数试剂盒(Cell counting kit-8,CCK-8) 检测槲皮素对U937 细胞增殖的抑制作用;实验随机分为对照组 (Control)、槲皮素10、20 组和40 μmol/ L 组。采用流式细胞仪AnnexinV-FITC/ PI 双染法检测U937 细胞凋亡情况;采用荧光染 料3,3‘-二己基含氧碳菁碘代物[3,3‘-dihexyloxacarbocyanine iodide,DiOC6(3)]染色,流式细胞仪检测U937 细胞的变化; 采用Western blot 检测U937 细胞Bcl-2、Bax、Cytc 表达;采用比色法检测U937 细胞Caspase-3、Caspase-9 活性。结果:槲皮素可 抑制U937 细胞的增殖,抑制率显著升高,且呈时间-剂量依赖性。槲皮素亦可显著抑制U937 细胞凋亡率,与对照组比较(P< 0.01)。槲皮素显著降低U937 细胞驻鬃m,与对照组比较(P<0.01)。槲皮素显著下调U937 细胞Bcl-2 表达,上调Bax 表达,下 调Bcl鄄2/ Bax 比值及上调Cyt c 表达,与对照组比较(P<0.01)。槲皮素显著升高U937 细胞Caspase-3、Caspase-9 活性,与对照 组比较(P<0.01)。结论:槲皮素可显著抑制U937 细胞增殖,线粒体凋亡途径激活是槲皮素诱导U937 细胞凋亡的途径之一。     

甘露聚糖结合凝集素诱导人白血病细胞系U937细胞凋亡

目的研究甘露聚糖结合凝集素（MBL）对白血病细胞系U937凋亡的影响。方法不同浓度MBL处理U937细胞后,应用CCK-8法分析细胞增殖情况,Hoechst33258染色观察细胞核及染色质,AnnexinV/PI双染流式细胞术分析细胞凋亡率,real-timePCR和免疫印迹分析凋亡相关基因及蛋白表达。结果 30～50μg/mlMBL培养72h,U937细胞增殖明显受抑,出现不同程度核固缩、核碎裂;随MBL浓度升高或作用时间延长,凋亡细胞数逐渐增多;Fas、Caspase-3mRNA、Fas和FasL蛋白表达量升高,Caspase-3和多腺苷二磷酸多聚酶（PARP）蛋白被剪切激活或失活。结论 MBL可诱导白血病细胞U937细胞凋亡,其机制与上调Fas表达、剪切Caspase-3和PAPR有关。     

三磷酸腺苷诱导人白血病细胞U937凋亡的电镜观察

目的 为探讨三磷酸腺苷（ＡＴＰ）对人白血病细胞Ｕ９３７的促凋亡作用。方法 应用ＡＴＰ（０．２３ｇ／Ｌ）作用于人白血病细胞Ｕ９３７（ｈｕｍａｎ ｈｉｓｔｏｃｙｔｉｃ ｌｙｍｐｈｏｍａ）,⑴用白细胞计数器每日计数器细胞和计算抑制率;⑵用流式细胞分析仪检测ＡＴＰ对Ｕ９３７细胞周期改变和凋亡的影响;⑶苏木精－伊红以和电子显微镜检测凋亡小体的形成过程;⑷用苯胺黑染色检测凋亡小体的生命本性。结果 ⑴ＡＴＰ对Ｕ     

Apoptin基因/壳聚糖纳米粒的制备及其对U937细胞凋亡的诱导作用

目的以羧甲基壳聚糖为基质材料,制备apoptin基因缓释微球,探讨其对U937细胞凋亡的作用。方法采用复凝聚法制备apoptin/壳聚糖微球,分别用光镜观察微球形态、内切酶研究其稳定性、DNA电泳阻滞分析apoptin/壳聚糖最佳比例、PCR测定apoptin基因作为复制摸板能力、用MTT法检测其抗肿瘤活性。结果壳聚糖与apoptin基因可形成稳定的微球,其直径在200～300之间,成球性较好,apoptin/壳聚糖微球P/N最佳质量比为5.5:1。微球能够有效防止DNA酶的降解作用,apoptin/微球载体中的基因仍具有DNA复制摸板功能,并能有效地转染U937细胞,转染48h可诱导U937细胞发生凋亡,从而抑制瘤细胞生长。结论apoptin基因与羧甲基壳聚糖可形成稳定的缓释微球,并能有效地转染肿瘤细胞,诱导肿瘤细胞发生凋亡。     

二甲双胍对U937 细胞增殖、周期及凋亡的影响

目的：探究二甲双胍（metformin）对U937细胞增殖、周期及凋亡的影响。 方法：以U937细胞为研究对象,予不同浓度的二甲双胍处理,分别在24、48和72 h收集细胞。CCK-8法检测细胞增殖情况,流式检测细胞凋亡及细胞周期,并使用Western blot方法检测促凋亡蛋白Bax、抑凋亡蛋白Bcl-2、p-AMPK、p53的表达情况。结果：CCK8结果显示二甲双胍抑制U937的增殖,且呈时间-剂量依赖性。流式结果显示二甲双胍处理后细胞周期停滞在G0/G1期,G0/G1期细胞比例的增加呈时间-剂量依赖性。二甲双胍可诱导细胞凋亡,且凋亡率呈剂量依赖性;二甲双胍浓度为20 mmol/L时,凋亡率呈时间依赖性。Western blot结果显示二甲双胍处理后,p-AMPK、p53、Bax的表达上调,而Bcl-2的表达下调。 结论：二甲双胍能抑制U937细胞的增殖,阻滞细胞周期在G0/G1期,诱导细胞凋亡;其机制可能与其上调胞内促凋亡蛋白Bax的表达、下调抑凋亡蛋白Bcl-2的表达、激活AMPK/p53通路有关。     

ATP对人白血病细胞U937凋亡的影响

目的　探讨ATP诱导人白血病细胞U937细胞凋亡的机理。　方法　应用ATP(0 2 3g L)作用于培养的U937细胞 ,应用免疫荧光细胞化学方法检测连接蛋白Cx4 3、F 肌动蛋白 (F actin)、纽蛋白 (vinculin)的表达。　结果　ATP诱导U937细胞凋亡小体形成的同时Cx4 3表达增强、F 肌动蛋白重组 ,纽蛋白组装改善。　结论　ATP诱导人白血病细胞凋亡时 ,凋亡小体的形成与间隙连接蛋白Cx4 3表达、F 肌动蛋白重组 ,纽蛋白组装有着平行关系 ,表明它们在U937凋亡小体形成过程所起的重要作用     

人巨细胞病毒感染抑制原巨核细胞增殖并诱导其凋亡

目的探讨人巨细胞病毒（HCMV AD169株）感染对CHRF原巨核细胞成活率的影响及其机制。方法采用CHRF细胞培养技术，利用HCMV原液直接感染CHRF细胞株；用RT-PCR观察鉴定HCMV是否能直接感染CHRF细胞株：用MTT法检测细胞存活率；流式细胞仪分析HCMV感染后诱导细胞凋亡发生率；免疫印迹分析caspase-3活性。结果①HCMV AD169能直接感染CHRF细胞：②HCMV AD169感染浓度和时间依赖性地降低CHRF细胞成活率；③HCMV AD169诱导CHRF细胞发生凋亡及caspase-3的激活。结论体外感染HCMV通过抑制增殖和诱导凋亡降低CHRF细胞的成活率。这些结果有助于理解HCMV感染引起血小板减少症的病理机制。     

Streptococcal Pyrogenic Exotoxin B Induces Apoptosis and Reduces Phagocytic Activity in U937 Cells

Treatment of U937 human monocyte-like cells with Streptococcus pyogenes led to an induction of apoptosis in these cells. A comparison between the wild-type strain and its isogenic protease-negative mutant indicated that the production of streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, caused a greater extent of apoptosis in U937 cells. Further study using purified SPE B showed that this protease alone could induce U937 cells to undergo apoptosis, which was characterized by morphologic changes, DNA fragmentation laddering on the gel, and an increase in the percentages of hypodiploid cells. The protease activity of SPE B was required for apoptosis to proceed, since treatment with cysteine protease inhibitor E64 or heat inactivation abrogated this death-inducing effect. The SPE B-induced apoptosis pathway was interleukin-1β converting enzyme (ICE) family protease dependent. Further experiments showed that the phagocytic activity of U937 cells was reduced by SPE B. Treatment with E64 and heat inactivation both abrogated this phagocytosis-inhibitory effect. Taken together, the present data show that SPE B not only possesses the ability to induce apoptosis in monocytic cells but also helps bacteria to resist phagocytosis by host cells.     

Phagocytosis of IgA Immune Complexes by Human U937 Cells

Human promonocytic cell line U937 can express both IgAFc receptors ( FcαRⅠ, CD89 ) and IgG Fc receptors(FcαγⅠ, FcγRⅡ and FcγRⅢ)[1]. These receptors canmediate a variety of cell reactions including phagocytosis ofimmune complexes ( ICs ), degranulation, respiratorybursts, release of cytokines and enhancement of antibody dependent cell mediated cytotoxicity (ADCC) [2]. AfterIgA and IgG form ICs with their corresponding antigens,the ICs are bound by FcR on phagocyt…     

蓖麻毒素诱导U937细胞分泌IL-6和IL-8的作用

目的：进一步研究蓖麻毒素是否具有诱生Ｕ９３７细胞分泌细胞因子作用。方法：采用ＭＴＴ法检测了蓖麻毒素对Ｕ９３７细胞的毒性，并采用ＥＬＩＳＡ法测定细胞２上清中的Ｉ－６和ＩＬ－８。结果：蓖麻毒素对Ｕ９３７细胞的生具有时间效应及剂量效应。随着作用时间的延长。诱生２种细胞因子的量逐渐增加；随蓖麻毒素剂量的增加，诱生２种细胞因子的量均减少。结论：蓖麻毒素诱导２种细胞因子的产生为其抗癌应用或其它作用提供理论依据     

Induction of protein oxidation by cobalt and chromium ions in human U937 macrophages

Metal particles and ions from hip prostheses have the potential to induce the production of reactive oxygen species (ROS), making them prime suspects for disturbing the cellular balance of oxidants/antioxidants (redox state of the cell). To better understand the cellular effect of metal ions from metal-on-metal prostheses, the aim of this study was to examine the effect of cobalt (Co2+) and chromium (Cr3+) ions on protein oxidation in human U937 macrophages. Protein oxidation was measured by Western blot using antibodies directed against dinitrophenylhydrazine (DNP)-derivatized protein carbonyls, the most commonly measured products of protein oxidation in biological samples. Three DNP-derived proteins were detected. The first has a molecular weight of 16 kDa and is expressed at a very low level. The second has a molecular weight of 48 kDa and its level is not regulated by metal ions. The third is a 69 kDa protein and its level is regulated by Co2+ and Cr3+ ions. Therefore, the last band served as a marker of protein oxidation in the present study. Results showed that Co2+ and Cr3+ ions induced a time- and dose-dependent protein oxidation reaching 6.5 and 2.9 times the control after 72 h, respectively, which were inhibited by the antioxidant glutathione monoethyl-ester. Finally, results showed that the oxidized proteins are mainly found in the cytoplasmic fraction of the cells and are absent from the nucleus. In conclusion, our results suggest that metal ions from metal-on-metal prostheses have the potential to modify the redox state of cells both locally (periprosthetic environment) or systematically (circulating cells). The long term effect of these ions on protein oxidation in vivo remains to be investigated.     

Human Monocytic U937 Cells Kill Salmonella In Vitro by NO-Independent Mechanisms

Nitric oxide (NO) has a central role in host defense against intracellular microbes. HLA-B27 has been shown to directly modulate host-microbe interaction in vitro, leading to the impaired elimination of Salmonella in human monocytic U937 cells. Here, we studied whether impaired elimination of Salmonella would result from differences in NO production between HLA-B27- and HLA-A2-transfected U937 cells. Both human monocytic transfectants produced NO equally well and killed Salmonella via NO-independent mechanisms.     

Br-cAMP Induction of Apoptosis in Synchronized CHO Cells

The proliferation of suspension cultures of malignant CHO cells was inhibited by 0.5 mM Br-cAMP treatment and restored by its removal. This treatment also inhibited histone H1 phosphorylation completely, reduced histones H2A and H4 phosphorylations, induced DNA degradation, and produced cells containing micronuclei. Agarose gel electrophoresis of the degraded DNA fragments produced a "ladder" pattern confirming these cells were undergoing apoptosis. Cell cycle synchrony experiments demonstrated culture growth inhibition was the result of two different cell cycle-specific processes: [1] arrested cell cycle traverse at a restriction point in mid-G1, and [2] rapid apoptosis following cell division. Br-cAMP did not stop cells in late-G1, S, G2, or M from traversing the cell cycle and dividing, but rather, induced apoptosis following mitosis. The restriction point of Br-cAMP arrest was located in the middle of a wider band of G1 arrest induced by isoleucine deprivation. The cells synchronized in G1 before the restriction point were held in G1-arrest by Br-cAMP and spared apoptotic death. These studies support the further study of cAMP derivatives as agents to induce tumor regression by apoptosis and reverse transformation.