Phosphoinositide 3-Kinase/Akt and Nuclear Factor-κB Are Involved in Staphylococcus Aureus-induced Apoptosis in U937 Cells

Objective To explore the mechanisms involved in Staphylococcus aureus （S. aureus） invading human monocytic U937 cells. Methods S. aureus were added to U937 cells at multiplicity of infections （MOI） of 20：1 for 0, 15, 30, 60, and 90 minutes, respectively. Cell apoptosis was analyzed with Hoechst 33258 staining and Annexin V-fluorescein isothiocyanate （FITC）/propidium iodide （PI） flow cytometry analysis. Akt and nuclear factor-κB （NF-κB） activities were detected by Western blotting. Results Infection of U937 cells with S. aureus induced rapid cell death in a time-dependent manner, and the cells displayed characteristic features of apoptosis. S. aureus-induced apoptosis was associated with a prominent downregulation of activated （phosphorylated） Akt and NF-κB. The inhibition of phosphorylated Akt by LY294002 led to the inhibition of NF-κB in a dose-dependent manner. Inhibition of Akt with LY294002 caused further increase in apoptosis of U937 cells. Conclusions S. aureus can stimulate the apoptosis of U937 ceils. S. aureus induces apoptosis of U937 cells by inhibiting Akt-regulated NF-κB.

The U937 cell line induced to express CD14 protein by 1,25-dihydroxyvitamin D3 and be sensitive to endotoxin stimulation

BACKGROUND: CD14 was first described as a differentia- tion antigen on the surface of myeloid lineage cells. It acts as a glycosylphosphatidylinositol ( GPI)-anchored receptor for the complex of lipopolysaccharide (LPS) and plays a key role in the activation of LPS-induced monocytes. The purpose of this study was to observe the expression of CD14 protein and its gene in the human U937 promonocytic cell line when these cells were exposed to 1,25-dihydroxyvita- min D3 ( VitD3 ) and investigate their sensitivity to endo- toxin stimulation. METHODS: U937 cells were exposed to (0.1 μmol) VitD3 for 24 hours and were induced to express the CD14 mRNA gene and CD14 protein, then their responses were observed when they were stimulated with different concentrations of LPS for different time. RESULTS: The U937 cells induced by VitD3 were found to stably express CD14 mRNA and CD14 protein. And CD14 protein enhanced the sensitivity of U937/CD14 cells to li- popolysaccharide ( LPS ) stimulation. NF-ΚB in U937/ CD14 cells can be activated with low concentration of LPS (1 ng/ml-10 ng/ml), the TNF-α mRNA gene was in- duced , and then TNF-α was produced and released into the supernatant of culture. CONCLUSION: VitD3 can induce U937 cell to express the CD14 gene and CD14 protein and enhance the response of this type of cells to LPS stimulation.

Inhibiting effect of vascular endothelial growth factor (VEGF) antisense oligodeoxynucleotides on VEGF expression in U937 cells

Objective:To study the effect of VEGF antisense oligodeoxynucleotide(VEGF ASODN)on VEGF expression in acute monocyte leukemic cell line U937 in vitro.Methods:U937 cells were incubated with VEGF ASODN(final concentra-tion as follows:10,20 and 30 μmol/L respectively)or scrambled sequence,compared with negative control.The expression of VEGF mRNA was measured by semi-quantitative RT-PCR,VEGF protein was measured by Western blot.Results:VEGF ASODN obviously inhibited expression of VEGF mRNA in U937 cell,compared with scrambled sequence and negative control(P<0.05).And the inhibition effect was most remarkable after 24 h,which is related with the dose of VEGF ASODN(P<0.05).Scrambled sequence groups had no significant difference compared with negative control groups(P>0.05).VEGF ASODN obvi-ously inhibited expression of VEGF protein,compared with scrambled sequence and negative control(P<0.05).Conclusion:The expressions of VEGF at mRNA and protein levels in leukemic cell line U937 are down-regulated after being treated with VEGF ASODN.

Phagocytosis of IgA Immune Complexes by Human U937 Cells

In order to study FcαRⅠ mediated phagocytosis of IgA immune complexes by U937 cells, antigen 8.9NIP/BSA was labeled with FITC and reacted with anti-NIP IgA or anti-NIP IgG antibody to form immune complexes (ICs). They were then incubated with phorbol 12-myristate 13-acetate (PMA) stimulated U937 cells.The phagocytosed ICs were quantified by flow cytometry. The results was that the expression of FcαRⅠ on U937 cells was higher than that of FcγRⅠ, FcγRⅡ and FcγRⅢ. After stimulation by PMA, expression of FcαRⅠ on U937 cells was markedly upregulated and the phagocytosis of IgA ICs was enhanced. FcαRⅠ mediated specific IgA phagocytosis was stronger than FcγRⅠ and FcγRⅡ mediated IgG phagocytosis. Complement receptors, CR1 and CR3, enhanced U937 cell phagocytosis of IgA ICs. It concludes that FcαRⅠ mediated strong phagocytosis of IgA ICs.

Resveratrol Inhibits the Secretion of Vascular Endothelial Growth Factor and Subsequent Proliferation in Human Leukemia U937 Cells

This study examined the effect of resveratrol on the secretion of vascular endothelial growth factor （VEGF） and subsequent proliferation of human leukemia U937 cells, and explored the mechanisms involved. Human leukemia U937 cells were treated with resveratrol of different concentrations （12.5-200 μmol/L） for different time lengths （12-48 h）. The proliferation of the U937 leukemic cells was determined by MTT assay. Apoptosis was observed by Annexin- V-FIFC/PI double staining and flow cytometry （FCM）. Cells cycle was analyzed by PI staining and FCM. The content of VEGF was determined by ELISA. Human umbibical vein endothelial cells were examined for vasoformation in vitro after exposures to resveratrol of various concetrations. The results showed that resveratrol inhibited the proliferation of U937 leukemia cells in a dose- and time-dependent manner. Resveratrol induced apoptosis and S-phase cell cycle arrest in human leukemic U937 cells. Resveratrol inhibited the secretion of VEGF in U937 cells. Resveratrol inhibited the vasoformation of human vein endothelial cells in a dose-dependent manner. It was concluded that resveratrol could down-regulate the secretion of VEGE induce apoptosis and suppress the proliferation of U937 cells.

Effect of N-tosyl-L-phenylalanylchloromethyl Ketone on Tumor Necrosis Factor-alpha-induced NF-κB Activation and Apoptosis in U937 Cell Line

Summary: To investigate the effect of N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) on tumor necrosis factor-alpha-induced NF-κB activation and apoptosis in U937 cell line, changes and subcellular localization of NF-κB/p65 and IκB-α were observed by fluorescencemicroscopy and expression and degradation of IκB-α by flow cytometry. The apoptosis of U937 cells was measured by flow cytometry and electrophoresis of DNA. Immunolfluorescence assay showed that NF-κB/p65, IκB-α only localized in cytoplasm. After TNF-α stimulation, p65 was localized only in nuclei, and IκB-α was only localized in cytoplasm and decreased. The changes of TNF-α stimulation were specifically inhibited by TPCK. Flow cytometry also revealed the downregulation of IκB-α protein during TNF-α-induced apoptosis and the down-regulation was specifically inhibited by TPCK. Flow cytometry also showed the apoptosis of U937 cells after TNF-α induction. DNA ladder can be detected in cells treated by TNF-α. It is concluded that degradation of IκB-α protein and NF-κB/p65 translocation occur during TNF-α-induced apoptosis of U937 cells, suggesting the activation of NF-κB. TPCK-sensitive protease plays an important role in the degradation of IκB-α protein induced by TNF-α in U937 cells. TPCK sensitive protease also plays an important role in the apoptosis of U937 cells induced by TNF-α.

Effect of Vitamin K1 on Cell Growth Inhibition and Apoptosis on the U937 Cell Line

This experiment was conducted in order to verify the role of Vitamin K1 as a cell growth inhibitor on the U937 cell line. This experiment was performed in two parts—one with a lesser concentration of Vitamin K1, and the other with a range of concentrations from low-to-high. Through the remaining number of U937 cells, as well as cell areas, it was concluded that the presence of Vitamin K1 reduces the number of cancer cells. It was also concluded that as Vitamin K1 concentration increases, so does the frequency and effects of apoptosis.

PIM1基因对急性髓系白血病U937细胞增殖、凋亡及JAK2/STAT3信号通路的影响

目的:探讨PIM1基因对急性髓系白血病(AML)U937细胞增殖、凋亡的影响,以及对JAK2/STAT3通路的调控作用。方法:收集初诊成人AML患者和单纯缺铁性贫血患者的骨髓单个核细胞,荧光定量PCR检测PIM1 mRNA表达。将AML细胞系U937细胞分为:U937组(U937细胞正常培养)、Si-PIM1组(U937细胞转染含PIM1 mRNA的低表达腺病毒载体)、Si-NC组(U937细胞转染不含PIM1 mRNA的低表达腺病毒载体)、CoA1组(U937细胞中加入浓度为20μmol/L的JAK2激活剂CoA1)、Si-PIM1+CoA1组(U937细胞转染含PIM1 mRNA低表达的腺病毒载体并加入浓度为20μmol/L的CoA1)。培养24 h。荧光定量PCR和蛋白印迹法检测U937细胞PIM1 mRNA和蛋白、JAK2/STAT3通路、细胞周期、凋亡相关蛋白表达;噻唑蓝法检测细胞增殖活性;流式细胞术检测细胞周期变化及凋亡率。结果:AML患者骨髓单个核细胞中PIM1 mRNA表达水平高于单纯缺铁性贫血患者(P<0.05)。与U937组相比,Si-PIM1组细胞PIM1 mRNA和蛋白、p-JAK2/JAK2、p-STAT3/STAT3、Cyclin D1、CDK2蛋白、细胞增殖活性、S期比例、G2/M期比例降低(均P<0.05),p27、Caspase-3蛋白、G0/G1期、凋亡率升高(均P<0.05),而CoA1组上述指标的变化情况与Si-PIM1组正好相反,CoA1可逆转Si-PIM1对U937细胞的作用效果。U937组、Si-PIM1+CoA1组、Si-NC组U937细胞上述指标差异无统计学意义(P>0.05)。结论:敲低PIM1基因表达可抑制U937细胞增殖、促进凋亡,缓解ALM进程,且上述作用可能与抑制JAK2/STAT3通路活化有关。

长链非编码RNA KIAA0125对急性髓系白血病U937细胞增殖和凋亡的影响

背景:U937细胞可以作为急性髓系白血病细胞模型,用于研究急性髓系白血病的生物学特性、信号通路和治疗靶点。目前虽然已有研究报道长链非编码RNA KIAA0125在急性髓系白血病中呈高表达,但其在U937细胞中的生物学功能尚不清楚,在急性髓系白血病发生发展中的作用机制有待进一步阐明。目的:探讨长链非编码RNA KIAA0125在急性髓系白血病患者外周血中的表达水平及对U937细胞增殖、凋亡的影响。方法:RNA-seq分析急性髓系白血病患者骨髓单核细胞样本,筛选得到差异表达基因——长链非编码RNA KIAA0125,利用qRT-PCR检测长链非编码RNA KIAA0125在急性髓系白血病患者外周血中的表达进行验证,通过GEPIA数据库统计分析173例急性髓系白血病患者和70例健康人骨髓细胞中长链非编码RNA KIAA0125 mRNA的表达与预后的关系。随后使用重组慢病毒技术及CRISPR/Cas9-SAM技术分别构建敲低/过表达长链非编码RNA KIAA0125的U937细胞系,qRT-PCR检测长链非编码RNA KIAA0125敲低/过表达效率。接下来,使用CCK-8实验、流式细胞术及Western blot检测敲低/过表达长链非编码RNA KIAA0125对U937细胞增殖、凋亡的影响。最后,使用Western blot检测敲低/过表达长链非编码RNA KIAA0125对Wnt/β-catenin信号通路相关蛋白的影响。结果与结论:①qRT-PCR结果显示长链非编码RNA KIAA0125在急性髓系白血病患者外周血中呈高表达,GEPIA数据库显示长链非编码RNA KIAA0125在急性髓系白血病患者骨髓细胞中呈高表达,高表达组具有更差的生存期;②敲低组长链非编码RNA KIAA0125的敲低效率为70%,成功构建了稳定敲低长链非编码RNA KIAA0125表达的U937细胞,过表达组长链非编码RNA KIAA0125的表达是Vector组的4倍,成功构建了稳定过表达长链非编码RNA KIAA0125的U937细胞;③敲低长链非编码RNA KIAA0125抑制U937细胞的增殖并促进其凋亡,过表达长链非编码RNA KIAA0125则促进U937细胞的增殖但对U937细胞的凋亡无显著影响;④敲低长链非编码RNA KIAA0125抑制Wnt/β-catenin信号通路活性,而过表达长链非编码RNA KIAA0125则激活Wnt/β-catenin信号通路。结果表明,长链非编码RNA KIAA0125在急性髓系白血病外周血中呈高表达,其可能通过调控Wnt/β-catenin信号通路影响U937细胞的增殖和凋亡,可能是急性髓系白血病的潜在预后标志物。

Effect of Danhong injection on expressions of macrophage scavenger receptor 1 and sub-family A member 1 in human U937 cells

OBJECTIVE： To study the effects of Danhong injec- tion （DHI） on expression of the macrophage scaven- ger receptor 1 （MSR1） and ATP-binding cassette, sub-family A member 1 （ABCA1） genes, which en- code scavenger receptor-A I （SR-AI） and ATP-bind- ing cassette transporter 1 （ABCA1）, respectively, as a potential anti-atherosclerotic mechanism. METHODS： Human U937 cells were stimulated by in- cubation with 100 nM phorbo112-myristate 13-ace- tate （PMA） for 48 h.These stimulated, monocyte-like cells were then incubated for 24 h with 50 mg/L oxi- dized low-density lipoprotein （ox-LDL, to induce foam cell formation）, together with a liver X recep- tor （LXR） agonist or with different DHI concentra- tions. MSR1 and ABCA1 mRNA levels were mea- sured by fluorescence-based quantitative PCR. RESULTS： Compared with control cells （which re- ceived only ox-LDL）, cells treated with both ox-LDL and 10 IJmol/L LXR agonist showed lower MSR1 ex-pression （but this effect was not statistically signifi- cant, P〉0.05） and higher ABCA1 expression （P〈 0.01）. Cells that received ox-LDL and 3 mL/L DHI possessed higher MSR1 mRNA levels than the con- trols, whereas cells treated with ox-LDL and higher DHI concentrations （10, 30 or 60 mL/L） showed low- er MSR1 expression levels （but the differences ob- served between DHI concentration groups were not statistically significant, P〉0.05）. ABCA1 expression in cells treated with ox-LDL and 3, 10 or 30 mL/L DHI was higher than in the control cells, and increased with increasing DHI concentration （P〈0.05）. ABCA1 expression in cells treated with ox-LDL and the highest DHI concentration tested （60 mL/L） was not significantly different from that in the controls. ABCA1 mRNA levels in cells treated with ox-LDL and DHI were similar to, or lower than, those in cells treated with ox-LDL and the LXR agonist. CONCLUSION： DHI does not affect MSR1 mRNA lev- els in ox-LDL-treated U937 cells. However, at certain concentrations （10 and 30 mL/L）, DHI significantly increases ABCA1 mRNA levels. Therefore, the an- ti-atherosclerotic action of DHI might be mediated by an increased expression of ABCA1.

Study on the bone marrow mesenchymal stem cells induced drug resistance in the U937 cells and its mechanism

Background The hematopoietic microenvironment （HM） plays a critical role in malignant cell growth, patient survival, and response to chemotherapy in hematologic malignancies. However, mechanisms associated with this environmental influence remain unclear. In this study, we investigated the role of bone marrow derived mesenchymal stem cells （MSCs） in U937 cell line, the MSCs. to find out the relations between leukemia drug resistance and Methods U937 cells were cultured in suspension or grew adherently with MSCs. The cell growth curve was drawn and the cell cycle was measured by flow cytometry. Apoptosis and sensitivity of U937 to daunoblastina （DNR） were quantified by DNA ladder detection and trypan blue exclusion assays, respectively. The gene expression profile chip technology was used to determine and analyze the changes in apoptosis-related gene expression after adherent culture and the expression of MDR 1 mRNA was assessed by reverse transcriptional polymerase chain reaction （RT-PCR） at the same time. Results In the adherent culture, the proliferation of the U937 cells was inhibited, the G0/G1 phase cells increased （F=64.9726, P〈0.0001）, G2/M phase cells were decreased （F=98.1361, P〈0.0001） and the natural apoptosis rate was decreased （F=24.0866, P〈0.0001） compared with those in the suspended culture. U937 cell viability was enhanced and cell apoptosis was blocked during DNR treatment in adherent culture with MSCs. Thirty-nine differently expressed genes were screened from the 487 apoptosis related genes in the adherent culture U937 cells. Among the 37 upregulated genes, Bcl-XL was upregulated most significantly. Two genes were downregulated. Adherent culture did not induce MDR1 mRNA expression in U937 cells. Conclusions MSCs play a role in modulating the proliferation of U937 cells and response of U937 cells to DNR, and Bcl-XL apoptosis-inhibiting gene may be most important in determining the sensitivity of leukemic cells to treatment, which is not related to MDR1.

蓝萼甲素对急性髓系白血病U937细胞增殖、凋亡、自噬及SIRT1/FoxO1信号通路的影响

目的:探究蓝萼甲素对急性髓系白血病(AML)U937细胞增殖、凋亡、自噬及沉默信息调节因子1(SIRT1)/叉头框转录因子O1(FoxO1)信号通路的影响。方法:体外培养AML U937细胞,取培养至对数生长期的U937细胞分为对照组(常规培养U937细胞)、三氧化二砷组(在含U937细胞的培养基中加入2μmol/L的三氧化二砷)、蓝萼甲素低(在含U937细胞的培养基中加入2μmol/L蓝萼甲素)、高(在含U937细胞的培养基中加入4μmol/L蓝萼甲素)浓度组,继续培养48 h后。四甲基偶氮唑蓝法检测U937细胞增殖率,流式细胞术检测U937细胞凋亡率,单丹磺酰尸胺荧光染色观察U937细胞自噬小体数量,荧光定量PCR法检测U937细胞SIRT1、FoxO1 mRNA表达水平,蛋白印迹法检测U937细胞SIRT1、FoxO1蛋白表达水平。结果:与对照组相比,三氧化二砷组、蓝萼甲素低、高浓度组U937细胞增殖率显著降低(均P<0.05),凋亡率、自噬小体数量、SIRT1、FoxO1 mRNA和蛋白表达水平显著升高(均P<0.05);与三氧化二砷组相比,蓝萼甲素低、高浓度组U937细胞增殖率显著升高(均P<0.05),凋亡率、自噬小体数量、SIRT1、FoxO1 mRNA和蛋白表达水平显著降低(均P<0.05);与蓝萼甲素低浓度组相比,蓝萼甲素高浓度组U937细胞增殖率显著降低(P<0.05),凋亡率、自噬小体数量、SIRT1、FoxO1 mRNA和蛋白表达水平显著升高(均P<0.05)。结论:蓝萼甲素能抑制U937细胞的增殖,促进其凋亡和自噬,其机制可能与激活SIRT1/FoxO1信号通路有关。

The Establishment and Validation of the Human U937 Cell Line as a Cellular Model to Screen Immunomodulatory Agents Regulating Cytokine Release Induced by Influenza Virus Infection

Severe influenza infections are often associated with the excessive induction of pro-inflammatory cytokines,which is also referred to as"cytokine storms".Several studies have shown that cytokine storms are directly associated with influenzainduced fatal acute lung injury and acute respiratory distress syndrome.Due to the narrow administration window,current antiviral therapies are often inadequate.The efforts to use immunomodulatory agents alone or in combination with antiviral agents in the treatment of influenza in animal models have resulted in the achievement of protective effects accompanied with reduced cytokine production.Currently,there are no immunomodulatory drugs for influenza available for clinical use.Animal models,despite being ideal to study the anti-inflammatory responses to influenza virus infection,are very costly and time-consuming.Therefore,there is an urgent need to establish fast and economical screening methods using cellbased models to screen and develop novel immunomodulatory agents.In this study,we screened seven human cell lines and found that the human monocytic cell U937 supports the replication of different subtypes of influenza viruses as well as the production of the important pro-inflammatory cytokines and was selected to develop the cell-based model.The U937 cell model was validated by testing a panel of known antiviral and immunomodulatory agents and screening a drug library consisting of 1280 compounds comprised mostly of FDA-approved drugs.We demonstrated that the U937 cell model is robust and suitable for the high-throughput screening of immunomodulators and antivirals against influenza infection.

N-Terminal Truncation of TACO Inhibits PMA-Induced U937 Cell Adhesion

The effect of TA001-299, the N-terminal truncation of TACO, on phorbol 12-myristate 13-acetate （PMA）-induced U937 cell adhesion was investigated. Full-length TACO and several truncations were overexpressed in U937 cells. The effects of the expressed proteins on U937 cell adhesion mediated by PMA-induced differentiation were observed by fluorescence microscopy. The results show that the overexpression of TACO1-299 inhibits cell adhesion while overexpressions of the other proteins do not have this effect. The actin-binding capability of TACO1-299 was investigated and the results show that TACO1-299 lacks the ability of TACO to bind F-actin. The inhibitive effect of TACO1-299, the functional domain of TACO, suggests that TACO may play a role in cell differentiation mediating adhesion of monoblastic leukemia cells.

Effect of Caffeic acid on the Tumor Cells U937 Evaluated by an Electrochemical Voltammetric Method

Electrochemical voltammetric method can;be used to monitor cell health state during its growth. Here we studied the effect of caffeic acid on leukemia cells U937 by the voltammetric behavior of the cells. The result showed that this drug had a negative influence on cell health. which suggests that caffeic acid may be used in inhibition of tumor cells.

阿魏酸对U937细胞生长的抑制作用及其相关机制研究

目的:探讨阿魏酸(FA)对人急性髓系白血病(AML)细胞系U937细胞增殖、凋亡及Toll样受体4(TLR4)/核因子κB(NF-κB)信号通路的影响。方法:使用不同浓度的FA(0、10、25、50、100、200μmol/L)分别处理人AML细胞系Kasumi-1、HL-60、U937细胞24 h后,采用CCK-8法检测细胞存活率,计算各个细胞系的半数抑制浓度(IC_(50))。将U937细胞分为对照组、FA组(50μmol/L FA)、FA+pcDNA组(50μmol/L FA+转染空载质粒)、FA+pcDNA-TLR4组(50μmol/L FA+转染TLR4过表达质粒)。采用流式细胞术检测各组U937细胞周期与细胞凋亡;平板克隆形成实验检测U937细胞克隆形成能力;荧光定量PCR检测U937细胞TLR4、NF-κB p65 mRNA水平;蛋白印迹法检测U937细胞细胞周期蛋白D1(CyclinD1)、细胞周期蛋白E(CyclinE)、Bcl-2相关X蛋白(Bax)、B淋巴细胞瘤-2(Bcl-2)、半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)、TLR4、NF-κB p65蛋白表达。结果:随着FA浓度的升高,Kasumi-1、HL-60、U937细胞存活率逐渐下降(r=-0.919,r=-0.909,r=-0.900),U937细胞的IC_(50)为50.25±2.23μmol/L。与对照组比较,经药物处理U937细胞后,FA组G_(0)/G_(1)期细胞比例、细胞凋亡率、Bax、Caspase-3蛋白表达水平均显著升高(P<0.05),细胞克隆形成数、S期和G_(2)/M期细胞比例、CyclinD1、CyclinE、Bcl-2蛋白及TLR4、NF-κB p65 mRNA和蛋白表达水平均显著降低(P<0.05);与FA组和FA+pcDNA组比较,FA+pcDNA-TLR4组G_(0)/G_(1)期细胞比例、细胞凋亡率、Bax、Caspase-3蛋白表达水平均显著降低(P<0.05),细胞克隆形成数、S期和G_(2)/M期细胞比例、CyclinD1、CyclinE、Bcl-2蛋白及TLR4、NF-κB p65 mRNA和蛋白表达水平均显著升高(P<0.05)。结论:FA通过抑制TLR4/NF-κB信号通路抑制U937细胞增殖,促进细胞凋亡。

雷公藤红素对U937细胞Notch 1、NF-κB信号蛋白通路的调控作用

背景与目的:白血病是高度依赖NF-κB的恶性肿瘤,NF-κB与肿瘤的发生和转移以及肿瘤细胞的增殖、凋亡、耐药相关,现已证实NF-κB家族是Notch信号通路的一个靶基因。本研究探讨雷公藤红素对白血病U937细胞凋亡和细胞中Notch1、NF-κB表达水平的影响。方法:以不同浓度雷公藤红素(0.25～16.0μmol/L)分别作用于U937细胞12～60h,MTT法检测细胞增殖活性,透射电子显微镜、流式细胞术观察雷公藤红素对U937细胞凋亡的影响,Western blot、RT-PCR法分别检测雷公藤红素对U937细胞内Notch1通路蛋白、基因表达水平的调控作用,激光共聚焦显微技术检测细胞凋亡时NF-κB的核浆分布变化。结果:雷公藤红素能明显抑制U937细胞增殖,具有浓度依赖和时间依赖性。此外,雷公藤红素以浓度依赖性方式诱导U937细胞凋亡,并伴随明显的凋亡细胞形态学改变,而雷公藤红素的凋亡诱导效应可能与其将细胞阻滞于G0/G1期有关。雷公藤红素对Notch1通路蛋白及基因表达水平均有不同程度的抑制作用,该抑制作用呈明显的量效关系。NF-κB在胞核表达减少,胞浆表达增多。与对照组相比差异具有统计学意义(P<0.05)。结论:雷公藤红素明显抑制U937细胞的增殖,并诱导其凋亡,其抗白血病效应可能与下调Notch1信号通路以及NF-κB蛋白表达有关。

华蟾素诱导U937细胞凋亡及其作用机制

目的：研究华蟾素诱导白血病U937细胞凋亡，探讨其可能的作用机制。方法：MTT法检测细胞存活率，瑞氏染色及荧光染色观察细胞凋亡形态学改变，琼脂糖凝胶电泳观察DNA片段化改变，TdT原位标记计算凋亡率，流式细胞术检测bcl-2表达，半定量RT-PCR检测Fas和Fas-1 mRNA水平。结果：与对照组相比，0．225～1．8μg/mL华蟾素作用1-3d明显抑制U937细胞生长，具有剂量．时间相关性，24h时的IC50为1．36μg/mL。0．9μg/mL华蟾素作用1d，U937细胞出现凋亡典型形态学改变；DNA电泳出现凋亡特有“梯子”条带。0．225、0．45和0．9μg/mL华蟾素作用1d，TdT原位标记检测凋亡率分别为4．8％、13．57％和24．33％。凋亡细胞bcl-2表达及Fas-1 mRNA水平下降，Fas mRNA水平增高。结论：华蟾素可能通过抑制bcl-2、Fas-1基因及活化Fas基因的途径来抑制U937细胞生长并诱导凋亡。

大黄素诱导白血病U937细胞凋亡及机制初探

目的研究中药大黄素(Emodin)对人髓系白血病细胞株U937细胞增殖及凋亡的影响,探讨bcl-2/bax比值变化和procaspase-3(CPP32)的激活在其中的作用。方法MTT法绘制细胞生长曲线;克隆形成试验观察大黄素对U937细胞增殖的影响;线粒体膜电位检测、DNA倍体分析及DNA凝胶电泳分析细胞凋亡;PCR及检测大黄素作用前后bcl-2/bax基因及蛋白表达的变化;流式细胞术测定大黄素作用前后caspase-3活性变化及检测CPP32的蛋白表达的变化。结果大黄素能抑制U937细胞增殖,作用72h的半数抑制浓度(IC50)约为30μmol·L-1;线粒体膜电位、亚G1峰(凋亡峰)及DNA片段化的检出证实大黄素能诱导U937细胞凋亡,并呈量效关系。大黄素作用后G0/G1期细胞比例较对照组增高,S期比例下降,且与药物浓度呈正相关。大黄素作用后U937细胞bcl-2/bax基因及蛋白的表达水平比值下降,被激活的caspase-3阳性细胞增多,CPP32蛋白表达水平下降,并呈时效关系。结论大黄素能通过诱导凋亡来抑制U937细胞增殖,bcl-2/bax比值的降低及CPP32的活化可能参与了大黄素抑制U937细胞增殖和诱导凋亡的过程。

白花蛇舌草提取物诱导U937细胞凋亡的实验研究

目的探讨中草药白花蛇舌草(HDW)醇提取物在体外对人白血病细胞株的增殖抑制和凋亡作用。方法以白血病U937细胞为研究对象,以不同浓度和不同时间HDW醇提取物为干预因素,用MTT法检测HDW醇提取物对U937细胞的抑制作用;用细胞形态学、流式细胞术、DNA电泳观察细胞凋亡情况。结果U937细胞经HDW醇提取物作用后,呈时间和剂量依懒性。光镜观察可见细胞膜完整、核碎裂、凋亡小体等形态学特征,DNA电泳呈现典型的梯形条带,流式细胞仪分析表明0.5,1,2,4 mg/mL的HDW醇提取物使U937细胞发生凋亡率分别为4.18%,56.96%,82.43%,56.41%。结论HDW醇提取物抗肿瘤效应强,同时抑制U937细胞的增殖及诱导细胞凋亡。