硫化砷对白血病细胞的生长抑制及作用机制

 目的 研究硫化砷（As4S4）通过体外培养对白血病细胞HL-60细胞的生长抑制作用及其分子机制。方法 以不同浓度（7.5 ~ 60 mmol／L）的As4S4作用于体外培养HL-60细胞12 ~ 48 h,四甲基偶氮唑蓝（MTT）法检测细胞生长抑制率,流式细胞仪观察细胞凋亡率,免疫组化法检测bcl-2、p53蛋白表达,应用RT-PCR法检测HL-60细胞中p53 mRNA表达。结果 不同浓度的As4S4作用12 ~ 48 h后,可显著抑制HL-60细胞的生长,呈时间浓度依赖性,并诱导细胞发生凋亡,凋亡率为30.18 % ~ 70.98 %,不同作用时间、不同浓度间凋亡率差异有统计学意义（P＜0.01）,RT-PCR结果显示As4S4作用24 h后,下调p53 mRNA的表达。免疫组化结果显示,bcl-2、p53蛋白表达逐渐降低,并呈浓度依赖性。结论 As4S4能够显著抑制HL-60细胞的生长。诱导其凋亡,并下调bcl-2、p53的表达,可能是其重要机制。     

苦参碱诱导HL-60细胞株凋亡作用的实验研究

 目的　研究苦参碱（MAT）诱导HL-60细胞株凋亡的作用及其机制。方法　采用 CCK-8法检测不同浓度MAT对HL-60细胞的增殖抑制作用;流式细胞术检测细胞凋亡以及线粒体跨膜电位的变化;分光光度法检测Caspase-9活性。结果　0.25～2.0 mg／ml MAT对HL-60细胞有生长抑制作用,与对照组相比差异有统计学意义（F＝67.83,P＜0.05）;MAT处理48 h后,细胞凋亡率明显增高,并呈剂量依赖性（t值分别为4.685、6.300、9.641、6.786,均P＜0.05）;1.0 mg／ml MAT处理后48 h内,细胞线粒体跨膜电位逐渐降低（F＝54.83,P＜0.05）,Caspase-9活性逐渐升高,呈时间依赖性（F＝72.31,P＜0.05）。结论　MAT可能通过降低细胞线粒体跨膜电位、激活Caspase-9而诱导HL-60细胞凋亡。     

三七皂苷R1对HL-60细胞凋亡及survivin、p53表达的影响

[目的]探讨三七皂苷R1对人白血病细胞株HL-60细胞凋亡作用及其机制。[方法]光镜下观察三七皂苷R1作用下HL-60细胞形态．采用MTT比色法观察三七皂苷R1对HL-60细胞增殖的抑制作用。采用流式细胞术检测细胞凋亡改变．并以RT-PCR检测凋亡调节基因survivin、p53的表达。[结果]三七皂苷R1 75μg／ml～1200μg／ml可抑制HL-60细胞的生长，且呈时间和浓度依赖性。三七皂苷R1作用后细胞呈现凋亡特征．流式细胞术显示凋亡细胞比例升高，凋亡率随作用剂量的增高而升高。RT-PCR检测可见在三七皂苷R1150μg／ml作用下p53mRNA表达显著增加，而survivin mRNA表达减少。[结论]三七皂苷R1能诱导人白血病细胞株HL-60细胞凋亡，其作用可能与凋亡调节基因p53的上调和survivin的下调有关。     

三氧化二砷诱导HL-60细胞凋亡效应及抑制细胞ERK的活性

目的：初步探讨三氧化二砷（arsenic trioxide,As2O3）促进HL-60细胞凋亡及其可能机制。方法：不同浓度的As2O3（0、2.5、5、10μmol/L）作用于HL-60细胞24h后,MTT法检测细胞增殖,流式细胞术检测细胞凋亡,Western blot检测Caspase-3活化、ERK活性和cyclinD1蛋白的表达,RT-PCR法检测cyclinD1mRNA的表达。结果：As2O3可抑制HL-60细胞增殖,诱导HL-60细胞的凋亡,并呈浓度依赖性（P〈0.05）;As2 O3可使HL-60细胞Caspase-3激活,并抑制ERK活性,但不能下调cyclinD1的表达（P〉0.05）。结论：As2 O3能抑制HL-60细胞增殖,并诱导其凋亡,其效应可能与As2 O3抑制HL-60细胞ERK活性有关。     

PARP抑制剂olaparib对急性髓系白血病细胞HL-60抑制作用研究

目的 研究PARP抑制剂olaparib对人急性髓系白血病细胞株HL-60细胞的抑制作用。方法 对数生长期HL-60细胞经不同浓度(0、1.25、2.5、5、10 μmol/L)olaparib作用不同时间后,CCK-8法检测olaparib对HL-60细胞的增殖抑制作用;Annexin-V/PI双标法检测HL-60细胞凋亡水平,Western blot检测HL-60细胞内相关信号蛋白(PARP-1、Caspase-3)表达变化。结果 与对照组相比,经不同浓度(1.25、2.5、5、10 μmol/L)olaparib作用48 h后的HL-60细胞出现增殖抑制,并且随着作用时间的延长,抑制率逐渐增加;同时发现olaparib诱导HL-60细胞发生凋亡,并显示出剂量依赖效应;Western blot结果显示,olaparib处理后的HL-60细胞内PARP活性受到抑制,Caspase-3活化。结论 PARP抑制剂olaparib对HL-60细胞不仅具有增殖抑制作用,同时可通过激活Caspase-3,抑制PARP活性,诱导HL-60细胞凋亡。     

千金子甾醇诱导HL-60细胞凋亡机制研究

目的探讨Bcl-2/Bax信号通路在千金子甾醇诱导HL-60白血病细胞发生凋亡中的作用及其分子机制研究。方法HL-60细胞培养体系中分别加入大、中、小剂量千金子甾醇溶液,甾醇溶液作用细胞24h后,采用CCK-8法检测千金子甾醇对HL-60细胞增殖的抑制作用,光镜下观察细胞形态学变化,AnnexinⅤ/PI流式细胞术检测细胞凋亡,RT-PCR法检测Bcl-2/Bax、Caspase-9和Caspase-3mRNA转录水平,ELISA法检测Caspase-9和Caspase-3蛋白活性。结果 CCK-8法检测结果显示,与对照组比较,千金子甾醇能明显抑制HL-60细胞增殖（F=42.97,P〈0.001）,各个浓度之间进行比较,差异有统计学意义,P〈0.05。流式细胞术检测细胞凋亡率显著增加（F=56.74,P〈0.001）,经10、20和40μg/mL千金子甾醇处理24h后,HL-60细胞早期凋亡率分别为（23.4±3.1）%、（35.7±4.3）%和（53.2±3.9）%,细胞呈典型凋亡形态学改变。千金子甾醇作用后,Bax mRNA转录水平显著升高,Bcl-2mRNA转录水平显著降低,且呈化合物剂量依赖性（F=53.45,P〈0.001）,Caspase-9和Caspase-3 mRNA转录水平升高,且呈化合物剂量依赖性（F=34.21,P〈0.001）,千金子甾醇对HL-60细胞作用24h后Caspase-9和Caspase-3蛋白活性显著升高（F=54.33,P〈0.001）,且随着千金子甾醇浓度增加蛋白活性逐渐升高。结论千金子甾醇通过调节Bcl-2/Bax凋亡信号通路,诱导HL-60细胞凋亡,其作用呈明显剂量依赖性。     

细胞色素C诱导HL-60细胞凋亡及其周期特异性分析

目的分析细胞色素C诱导HL-60细胞凋亡的时间效应及其细胞周期的特异性.方法 (1)利用透射电镜观察细胞色素C诱导HL-60细胞凋亡时凋亡小体的形成;(2)应用流式细胞仪技术检测细胞色素C诱导HL-60细胞的凋亡率并分析其凋亡的时-效关系以及凋亡与细胞周期的关系.结果 (1)细胞色素C作用HL-60细胞24小时发生凋亡,形成凋亡小体;(2)细胞色素C诱导HL-60细胞凋亡的作用体现一定的时间效应,作用时间不同,诱导凋亡率亦不相同,其中作用24小时凋亡率最高;(3)细胞色素C诱导HL-60凋亡的作用具有细胞周期特异性,随凋亡率升高,S期和G2期细胞比例随之下降,且S期细胞比例与凋亡率二者呈显著负性关系(r=0.718,P＜0.01).结论细胞色素C诱导HL-60细胞凋亡与细胞周期密切相关,其周期特异性具有一定的实际意义.     

Toremifene诱导MCF-7/ADR细胞凋亡的研究

目的研究Toremifene体外诱导乳腺癌耐药细胞MCF-7/ADR凋亡和凋亡相关基因Fas、FasL、p53和Caspase-3表达的关系.方法以不同浓度Toremifene(0.24μg/ml、2.4μg/ml、24μg/ml)诱导MCF-7/ADR细胞凋亡;以MTT法观察不同处理浓度的Toremifene对MCF-7/ADR细胞DNA合成活性的影响;以免疫组化检测Fas、FasL、p53和Caspase-3蛋白表达.结果不同浓度Toremifene处理的MCF-7/ADR细胞出现DNA合成活性下降,抑制强度与浓度有关(P＜0.05);Fas、FasL、p53和Caspase-3蛋白呈上调表达.结论Toremifene能诱导细胞凋亡;增加Fas、FasL、p53和Caspase-3基因表达;并且与启动Caspase-3凋亡信号和p53直接介导的凋亡有关.     

可溶性CD40配体对白血病HL-60细胞Caspase-3及Caspase-8表达的影响

目的 Caspase-3和Caspase-8在多种肿瘤中异常表达,与白血病的疗效等密切相关.本研究分析可溶性CD40配体(soluble CD40 ligand,sCD40L)对人白血病HL-60细胞Caspase-3及Caspase-8表达的影响,探讨其对HL-60细胞的作用机制.方法 2.0、4.0和6.0 mg/L的sCD40L作用HL-60细胞48 h,采用流式细胞术检测HL-60细胞凋亡水平及细胞周期,RT-PCR检测HL-60细胞中Caspase-3和Caspase-8基因的表达水平,蛋白质免疫印迹法检测HL-60细胞中Caspase-3和Caspase-8的蛋白表达.结果 2.0、4.0和6.0 mg/L的sCD40L作用HL-60细胞48 h后,浓度依赖性诱导HL-60细胞的凋亡,凋亡率分别为(48.17±3.22)％、(60.73±5.46)％及(71.26±5.83)％,与对照组(36.42±2.75)％比较,差异有统计学意义,F=36.373,P=0.003.sCD40L阻滞HL-60细胞在G0/G1期,RT-PCR结果显示,Caspase-3和Caspase-8 mRNA的表达上调;蛋白质印迹法结果显示,Caspase-3和Caspase-8蛋白表达增强.结论 sCD40L在体外能够以浓度依赖性促进HL-60细胞凋亡,阻滞细胞在G0/G1期,其可能机制是通过激活Caspase-3和Caspase-8.     

蛋白酶体抑制剂MG132诱导HL-60细胞凋亡前G2/M期阻滞及机制

背景和目的:蛋白酶体(proteasome)抑制剂能够诱导多种肿瘤细胞凋亡,是一种潜在的有应用前景的抗肿瘤剂.本研究旨在探讨蛋白酶体抑制剂MGl32(Z-Leu-Leu-Leu-CHO)诱导白血病细胞HL-60凋亡和C2/M期阻滞的机制.方法:采用荧光显微镜观察、流式细胞术和免疫印迹研究测定MG132诱导HL-60细胞凋亡和周期阻滞及机制.结果:2μmol/L的MG132能够有效地诱导HL-60细胞凋亡,用药后24 h就显现有细胞凋亡;在MG132诱导HL-60细胞凋亡出现之前有一个明显的G2/M期阻滞,加MG132后12 h时G2/M期时相百分比为63.42±2.02;24 h时加MG132组细胞凋亡为16.67±1.48,与对照组G2/M期时相百分比为7.29±3.01及细胞凋亡为0相比,两者之间有显著性差别(P＜0.01);咖啡因CAF能够减少MG132诱导HL-60细胞出现的G2/M期阻滞,同时也减少凋亡细胞的比例;细胞周期检查点的负调控因子p21waf/cip1蛋白在加MG132处理后3 h有明显的表达,但并未能检测到p53和p27蛋白.结论:MG132诱导HL-60细胞凋亡之前有一个明显的G2/M期阻滞,p21蛋白表达明显上调提示:是p21waf/cip1而不是p53或其同源蛋白参与了其中的调控.     

Effective treatment of leukemic cell lines with wt1 siRNA.

The expression of wt1 and bcl-2 is considered to have a proliferating and survival supporting effect in leukemia blast cells. Here we describe the use of siRNA against wt1 and bcl-2 in leukemic cell lines for successful growth inhibition. We have used two different sequences designated as siRNA-A and siRNA-B corresponding to positions within the wt1 coding sequence to downregulate wt1 and a commercially available siRNA kit to downregulate bcl-2. WT1 and bcl-2 gene expression in transfected leukemic cell lines were evaluated with RT-PCR and western blot analyses. MTT assay was used to measure the cell viability and flow cytometry using annexin V/PI-staining for apoptosis. K562 and HL-60 cell lines transfected with siRNA-A targeted to wt1 had greatly decreased levels of both wt1 mRNA and protein expression. In contrast, siRNA-B and control siRNA led almost to no effect on wt1 mRNA and protein expression. siRNA-A-reduced wt1 mRNA expression was associated with a decreased cell proliferation and increased number of apoptotic cells in K562 and HL-60 cells by 24 and 48 h after transfection. Combined treatment with wt1 siRNA and bcl-2 siRNA simultaneously was not able to override the cell growth and apoptosis effects compared to single treatment with wt1 siRNA. siRNAs targeted against human wt1 might be a valuable tool as antiproliferative agent against wt1 expressing leukemic cells.     

Induction of apoptosis in HL-60 cells by eicosapentaenoic acid (EPA) is associated with downregulation of bcl-2 expression.

Dietary polyunsaturated fatty acids (PUFAs) have been reported as a potential group of natural products which modulate tumor cell growth. In present study, eicosapentaenoic acid (EPA) was found to inhibit proliferation of human leukemic HL-60 and K-562 cells in vitro. EPA arrested cell cycle progression at G0/G1 phase, and induced necrosis in both HL-60 and K-562 cells. However, EPA induced apoptosis only in HL-60 but not K-562 cells. Also, bcl-2 protein expression was downregulated in much greater extent than that of bax showing that depression of bcl-2 might be an important step during the EPA-induced apoptosis in HL-60 cells.     

Bcl-2, bax and bcl-xL expression in human sensitive and resistant leukemia cell lines.

With the growing understanding of cytostatic drug-induced programmed cell death new drug-resistance mechanisms based on the altered ability of cells to die by apoptosis have been defined. At first, the sensitive and P-glycoprotein (P-gp)-related resistant cell lines were tested to induce apoptosis by a non-P-gp transported drug, such as cytosine arabinoside (ara-C). It was demonstrated that ara-C induces apoptosis in sensitive as well as in P-gp-related resistant cell lines, as expected. Furthermore, the role of bcl-2 and bcl-xL apoptosis inhibitors as well as bax expression (apoptosis inducer) in human sensitive leukemic cell lines (CCRF-CEM and HL-60) as compared to their resistant variants such as CCRF-CEM/ACT400, CCRF-CEM/VCR1000, HL-60/IDA40, HL-60/DNR250 was evaluated. In addition to the P-gp-related resistance, a possible multidrug resistance-associated protein (MRP) and the lung resistance protein (LRP)-related resistance were assessed by flow cytometry using the monoclonal antibodies 4E3.16, MRPr1 and LRP56. Furthermore, the function of P-gp was determined with the rhodamine-123 (R-123) accumulation test. Bcl-2 and bax were analyzed by both flow cytometry and ECL Western blot, bcl-xL by ECL-Western blot alone. Comparison of the two sensitive cell lines demonstrated different bcl-2, bax and bcl-xL patterns. The common characteristic was the increased expression of one of the apoptosis inhibitor proteins, such as bcl-2 or bcl-xL. The sensitive CCRF-CEM showed a high bax level, where a decrease of about 75% in resistant variants was measured. Compared to their sensitive counterpart HL-60, a low bax expression was analyzed, which increased in the resistant variant. The common characteristic of all resistant cell lines was the decreased expression of bax compared to bcl-2 or bcl-xL. In the P-gp-related resistant HL-60/DNR250 only an increase in bcl-xL was seen, whereas in the LRP-expressing as well as P-gp and MRP negative resistant HL-60/IDA40 both apoptotic inhibitor proteins bcl-2 and bcL-xL showed maximum increase, compared to the other resistant cell lines. The P-gp-related resistant cell lines CCRF-CEM/ACT400 and CCRF-CEM/VCR1000 also showed an increased expression of both bcl-2 and bcl-xL. Summarizing these results, it was shown that the examined sensitive human leukemic cell lines and their resistant variants demonstrated a different pattern of markers for preventing and promoting apoptosis. An association between P-gp and possible LRP-expressing leukemic cells as well as apoptosis-preventing markers (bcl-2, bcl-xL) seems to exist. The clinical relevance of the coexpression of various resistance mechanisms remains to be confirmed in large leukemia patient groups.     

甲异靛诱导白血病细胞HL-60凋亡及机制探讨

背景与目的:甲异靛可有效治疗慢性粒细胞白血病,但其抗白血病的机制尚不清楚。本研究拟观察甲异靛诱导急性白血病细胞株HL-60细胞凋亡的作用及促凋亡机制。方法:用台盼蓝拒染实验观察甲异靛对HL-60细胞增殖抑制作用;琼脂糖凝胶电泳检测DNA条带;荧光显微镜观察细胞形态学的变化;流式细胞术检测细胞凋亡率和Fas蛋白的表达;免疫蛋白印迹法分析caspase-9、caspase-8、caspase-3、PARP、bcl-2、bax和胞浆细胞色素c的含量。结果:甲异靛可抑制HL-60细胞增殖和诱导其凋亡。20μmol/L甲异靛处理HL-60细胞12～48h可明显抑制HL-60细胞增殖;20μmol/L甲异靛作用于HL-60细胞1h,凋亡百分比为(3.70±0.56)%,当延长至3h、6h和12h凋亡细胞比例分别上升至(19.80±1.13)%、(29.20±2.69)%和(47.05±7.70)%,较阴性对照组[(2.65±0.78)%]明显增高(P<0.05)。HL-60细胞经甲异靛处理3h后出现细胞核染色质浓集和DNA梯形条带。甲异靛处理HL-60细胞1h后死亡受体Fas阳性率由(9.35±0.21)%升高到(21.30±1.27)%(P<0.05)。甲异靛可活化HL-60细胞的caspase-8、caspase-9、caspase-3和PARP,降低抗凋亡蛋白bcl-2的表达和上调促凋亡蛋白bax,并升高细胞浆中细胞色素c的浓度。caspase-3抑制剂(z-DEVD-fmk)可以减少甲异靛对HL-60细胞的增殖抑制,降低细胞凋亡率。100μmol/Lz-DEVD-fmk预处理HL-60细胞后再加入20μmol/L甲异靛,5h后凋亡率为(16.5±5.5)%,甲异靛组为(29.8±5.4)%(P<0.05);12h后计数,抑制剂加甲异靛组活细胞高达(3.57±0.18)×105/ml,甲异靛组活细胞仅为(1.80±0.14)×105/ml(P<0.05)。结论:甲异靛可诱导HL-60细胞凋亡,其机制与caspases和bcl-2家族蛋白的调节有关。     

雷帕霉素对人非霍奇金淋巴瘤Raji细胞生物学行为的影响及其机制研究

目的 探讨不同浓度雷帕霉素作用不同时间对人非霍奇金淋巴瘤Raji细胞生物学行为的影响及其相关机制.方法采用0、10、50、100、250、500 nmol/L雷帕霉素分别作用Raji细胞24、48、72 h,采用CCK-8法测定Raji细胞增殖抑制率;采用流式细胞术测定Raji细胞凋亡及细胞周期;采用Caspase-3、Caspase-9活性检测试剂盒检测Raji细胞中Caspase-3、Caspase-9的酶活性;采用蛋白印迹法及反转录聚合酶链反应(RT-PCR)检测Raji细胞中bcl-2、p53蛋白及其mRNA表达情况.结果作用24 h后,随着雷帕霉素浓度由0 nmol/L逐渐增加至500 nmol/L,Raji细胞增殖抑制率由(23.7±4.2)％升高至(51.7±3.7)％(P<0.01);细胞凋亡率由(4.9±1.9)％升高至(20.5±1.5)％(P<0.01);G0/G1期细胞比例由(40.8±1.4)％增加至(63.6±1.7)％(P<0.01);Caspase-3酶活性由0.16±0.05增加至1.08±0.04(P<0.01);Caspase-9酶活性由0.19±0.04增加至1.34±0.06(P<0.01);bcl-2 mRNA表达量由0.90±0.03减少至0.46±0.03,p53 mRNA表达量由2.51±0.41增加至5.85±0.21,并且bcl-2蛋白表达降低,p53蛋白表达增高.Raji细胞48 h和72 h实验结果与24 h实验结果趋势一致.结论雷帕霉素可能通过Caspase-3、Caspase-9、bcl-2、p53途径抑制Raji细胞增殖,并诱导Raji细胞凋亡.     

Induction of apoptosis by a ribosome-inactivating protein from Agrostemma githago is associated with down-regulation of anti-apoptotic bcl-2 protein expression.

Agrostin is a type 1 ribosome-inactivating protein (RIP) isolated from the seeds of Agrostemma githago. 3[H]-thymidine incorporation in human leukemic HL-60 cells was significantly reduced after incubation with agrostin showing that the RIP was inhibitory on the cell proliferation. Results from flow cytometric studies illustrated that apoptosis was induced by agrostin, which was associated with activation of endonucleases and DNA fragmentation of the leukemic cells. Anti-apoptotic bcl-2 protein level was also reduced by agrostin showing that the associated apoptotic pathway might involve down-regulation of the intracellular bcl-2 protein level.