萘酰亚胺-多胺缀合物NNINspm通过PI_3 K/Akt信号通路诱导肝癌细胞凋亡

目的探讨新型萘酰亚胺-多胺缀合物NNINspm对多胺转运体的识别及诱导肝癌HepG2细胞凋亡的机制。方法以MTT法检测细胞毒性;流式细胞仪检测细胞周期、凋亡率及线粒体膜电位的变化;高内涵活细胞成像系统检测NNINspm对多胺转运体识别及Akt易位的影响;Western blot检测NNINspm对cytochrome C、14-3-3、Bad、Bcl-xL、mTOR、p70S6K、Cdk4、p27kip1、Akt、Caspase-3、Caspase-9等蛋白表达的影响。结果NNINspm具有良好的多胺转运体识别能力及肿瘤细胞靶向性,其通过抑制Akt磷酸化从而引起一系列的信号分子发生改变,如14-3-3蛋白与Bad解离并与Bcl-xL结合,随后引起cytochromeC释放及caspase-9及caspase-3活化并最终诱导细胞凋亡;此外,NNINspm诱导mTOR和p70S6K脱磷酸化,Cdk4下调及p27kip1上调并最终诱导细胞周期阻滞于G0/G1期。结论NNINspm通过PI3K/Akt信号途径诱导肝癌HepG2细胞凋亡。     

乙酰水杨酸增强多胺衍生物ANISpm抗肝癌作用及其机制研究

探讨乙酰水杨酸增强多胺衍生物ANISpm抗肝癌作用及其作用机制。采用MTT法检测细胞毒性;应用高内涵活细胞成像系统检测细胞内ANISpm含量的变化及对细胞凋亡和线粒体膜电位的影响;采用Western blotting方法检测细胞色素c,精脒/精胺乙酰转移酶,Caspase-3、-8、-9等蛋白表达的变化;应用高效液相色谱法检测细胞内多胺含量的变化。应用H22肿瘤移植模型评价对实体瘤生长的影响。实验结果显示,乙酰水杨酸体内外均具有增强ANISpm抗肝癌的作用,其机制为乙酰水杨酸通过上调肝癌细胞内精脒/精胺乙酰转移酶的活性,降低细胞内多胺含量从而增加了ANISpm的摄取,并通过ANISpm诱导肝癌细胞凋亡。该凋亡作用与ANISpm诱导细胞线粒体膜电位降低,促进细胞色素c释放以及活化Caspase-3、-8、-9等有关。     

三羟基苯甲酸二聚体诱导HL-60细胞凋亡的作用

三羟基苯甲酸二聚体是从菱角中分离出的抗肿瘤单体化合物。本研究主要探讨三羟基苯甲酸二聚体对人早幼粒细胞性白血病细胞株HL-60细胞的抑制作用及诱导其凋亡的分子机制。通过MTT法检测三羟基苯甲酸二聚体对HL-60细胞的增殖抑制作用; 流式细胞仪检测细胞凋亡、细胞内活性氧及线粒体膜电位的变化; 蛋白印迹 技术 ( Western blotting ) 检测胞浆和线粒体细胞色素c水平, 分光光度法测定Caspase-9、Caspase-3蛋白活性。结果发现, 三羟基苯甲酸二聚体显著抑制HL-60细胞的增殖, 其作用呈时间和剂量依赖性。与对照组比较, 三羟基苯甲酸二聚体可增加HL-60细胞内活性氧水平, 降低HL-60细胞线粒体膜电位, 促进线粒体中细胞色素c释放入胞浆, 激活Caspase-9、Caspase-3蛋白。因此三羟基苯甲酸二聚体可能通过线粒体信号传导途径诱导HL-60细胞凋亡。     

华蟾素诱导HL-60细胞凋亡及机制研究

目的：观察华蟾素（cinobufacini）对白血病HL-60细胞的增殖抑制作用和诱导凋亡作用的机制。方法：以HL-60细胞为研究对象，采用MTT法观察细胞增殖作用；Annexin V-FITC／PI双染和吖啶橙／溴乙锭（AO／EB）荧光染色法检测细胞凋亡；罗丹明染色法检测线粒体膜电位；分光光度法检测Caspase-3活性。结果：在0．78～6．25μg·ml^-1，华蟾素能明显的抑制HL-60细胞的增殖；华蟾素作用24h后，AnnexinV阳性的细胞从7．81％增加至66．02％，而且在荧光显微镜下可以明显观察到凋亡细胞；线粒体膜电位下降和Caspase-3活性升高。结论：华蟾素能够抑制HL-60细胞增殖，这种作用与其诱导细胞凋亡破坏线粒体功能和激活Caspase-3有关。     

锰超氧化物岐化酶模拟化合物诱导K562细胞凋亡的机制研究

目的观察锰超氧化物岐化酶模拟化合物(mimics of manganese superoxide dismutase,MnSODm)对人白血病K562细胞凋亡诱导作用,并探讨其分子机制。方法以人白血病K562细胞为靶细胞,四氮唑蓝比色法(MTT法)测定细胞增殖活性;Annexin V/PI双标记和细胞形态学法检测细胞凋亡;RT-PCR检测bcl-2和bax基因mRNA的表达水平;流式细胞术(FCM)测定Bcl-2和Bax蛋白表达水平、线粒体跨膜电位(Δψm)、细胞色素C(Cyt C)释放和Caspase-3活性变化。结果0.5~10mg·mL-1MnSODm明显抑制K562细胞增殖(P<0.01),Annexin V/PI染色显示凋亡细胞明显增多,光学显微镜和透射电镜观察呈现典型的凋亡形态改变;bcl-2基因mRNA和蛋白表达下调,bax基因mRNA和蛋白表达上调,线粒体Δψm降低,Cyt C释放增多,Caspase-3活性增强。结论MnSODm调控Bax/Bcl-2表达,通过线粒体途径诱导K562细胞凋亡。     

新型多胺缀合物NNAMB诱导B16细胞凋亡及分化作用

目的评价新型多胺缀合物NNAMB对B16黑色素瘤细胞诱导凋亡及分化作用。方法以MTT法、台盼蓝拒染法检测细胞活力;Hoechst33258染色观察细胞形态变化;流式细胞仪检测细胞周期变化、凋亡率及线粒体膜电位的变化;酶标仪检测caspase-3、-8、-9的活性及B16细胞内黑色素含量、酪氨酸酶活性等的变化。结果NNAMB在高剂量(>0.1μmol·L-1)下呈现剂量及时间依赖性的抑制B16黑色素瘤细胞的生长、诱导凋亡、降低线粒体膜电位、促进Caspase-3及-9的活化,但caspase-8活性与对照组细胞相比变化差异无显著性;NNAMB在低剂量(<0.1μmol·L-1)下通过增强酪氨酸酶活性,增加黑色素生成等诱导B16细胞分化。结论NNAMB在高剂量下通过线粒体/caspase-9/caspase-3途径诱导B16细胞凋亡;低剂量诱导细胞分化。     

新型蒽醌类衍生物HG251诱导人白血病K562/DOX细胞凋亡的机制

目的探讨新型蒽醌类衍生物HG251诱导K562/DOX细胞凋亡的机制。方法以MTT法检测细胞活力,流式细胞仪检测细胞周期变化、凋亡率、线粒体膜电位的变化,Western blot检测P-gp及凋亡相关蛋白如半胱天冬蛋白酶-3、-8、-9、p53、Bcl-xL、cytochrome C的表达。结果HG251剂量依赖性的抑制K562/DOX细胞的生长、降低线粒体膜电位并诱导其凋亡;上调p53并下调Bcl-xL;诱导半胱天冬蛋白酶-3、-8、-9的活化及cytochrome C的释放,但对P-gp的表达无影响。结论HG251通过干扰p53及Bcl-xL的表达而克服K562/DOX细胞的多药耐药,并通过细胞膜死亡受体途径及线粒体途径诱导其细胞凋亡。     

辛伐他汀通过线粒体途径诱导K562细胞凋亡

目的观察辛伐他汀诱导K562细胞凋亡不同时间的膜电位(Δψm),caspase-3、9和细胞色素C的改变,以推测其凋亡通路。方法采用浓度为20μmol.L-1的辛伐他汀处理K562细胞24、48、72 h,采用流式细胞技术检测细胞凋亡率和线粒体膜电位,分光光度法检测caspase-3、9蛋白活性,免疫组织化学法检测细胞色素C蛋白。结果浓度为20μmol.L-1辛伐他汀作用K562细胞24、48、72 h后,凋亡率分别为(6.1±0.35)%、(14.15±0.42)%(、30.70±0.65)%,随着凋亡率增加线粒体膜电位降低分别为(39.6±4.80)%,(24.4±2.45)%,(6.0±1.62)%;caspase-3、9蛋白活性与对照组相比上调,细胞浆内细胞色素C升高。结论辛伐他汀诱导K562细胞凋亡时线粒体膜电位下降,caspase-3、9活性增高和细胞色素C释放,推测辛伐他汀诱导K562细胞的凋亡可能经过线粒体凋亡途径。     

丙戊酸钠诱导K562细胞凋亡的机制探讨

目的 探讨丙戊酸钠(VPA)诱导K562细胞凋亡的可能机制.方法 将K562细胞分为经VPA 2.0mmol/L处理的实验组(A组)和正常对照组(B组),分别培养24、48、72 h.流式细胞术检测细胞凋亡率和线粒体膜电位改变,分光光度法检测半胱氨酸天门冬氨酸蛋白酶(Caspase)8、Caspase-9蛋白活性.结果 A组细胞凋亡率、细胞线粒体跨膜电位破坏率呈时问依赖性地增加,且明显高于B组(P<0.05);与B组相比,A组不同时间的Caspase-8、Caspase-9活性均上调(P<0.05).结论 VPA诱导K562细胞凋亡的机制可能与线粒体跨膜电位崩溃或死亡途径有关.     

柑橘提取物诺必擂停对K562、HL-60细胞株增殖抑制作用

目的观察柑橘提取物诺必擂停对白血病细胞株K562、HL-60增殖的抑制作用。方法采用MTT法检测诺必擂停对细胞增殖的抑制率,电镜下观察细胞的形态变化。结果诺必擂停对白血病细胞株K562、HL-60的增殖有显著的抑制作用。电镜下可见细胞凋亡的形态学表现。结论柑橘提取物诺必擂停能够明显抑制白血病细胞株K562、HL-60的体外增殖,其机制与诱导K562、HL-60的凋亡有关。     

Cytotoxic and apoptogenic effect of Swietenia mahagoni (L.) Jacq. leaf extract in human leukemic cell lines U937, K562 and HL-60

The apoptogenic activity of Swietenia mahagoni leaf extract (SMLE) was investigated against three human leukemic cell lines – U937, K562 and HL-60. SMLE inhibited cell growth and metabolic activity of the leukemic cells and showed characteristic features of apoptosis. Flow-cytometric analysis showed that SMLE arrested U937 and K562 cell populations in the G2-M phase and the HL-60 cell population in the G1 phase of cell cycle. SMLE induced apoptosis was found to be mediated through mitochondrial intrinsic pathway involving the release of cytochrome c into the cytosol and activation of caspase-9 and caspase-3. Two flavonoids, catechin and quercetin-3-O-glucoside, isolated from SMLE, were found to inhibit the growth and metabolic activity of U937, K562 and HL-60 cells at much lower concentrations thus indicating that these two flavonoids might be the active ingredients responsible for the anti-leukemic activity of SMLE.     

Synthesis,Cytotoxicity, and Cell Death Profile of Polyaminoanthraquinones as Antitumor Agents

Investigation on designed polyaminoanthraquinones revealed that the anthraquinones bearing triamine motifs are generally more potent than their counterparts with diamine or tetramine motifs. Compared with the reference drug mitoxantrone (MTX), 9b and 9c exhibited better inhibitory activity on cancerous HepG2 cells and preferable cell selectivity in the further screen of normal QSG7701 cells, although they were not assimilated by cancer cells via the polyamine transporter. The presence of polyamine motifs elevated the interaction of compounds 9b and 9c with lysosomes and resulted in distinct mode of cell death. 9c and MTX could cause caspases‐dependent HepG2 cell apoptotic death involving in mitochondrial membrane potential (MMP) loss, cytochrome c release, and caspase‐3 activation. However, 9b , which contained only one less methylene group in the polyamine tail, produced cytotoxicity by necrosis. In conclusion, the modification of anthraquinones with polyamines may furnish potent anticancer drug candidates against hepatocellular carcinoma undergoing distinct cell death mechanisms.     

Anti-tumour effects of HL-37, a novel anthracene derivative, in-vivo and in-vitro

Many anthracene derivatives possess excellent anti-tumour activity and are extensively used clinically as anti-tumour agents. However, their clinical use is frequently limited by emergence of multidrug resistance (MDR) in tumour cells. Therefore, new agents with the ability to overcome MDR are needed for cancer treatment. HL-37, a novel anthracene derivative, exhibited potent anti-cancer activity in both drug-sensitive (K562) and multidrug-resistant (K562/DOX) leukaemia cells. Mechanistically, we found that HL-37 was neither a substrate nor an inhibitor of P-glycoprotein (P-gp) and could overcome apoptotic resistance via up-regulation of p53 protein and down-regulation of Bcl-xL protein. In addition, HL-37 also induced K562/DOX cell apoptosis and a decrease in G(0)/G(1) phase. Moreover, reduction of mitochondrial membrane potential, release of cytochrome c and an increased expression of cleaved protein fragment of caspase-3, caspase-9 and caspase-8 were also observed. Importantly, HL-37 was found to be better tolerated and more effective at inhibiting tumour growth than bisantrene in a xenograft mouse model.     

Iso-suillin from the mushroom Suillus flavus induces cell cycle arrest and apoptosis in K562 cell line

Iso-suillin, an isomer of suillin that belongs to the prenylphenol class of fungal derivatives, was isolated from petroleum ether extracts of Suillus flavus. The IC₅₀ value of iso-suillin in K562 cells was 0.87 μM, which was lower than the positive control cisplatin (19.33 μM). Iso-suillin-treated K562 cells exhibited an increased rate of apoptosis, mitochondrial membrane potential (MMP) depolarization, and G0/G1 arrest. Western blot analysis revealed that these cells displayed significantly upregulated expression of several apoptosis-related proteins, including cytochrome c, caspase 9, FADD (Fas-associating protein with a novel death domain), caspase 8, caspase 3, and Bax. Moreover, the expression of two anti-apoptosis proteins, NF-κB and Bcl-2, was downregulated. Inhibitors of caspase 9 and caspase 8 protected the K562 cells from apoptosis. Taken together, our results suggest that iso-suillin induces K562 apoptosis through the mitochondrial and death receptor pathways and that iso-suillin may represent a candidate anti-leukemia treatment.     

Saucernetin-7 isolated from Saururus chinensis induces caspase-dependent apoptosis in human promyelocytic leukemia HL-60 cells

In the present study, we investigated the effect of saucernetin-7 (a biologically active compound isolated from the underground parts of Saururus chinensi) on the induction of apoptosis and the putative pathways of its action in HL-60 human promyelocytic leukemia cells. Saucernetin-7-treated HL-60 cells displayed several features of apoptosis, including DNA fragmentation, DNA laddering by agarose gel electrophoresis, and externalization of annexin-V targeted phosphatidylserine (PS) residues. z-VAD-fmk (a broad-caspase inhibitor) almost completely suppressed saucernetin-7-induced DNA ladder formation, thereby implicating the caspase cascade in the apoptotic process. We also observed that saucernetin-7 caused the activations of caspase-3, -8 and -9, and that it induced Bid cleavage, the mitochondrial translocation of Bax from the cytosol, and cytochrome c release from mitochondria, but it had no effect on Bcl-2 and Bcl-xL levels. Taken together, the present study demonstrates that saucernetin-7 is a potent inducer of apoptosis and that its activity is facilitated by caspase-8 activation, Bid cleavage, Bax translocation to mitochondria, release of cytochrome c into cytoplasm, and subsequently caspase-3 activation, which offers a potential mechanism for the apoptosis-inducing activity of saucernetin-7.     

Riccardin D, a novel macrocyclic bisbibenzyl, induces apoptosis of human leukemia cells by targeting DNA topoisomerase II

We studied the effect of riccardin D, a macrocyclic bisbibenzyl, which was isolated from the Chinese liverwort plant, on human leukemia cells and the underlying molecular mechanism. Riccardin D had a significant antiproliferative effect on human leukemia cell lines HL-60, K562 and its multidrug resistant (MDR) counterpart K562/A02 cells, but showed no effect on the topoisomerase-II-deficient HL-60/MX2 cells, as measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The pBR322 DNA relaxation assay revealed that riccardin D selectively inhibited the activity of topoisomerase II (topo II). The suppression of topo II activity by riccardin D was stronger than that of etoposide, a known topo II inhibitor. After treatment with riccardin D, nuclear extracts of leukemia K562 and K562/A02 cells left the majority of pBR322 DNA in a supercoiled form. Further examination showed that riccardin D effectively induced HL-60, K562 and K562/A02 apoptosis as evidenced by externalization of phosphatidylserine and formation of DNA ladder fragments. The activation of cytochrome c, caspase-9, caspase-3 and cleaved poly ADP-ribose polymerase (PARP) was also enhanced, as estimated by Western blot analysis. By contrast, riccardin D was unable to induce apoptosis in the topoisomerase-II-deficient HL-60/MX2 cells, indicating that the induction of apoptosis by riccardin D was due to the inhibition of topo II activity. In addition, riccardin D was able to significantly decrease P-glycoprotein (P-gp) expression in K562/A02 cells. Taken together, our data demonstrate that riccardin D is a novel DNA topo II inhibitor which can induce apoptosis of human leukemia cells and that it has therapeutic potential for both regular and MDR strains of leukemia cells.     

Trimidox induces apoptosis via cytochrome c release in NALM-6 human B cell leukaemia cells

Trimidox (3,4,5-trihydroxybenzamidoxime) has been shown to reduce the activity of ribonucleotide reductase accompanied by growth inhibition and the differentiation of mammalian cells. Here we examine the induction of apoptosis by trimidox in several human leukaemia cell lines, focusing on the release of cytochrome c and the activation of caspase proteases in the human B cell line NALM-6. Induction of apoptosis by trimidox (300 microM) was detected in NALM-6, HL-60 (premyelocytic leukaemia cells), MOLT-4 (an acute lymphoblastic leukaemia cells), Jurkat (a T-cell leukaemia cells), U937 (expressing many monocyte-like characteristics), and K562 (erythroleukaemia). NALM-6 was most affected by trimidox among leukaemia cells; therefore, we employed NALM-6 cells in the subsequent experiments. The cells showed a time-dependent increase in DNA damage after trimidox (250 microM) treatment. A significant increase in the amount of cytochrome c release was detected after treatment with trimidox. Bcl-2 and Bax protein expressions were not changed by trimidox. Caspase-3 and -9 were activated by incubation with trimidox, whereas caspase-8 was not. Furthermore, trimidox-induced apoptosis was prevented by a broad-spectrum caspase inhibitor, a caspase-3, and a caspase-9 inhibitor, but not by a caspase-8 inhibitor. Inhibition of c-Jun NH2-terminal kinase (JNK) by SP600125 appreciably protected cells from trimidox-induced apoptosis, but no effect inhibition of p38 mitogen-activated protein kinase (MAPK) by SB203580. In contrast, extracellular signal-regulated kinase (ERK) inhibitors U0126 and PD98059 strongly potentiated the apoptotic effect of trimidox. This report shows that the induction of apoptosis by trimidox occurs through a cytochrome c-dependent pathway, which sequentially activates caspase-3 and caspase-9.