白藜芦醇对白血病K562细胞增殖、凋亡的影响及机制探讨

目的 探讨白藜芦醇对白血病K562细胞生长的影响及相关作用机制.方法 用不同浓度白藜芦醇作用于K562细胞,CCK-8法观察白藜芦醇对K562细胞生长增殖的影响,AnnexinV-FITC/PI双染法观察白藜芦醇对K562细胞凋亡的影响,PI染色法观察白藜芦醇对K562细胞周期的影响,Western blot法检测K562细胞中的Bcl-2、Bcl-xl、Bax、Cyclin D1蛋白.结果 白藜芦醇作用后的K562细胞的增殖被抑制并且凋亡增加,呈时间-剂量依赖性;同时,凋亡相关分子Bcl-2、Bcl-xl表达下调,Bax表达上调;白藜芦醇作用K562细胞后,G1期细胞增多,S期细胞减少,细胞周期调节蛋白Cyclin D1表达下降.结论 白藜芦醇可抑制K562细胞增殖并诱导其凋亡,其机制可能与下调细胞内Bcl-2、Bcl-xl、Cyclin D1表达并上调Bax的表达有关.     

旋毛虫培养液对人白血病细胞K562凋亡和坏死的影响

在对旋毛虫的研究过程中，有研究者曾对旋毛虫与肿瘤的关系进行了探讨。发现感染旋毛虫的小鼠再接种某些肿瘤细胞后，肿瘤细胞生长缓慢，甚至完全不生长，提示旋毛虫感染可以提高小鼠对肿瘤的防御机能。为了解旋毛虫致死肿瘤细胞的相关机制，本实验观察旋毛虫培养液对K562细胞凋亡和坏死的影响，现将结果报告如下。     

硒诱导红白血病K562细胞凋亡机制的探讨

目的 探讨微量元素硒对人红白血病细胞株（K562细胞株）诱导凋亡的机制。方法 采用免疫光技术检测加硒培养组（实验组）K562细胞的凋亡细胞核变化和凋亡小体的数量,同时还应用化学检测与细胞凋亡有关的酶。结果 实验组凋亡细胞明显增多,且呈剂量依赖性,实验组细胞内谷胱甘肽过氧化物酶（GSH－Px)的活性及环磷酸苷（cAMP)的含量也明显高于对照（P＜0．01）。结论 硒能够诱导K562细胞凋亡,可提高该细胞内GSH－Px的活性及cAMP的含量。     

弓形虫诱导人白血病细胞K562凋亡的实验观察

目的 探讨弓形虫对体外培养的人白血病细胞K562（简称K562细胞）有无抑制作用和诱导细胞凋亡作用。方法 取培养至对数生长期的K562细胞（浓度为5×10^-4/ml和1×10^-6/ml）分别接种于96孔培养板（100 μl/孔）及50 ml培养瓶（1.5 ml/瓶）中，加入不同浓度的弓形虫速殖子（1×10⁴、2×10⁴、4×10⁴、8×10⁴及16×10⁴个/ml），作用48 h, 用四甲基氮噻唑蓝（MTT）法检测其对K562细胞增殖的抑制作用；荧光显微镜、琼脂糖凝胶电泳及流式细胞仪检测细胞凋亡。 结果 上述不同浓度弓形虫速殖子作用48 h，对K562细胞增殖的抑制率依次为17%、28%、48%、50%及55%。各实验组吸光度（A₄₉₀）与对照组比较差异均有统计学意义（t=3.606及5.918， P<0.05； t=9.171、7.841、7.067， P<0.01）。荧光显微镜观察实验组培养的K562细胞，出现细胞核固缩及凋亡小体。琼脂糖凝胶电泳见DNA梯形条带。流式细胞仪检测到细胞凋亡峰（48 h），上述不同浓度弓形虫速殖子诱导K562细胞凋亡数分别占总数的5.53%、7.12%、10.34%、21.14% 及29.68%。对照组未出现凋亡小体。 结论 弓形虫速殖子对体外培养K562细胞增殖有明显的抑制作用，并可诱导K562细胞凋亡。     

白血病抑制因子对K562细胞增殖、凋亡及p53蛋白表达的影响

目的探讨白血病抑制因子（LIF）体外对K562细胞增殖、凋亡的影响及机制。方法取对数生长期K562细胞接种于96孔板中,随机分为对照组和观察1—3组,分别加入质量浓度为0、5、10、40μg/L的重组人LIF,继续培养6、12、24、48h;应用MTT法、Hoeehst染色法观察各组K562细胞增殖活性、凋亡率,采用免疫组化法检测观察3组和对照组p53蛋白表达情况。结果观察1～3组不同时间细胞增殖活性均显著低于对照组,且观察1组〉观察2组〉观察3组、6h〉12h〉24h〉48h（P均〈0．05）;观察1—3组不同时间细胞凋亡率均显著高于对照组,且观察1组〈观察2组〈观察3组、6h〈12h〈24h〈48h（P均〈0．05）;观察3组各时间点p53蛋白阳性表达率均明显高于对照组,且6h〈12h〈24h〈48h（P均〈0．05）。结论LIF能以浓度-时间依赖性抑制K562细胞增殖并诱导其凋亡,机制可能为上调p53蛋白表达。     

青蒿琥酯诱导白血病K562细胞凋亡的临床研究

青蒿素是从菊秋植物黄花蒿中提取的有效单体 ,是一种新的化学结构抗疟药。青蒿琥酯是其衍生物 ,是具有过氧化桥的倍半萜内酯类化合物 ,具有水溶性好、抗疟活性高等特点。近年来 ,有人报道青蒿琥酯具有体内外抗肿瘤作用 ,对人肝癌细胞有诱导凋亡作用 [1]。2 0 0 2年 7月～ 2 0 0 3年 3月 ,我们观察了青蒿琥酯对体外培养的人慢性粒细胞白血病细胞系K5 62细胞的凋亡诱导作用 ,旨在为其治疗肿瘤提供理论依据。1　材料与方法1 .1　材料　注射用青蒿琥酯 ,5 %碳酸氢钠 1 ml,RP-MI1 640培养液 ,4℃保存。1 .2　方法1 .2 .1　细胞系及细胞培养　K…     

防风多糖诱导人白血病K562细胞凋亡的研究

目的:探讨防风多糖对体外培养人白血病K562细胞有无调亡诱导作用.方法:MTT法检测防风多糖对K562细胞的增殖抑制作用;荧光显微镜观察细胞的形态学变化;琼脂糖凝胶电泳分析细胞凋亡的DNA断裂;流式细胞术采用Annexin-V/PI双染实验检测细胞凋亡.结果:MTT法检测显示防风多糖对K562细胞具有显著生长抑制作用;荧光显微镜下观察发现防风多糖作用的K562细胞中出现核固缩、凋亡小体;琼脂糖凝胶电泳呈现DNA梯形条带即(DNA ladder);流式细胞仪分析结果显示细胞凋亡百分率随防风多糖浓度增加而增加.结论:防风多糖对体外培养人白血病K562细胞具有增殖抑制及凋亡作用.     

海生素对K562/ADM细胞增殖和凋亡基因表达的影响

目的 探讨海生素(HSS)抗白血病作用及其机制.方法 分别以不同质量浓度(.1～1 000.0 μg/ml)HSS处理白血病耐药细胞K562/ADM,采用MTT法测定细胞增殖情况,免疫细胞化学法检测凋亡相关蛋白Bcl-2、Bax表达,流式细胞仪(FCM)测定凋亡率,Western blot法检测caspase-3表达.结果 HSS在较高质量浓度时可抑制K562/ADM细胞生长,且具有时效和量效性;经HSS处理的K562/ADM细胞呈现凋亡特有的亚G1峰,凋亡比率随HSS质量浓度和时间延长而增高;HSS处理后,K562/ADM细胞中Bcl-2呈阴性表达,Bax呈强阳性表达;caspase-3表达上调.结论 HSS在体外可明显抑制K562/ADM细胞增殖;可能通过下调Bcl-2表达、上调Bax及caspase-3表达诱导K562/ADM细胞凋亡.     

大蒜素对K562细胞增殖抑制和诱导凋亡作用的实验研究

目的:观察大蒜素对体外培养的人白血病细胞系K562细胞增殖抑制及诱导凋亡作用。方法:在体外设定的浓度梯度和作用时间下应用大蒜素处理K562细胞,采用锥虫蓝拒染法计数活细胞数,并计算细胞生长率, Wright-Giemsa染色、光镜观察细胞形态,琼脂糖凝胶电泳测定DNA梯带(DNA,ladder),流式细胞仪检测细胞凋亡。结果:①大蒜素能够抑制K562细胞增殖;②0．1-5．0 mg／L大蒜素可诱导K562细胞凋亡。结论:大蒜素可抑制K562细胞生长,诱导其凋亡。     

香芹芥酚诱导人白血病K562细胞凋亡的研究

目的探讨香芹芥酚对人白血病K562细胞凋亡作用的影响。方法采用不同浓度的香芹芥酚处理体外培养的K562细胞,MTT比色法观察细胞存活率;Hoechst染色法观察细胞凋亡形态学变化,Annexin-V/PI双染色流式细胞术检测细胞凋亡率;Western-blot法检测凋亡相关基因Bcl-2、Bax表达水平的改变。结果人白血病K562细胞存活率随着香芹芥酚作用时间延长和浓度增高而降低（P〈0.05）。香芹芥酚处理K562细胞48 h后出现较典型的细胞凋亡特征形态学改变,Annexin-V/PI双染法显示随着香芹芥酚作用浓度增大,凋亡细胞比例增大。West-ern-blot结果表明,香芹芥酚可以浓度依赖性降低凋亡相关基因Bcl-2的表达和增加Bax基因的表达。结论香芹芥酚具有诱导人白血病K562细胞凋亡的作用,其分子机制可能通过调控Bcl-2、Bax的基因及蛋白水平而诱导凋亡。     

Oridonin-induced apoptosis in leukemia K562 cells and its mechanism

Oridonin, an extract from the Chinese herb Rabdosia rubescens, is currently one of the most important traditional Chinese herbal medicines. Recently oridonin has been reported to have anti- tumor effects in a large variety of malignant diseases. In this study, we investigated the apoptotic inducing effect of oridonin in leukemia K562 cells and its mechanism. Cell growth inhibition was measured using a microculture tetrazolium assay, apoptosis was measured by flow cytometry and electron microscopy as well as by DNA fragmentation analysis. Telomerase activity was measured by TRAP-enzyme- linked immunosorbent assay, and the expression of Bcl-2 and Bax proteins was detected by western blot analysis. The results showed that oridonin could inhibit the proliferation and induce apoptosis on leukemia K562 cells remarkably. Telomerase activity as well as Bcl-2 expression was down- regulated, while Bax expression was up-regulated concurrently, when apoptosis ocurred. We therefore conclude that oridonin demonstrated anti-proliferative and apoptosis-inducing effects on K562 cells in vitro, and that changes in bcl-2 and bax protein levels as well as telomerase activity may play an important role in its mechanism of action.     

毒胡萝卜素诱导K562细胞凋亡及其调控机制的研究

目的探讨毒胡萝卜索（TG）对K562细胞凋亡诱导作用及其调控机制。方法Hoechst33258染色荧光显微镜观察凋亡细胞形态改变;Annexin V—FITC／PI双染检测细胞凋亡率变化;RT—PCR检测bcl-2、bax、bcl—XL 、XIAP、survivin基因表达变化并通过免疫组织化学技术检测其在蛋白质水平的表达。结果TG作用后,K562细胞呈典型的凋亡细胞形态;细胞凋亡率均明显升高（P〈0.05）,且在一定范围内呈浓度和时间依赖性;bax、bcl—XL、XIAP mRNA和蛋白质表达上调,survivin mRNA和蛋白质表达下调,bcl-2／bax比率降低。结论TG可诱导K562细胞发生内质网应激反应性凋亡,其机制可能与Bax表达上调、survivin表达下调有关,bcl-XL XIAP表达上调可能发挥拮抗凋亡的作用。     

High expression of bcl-x(L) in K562 cells and its role in the low sensitivity of K562 to realgar-induced apoptosis

Arsenic compounds (As(2)O(3 )or()As(4)S(4)) have been used successfully for the treatment of acute promyelocytic leukemia (APL) for quite a long time. It has been noticed that the sensitivity to apoptosis induced by As(2)O(3 )varies among various leukemia cells. It was reported by several groups that As(2)O(3) could induce apoptosis in APL-derived NB4 cells at concentrations of 0.5-1 mumol/l, whereas in other leukemia cells like K562, As(2)O(3) has no effects at the same concentration. K562 cells undergo apoptosis only when the concentration of As(2)O(3 )is greater than 2 mumol/l. Another arsenic compound, realgar (As(4)S(4)), a traditional Chinese mineral medicine, has been used to treat APL effectively and demonstrated to have lower toxicity than As(2)O(3). It would be interesting to know whether NB4 and K562 cells will show different sensitivity to realgar as well and if there is a difference, what is the cellular mechanism of it. In our present study, K562 cells were much less sensitive than NB4 cells to apoptosis induced by realgar. We confirm that the expression of bcl-x(L) is significantly higher in K562 cells than that in NB4 cells and is not downregulated upon realgar treatment. K562 cells become sensitive to realgar at clinically acceptable concentrations when bcl-x(L) expression level is downregulated by transfecting bcl-x(L) antisense RNA vector into the cells. Our results suggest that the increased bcl-x(L) expression in K562 cells contributes to its insensitivity to realgar-induced apoptosis.     

Hormonal effects on cell proliferation in a human erythroleukemia cell line (K562)

We have investigated the hormonal responsiveness of K562 cells using a serum-substituted in vitro clonogenic assay. Dexamethasone inhibited colony formation by the K562 cells, and the inhibitory effect could be reversed by progesterone (10(-6) M). Fluoxymesterone caused a prominent enhancement of K562 colony growth, whereas estriol had no effect. Stimulation by triiodothyronine was maximal at 10(-7) M, and the thyroid effect could be abrogated by the beta 2-adrenergic antagonist butoxamine in equimolar concentrations. Using standard tissue culture conditions, the beta-adrenergic agent isoproterenol, but not the alpha catecholamine phenylephrine, enhanced the proliferation of K562 cells. When K562 cells were grown under hormone-depleted conditions, they developed responsiveness to phenylephrine and were no longer stimulated by isoproterenol. DbcAMP and prostaglandins of the E series also caused K562 colony enhancement. Prostaglandin F2 alpha had no effect on cell proliferation. Insulin was an effective stimulant of colony formation of K562 cells, as were human growth hormone and ovine prolacin. Bovine growth hormone had no effect. Our results are consistent with the identificaiton of K562 as an erythroid line, and they indicate that K562 cells respond to endocrine hormones in a manner analogous to normal erythroid progenitors.     

Interferon-alpha suppresses proliferation of chronic myelogenous leukemia cells K562 by extending cell cycle S-phase without inducing apoptosis

We examined the effects of interferon-alpha (IFN-alpha) treatment on the growth, cell cycle, proliferation, and apoptotic parameters as well as adhesive properties and proteome of chronic myelogenous leukemia (CML)-derived K562 cells. IFN-alpha treatment (200 to 600 U/ml, 24 to 72 h) suppressed growth and caused accumulation of K562 cells in the S-phase of cell cycle (increase in S-phase cells by up to 52% in comparison with the untreated controls) at the expenses of cells in G1-phase. No transition of cells to G0-phase occurred as followed from Ki-67 protein determination. Although the level of chimeric gene product, BCR-ABL mRNA coding for BCR-ABL protein with anti-apoptotic properties, decreased by 30%, apoptosis was not triggered as judged from Annexin-V, APO2.7, and TUNEL assays. Adhesion of K562 cells to fibronectin-coated surfaces increased by up to 52% as determined by calcein assay. The proteomic analysis (2-D electrophoresis in combination with mass spectrometry, MALDI-MS) revealed a single protein, ubiquitine cross-reactive protein (UBCR), whose level markedly increased due to IFN-alpha treatment. The ubiquitination-like directed degradation processes may thus play a role in the mechanism of IFN-alpha antiproliferative effects.     

Effects of STI571 and p27 gene clone on proliferation and apoptosis of K562 cells

AIM: To investigate the combined effect of STI571 and p27 gene clone on the regulation of proliferation, cell cycle and apoptosis of K562 cell line. METHODS: p27 gene was obtained by RT-PCR, and its sequence was approved to be correct. Then p27-pcDNA3.1 vector was constructed and transfected into K562 cell line. p27-pcDNA3.1-K562 cell clone was screened by G418 after transfection, p27 protein was identified by Western blot. MTT was used to detect the survival rate of the cell. Flow cytometry was used to detect cell cycle and apoptosis index. RESULTS: The expression of p27 protein could be detected by Western blot in p27-pcDNA3.1-K562 cells. A strong inhibition of cell proliferation was observed in p27-pcDNA3.1 -K562 cells as compared with that of the control (pcDNA3.1 -K562 cells). The cells at G0/G1 phase were significantly increased, and cells at S phase were greatly declined. The apoptosis index was increased greatly after p27-pcDNA3.1-K562 cells were treated with STI571, and survival rate of the cell was markedly declined (0.35-0.58, P<0.05-0.048 vs STI571-K562 cell,0.35-0.72,P<0.01-0.001 vs p27-K562 cell). CONCLUSION: p27 and STI571 have a synergistic action on inhibition of proliferation and induction of apoptosis on K562 cells.     

人ZEB1基因真核表达载体的构建及其对肝癌细胞株HepG2增殖凋亡的影响

目的：探讨ZEB1基因与肝癌的关系,进一步揭示ZEBl基因在肝癌发生发展过程中的作用。方法：利用基因重组技术构建pCI-neo-ZEB1真核表达载体：脂质体介导转染技术转染肝癌细胞系HepG2。采用WesternBlot技术检测重组质粒的转染效率,CCK8比色法测定重组质粒转染对HepG2细胞体外增殖能力的影响,流式细胞术检测重组质粒转染后HepG2细胞凋亡率。结果：重组质粒经Nhel和Xbal双酶切、测序与ZEBl基因序列一致;利用脂质体介导将pCI-neo-ZEB1重组质粒转染HepG2细胞株,经WesternBlot技术检测ZEB1基因在蛋白水平稳定高表达;与对照组比较,人HepG2细胞株转染pCI-neo-ZEB1真核表达载体后细胞增殖能力增强,细胞凋亡率明显降低。结论：成功构建重组质粒Pci-neo-ZEB1并转入肝癌细胞株HepG2后,细胞增殖能力增强,凋亡减少。     

淫羊藿提取物IC163对K562细胞的诱导分化作用观察

目的:观察淫羊藿提取物IC163对K562细胞是否有分化诱导作用。方法:用不同浓度IC163作用于K562细胞6d,通过W-G染色观察细胞形态学变化、细胞内血红蛋白测定、细胞内血红蛋白联苯胺染色和流式细胞术检测膜CD71和CD235a分化抗原4个方面来评价IC163对K562细胞的诱导分化作用。结果:8μmol/L的IC163可明显上调K562细胞膜CD71和CD235a分化抗原的表达,升高细胞内Hb含量,在形态上有趋向红系分化的改变。结论:IC163有诱导K562细胞分化的作用。     

齐墩果酸对K562细胞系VEGF表达影响的实验研究

目的观察齐墩果酸(Oleanolic Acid,OA)对慢性粒细胞白血病系K562细胞中血管内皮生长因子(VEGF)表达的影响。方法采用MTT实验观察OA对体外培养K562细胞增殖抑制作用,用RT-PCR以及Western印迹法研究OA处理后K562细胞中VEGF基因表达的变化。并用ELISA方法检测培养液中VEGF的表达。结果OA能抑制K562细胞生长,呈一定的量效特征;并能抑制K562细胞中VEGF的表达。结论OA通过下调VEGF表达,抑制白血病细胞的增殖。