DNA断端标记法分析HL—60和U937白血病细胞株凋亡

使用DNA断端标记法（TDT法）定量观察了白血病细胞株HL－60和U937对顺氯氨铂，羟基喜树碱，长春新碱3种抗肿瘤药物所发生的凋亡变化。HL－60对顺氯氨铂很敏感。U937对羟基树碱、长春新碱敏感。比较了核酸电泳检测的结果。并首次报道了用TDT法在荧光显微镜下可观察到细胞凋亡的三种不同形态。     

HAG方案促白血病细胞株凋亡的机制

 目的　探讨HAG方案对白血病细胞株HL-60和U937的体外作用效果及机制,为临床急性白血病治疗提供指导。方法　以HL-60及U937为实验模型,体外分为单药组,加阿糖胞苷（Ara-C）、高三尖杉酯碱,二药联合组（HA）和以G-CSF为预激的HAG三药组,分别作用 24、48 h后收集细胞,进行细胞计数,细胞形态观察,CCK-8法检测不同药物的组合对二种细胞株的生长抑制率,流式细胞术检测细胞凋亡标志AnnexinⅤ和PI、细胞分化抗原CD11b、线粒体膜电位JC-1及Caspase-3。结果　G-CSF预激24 h后,S期细胞明显增多（P＜0.05）。经HAG作用48 h后,HL-60和U937细胞数量明显减少,形态观察显示凋亡小体增多,早期凋亡标志AnnexinⅤ明显增高,三药联合组与单药组及两药联合组比较差异有统计学意义（P＜0.05）,且对U937细胞株凋亡作用优于HL-60细胞株。CD11b在三组间表达差异无统计学意义（P＞0.05）。药物作用后HL-60和U937线粒体膜电位崩塌的细胞比例增加,三药组显著高于单药组及对照组差异有统计学意义（P＜0.05）;药物作用后Caspase-3被激活,三药组及单药组与对照组相比Caspase-3的荧光强度显著升高,差异有统计学意义（P＜0.05）。结论　HAG的体外研究证实该方案主要通过降低线粒体膜电位途径从而起到诱导肿瘤细胞凋亡的作用。     

Acetyl derivative of quercetin 3-methyl ether-induced cell death in human leukemia cells is amplified by the inhibition of ERK

Flavonoids are polyphenolic compounds that are ubiquitously in plants and display a vast array of biological activities. Here we have studied the effect of the phenylbenzo-gamma-pyrone-derivative quercetin 3-methyl ether tetracetate (QD), obtained by acetylation of the natural product quercetin 3-methyl ether, on cell viability of human leukemia HL-60 and U937 cell lines. The results show that QD was cytotoxic and induced G2-M phase cell cycle arrest on both cell lines and it was a potent apoptotic inducer on HL-60 cells. QD-induced apoptosis is (i) mediated by caspase activation, since it was prevented by the non-specific caspase inhibitor z-VAD-fmk, (ii) associated with cytochrome c release and (iii) triggered in Bcl-2 over-expressing U937 cells. The treatment of HL-60 and U937 cells with QD also induces the activation of the mitogen-activated protein kinases (MAPKs) pathway, including c-Jun N-terminal kinase, p38 mitogen-activated protein kinase and extracellular signal-regulated kinases (ERK) 1/2. Inhibition of c-Jun N-terminal kinase by SP600125 and of p38 mitogen-activated protein kinase by SB203580 had no influence on QD-mediated apoptosis. In contrast, inhibition of ERK1/2 with the pharmacologic inhibitors U0126 or PD98059, together with QD, resulted in an important enhancement of apoptosis. Cells are sensitized to QD-mediated apoptosis after blocking ERK1/2, which suggests that inhibition of this pathway is a valuable strategy to increase the sensitivity of human leukemia HL-60 cells toward QD.     

beta(2)-microglobulin induces apoptosis in HL-60 human leukemia cell line and its multidrug resistant variants overexpressing MRP1 but lacking Bax or overexpressing P-glycoprotein.

In this study, we examined whether exogenous beta(2)-microglobulin (beta(2)m) can induce apoptosis in the drug sensitive HL-60 leukemia cell line and its drug resistant variants and investigated the molecular mechanism of beta(2)m-induced apoptosis. Our data revealed that beta(2)m is very significantly down-regulated in two multidrug resistant variants of the HL-60 cells: (a) the MRP1-bearing, Bax-deficient HL-60/ADR cell line, and (b) the P-glycoprotein (P-gp) overexpressing HL-60/VCR cell line. However, exogenous beta(2)m induced similar levels of apoptosis in HL-60 cells and these drug resistant variants. beta(2)m-induced apoptosis in HL-60 and HL-60/VCR cells was associated with decreased mitochondrial membrane potential (Deltapsim) but did not affect Deltapsim in HL-60/ADR cells. Surprisingly, cyclosporin A (CsA), a known inhibitor of the mitochondrial permeability transition (MPT) pore, inhibited beta(2)m-induced apoptosis in HL-60/ADR cells but not in HL-60 and HL-60/VCR cells, suggesting that the pro-apoptotic effect of beta(2)m in these cells is not through MPT pore formation. Furthermore, beta(2)m induced the release of cytochrome c and the apoptosis-inducing factor (AIF) from mitochondria in HL-60 and HL-60/VCR cells, but not in HL-60/ADR cells. Additionally, Z-VAD-fmk, a general inhibitor of caspases which inhibited cytochrome c release in HL-60 and HL-60/VCR cells, had no effect on AIF release in any of these cell lines, but inhibited beta(2)m-induced apoptosis in all three cell lines. However, Western blot analysis revealed that caspases-1, -3, -6, -8, and -9 are not activated during beta(2)m-induced apoptosis in these cells. Therefore, beta(2)m-induces apoptosis through an unknown caspase-dependent mitochondrial pathway in HL-60 and HL-60/VCR cells and by a Bax-independent, non-mitochondrial, caspase-dependent pathway in HL-60/ADR cells.     

6,8-Dihydroxy-7-methoxy-1-methyl-azafluorenone Induces Caspase-8- and -9-mediated Apoptosis in Human Cancer Cells

6,8-Dihydroxy-7-methoxy-1-methyl-azafluorenone (DMMA), a purified compound from Polyalthia cerasoidesroots, is cytotoxic to various cancer cell lines. The aims of this study were to demonstrate the type of cancercell death and the mechanism(s) involved. DMMA inhibited cell growth and induced apoptotic death in humanleukemic cells (HL-60, U937, MOLT-4), human breast cancer MDA-MB231 cells and human hepatocellularcarcinoma HepG2 cells in a dose dependent manner, with IC50 values ranging between 20-55 μM. DMMA alsodecreased cell viability of human peripheral blood mononuclear cells. The morphology of cancer cells inducedby the compound after staining with propidium iodide and examined under a fluorescence microscope wascondensed nuclei and apoptotic bodies. Mitochondrial transmembrane potential (MTP) was decreased after 24hexposure in all five types of cancer cells. DMMA-induced caspase-3, -8, and -9 activity was strongly induced inhuman leukemic HL-60 and MOLT-4 cells, while in U937-, MDA-MB231- and HepG2-treated cells there waspartial induction of caspase. In conclusion, DMMA-induced activation of caspase-8 and -9 resulted in executionof apoptotic cell death in human leukemic HL-60 and MOLT-4 cell lines via extrinsic and intrinsic pathways.     

From molecular characteristics to cellular events in apoptosis-resistant HL-60 cells

The ability to induce apoptosis in tumor cells is critical to elicit a positive response to cytotoxic chemo-therapy. In this study, we investigated the effect of the topoisomerase I inhibitors camptothecin and SN-38, known to cause an unusual form of DNA damage, on apoptotic pathways using the leukemic cell line HL-60 and its vincristine-resistant variant HL-60 VCR. Both camptothecin and SN-38 induced high levels of apoptosis in sensitive cells when compared to the multidrug-resistant ones. Interestingly, a higher BCL-2/BAX ratio was observed in HL-60 VCR at the basal state and during treatments. Moreover, these cells which did not exhibit Bcr-abl translocation or bcrp efflux pump, overexpressed topoisomerase I protein. The data provide evidence that BCL-2 protein could protect HL-60 VCR from mitochondrial membrane depolarization and block ROS production in these cells. Finally, our results suggest that dysregulation of proteins associated with DNA replication and apoptotic process could contribute to the multidrug-resistance phenotype.     

Pycnogenol induces differentiation and apoptosis in human promyeloid leukemia HL-60 cells

Pycnogenol, rich of many phytochemicals of medical value, is a commercialized nutrient supplement extracted from the bark of European coastal pine. In this study, we investigated the anti-tumor effects of Pycnogenol on HL-60, U937 and K562 human leukemia cell lines. We found that Pycnogenol inhibited cell proliferation dose- and time-dependently, and the IC(50)s of Pycnogenol on HL-60, U937 and K562 cells were 150, 40 and 100 microg/ml, respectively. When HL-60 cells were incubated with low concentrations of Pycnogenol (50, 100 and 125 microg/ml) for 24 h, a prominent G0/G1 arrest was observed, followed by gradual accumulation of sub-G0/G1 nuclei. At 48 h of treatment, 50-70% of HL-60 cells differentiated, as evidenced by morphological changes, NBT reduction, induction of NSE activity, and increases of cell surface expression of CD11b. However, results from Annexin V/PI staining, DAPI staining and DNA fragmentation assay indicated that Pycnogenol induced HL-60, U937 and K562 cell apoptosis at their respective IC(50)s after 24 h of treatments. Pretreatment of z-DEVD-fmk, a caspase-3 specific inhibitor, not only decreased caspase-3 activity but also reduced the percentage of apoptotic cells induced by Pycnogenol. This indicated that caspase-3 activation was involved in Pycnogenol induced-apoptosis. In conclusion, Pycnogenol induced differentiation and apoptosis in leukemia cells. Our data suggest that Pycnogenol could serve as a potent cancer chemopreventive or chemotherapeutic agent for human leukemia.     

Modulation of anti-apoptosis by endogenous IAP expression in MKN45 human gastric cancer cells

BACKGROUND: This study was designed to clarify differences in apoptotic signal transduction between gastric cancer cells and leukemia cells. MATERIALS AND METHODS: In order to study apoptotic signal transduction of gastric cancer cells, MKN45 gastric cancer cells expressing the wild-type p53 gene and U937 myeloid leukemia cells expressing a mutated p53 gene were prepared. Cisplatin (CDDP) was used to induce apoptosis. We compared apoptotic signal transduction downstream to mitochondria between those two lines. RESULTS: In contrast to U937 cells, MKN45 gastric cancer cells revealed delayed response in release of mitochondrial cytochrome c into the cytosol following caspase 3 activation. In signal pathways downstream of caspase 3 cleavage, of the three substrates detected, poly (ADP-ribose) polymerase (PARP) and PKC (protein kinase c) delta were not activated in MKN45 cells compared with U937 cells, resulting in delayed appearance of DNA ladder formation during CDDP-induced apoptosis. MKN45 constitutively expressed cLAP1, regardless of CDDP treatment, compared with no expression in U937 Drug sensitivity testing showed that MKN45 was more resistant to CDDP than U937 cells. CONCLUSION: We demonstrated that there is a delayed mitochondrial response and incomplete activation of caspase 3 in MKN45 gastric cancer cells compared with U937 leukemia cells. In addition, there was endogenous cLAP1 expression in MKN45 cells, which may be a factor in the presumed anti-apoptotic system in these human gastric cancer cells.     

Terpinen-4-ol Induces Autophagic and Apoptotic Cell Death in Human Leukemic HL-60 Cells

Background: Terpinen-4-ol, a monoterpene, is found as the main component of essential oil extracts frommany plants. In this study apoptotic and autophagic types of cell death induced by terpinen-4-ol and associatedmechanisms were investigated in human leukemic HL-60 cells. Materials and Methods: The cytotoxicity ofhuman leukemic U937 and HL-60 cells was determined by MTT assay. Cytochrome c release, expression of Bax,Bcl-2, Bcl-xl and cleaved Bid were determined by Western blotting. Cell morphology was examined under atransmission electron microscope. LC3-I/II, ATG5 and Beclin-1 levels were detected by immunoblotting. Results:Terpinen-4-ol exhibited cytotoxicity to human leukemic HL-60 but not U937 cells. The apoptotic response toterpinen-4-ol in HL-60 cells was due to induction of cytochrome c release from mitochondria and cleavage of Bidprotein after the stimulation of caspase-8. There was a slightly decrease of Bcl-xl protein level. The characteristiccell morphology of autophagic cell death was demonstrated with multiple autophagosomes in the cytoplasm.At the molecular level, the results from Western blot analysis showed that terpinen-4-ol significantly inducedaccumulation of LC3-I/II, ATG5 and Beclin-1, regulatory proteins required for autophagy in mammalian cells.Conclusions: Terpinen-4-ol induced-human leukemic HL-60 cell death was via both autophagy and apoptosis.     

The novel synthesized 2-(3-(methylamino)phenyl)-6-(pyrrolidin-1-yl)quinolin-4-one (Smh-3) compound induces G2/M phase arrest and mitochondrial-dependent apoptotic cell death through inhibition of CDK1 and AKT activity in HL-60 human leukemia cells

2-Phenyl-4-quinolone series compounds have exhibited growth inhibitory influence on several human cancer cell lines. In this study, we investigated the effects of 2-(3-(methylamino)phenyl)-6-(pyrrolidin-1-yl)quinolin-4-one (Smh-3) on viability, cell cycle and apoptotic cell death which occurred in different leukemia cell lines (HL-60, U937 and K562) in a dose- and time-dependent manner, but which did not obviously impair the viability of normal human umbilical vein endothelial cells (HUVEC) in vitro. The approximate IC50 was 103.26 ± 4.59 nM for a 48 h treatment in HL-60 cells. Cell cycle analysis showed that 100 nM Smh-3 induced signi-ficant G2/M arrest in examined cells. Within 0, 12, 24 and 48 h of treatment, Smh-3 inhibited CDK1 activity and decreased protein levels of CDK1, cyclin A and cyclin B. Smh-3-induced chromatin condensation and DNA fragmentation were determined by DAPI and TUNEL staining. Cell apoptosis was significantly reduced after pretreatment with a pan-caspase inhibitor (Z-VAD-fmk) and results indicated that Smh-3-induced apoptosis was mainly mediated by activation of the caspase cascade in HL-60 cells. Results from colorimetric assays and Western blot analysis indicated that activities of caspase-9, -7 and -3 were promoted in Smh-3-treated HL-60 cells during cell apoptosis. Smh-3-induced apoptosis in HL-60 cells was accompanied by an apparent increase in ROS production, and protein levels of cytosolic cytochrome c, apoptotic protease activating factor-1 (Apaf-1) and apoptosis-inducing factor (AIF). Strikingly, Smh-3 induced apoptosis in HL-60 cells by simultaneously suppressing protein levels of AKT, p-AKT, p-mTOR and p-BAD and inducing BAD protein levels. Taken together, we conclude that Smh-3 acts against leukemia cells in vitro via G2/M phase arrest, down-regulation of AKT activity and induction of mitochondrial-dependent apoptotic pathways.     

Correlation between the Sensitivity to TRAIL and the Expression Level of DR5 on the Surface of Tumor Cells

OBJECTIVE To investigate the correlation between the sensitivity to the tumor necrosis factor- related apoptosis inducing ligand (TRAIL) and the level of expression of the death receptor 5 (DR5) on the surface of tumor cells.METHODS Anti-DR5 mAbs were used to directly detect the level of expression of DR5 on the surface of tumor cells. Using a TRAIL apoptosis kit and flow cytometry, the sensitivity of the tumor cells to TRAIL-induced apoptosis was determined and the correlation between DR5 expression and sensitivity to TRAIL analyzed.RESULTS The expression level of DR5 on the surface of different tumor cells was as follows: 97.9% in U937 cells, 95.1% in Jurkat cells, 93.8% in SW480 cells, 86.2% in HCT116 cells, 64.2% in HL-60 cells, 46.6% in Hela cells and 13.1% in K562 cells. The TRAIL-induced apoptotic rate was 72.6% in U937 cells, 85.2% in Jurkat cells, 78.6% in SW480 cells, 70.2% in HCT116 cells,60.1% in HL-60 cells, 45.4% in Hela cells and 12.3% in K562 cells. Statistical analysis showed there was a significant positive correlation (r=0.997, P<0.001) between DR5 expression and sensitivity to TRAIL.CONCLUSION The sensitivity of tumor cells to TRAIL is related to the level of expression of DR5 on the surface of tumor cells. These results confirm the importance of DR5 expression for induction of apoptosis by TRAIL.     

肿瘤细胞对TRAIL敏感性与其表面DR5表达水平的相关性研究

目的　探讨肿瘤细胞表面DR5表达水平与其对肿瘤坏死因子相关的凋亡诱导配体(TRAIL)敏感性之间的关系。方法　利用抗DR5特异性单克隆抗体 ,采用流式细胞仪技术直接检测不同肿瘤细胞系表面DR5的表达水平 ,并采用TRAIL凋亡检测试剂盒检测肿瘤细胞对TRAIL诱导凋亡的敏感性 ,研究两者之间的关系。结果　不同肿瘤细胞表面DR5的表达水平分别为 :U937细胞97.9%、Jurkat细胞 95 .1%、SW4 80细胞 93.8%、HCT116细胞 86 .2 %、HL 6 0细胞 6 4 .2 %、HeLa细胞4 6 .6 %、K5 6 2细胞 13.1% ;TRAIL诱导的细胞凋亡率分别为 :U937细胞 72 .6 %、Jurkat细胞 85 .2 %、SW4 80细胞 78.6 %、HCT116细胞 70 .2 %、HL 6 0细胞 6 0 .1%、HeLa细胞 4 5 .4 %、K5 6 2细胞 12 .3%。经统计学分析 ,两者之间呈现非常明显的正相关 (r=0 .997,P <0 .0 0 1)。结论　肿瘤细胞对TRAIL的敏感性与其表面DR5表达水平有关 ,表明DR5的表达水平在TRAIL诱导细胞凋亡方面起着十分重要的作用     

The role of cordycepin in cancer treatment via induction or inhibition of apoptosis: implication of polyadenylation in a cell type specific manner

Purpose Most anticancer drugs show their antiproliferative and cytotoxic activity via induction of apoptosis. In the present study we assessed the implication and role of cordycepin, a polyadenylation-specific inhibitor and a well-known chemotherapeutic drug, in apoptosis, induced by the anticancer drug etoposide. Methods For this purpose, a variety of leukemia and lymphoma cell lines (U937, K562, HL-60, Daudi, Molt-4) were treated with the anticancer drugs etoposide and/or cordycepin and assessed for poly(A) polymerase (PAP) activity and isoforms by the highly sensitive PAP activity assay and western blotting, respectively. Induction of apoptosis was determined by endonucleosomal DNA cleavage, DAPI staining, caspase-6 activity assay and ΔΨ_m reduction, whereas cytotoxicity and cell cycle status were assessed by Trypan blue staining, MTT assay and flow cytometry. Results and conclusions The results showed that PAP changes in all cell lines, in response to apoptosis induced by etoposide, in many cases even prior to hallmarks of apoptosis (endonucleosomal cleavage of DNA, ΔΨ_m reduction). A further elucidation to this apoptosis–polyadenylation correlation was added, by cell treatment with cordycepin, resulting in either suppression (U937, K562) or induction (HL-60) of the apoptotic process, according to the cell type. However, inhibition of polyadenylation did not influence the cell lines Daudi and Molt-4 used, where alternative apoptotic pathways are induced through cleavage of DNA into high molecular weight fragments.     

Alkylphosphocholines induce apoptosis in HL-60 and U-937 leukemic cells

Alkylphosphocholines (APC) represent a new group of ether-lipid-related compounds with remarkable activity against transformed cells in vitro and good tolerability in vivo. Their mechanism of action remains unknown. The aim of the present study was to investigate the effects of a series of APC on three human leukemic cell lines: K-562, HL-60, and U-937. The tetrazolium dye-reduction (MTT) assay and cell counting were used to determine the cytotoxicity of the APC used. DNA gel electrophoresis and enzyme-linked immunosorbent assay (ELISA) detection of oligonucleosomes were performed to identify and quantify DNA fragmentation. Electron and phase-contrast microscopy were used to detect morphologic changes specific for programmed cell death. HL-60 and U-937 cells were found to be sensitive, but K-562 cells were relatively resistant to APC exposure. APC with long alkyl chains exerted stronger cytotoxicity than did those with short alkyl chains. DNA fragmentation was found after treatment with APC in HL-60 and U-937 cells but not in K-562 cells. In HL-60 cells the increase in mono- and oligonucleosome formation as measured by ELISA was correlated with the length of the alkyl chains at 14 h of exposure to APC but plateaued at 20 h. The morphologic alterations in HL-60 and U-937 cell lines, such as cell shrinkage, chromatin condensation, and formation of apoptotic bodies, confirmed the induction of apoptosis after APC exposure. It is concluded that programmed cell death plays an important role in the cytotoxicity of APC against certain human leukemic cell lines. The antineoplastic profiles of APC with long alkyl chains render them attractive for further therapeutic application. Received: 1 September 1996 / Accepted 4 July 1997     

Cisplatin (CDDP) specifically induces apoptosis via sequential activation of caspase-8, -3 and -6 in osteosarcoma

Purpose: Osteosarcoma is a common malignant tumor. The first choice of treatment plan for osteosarcoma is chemotherapy. In particular, preoperative chemotherapy is most important in clinical treatment in orthopedics. In these chemotherapies, multiple anticancer drugs such as Adriamycin (ADM), CDDP, cyclophosphamide (CPM), methotrexate (MTX) and vincristine (VCR) are commonly used in combination. Recently, anticancer drugs have been shown to trigger apoptosis in various cancer cells. However, many studies on this topic have been examined using leukemia cell lines, and many kinds of cancer cells established from solid tumor are resistant to the induction of apoptosis by anticancer drugs. So in this study, we examined the effects of the anticancer drugs ADM, CDDP, CPM, MTX and VCR on osteosarcoma cells in vitro. We also examined the signaling pathways of each anticancer drug by studying the induction of apoptosis and activation of caspases in the osteosarcoma cells. Methods: We examined the effects of the anticancer drugs ADM, CDDP, CPM, MTX and VCR, which are used clinically for the treatment of osteosarcoma, on cells of the human osteosarcoma (HOS) cell line. The cytotoxic effects of the anticancer drugs were evaluated using the MTT assay. We used both flow cytometry and activation of caspases to confirm the induction of apoptosis in the HOS cells. To dissect the pathway of the caspase cascade in apoptosis in HOS cells, we used the tetrapeptides YVAD-CHO, DMQD-CHO, VEID-CHO and IETD-CHO, which selectively inhibit caspase-1, -3, -6 and -8, respectively. Results: ADM, CDDP, CPM and VCR, but not MTX, induced death of HOS cells in a dose-dependent manner. CDDP at 10 μM, CPM at 7.5 μM, ADM at 20 μM and VCR at 150 μM caused 80% cell death of HOS cells after 12 h. However, the percentages of apoptotic cells were 5.6% (medium alone), 75.9% (CDDP), 20.0% (CPM), 22.2% (ADM), 20.5% (VCR) and 13.1% (MTX). In addition, direct measurement of caspase-3 activity revealed that CDDP but not the other drugs activated caspase-3 in HOS cells. These analyses revealed that only CDDP induced apoptosis of HOS cells via activation of caspases. Furthermore, DMQD-CHO, VEID-CHO and IETD-CHO inhibited CDDP-induced apoptosis of HOS cells, suggesting that caspase-3, -6 and -8 are involved in the signaling pathway of CDDP-induced apoptosis. In contrast, none of the caspase inhibitors inhibited cell death induced by the other anticancer drugs. Conclusions: This study demonstrates that CDDP specifically induces apoptosis via activation of caspases and the other anticancer drugs induce death of HOS cells via different signaling pathways. It also demonstrates that caspase-8 is a key molecule in the earliest stage of the signaling pathway of CDDP-induced apoptosis of HOS cells, and caspase-3 works downstream of caspase-8. Received: 29 March 1999 / Accepted: 20 July 1999     

二烯丙基二硫作用于HL-60细胞后凋亡相关基因的差异表达

背景与目的:二烯丙基二硫(diallyl disulfide,DADS)对多种肿瘤细胞有促凋亡作用,白血病是儿童最常见的恶性肿瘤,近期研究提示DADS能够在体外诱导人白血病细胞发生凋亡,但其具体作用机制尚不清楚.本实验旨在研究DADS诱导人白血病细胞HL-60凋亡的生物学效应,并探讨其分子机制.方法:运用DNA含量分析、Annexin V/PI双标记流式细胞仪、DNA琼脂糖凝胶电泳以及透射电子显微镜形态学观察等方法来证实细胞凋亡.通过基因芯片检测60 μmol/L DADS作用于HL-60细胞4 h后凋亡相关基因的表达谱,采用RT-PCR技术验证上调基因Fas-L和下调基因Bag-1.结果:15、30、60和120 μmol/L DADS作用于HL-60细胞24 h后,DNA含量分析出现了明显的亚二倍体峰;60 μmol/L DADS作用4、8、12、24 h后,Annexin V/PI双标流式细胞仪检测表明早期凋亡细胞显著增加.60 μmol/L DADS作用24 h后,在DNA琼脂糖凝胶上可见特征性的梯形条带.电子显微镜观察到细胞体积缩小,核浓缩和凋亡小体形成等典型的形态学改变.通过基因芯片检测发现,60 μmol/L DADS作用4 h后有8个凋亡相关基因表达差异显著,选择其中Fas-L和Bag-1两个基因运用RT-PCR技术进行验证,其结果与基因芯片结果一致.结论:DADS能够诱导人白血病细胞HL-60凋亡,这可能是多个基因和多条信号转导通路共同作用的结果.     

Ethanolic extract of fermented Thunb induces human leukemic HL-60 and Molt-4 cell apoptosis via oxidative stress and a mitochondrial pathway

Houttuynia cordata Thunb (HCT) is a medicinal plant of the Saururaceae family which features antimutagenic and antiviral properties. For extraction, the whole plants were fermented or non-fermented with yeast and ethanol then the whole plants were dried, ground and extracted with 95% ethanol or water. The aims of this study were to compare cytotoxic effects, apoptosis induction, and mechanism(s) with the ethanolic and water extracts of fermented and non-fermented HCT. Cytotoxicity was assessed using the MTT assay in human leukemic HL-60, Molt-4 and peripheral blood mononuclear cells (PBMCs). Apoptotic death was characterized by staining with propidium iodide and examined under a fluorescence microscope. Peroxide radical production and reduction of mitochondrial transmembrane potential (MTP) were determined using 2',7'-dichlorohydrofluorescein diacetate and 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, respectively. The expression of caspase-9 was identified by immunoblotting. The ethanolic extract of fermented HCT was cytotoxic to HL-60 >Molt- 4 > PBMCs, to a greater extent than the non-fermented preparation and the number of apoptotic cells was higher. The alcoholic (fermented) extract produced more radicals than the non-fermented in HL-60 cells but the converse was observed in Molt-4 cells. Reduction of MTP was found in HL-60 and Molt-4 cells treated with the alcoholic (fermented) extract and caspase-9 was cleaved dose-dependently in both cells. In conclusion, the alcoholic extract of fermented HCT was more toxic to human leukemic cells than the non-fermented and both cell lines underwent apoptosis via oxidative stress and a mitochondrial pathway.     

十字孢碱促进多柔比星诱导的多药抗药性肿瘤细胞系的凋亡

 【摘要】　目的　明确蛋白激酶C（PKC）活性的抑制是否能促进化疗药物诱导的多药抗药肿瘤细胞系的凋亡。方法　选用口腔鳞癌细胞KB／S及其多药抗药株KB／VCR，常规细胞培养，比较单独或联合PKC抑制剂十字孢碱的情况下，多柔比星（ADM）诱导这2种细胞的凋亡情况。凋亡采用流式细胞术和吖啶橙荧光染色检测，并经电子显微镜观察证实。结果　ADM 0.04 μg／ml，作用36 h有96.68 % KB／S细胞凋亡，作用48 h有64.99 ％的KB／VCR细胞凋亡；将ADM质量浓度增加到0.4 μg／ml和2.0 μg／ml时，KB／VCR细胞凋亡比例分别为69.74 ％和37.18 ％；合用十字孢碱后，凋亡细胞比例分别增加到82.58 ％和47.65 ％，经统计学处理，前者χ 2 = 4.5，P＜0.05；后者χ 2 = 2.2，P＞0.05。这些结果均经电镜和吖啶橙染色证实。结论　耐受凋亡可能是肿瘤细胞多药抗药的机制之一，而PKC抑制剂可解除这种耐受。