Houttuynia cordata Thunb fraction induces human leukemic Molt-4 cell apoptosis through the endoplasmic reticulum stress pathway

Houttuynia cordata Thunb (HCT) is a native herb found in Southeast Asia which features various pharmacological activities against allergy, inflammation, viral and bacterial infection, and cancer. The aims of this study were to determine the cytotoxic effect of 6 fractions obtained from silica gel column chromatography of alcoholic HCT extract on human leukemic Molt-4 cells and demonstrate mechanisms of cell death. Six HCT fractions were cytotoxic to human lymphoblastic leukemic Molt-4 cells in a dose-dependent manner by MTT assay, fraction 4 exerting the greatest effects. Treatment with IC50 of HCT fraction 4 significantly induced Molt-4 apoptosis detected by annexinV-FITC/propidium iodide for externalization of phosphatidylserine to the outer layer of cell membrane. The mitochondrial transmembrane potential was reduced in HCT fraction 4-treated Molt-4 cells. Moreover, decreased expression of Bcl-xl and increased levels of Smac/Diablo, Bax and GRP78 proteins were noted on immunoblotting. In conclusion, HCT fraction 4 induces Molt-4 apoptosis cell through an endoplasmic reticulum stress pathway.     

Arsenic trioxide induces oxidative stress,DNA damage,and mitochondrial pathway of apoptosis in human leukemia (HL-60) cells

Background

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), which accounts for approximately 10% of all acute myloid leukemia cases. It is a blood cancer that is formed by chromosomal mutation. Each year in the United States, APL affects about 1,500 patients of all age groups and causes approximately 1.2% of cancer deaths. Arsenic trioxide (ATO) has been used successfully for treatment of APL patients, and both induction and consolidated therapy have resulted in complete remission. Recently published studies from our laboratory have demonstrated that ATO pharmacology as an anti-leukemic drug is associated with cytotoxic and genotoxic effects in leukemia cells.

Methods

In the present study, we further investigated the detailed molecular mechanism of ATO-mediated intrinsic pathway of apoptosis; using HL-60 cells as a test model. Oxidative stress was assessed by spectrophotometric measurements of MDA and GSH levels while genotoxicity was determined by single cell gel electrophoresis (Comet assay). Apoptosis pathway was analyzed by Western blot analysis of Bax, Bcl2 and caspase 3 expression, as well as immunocytochemistry and confocal imaging of Bax and Cyt c translocation and mitochondrial membrane potential depolarization.

Results

ATO significantly (p < 0.05) induces oxidative stress, DNA damage, and caspase 3 activityin HL-60 cells in a dose-dependent manner. It also activated the intrinsic pathway of apoptosis by significantly modulating (p < 0.05) the expression and translocation of apoptotic molecules and decreasing the mitochondrial membrane potential in leukemia cells.

Conclusion

Taken together, our research demonstrated that ATO induces mitochondrial pathway of apoptosis in HL-60 cells. This apoptotic signaling is modulated via oxidative stress, DNA damage, and change in mitochondrial membrane potential, translocation and upregulation of apoptotic proteins leading programmed cell death.     

丹参多酚酸盐通过线粒体途径诱导人肝癌SMMC-7721细胞的凋亡

目的：研究丹参多酚酸盐(salvianolate)体外诱导人肝癌细胞SMMC-7721凋亡作用及其可能机制。方法：不同质量浓度丹参多酚酸盐(0.5、1、2 mg/ml)与肝癌细胞共培养24 h后,流式细胞仪检测肝癌细胞凋亡,线粒体膜电位试剂盒(JC-1)检测线粒体膜电位变化;比色法测定1.0 mg/ml丹参多酚酸盐作用后肝癌细胞内caspase8、caspase9 及caspase3的活性,流式细胞仪检测培养体系内加入caspase9抑制剂(zLEHDfmk)或caspase3抑制剂(zDEVDfmk)后细胞凋亡率的变化,Western blotting检测肝癌细胞内线粒体凋亡途径相关蛋白Bax、Bcl2表达水平。结果：丹参多酚酸盐显著诱导肝癌细胞SMMC7721凋亡(P<0.05),同时线粒体膜电位随着药物浓度的升高而加剧下降(P<0.05)。1.0 mg/ml 丹参多酚酸盐处理肝癌细胞24 h后caspase-9与caspase-3的活性明显升高(P<0.05),而caspase-8的活性无明显变化(P>0.05);当培养体系内加入caspase-9或caspase3活性抑制剂后,丹参多酚酸盐诱导肿瘤细胞凋亡的作用明显降低(P<0.05)。Western blotting检测显示,丹参多酚酸盐处理组前凋亡蛋白Bax表达明显升高,抗凋亡蛋白Bcl2表达降低。结论：丹参多酚酸盐(0.5~2.0 mg/ml)剂量具有促进肝癌细胞凋亡的作用,且有剂量依赖的趋势,其机制与线粒体凋亡途径有关。     

Apoptosis Induction in Human Leukemic Promyelocytic HL-60 and Monocytic U937 Cell Lines by Goniothalamin

Goniothalamin is an active compound extracted from Goniothalamus griffithii, a local plant found innorthern Thailand. Goniothalamin inhibits cancer cell growth but is also toxic to normal cells. The aims ofthis study were to identify the cytotoxic effect of goniothalamin and the mechanism of cell death in humanHL-60 and U937 cells. Cytotoxicity was determined by MTT assay and cell cycle profiles were demonstratedby staining with propidium iodide (PI) and flow cytometry. Apoptosis was confirmed by staining withannexin V-FITC/propidium iodide (PI) and flow cytometry. Reduction of mitochondrial transmembranepotential was determined by staining with dihexyloxacarbocyanine iodide and flow cytometry and expressionof Smac, caspase-8 and -9 was demonstrated by Western blotting. Goniothalamin inhibited growth ofHL-60 and U937 cell lines. An increase of SubG1 phase was found in their cell cycle profiles, indicatingapoptosis as the mode of cell death. Apoptosis was confirmed by the flip-flop of phosphatidylserine usingannexin V-FITC/PI assay in HL60 and U937 cells in a dose response manner. Furthermore, reduction ofmitochondrial transmembrane potential was found in both cell types while expression of caspase-8, -9 andSmac/Diablo was increased in HL-60 cells. Taken together, our results indicate that goniothalamin-treatedhuman leukemic cells undergo apoptosis via intrinsic and extrinsic pathways.     

Sevoflurane inhibits proliferation, induces apoptosis, and blocks cell cycle progression of lung carcinoma cells

Purpose: Sevoflurane, an inhalational anesthetic, is used extensively during lung cancer surgery. However, the effect of sevoflurane on growth of lung carcinoma cells remains unclear. The purpose of this study is to investigate effects on proliferation, apoptosis, and cell cycling in the A549 human lung adenocarcinoma cell line. Methods: A549 cells were treated with 1.7%, 3.4%, and 5.1 % sevoflurane for 2, 4, and 6 hours. Cell proliferation was evaluated by the MTT assay and colony formation assay. Apoptosis and cell cycle was analyzed by flow cytometry. Expression of X-linked inhibitor of apoptosis protein (XIAP), survivin, Bcl-2, Bax, caspase-3, cyclin A, cyclin B1, and cdc2 was measured by Western blotting. Results: Sgnificant inhibition of cell proliferation and induction of apoptosis were found in A549 cells after sevoflurane treatment. Simultaneously, expression of XIAP and survivin was surpressed, while that of caspase-3 increased significantly, but Bcl-2 and Bax were not altered. Sevoflurane caused cell cycle arrest at the G2/M phase. At the same time, data revealed that cyclin A, cyclin B1, and cdc2 expression was down-regulated after sevoflurane treatment. Conclusion: This study demonstrated that sevoflurane inhibited proliferation, and induced apoptosis in human lung adenocarcinoma A549 cells, associated with down-regulated expression of XIAP and suvivin, and activating caspase-3.     

Rotenone, a mitochondrial NADH dehydrogenase inhibitor, induces cell surface expression of CD 13 and CD38 and apoptosis in HL-60 cells

We previously demonstrated that the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene was overexpressed in human acute myelogenous leukemia (AML) cells. Since this finding suggested that ND2 gene expression was related to myeloid differentiation, we here investigated the effects of rotenone, a specific NADH dehydrogenase inhibitor, on HL-60 cell growth, differentiation and death. Fifty nM rotenone inhibited the growth of HL-60 cells and caused an increase in the cell population in the Gz +M phase. In the quantitative comparison of myeloid antigen, the expression of CD13 and CD38 were relatively increased in the rotenone-treated cells. These findings suggest that the inhibition of NADH dehydrogenase changes the cell cycle and induces some specific surface antigens of HL-60 cells. On the other hand, the expression of ND2 gene remained unchanged after the rotenone treatment, suggesting the rotenone-mediated mitochondrial inhibition did not affect the mitochondrial gene expression. Five pM rotenone strongly inhibited the cellular proliferation. Electron microscopy and an electrophoretic analysis of DNA showed that the majority of the HL-60 cells were induced into typical apoptosis within 24-48 hours. On the basis of this and other studies, we believe that mitochondrial function is directly involved in both cellular differentiation and apoptotic cell death.     

三七皂苷R1通过线粒体相关通路促进白血病细胞株HL-60凋亡

目的:观察三七皂苷(notoginsenoside) R1对白血病细胞株HL-60凋亡的影响,探讨其可能的作用机制.方法:采用MTT法和流式细胞术(Annexin V-FITC双染法)分别检测三七皂苷R1(10、20、40及80 μmol/L)处理HL-60细胞12、24、36及48 h后HL-60细胞的凋亡情况,Western blotting检测HL-60细胞内Bcl-2、Bax及细胞色素C(cytochrome-C,Cyt C)蛋白的表达水平,JC-1染色法观察HL-60线粒体膜电位的变化.结果:MTT和流式细胞术检测显示三七皂苷R1浓度依赖性诱导HL-60细胞的凋亡,且细胞存活率随处理时间的增加而降低;与空白对照组相比,加入三七皂苷R1后细胞中Bcl-2蛋白表达显著减少[(0.45 ±0.03) vs (1.00 ±0.00),P＜0.05]、Bax蛋白表达显著增加[(1.72 ±0.08) vs (1.00±0.00),P＜0.05];Bcl-2/Bax比值减小[(0.21±0.01) vs (1.00±0.00),P＜0.05];线粒体膜电位降低[(0.56±0.09) vs (1.00±0.00),P＜0.05];胞质(cyto)中Cyt-C蛋白表达水平显著下降[(0.42±0.03) vs (1.00±0.00),P＜0.05].结论:三七皂苷R1可显著诱导HL-60细胞凋亡,其作用机制可能是通过线粒体通路促进细胞的凋亡;本实验可为三七皂苷R1用于临床治疗白血病提供实验依据.     

Avemar, a nontoxic fermented wheat germ extract, induces apoptosis and inhibits ribonucleotide reductase in human HL-60 promyelocytic leukemia cells

Avemar (MSC) is a nontoxic fermented wheat germ extract demonstrated to significantly improve the survival rate in patients suffering from various malignancies. We investigated its effects in human HL-60 promyelocytic leukemia cells. After 24, 48, and 72 h of incubation, Avemar inhibited the growth of HL-60 cells with IC₅₀ values of 400, 190, and 160 μg/ml, respectively. Incubation with MSC caused dose-dependent induction of apoptosis in up to 85% of tumor cells. In addition, Avemar attenuated the progression from G2–M to G0–G1 phase of the cell cycle and was also found to significantly reduce the in situ activity of ribonucleotide reductase, the key enzyme of de novo DNA synthesis. We conclude that Avemar exerts a number of beneficial effects which could support conventional chemotherapy of human malignancies.     

Thymoquinone induces apoptosis through activation of caspase-8 and mitochondrial events in p53-null myeloblastic leukemia HL-60 cells

Thymoquinone (TQ), the major biologically active component isolated from a traditional medicinal herb, Nigella sativa Linn, is a potential chemopreventive and chemotherapeutic compound. Despite the promising antineoplastic activities of TQ, the molecular mechanism of its pharmacologic effects is poorly understood. Here, we report that TQ exhibits antiproliferative effect, induces apoptosis, disrupts mitochondrial membrane potential and triggers the activation of caspases 8, 9 and 3 in myeloblastic leukemia HL-60 cells. The apoptosis induced by TQ was inhibited by a general caspase inhibitor, z-VAD-FMK; a caspase-3-specific inhibitor, z-DEVD-FMK; as well as a caspase-8-specific inhibitor, z-IETD-FMK. Moreover, the caspase-8 inhibitor blocked the TQ-induced activation of caspase-3, PARP cleavage and the release of cytochrome c from mitochondria into the cytoplasm. In addition, TQ treatment of HL-60 cells caused a marked increase in Bax/Bcl2 ratios due to upregulation of Bax and downregulation of Bcl2 proteins. These results indicate that TQ-induced apoptosis is associated with the activation of caspases 8, 9 and 3, with caspase-8 acting as an upstream activator. Activated caspase-8 initiates the release of cytochrome c during TQ-induced apoptosis. Overall, these results offer a potential mechanism for TQ-induced apoptosis in p53-null HL-60 cancer cells.     

Dulxanthone A induces cell cycle arrest and apoptosis via up-regulation of p53 through mitochondrial pathway in HepG2 cells

Natural products derived from plants provide a rich source for development of new anticancer drugs. Dulxanthone A was found to be an active cytotoxic component in Garcinia cowa by bioactivity-directed isolation. Studies to elucidate the cytotoxic mechanisms of dulxanthone A showed that dulxanthone A consistently induced S phase arrest and apoptosis in the most sensitive cell line HepG2. Furthermore, p53 was dramatically up-regulated, leading to altered expression of downstream proteins upon dulxanthone A treatment. Cell cycle related proteins, such as cyclin A, cyclin B, cyclin E, cdc-2, p21 and p27 were down-regulated. Some apoptosis correlated proteins were also altered following the drug treatment. Bcl-2 family members PUMA was up-regulated while Bcl-2 and Bax were down-regulated. However, the expression ratio of Bax/Bcl-2 was increased. This resulted in the release of cytochrome C from the mitochondria to the cytosol. Concurrently, Apaf-1 was stimulated with p53 by dulxanthone A. In result, cytochrome C, Apaf-1 and procaspase-9 form an apoptosome, which in turn triggered the activation of caspase-9, caspase-3 and downstream caspase substrates. Lamin A/C and PARP were down-regulated or cleaved, respectively. Moreover, cell cycle arrest and apoptosis in HepG2 cells induced by dulxanthone A were markedly inhibited by siRNA knockdown of p53. In summary, dulxanthone A is an active cytotoxic component of G. cowa. It induces cell cycle arrest at lower concentrations and triggers apoptosis at higher concentrations via up-regulation of p53 through the intrinsic mitochondrial pathway in HepG2 cells. Dulxanthone A is therefore likely a promising preventive and/or therapeutic agent against Hepatoma.     

Study of differentiation of fresh myelogenous leukemic cells by compounds that induce a human promyelocytic leukemic line (HL-60) to differentiate

The human promyelocytic leukemia cell line known as HL-60 can be triggered to mature to functional granulocytes and/or macrophages after exposure to a variety of compounds. The findings have generated enthusiasm for possible therapy of leukemia using compounds that induce leukemic cell differentiation. We investigated whether five compounds known to trigger HL-60 differentiation to granulocytes could trigger the maturation of blast cells from 12 patients with myelogenous leukemia. Maturation was judged by morphology, superoxide production, phagocytosis, expression of Fc receptors, and development of alpha-napthyl acetate esterase activity. The blast cells from most patients showed little morphological, histological or functional maturation after exposure to the various compounds as compared to the blast cells cultured without the compounds. Actinomycin was able to induce significant maturation of leukemic cells of some patients when maturation was analyzed by several statistical methods. Our study suggests that many compounds which trigger differentiation of promyelocytic leukemia cells may not trigger differentiation of less mature myeloid leukemic cells.     

黄芩苷通过Notch通路对人结肠癌SW480细胞增殖和凋亡的影响

目的:探讨黄芩苷能否通过抑制人结肠癌SW480细胞中Notch通路的表达而抑制其增殖并促进其凋亡。方法:MTT法及流式检测术分别检测不同浓度黄芩苷对人结肠癌SW480细胞生长抑制及凋亡的影响；Western Blot法及RT-PCR法分别检测不同浓度黄芩苷对人结肠癌SW480细胞Notch1、Hes-1蛋白和Jagged1基因表达的影响。结果:随着药物剂量的增大，黄芩苷对人结肠癌SW480细胞的抑制率逐步上升；黄芩苷20 μmol/L组细胞凋亡率显著高于对照组；黄芩苷40 μmol/L组细胞凋亡率显著高于黄芩苷20 μmol/L组；黄芩苷20 μmol/L组细胞Notch1、Hes-1蛋白、Jagged1基因表达均显著低于对照组，黄芩苷40 μmol/L组Notch1、Hes-1蛋白、Jagged1基因表达均显著低于黄芩苷20 μmol/L组。结论:黄芩苷能抑制人结肠癌SW480细胞的增殖，促进其凋亡，这种作用可能是通过对细胞中Notch通路的负性调节而实现的。     

内质网激动剂调控PI3K/AKT/mTOR通路诱导人小细胞肺癌NCI-H446细胞凋亡

目的 检测内质网应激能否通过PI3K/AKT/mTOR通路对人小细胞肺癌NCI-H446细胞凋亡产生作用.方法 采用MTT法检测不同浓度衣霉素对人小细胞肺癌NCI-H446的细胞毒性,Annexin V/PI检测药物作用下人小细胞肺癌NCI-H446细胞凋亡情况,Western Blot检测PI3K/AKT/mTOR通路相关蛋白的表达.结果 衣霉素可抑制人小细胞肺癌NCI-H446细胞的活性,且呈时间和浓度依赖性.衣霉素能够激活内质网应激,抑制PI3K/AKT/mTOR信号通路,使PI3K、AKT、mTOR蛋白磷酸化下调,诱导细胞凋亡.结论 内质网激动剂能够调控PI3K/AKT/mTOR通路诱导人小细胞肺癌NCI-H446细胞凋亡.     

三七皂苷R1调控PI3K/AKT/mTOR信号通路诱导人下咽鳞状细胞癌FaDu细胞凋亡和自噬北大核心

目的:探讨三七皂苷R1(notoginsenoside R1,NGR1)对人下咽鳞状细胞癌(hypopharyngeal squamous cell carcinoma,HSCC)FaDu细胞凋亡以及自噬的影响,并对其涉及的信号通路进行研究。方法:75μmol/L、150μmol/L、300μmol/L NGR1作用于FaDu细胞24 h后,采用MTT检测细胞增殖能力;流式细胞术检测细胞凋亡;自噬双标腺病毒检测自噬流;Western blot检测自噬相关蛋白LC3Ⅱ/LC3Ⅰ以及PI3K/AKT/mTOR信号通路相关蛋白表达水平。结果:NGR1能够抑制FaDu细胞的增殖并促进细胞凋亡;NGR1可诱导FaDu细胞自噬,并呈一定浓度依赖性;Western blot结果显示,NGR1作用于Fa Du细胞24 h后,LC3Ⅱ表达明显增加,而p-PI3K、p-AKT、p-m TOR表达相较于Control组明显下降。结论:NGR1可抑制Fa Du细胞增殖,诱导细胞凋亡与自噬,其机制可能与抑制PI3K/AKT/m TOR信号通路有关。     

Role of glycolysis inhibition and poly(ADP-ribose) polymerase activation in necrotic-like cell death caused by ascorbate/menadione-induced oxidative stress in K562 human chronic myelogenous leukemic cells

Among different features of cancer cells, two of them have retained our interest: their nearly universal glycolytic phenotype and their sensitivity towards an oxidative stress. Therefore, we took advantage of these features to develop an experimental approach by selectively exposing cancer cells to an oxidant insult induced by the combination of menadione (vitamin K(3)) and ascorbate (vitamin C). Ascorbate enhances the menadione redox cycling, increases the formation of reactive oxygen species and kills K562 cells as shown by more than 65% of LDH leakage after 24 hr of incubation. Since both lactate formation and ATP content are depressed by about 80% following ascorbate/menadione exposure, we suggest that the major intracellular event involved in such a cytotoxicity is related to the impairment of glycolysis. Indeed, NAD(+) is rapidly and severely depleted, a fact most probably related to a strong Poly(ADP-ribose) polymerase (PARP) activation, as shown by the high amount of poly-ADP-ribosylated proteins. The addition of N-acetylcysteine (NAC) restores most of the ATP content and the production of lactate as well. The PARP inhibitor dihydroxyisoquinoline (DiQ) was able to partially restore both parameters as well as cell death induced by ascorbate/menadione. These results suggest that the PARP activation induced by the oxidative stress is a major but not the only intracellular event involved in cell death by ascorbate/menadione. Due to the high energetic dependence of cancer cells on glycolysis, the impairment of such an essential pathway may explain the effectiveness of this combination to kill cancer cells.     

Regulation of cell cycle progression and apoptosis by beta-carotene in undifferentiated and differentiated HL-60 leukemia cells: possible involvement of a redox mechanism.

Although epidemiologic studies have demonstrated that a high intake of vegetables containing beta-carotene lowers the risk of cancer, recent intervention studies have revealed that beta-carotene supplementation to smokers resulted in a high incidence of lung cancer. We hypothesized that beta-carotene may act as a pro- or anticancerogenic agent by modulating pathways involved in cell growth and that such a modulation may involve a redox mechanism. To test this hypothesis, cell proliferation, apoptosis and redox status were evaluated in undifferentiated and dimethylsulfoxide-differentiated HL-60 cells exposed to beta-carotene. The carotenoid modified cell cycle progression and induced apoptosis in a dose-dependent manner. These effects were more remarkable in undifferentiated cells than in differentiated cells. In accord with these findings, in undifferentiated cells, beta-carotene was more effective in decreasing cyclin A and Bcl-2 expression and in increasing p21 and p27 expression. Neither Bcl-xL nor Bax expression were significantly modified by the carotenoid. From a mechanistic point of view, the delay in cell growth by beta-carotene was highly coincident with the increased intracellular reactive oxygen species production and oxidized glutathione content induced by the carotenoid. Moreover, alpha-tocopherol minimized the effects of beta-carotene on cell growth. These data provide evidence that beta-carotene modulates molecular pathways involved in cell cycle progression and apoptosis and support the hypothesis that a redox mechanism may be implicated. They also suggest that differentiated cells may be less susceptible to the carotenoid than highly neoplastic undifferentiated cells.     

The newly synthesized 2-(3-hydroxy-5-methoxyphenyl)-6,7-methylenedioxyquinolin-4-one triggers cell apoptosis through induction of oxidative stress and upregulation of the p38 MAPK signaling pathway in HL-60 human leukemia cells

The aim of the present study was to discover the signaling pathways associated with 2-(3-hydroxy-5-methoxy-phenyl)-6,7-methylenedioxyquinolin-4-one (YYK1)-induced apoptosis in HL-60 human leukemia cells. YYK1 induced cytotoxic effects, cell morphological changes, decreased the cell number and increased reactive oxygen species (ROS) production and loss of mitochondrial membrane potential (ΔΨm) in HL-60 cells. YYK1-induced apoptosis was confirmed by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Results from colorimetric assays and western blot analysis indicated that activities of caspase-7/-3, caspase-8 and caspase-9 were increased in YYK1-treated HL-60 cells. Western blot analysis showed that the protein levels of extrinsic apoptotic proteins (Fas/CD95, FasL and FADD), intrinsic related proteins (cytochrome c, Apaf-1, AIF and Endo G), the ratio of Bax/Bcl-2 and phosphorylated p38 MAPK were increased in HL-60 cells after YYK1 treatment. Cell apoptosis was significantly reduced after pre-treatment with N-acetylcysteine (NAC; a ROS scavenger) or diphenyleneiodonium chloride (DPI; a NADPH oxidase inhibitor). Blockage of p38 MAPK signaling by SB202190 abolished YYK1-induced Fas/CD95 upregulation and apoptosis in HL-60 cells. We conclude that YYK1 induces both of extrinsic and intrinsic apoptotic pathways via ROS-mediated activation of p38 MAPK signaling in HL-60 human leukemia cells in?vitro.