Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC CANCER RESEARCH  

One promising method to visualize cancer cells is based on the detection of the fluorescent photosensitizer protoporphyrin IX (PpIX) synthesized from 5-aminolevulinic acid (ALA), but this method cannot be used in cancers that exhibit poor PpIX accumulation. PpIX appears to be pumped out of cancer cells by the ABC transporter G2 (ABCG2), which is associated with multidrug resistance. Genistein is a phytoestrogen that appears to competitively inhibit ABCG2 activity. Therefore, we investigated whether genistein can promote PpIX accumulation in human lung carcinoma cells. Here we report that treatment of A549 lung carcinoma cells with genistein or a specific ABCG2 inhibitor promoted ALA-mediated accumulation of PpIX by approximately 2-fold. ABCG2 depletion and overexpression studies further revealed that genistein promoted PpIX accumulation via functional repression of ABCG2. After an extended period of genistein treatment, a significant increase in PpIX accumulation was observed in A549 cells (3.7-fold) and in other cell lines. Systemic preconditioning with genistein in a mouse xenograft model of lung carcinoma resulted in a 1.8-fold increase in accumulated PpIX. Long-term genistein treatment stimulated the expression of genes encoding enzymes involved in PpIX synthesis, such as porphobilinogen deaminase, uroporphyrinogen decarboxylase, and protoporphyrinogen oxidase. Accordingly, the rate of PpIX synthesis was also accelerated by genistein pretreatment. Thus, our results suggest that genistein treatment effectively enhances ALA-induced PpIX accumulation by preventing the ABCG2-mediated efflux of PpIX from lung cancer cells and may represent a promising strategy to improve ALA-based diagnostic approaches in a broader set of malignancies.

DOI： 10.1158/0008-5472.CAN-15-1484

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

To identify physiologically important human N-myristoylated proteins, 90 cDNA clones predicted to encode human N-myristoylated proteins were selected from a human cDNA resource (4,369 Kazusa ORFeome project human cDNA clones) by two bioinformatic N-myristoylation prediction systems, NMT-The MYR Predictor and Myristoylator. After database searches to exclude known human N-myristoylated proteins, 37 cDNA clones were selected as potential human N-myristoylated proteins. The susceptibility of these cDNA clones to protein N-myristoylation was first evaluated using fusion proteins in which the N-terminal ten amino acid residues were fused to an epitope-tagged model protein. Then, protein N-myristoylation of the gene products of full-length cDNAs was evaluated by metabolic labeling experiments both in an insect cell-free protein synthesis system and in transfected human cells. As a result, the products of 13 cDNA clones (FBXL7, PPM1B, SAMM50, PLEKHN, AIFM3, C22orf42, STK32A, FAM131C, DRICH1, MCC1, HID1, P2RX5, STK32B) were found to be human N-myristoylated proteins. Analysis of the role of protein N-myristoylation on the intracellular localization of SAMM50, a mitochondrial outer membrane protein, revealed that protein N-myristoylation was required for proper targeting of SAMM50 to mitochondria. Thus, the strategy used in this study is useful for the identification of physiologically important human N-myristoylated proteins from human cDNA resources.

DOI： 10.1371/journal.pone.0136360

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INFORMA HEALTHCARE  

The induction of leukemic cell differentiation is a hopeful therapeutic modality. We studied the effects of monochloramine (NH2Cl) on erythroleukemic K562 cell differentiation, and compared the effects observed with those of U0126 and staurosporine, which are known inducers of erythroid and megakaryocytic differentiation, respectively. CD235 (glycophorin) expression, a marker of erythroid differentiation, was significantly increased by NH2Cl and U0126, along with an increase in c mRNA levels. Other erythroid markers such as. gamma-globin and CD71 (transferrin receptor) were also increased by NH2Cl and U0126. In contrast, CD61 (integrin beta 3) and CD42b (GP1b alpha) expression, markers of megakaryocytic differentiation, was increased by staurosporine, but did not change significantly by NH 2 Cl and U0126. NH2Cl retarded cell proliferation without a marked loss of viability. When ERK phosphorylation (T202/ Y204) and CD235 expression were compared using various chemicals, a strong negative correlation was observed (r =-0.76). Paradoxically, NH2Cl and staurosporine, but not U0126, induced large cells with multiple or lobulated nuclei, which was characteristic to megakaryocytes. NH 2 Cl increased the mRNA levels of gata1 and scl, decreased that of gata2, and did not change those of pu.1 and klf1. The changes observed in mRNA expression were different from those of U0126 or staurosporine. These results suggest that NH2Cl induces the bidirectional differentiation of K562. Oxidative stress may be effective in inducing leukemic cell differentiation.

DOI： 10.3109/10715762.2013.865840

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

A close relationship between cell death and pathological calcification has recently been reported, such as vascular calcification in atherosclerosis. However, the roles of cell death in calcification by osteoblast lineage have not been elucidated in detail. In this study, we investigated whether cell death is involved in the calcification on osteoblastic differentiation of human bone marrow mesenchymal stem cells (hMSC) under osteogenic culture in vitro. Apoptosis and necrosis occurred in an osteogenic culture of hMSC, and cell death preceded calcification. The generation of intracellular reactive oxygen species, chromatin condensation and fragmentation, and caspase-3 activation increased in this culture. A pan-caspase inhibitor (Z-VAD-FMK) and anti-oxidants (Tiron and n-acetylcysteine) inhibited osteogenic culture-induced cell death and calcification. Furthermore, calcification was significantly promoted by the addition of necrotic dead cells or its membrane fraction. Spontaneously dead cells by osteogenic culture and exogenously added necrotic cells were surrounded by calcium deposits. Induction of localized cell death by photodynamic treatment in the osteogenic culture resulted in co-localized calcification. These findings show that necrotic and apoptotic cell deaths were induced in an osteogenic culture of hMSC and indicated that both necrotic and apoptotic cells of osteoblast lineage served as nuclei for calcification on osteoblastic differentiation of hMSC in vitro. Copyright (c) 2013 John Wiley & Sons, Ltd.

DOI： 10.1002/cbf.2974

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Mitochondrial membrane permeability transition (MPT) plays a crucial role in apoptotic tail shortening during anuran metamor phosis. L-carnitine is known to shuttle free fatty acids (FFAs) from the cytosol into mitochondria matrix for -oxidation and energy production, and in a previous study we found that treatment with L-carnitine suppresses 3, 3', 5-triiodothyronine (T3) and FFA-induced MPT by reducing the level of FFAs. In the present study we focus on acetyl-L-carnitine, which is also involved in fatty acid oxidation, to determine its effect on T3-induced tail regression in Rana rugosa tadpoles and spontaneous tail regression in Xenopus laevis tadpoles. The ladder-like DNA profile and increases in caspase-3 and caspase-9 indicative of apoptosis in the tails of T3-treated tadpoles were found to be suppressed by the addition of acetyl-L-carnitine. Likewise, acetyl-L-carnitine was found to inhibit thyroid hormone regulated spontaneous metamorphosis in X. laevis tadpoles, accompanied by decreases in caspase and phospholipase A2 activity, as well as non-ladder-like DNA profiles. These findings support our previous conclusion that elevated levels of FFAs initiate MPT and activate the signaling pathway controlling apoptotic cell death in tadpole tails during anuran metamorphosis.

DOI： 10.1111/j.1601-5223.2013.02284.x

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Accumulation of protoporphyrin IX (PpIX) in malignant cells is the basis of 5-aminolevulinic acid (ALA)-mediated photodynamic therapy. We studied the expression of proteins that possibly affect ALA-mediated PpIX accumulation, namely oligopeptide transporter-1 and -2, ferrochelatase and ATP-binding cassette transporter G2 (ABCG2), in several tumor cell lines. Among these proteins, only ABCG2 correlated negatively with ALA-mediated PpIX accumulation. Both a subcellular fractionation study and confocal laser microscopic analysis revealed that ABCG2 was distributed not only in the plasma membrane but also intracellular organelles, including mitochondria. In addition, mitochondrial ABCG2 regulated the content of ALA-mediated PpIX in mitochondria, and Ko143, a specific inhibitor of ABCG2, enhanced mitochondrial PpIX accumulation. To clarify the possible roles of mitochondrial ABCG2, we characterized stably transfected-HEK (ST-HEK) cells overexpressing ABCG2. In these ST-HEK cells, functionally active ABCG2 was detected in mitochondria, and treatment with Ko143 increased ALA-mediated mitochondrial PpIX accumulation. Moreover, the mitochondria isolated from ST-HEK cells exported doxorubicin probably through ABCG2, because the export of doxorubicin was inhibited by Ko143. The susceptibility of ABCG2 distributed in mitochondria to proteinase K, endoglycosidase H and peptide-N-glycosidase F suggested that ABCG2 in mitochondrial fraction is modified by N-glycans and trafficked through the endoplasmic reticulum and Golgi apparatus and finally localizes within the mitochondria. Thus, it was found that ABCG2 distributed in mitochondria is a functional transporter and that the mitochondrial ABCG2 regulates ALA-mediated PpIX level through PpIX export from mitochondria to the cytosol.

DOI： 10.1371/journal.pone.0050082

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Accumulation of protoporphyrin IX (PpIX) in cancer cells is a basis of 5-aminolevulinic acid (ALA)-induced photodymanic therapy. We studied factors that affect PpIX accumulation in human urothelial carcinoma cell line T24, with particular emphasis on ATP-binding cassette transporter G2 (ABCG2) and serum in the medium. When the medium had no fetal bovine serum (FBS), ALA induced PpIX accumulation in a time- and ALA concentration-dependent manner. Inhibition of heme-synthesizing enzyme, ferrochelatase, by nitric oxide donor (Noc18) or deferoxamine resulted in a substantial increase in the cellular PpIX accumulation, whereas ABCG2 inhibition by fumitremorgin C or verapamil induced a slight PpIX increase. When the medium was added with FBS, cellular accumulation of PpIX stopped at a lower level with an increase of PpIX in the medium, which suggested PpIX efflux. ABCG2 inhibitors restored the cellular PpIX level to that of FBS(-) samples, whereas ferrochelatase inhibitors had little effects. Bovine serum albumin showed similar effects to FBS. Fluorescence microscopic observation revealed that inhibitors of ABC transporter affected the intracellular distribution of PpIX. These results indicated that ABCG2-mediated PpIX efflux was a major factor that prevented PpIX accumulation in cancer cells in the presence of serum. Inhibition of ABCG2 transporter system could be a new target for the improvement of photodynamic therapy.

DOI： 10.1007/s11010-011-0980-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Calcium ions (Ca2+) are involved in a number of physiological cellular functions including apoptosis. An elevation in intracellular levels of Ca2+ in A23187-treated HL-60 cells was associated,with the generation of both intracellular and extracellular reactive oxygen species (ROS) and induction of apoptotic cell death. A23187-induced apoptosis was prevented by cyclosporin A, a potent inhibitor of mitochondrial permeability transition (NIPT). The generation of extracellular ROS was suppressed by the NADPH oxidase inhibitor diphenylene iodonium, and by superoxide dismutase, but these agents had no effect on A23187-induced apoptosis. In contrast, the blocking of intracellular ROS by a cell-permeant antioxidant diminished completely the induction of MPT and apoptosis. In isolated mitochondria, the addition of Ca2+ induced a typical MPT concomitant with the generation of ROS, which leads to augmentation of intracellular ROS levels. These results indicate that intracellular not extracellular ROS generated by A23187 is associated with the opening of NIPT pores that leads to apoptotic cell death.

DOI： 10.1271/bbb.70304

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Although cAMP protects neuronal cells from various apoptotic stimulations, its mechanism is not fully elucidated. We report here the molecular mechanism of the 6-hydroxydopamine (6-OHDA)-induced apoptosis of pheochromocytoma PC12 cells and its suppression by 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate (pCPT-cAMP), which is a membrane permeable cAMP analog. Treatment of PC12 cells with 6-OHDA resulted in the activation of caspases and apoptosis, as detected by chromatin condensation. 6-OHDA also induced superoxide generation, Bid cleavage and mitochondrial membrane depolarization. In addition, Akt phosphorylation that was favorable to cell survival was decreased and p38 MAPK phosphorylation was increased by 6-OHDA. PC12 cell apoptosis was inhibited by pCPT-cAMP, Z-VAD-fmk (a broad-range caspase inhibitor) and tiron (a superoxide scavenger), although PC12 cell apoptosis was not inhibited by cyclosporine A (an inhibitor of mitochondrial membrane permeability transition). Moreover, pCPT-cAMP promoted Akt phosphorylation, but it did not prevent superoxide generation and mitochondrial membrane depolarization. Conversely, LY294002, an inhibitor of Akt upstream molecule PI3-kinase, enhanced 6-OHDA-induced apoptosis. These results indicated that the 6-OHDA-induced apoptosis of PC12 cells was initiated by superoxide generation followed by caspase cascade activation, which was associated with the suppressed Akt phosphorylation and increased p38 phosphorylation. It is likely that pCPT-cAMP prevented the 6-OHDA-induced apoptosis via activation of the PI3-kinase/Akt pathway without any effect on superoxide generation or mitochondrial membrane depolarization. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.brainres.2006.06.079

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Human cervical cancer is caused by high-risk types of human papillomavirus (HPV) such as HPV16 and HPV18, which possess the E6 and E7 oncogenes, whose concurrent expression is a prerequisite for cancer development and maintaining malignant phenotypes. Silencing these oncogenes is considered to be applicable in molecular therapies of human cervical cancer. However, it remains to be determined whether E6, E7, or both should be silenced to obtain most efficient antitumor activity by an HPV small-interfering RNA (siRNA). Herein, we report two types of siRNAs targeting HPV18 E6, that exerted a negative growth effect on HPV18-positive cervical cancer cells (HeLa and SW756), in part, inducing cell death. One siRNA (Ex-18E6), designed to target both E6-E7 mRNA and its splicing variant, E6*I-E7 mRNA, efficiently knocked down both E6 and E7 expression. The other (Sp-18E6), designed to specifically target E6-E7 mRNA but not E6*I-E7 mRNA, suppressed E6 to a similar level as Ex-18E6; however, it less efficiently inhibited E7 as compared to Ex-18E6. Although both siRNAs induced cell death, Sp-18E6 siRNA induced more prominent cell death than Ex-18E6. Our results suggest that E6-specific suppression may induce more potent anticancer activity than simultaneous E6 and E7 suppression, and that E6-specific targeting is a promising strategy for siRNA-based therapy for HPV-positive cervical cancer.

DOI： 10.1038/sj.cgt.7700891

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Language：English   Publisher：(公社)日本生化学会  

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Mitochondria reduce Cr(VI) to Cr(V) with concomitant generation of reactive oxygen species, thereby exhibiting cytotoxic effects leading to apoptosis in various types of cells. To clarify the mechanism by which Cr(VI) induces apoptosis, we examined the effect of Cr(VI) on Chinese hamster ovary (CHO) cells. Cr(VI) increased cellular levels of ceramide by activating acid sphingomyelinase (ASMase) and inhibiting the phosphorylation of pleckstrin homology domain-containing protein kinase B (Akt). Cr(VI) also induced cyclosporin A- and trifluoperazine-sensitive depolarization of mitochondria and activated caspase-3, 8 and 9, thereby causing fragmentation of cellular DNA. The presence of desipramine, an inhibitor of ASMase, and membrane permeable pCPT-cAMP suppressed the Cr(VI)-induced activation of caspases and DNA fragmentation. These results suggested that accumulation of ceramide play an important role in the Cr(VI)-induced apoptosis of CHO cells through activation of mitochondrial membrane permeability transition.

DOI： 10.1080/10715760410001694035

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We reported previously that alpha-tocopheryl-succinate (VES) induced apoptosis of cultured human promyelocytic leukemia cells (HL-60) (Free Radic Res 2000;33:407-18). We have now studied the effect of cholesteryl-hemisuccinate (CS) on the fate of HL-60 cells to clarify whether CS has an effect similar to that of VES. CS inhibited the growth of HL-60 cells without differentiation to granulocytes and induced DNA fragmentation and ladder formation. CS inhibited the phosphorylation of pleckstrin homology domain-containing protein kinase B (Akt) and initiated the activation of a caspase cascade. CS triggered the reaction leading to the cleavage of Bid and also released cytochrome c (Cyt. c) from mitochondria. In addition, CS induced mitochondrial membrane depolarization and translocation of Bax to mitochondria in HL-60 cells. However, CS did not induce an increase in the concentration of intracellular calcium ions in HL-60 cells. The membrane depolarization, Cyt. c release, and DNA fragmentation were inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), a pan-caspase inhibitor, but not by cyclosporin A, an inhibitor of membrane permeability transition. These results suggested that CS-induced apoptosis of HL-60 cells might be caused by inhibiting Akt phosphorylation following cleavage of Bid through caspase-8 activation and subsequently via an Apaf complex-caspase cascade pathway. (C) 2002 Elsevier Science Inc. All rights reserved.

DOI： 10.1016/S0006-2952(02)01518-6

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It has been reported that inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase suppress cell proliferation and induce apoptosis. One inhibitor which induces apoptosis is mevastatin. However, the molecular mechanism of apoptosis induction is not well understood so the effects of mevastatin on various functions of HL-60 cells were investigated. We confirmed that mevastatin activated caspase-3 by release of cytochrome c (Cyt. c) from mitochondria through a membrane permeability transition mechanism and also induced typical fragmentation and ladder formation of DNA in HL-60 cells. These effects were inhibited by mevalonate, a metabolic intermediate of cholesterol biosynthesis. Mevalonate and geranylgeraniol (GGOH) inhibited DNA fragmentation whereas farnesol (FOH) did not. Mevastatin also induced cell differentiation to monocytic cells via a mevalonate inhibitable mechanism. Furthermore, mevastatin decreased the amount of an isoprenylated membrane bound Rap1 small GTPase concomitant with an increase in cytosolic Rap1 which occurred before apoptosis and differentiation. On the contrary, both mevastatin and geranylgeranylacetone (GGA), which competes with geranylgeranyl pyrophosphate, induced membrane depolarization of isolated mitochondria without swelling and Cyt. c release. These results suggest that mevastatin-induced apoptosis of HL-60 cells might be caused indirectly by activation of the caspase cascade through the modulation of mitochondrial functions and that some relationship between a certain small GTPase molecule, such as Rap1, and mevastatin-induced apoptosis may exist.

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The biochemical properties and specificity of n-3 and n-6 polyunsaturated fatty acids (PUFAs) are not well known. Because PUFAs induce apoptosis of different cells, we studied the effect of various PUFAs, such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosapentaenoic acid (DPA), on the fate of cultured human promyelocytic leukemia cells (HL-60) to elucidate the mechanism of apoptosis and the difference in action between n-3 and n-6 PUFAs. Fairly low concentrations of PUFAs inhibited the growth of HL-60 cells and induced their apoptosis by a mechanism that is sensitive to DMSO, an antioxidant, and z-Val-Ala-Asp(OMe)-fluoromethylketone (z-VAD-fmk), a pan-caspase inhibitor. PUFAs stimulated the generation of reactive oxygen species (ROS) and activated various types of caspase-like proteases, such as caspase-3, -6, -8, and -9, but not caspase-1. In addition, PUFAs triggered the reaction leading to the cleavage of Bid, a death agonist member of the Bcl-2 family, and also released cytochrome c from mitochondria into the cytosol. PUFAs also decreased the mitochondrial membrane potential of intact HL-60 cells. All of these actions of n-3 PUFAs were stronger than those of AA, an n-6 PUFA, although the mechanism is not known. PUFAs stimulate swelling and membrane depolarization of isolated mitochondria in a cyclosporin A-sensitive manner. The results indicated that PUFA-induced apoptosis of HL-60 cells may be caused, in part, by direct action on the cells and by activation of the caspase cascade through cytochrome c release coupled with mitochondrial membrane depolarization. (C) 2001 Elsevier Science Inc. All rights reserved.

DOI： 10.1016/S0006-2952(01)00723-7

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Dibucaine, a local anesthetic, inhibited the growth of promyelocytic leukemia cells (HL-60) without inducing arrest of the cell cycle and differentiation to granulocytes. Typical DNA fragmentation and DNA ladder formation were induced in a concentration- and time-dependent manner. The half-maximal concentration of dibucaine required to induce apoptosis was 100 mu M. These effects were prevented completely by the pan-caspase inhibitor z-Val-Ala-Asp-(OMe)-fluoromethylketone (z-VAD-fmk), thereby implicating the cysteine aspartase (caspase) cascade in the process. Dibucaine activated various caspases, such as caspase-3, -6, -8, and -9 (-like) activities, but nut caspase-1 (-like) activity, and induced mitochondrial membrane depolarization and the release of cytochrome c (Cyt.c) from mitochondria into the cytosol. Processing of pro-caspase-3, -8, and -9 by dibucaine was confirmed by western blot analysis. Bid, a death agonist member of the Bcl-2 family, was processed by caspases following exposure of cells to dibucaine. However, 100 mu M dibucaine scarcely inhibited oxidative phosphorylation, but it induced membrane permeability transition in isolated rat liver mitochondria. Taken together, these data suggest that dibucaine induced apoptosis of HL-60 cells through activation of the caspase cascade in conjunction with Cyt.c release induced by a processed product of Bid and depolarization of the mitochondrial membrane potential. BIOCHEM PHARMACOL 60;7:905-915, 2000. (C) 2000 Elsevier Science Inc.

DOI： 10.1016/S0006-2952(00)00406-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HARWOOD ACAD PUBL GMBH  

Selective induction of apoptosis in tumor cells is important for treating patients with cancer. Because oxidative stress plays an important role in the process of apoptosis, we studied the effect of alpha-tocopheryl succinate (VES) on the fate of cultured human promyelocytic leukemia cells (HL-60). The presence of fairly low concentrations of VES inhibited the growth and DNA synthesis of HL-60 cells, and also induced their apoptosis via a mechanism that was inhibited by z-VAD-fluoromethylketone (z-VAD-fmk), an inhibitor of pan-caspases. VES activated various types of caspases, including caspase-3, 6, 8, and 9, but not caspase-1. VES triggered the reaction leading to the cleavage of Bid, a member of the death agonist Bcl-2 family, and released cytochrome c (Cyt.c) from the mitochondria into the cytosol by a z-VAD-fmk-inhibitable mechanism. VES transiently increased the intracellular calcium level [Ca2+](i) and stimulated the release of Cyt.c in the presence of inorganic phosphate (Pi). However, high concentrations of VES (similar to 100 mu M) hardly induced swelling of isolated mitochondria but depolarized the mitochondrial membrane potential by a cyclosporin A (CsA)-insensitive mechanism. These results indicate that VES-induced apoptosis of HL-60 cells might be caused by activation of the caspase cascade coupled with modulation of mitochondrial membrane function.

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Quercetin inhibits inducible ICAM-1 expression in human endothelial cells through the JNK pathway. Am. J. Physiol. 277 (Cell Physiol. 46): C403-C411, 1999.-The cell adhesion molecule intercellular adhesion molecule-1 (ICAM-1) plays a pivotal role in inflammatory responses. Quercetin (3,3',4',5,7-pentahydroxyflavone), a naturally occurring dietary flavonol, has potent anti-inflammatory properties. The effect of quercetin on ICAM-1 expression induced by agonists phorbol 12-myristate 13-acetate (PMA) and tumor necrosis factor-alpha (TNF-alpha) in human endothelial cell line ECV304 (ECV) was investigated. Quercetin treatment downregulated both PMA- and TNF-alpha-induced surface expression, as well as the ICAM-1 mRNA levels, in ECV cells in a dose-dependent (10-50 l-IM) manner. Quercetin had no effect on PMA- or TNF-alpha-induced nuclear factor-KB (NF-KB) activation. However, under similar conditions a remarkable dose-dependent downregulation of activator protein-1 (AP-1) activation was observed. This decrease in AP-1 activation was observed to be associated with the inhibitory effects of quercetin on the c-Jun NH2-terminal kinase (JNK) pathway. These results suggest that quercetin downregulates both PMA- and TNF-alpha-induced ICAM-1 expression via inhibiting both AP-1 activation and the JNK pathway.

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DOI： 10.1016/S0076-6879(99)01113-1

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Regulation of adhesion molecule expression and function by reactive oxygen species via specific redox sensitive mechanisms have been reported. The effects of clinically safe antioxidants in the regulation of adhesion molecule expression in human endothelial cells (ECV), and adherence of human Jurkat T cells to ECV cells were investigated. The thiol antioxidant, alpha-lipoate, at clinically relevant doses down-regulated phorbol 12-myristate 13-acetate (PMA)-induced adhesion molecule expression and cell-cell adhesion. Inhibition of PMA-induced ICAM-1 and VCAM-1 expression as well as PMA-induced adhesion of Jurkat T-cells to ECV cells by alpha-lipoate was dose dependent (50-250 mu M) The effect was significant for ICAM-1 (p <.01) and VCAM-I (p <.01) expression in cells pretreated with 100 mu M alpha-lipoate compared to PMA-activated untreated cells. Inhibition of PMA-induced adhesion molecule expression and cell-cell adhesion was more pronounced when a combination of antioxidants, alpha-lipoate and alpha-tocopherol, were used compared to the use of either of these antioxidant alone. The regulation of adhesion molecule expression and function by low concentration of antioxidants investigated does not appear to be NF-kappa B regulated or transcription dependent because no change in the mRNA response was observed. Protein kinase C (PKC) has been suggested to regulate PMA-induced adhesion molecule expression by post-transcriptional stabilization of adhesion molecule mRNA. alpha-Lipoate pretreatment did not influence the response of PKC activity to PMA. Oxidants are known to be involved in the regulation of cell adhesion processes. Treatment of ECV cells with PMA induced generation of intracellular oxidants. alpha-lipoate (100 or 250 mu M) treatment decreased PMA-induced generation of intracellular oxidants. The inhibitory effect of low concentration of alpha-lipaote alone or in combination with alpha-tocopherol on agonist-induced adhesion processes observed in this study may be of potential therapeutic value. (C) 1998 Elsevier Science Inc.

DOI： 10.1016/S0891-5849(98)00062-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Regulation of adhesion molecule expression and function by reactive oxygen species via specific redox sensitive mechanisms have been reported. The effects of clinically safe antioxidants in the regulation of adhesion molecule expression in human endothelial cells (ECV), and adherence of human Jurkat T cells to ECV cells were investigated. The thiol antioxidant, alpha-lipoate, at clinically relevant doses down-regulated phorbol 12-myristate 13-acetate (PMA)-induced adhesion molecule expression and cell-cell adhesion. Inhibition of PMA-induced ICAM-1 and VCAM-1 expression as well as PMA-induced adhesion of Jurkat T-cells to ECV cells by alpha-lipoate was dose dependent (50-250 mu M) The effect was significant for ICAM-1 (p <.01) and VCAM-I (p <.01) expression in cells pretreated with 100 mu M alpha-lipoate compared to PMA-activated untreated cells. Inhibition of PMA-induced adhesion molecule expression and cell-cell adhesion was more pronounced when a combination of antioxidants, alpha-lipoate and alpha-tocopherol, were used compared to the use of either of these antioxidant alone. The regulation of adhesion molecule expression and function by low concentration of antioxidants investigated does not appear to be NF-kappa B regulated or transcription dependent because no change in the mRNA response was observed. Protein kinase C (PKC) has been suggested to regulate PMA-induced adhesion molecule expression by post-transcriptional stabilization of adhesion molecule mRNA. alpha-Lipoate pretreatment did not influence the response of PKC activity to PMA. Oxidants are known to be involved in the regulation of cell adhesion processes. Treatment of ECV cells with PMA induced generation of intracellular oxidants. alpha-lipoate (100 or 250 mu M) treatment decreased PMA-induced generation of intracellular oxidants. The inhibitory effect of low concentration of alpha-lipaote alone or in combination with alpha-tocopherol on agonist-induced adhesion processes observed in this study may be of potential therapeutic value. (C) 1998 Elsevier Science Inc.

DOI： 10.1016/S0891-5849(98)00062-8

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Nitrogen monoxide (NO) has diverse physiological roles and also contributes to the immune defense against viruses, bacteria, and other parasites. However, excess production of NO is associated with various diseases such arthritis, diabetes, stroke, septic shock, autoimmune, chronic inflammatory diseases, and atheriosclerosis. Cells respond to activating or depressing stimuli by enhancing or inhibiting the expression of the enzymatic machinery that produce NO. Thus, maintenance of a tight regulation of NO production is important for human health. Phytochemicals have been traditionally utilized in ways to treat a family of pathologies that have in common the disregulation of NO production. Here we report the scavenging activity of Pycnogenol(R) (the polyphenols containing extract of the bark from Pinus maritima) against reactive oxygen and nitrogen species, and its effects on NO metabolism in the murine macrophages cell line RAW 264.7. Macrophages were activated by the bacterial wall components lipopolysaccharide (LPS) and interferon (LFN-gamma), which induces the expression of large amounts of the enzyme nitric oxide synthase (iNOS). Preincubation of cells with physiological concentrations of Pycnogenol(R) significantly decreased NO generation. it was Found that this effect was due to the combination of several different biological activities, i.e., its ROS and NO scavenging activity,inhibition of iNOS activity, and inhibition of iNOS-mRNA expression. These data begin to provide the basis for the conceptual understanding of the biological activity of Pycnogenol(R) and possibly other polyphenolic compounds as therapeutic agents in various human disorders. (C) 1998 Elsevier Science Inc.

DOI： 10.1016/S0891-5849(97)00430-9

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：EDITIONS SCIENTIFIQUES ET MEDICALES ELSEVIER  

EGb 761 has proven beneficial in pathologies related to cerebral and circulatory disorders. Such effects of EGb, 761 extract have been substantiated with placebo-controlled, double-blind clinical trials. Mechanisms underlying the beneficial effects of EGb 761 are only partially understood. One of the main mechanisms seems to be related to the antioxidant properties of EGb 761, which appear to be due to the synergistic action of its major constituents, such as flavonoids, terpenoids and the organic acids. EGb 761 directly scavenges hydroxyl, superoxide, peroxyl and nitric oxide radicals in vitro. EGb 761 also protects against free radical-mediated damage in biological model systems, including ischemia-reperfusion injury of organs and oxidative modification of low-density lipoprotein. EGb 761 inhibits nitric oxide production in macrophages by inhibiting nitric oxide synthase (NOS) activity and regulating inducible-NOS gene expression. EGb 761 down-regulates agonist-induced cell adhesion molecule expression and lymphocyte-endothelial cell adhesion. Exposure of human endothelial cells to EGb 761 resulted in modulation of several mRNA transcripts identified by differential display of mRNA. Such regulatory effects of EGb 761 on nitric oxide metabolism, cell adhesion processes and gene expression may be implicated in its beneficial effect in brain and circulatory disorders.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

Monochloramine derivatives are long lived physiological oxidants produced by neutrophils during the respiratory burst, The effects of chemically prepared monochloramine (NH2Cl) on protein kinase C (PKC) and PKC-mediated cellular responses were studied in elicited rat peritoneal neutrophils and human Jurkat T cells, Neutrophils pretreated with NH2Cl (30-50 mu M) showed a marked decrease in the respiratory burst activity induced by phorbol 12-myristate 13-acetate (PMA), which is a potent PKC activator. These cells, however, were viable and showed a complete respiratory burst upon arachidonic acid stimulation, which induces the respiratory burst by a PKC-independent mechanism, The NH2Cl-treated neutrophils showed a decrease in both PRC activity and PMA-induced phosphorylation of a 47-kDa protein, which corresponds to the cytosolic factor of NADPH oxidase, p47(phox). Jurkat T cells pretreated with NH2Cl (20-70 mu M) showed a decrease in the expression of the interleukin-a receptor a chain following PMA stimulation. This was also accompanied by a decrease in both PKC activity and nuclear transcription factor-kappa B activation, also without loss of cell viability, These results show that NH2Cl inhibits PKC-mediated cellular responses through inhibition of the inducible PKC activity.

DOI： 10.1074/jbc.272.42.26247

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS AUST  

Bio-Normalizer, a natural health food supplement prepared from Carica papaya and some other medicinal plants was investigated to determine its effects on cellular nitric oxide (nitrogen monoxide, NO) production and inducible nitric oxide synthase (iNOS) expression. Bio-Normalizer upregulated interferon (IFN)-gamma-induced NO production by macrophages in a dose-dependent manner. Such an effect of Bio-Normalizer on NO production was not due to changes in the activity of iNOS. Reverse transcription-polymerase chain reaction analysis revealed that the levels of iNOS mRNA were augmented by treatment of the cells with Bio-Normalizer and IFN-gamma. The ability of Bio-Normalizer to augment IFN-gamma-induced iNOS mRNA expression was independent of any changes on the mRNA stability. Treatment of cells with Bio-Normalizer alone did not affect NO production by macrophages. Tumor necrosis factor-alpha and interleukin-1 beta are involved in the induction of iNOS gene as well as the immune system. Bio-Normalizer augmented the mRNA expression of these cytokines in the presence of IFN-gamma. This suggests that Bio-Normalizer is not directly involved in the expression of iNOS, but shows synergistic interaction with IFN-gamma to induce NO synthesis.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The present study was conducted to evaluate the effect of Ginkgo blloba extract (EGb 761) on the synthesis of nitric oxide (NO) induced by lipopolysaccharide (LPS) plus interferon-gamma (IFN ?I) in the mouse macrophage cell line RAW 264.7. EGb 761 inhibited nitrite and nitrate production, taken as an index for NO, in a concentration-dependent fashion. The IC50 for inhibition of nitrite production by activated macrophages was about 100 mu g/mL EGb 761, The inducible NO synthase (iNOS) enzyme activity of cytosolic preparations from activated RAW 264.7 cells was inhibited by treatment with EGb 761. In addition, reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the expression of iNOS mRNA in activated macrophages was suppressed by high concentrations of EGb 761. However, NF-KB DNA binding activity induced by activation with LPS/IFN-gamma was not inhibited by EGb 761. These findings indicate that not only does EGb 761 directly act as an NO scavenger but also, that it inhibits NO production in LPS/IFN-gamma-activated macrophages by concomitant inhibiyion of induction of iNOS mRNA and the enzyme activity of iNOS. Thus, EGb 761 may act as a potent inhibitor of NO production under tissue-damaging inflammatory conditions. (C) 1997 Elsevier Science Inc.

DOI： 10.1016/S0006-2952(96)00873-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOS PRESS  

Lipoic acid (thiotic acid) is being used as a dietary supplement, and as a therapeutic agent, and is reported to have beneficial effects in disorders associated with oxidative stress, but its mechanism of action remains unclear. We present evidence that lipoic acid induces a substantial increase in cellular reduced glutathione in cultured human Jurkat T cells, human erythrocytes, C6 glial cells, NB41A3 neuroblastoma cells, and peripheral blood lymphocytes. The effect depends on metabolic reduction of lipoic acid to dihydrolipoic acid. Dihydrolipoic acid is released into the culture medium where it reduces cystine. Cysteine thus formed is readily taken up by the neutral amino acid transport system and utilized for glutathione synthesis. By this mechanism lipoic acid enables cystine to bypass the x(c)(-) transport system, which is weakly expressed in lymphocytes and inhibited by glutamate. Thereby lipoic acid enables the key enzyme of glutathione synthesis, gamma -glutamylcysteine synthetase, which is regulated by uptake-limited cysteine supply, to work at optimum conditions. Flow cytometric analysis of freshly prepared human peripheral blood lymphocytes, using monobromobimane labeling of cellular thiols, reveals that lipoic acid acts mainly to normalize a subpopulation of cells severely compromised in thiol status rather than to increase thiol content beyond physiological levels. Hence lipoic acid may have clinical relevance in restoration of severely glutathione deficient cells.

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Lipoic acid (thiotic acid) is being used as a dietary supplement, and as a therapeutic agent, and is reported to have beneficial effects in disorders associated with oxidative stress, but its mechanism of action remains unclear. We present evidence that lipoic acid induces a substantial increase in cellular reduced glutathione in cultured human Jurkat T cells, human erythrocytes, C6 glial cells, NB41A3 neuroblastoma cells, and peripheral blood lymphocytes. The effect depends on metabolic reduction of lipoic acid to dihydrolipoic acid. Dihydrolipoic acid is released into the culture medium where it reduces cystine. Cysteine thus formed is readily taken up by the neutral amino acid transport system and utilized for glutathione synthesis. By this mechanism lipoic acid enables cystine to bypass the x(c)(-) transport system, which is weakly expressed in lymphocytes and inhibited by glutamate. Thereby lipoic acid enables the key enzyme of glutathione synthesis, gamma -glutamylcysteine synthetase, which is regulated by uptake-limited cysteine supply, to work at optimum conditions. Flow cytometric analysis of freshly prepared human peripheral blood lymphocytes, using monobromobimane labeling of cellular thiols, reveals that lipoic acid acts mainly to normalize a subpopulation of cells severely compromised in thiol status rather than to increase thiol content beyond physiological levels. Hence lipoic acid may have clinical relevance in restoration of severely glutathione deficient cells.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS  

We observed that protein (bovine serum albumin) carbonyl content increases upon hypochlorite oxidation, and this increase is inhibited in a concentration dependent manner in the presence of hypochlorite scavengers. Based on this observation, we tested whether some known hypochlorite scavengers (lipoic acid, cysteine, and glutathione) and some other antioxidants (uric acid, ascorbic acid, alpha-tocopherol, and probucol) could prevent protein carbonyl formation. N-acetylcysteine, dihydrolipoic acid, cysteine, and glutathione (reduced form, GSH), which otherwise could not be tested in a previously reported 5-thio-2-nitro-benzoic acid test system, were successfully evaluated in our assay. The hypochlorite scavenging capacity of different compounds, compared by determining the IC50 (concentration which produces 50% inhibition), showed that the compounds tested have the following potency: dihydrolipoic acid > GSH, N-acetylcysteine > cysteine > S-methyl glutathione > lipoic acid, ascorbic acid > cystine, GSSG, and uric acid. No scavenging ability was observed for either alpha-tocopherol or probucol. (C) 1996 Academic Press, Inc.

DOI： 10.1006/abbi.1996.0130

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We previously reported that phorbol 12-myristate 13-acetate (PMA)-induced superoxide (O-2(.-)) generation of neutrophils was inhibited by hypericin, a photosensitizing pigment found in St, Johnswort (herb Hypericin triquetrifolium Turra), via a mechanism involving protein kinase C (PKC). To obtain further insights into the mechanism of inhibition, the effects of hypericin on stimulation-dependent O-2(.-) generation and related enzymes of neutrophils were investigated, Hypericin inhibited O-2(.-) generation of neutrophils induced by PKC-dependent and -independent stimuli in a ligand concentration-dependent manner. Oxygen was required for the light-dependent inhibition by hypericin. NADPH oxidase activity in a cell-free system and TNF-alpha-induced tyrosyl phosphorylation of neutrophil proteins were also inhibited by hypericin in a concentration- and light-dependent manner. However, tyrosine kinase of p60(sre), an enzyme not bound to a membrane, was not inhibited either in the light or in the dark, Oxygen uptake of neutrophils by photosensitization with hypericin resulted in the formation of singlet oxygen (O-1(2)), O-2(.-), and hydroxyl radical (. OH) and enhanced lipid peroxidation. The formation of O-1(2) was inhibited by azide, a quencher of O-1(2), but not by desferrioxamine (DSF), a ferric ion chelator, By contrast, both generation of . OH and lipid peroxidation were inhibited by DSF but not by azide. Furthermore, PMA-induced O-2(.-) generation inhibited by hypericin partially recovered in the presence of azide but not DSF. These results suggested that the light-dependent inhibition of O-2(.-) generation by hypericin might be due to inhibition of tyrosine kinase, PKC, and NADPH oxidase via an oxygen-dependent mechanism, possibly through both Type I and II photosensitization mechanisms. (C) 1995 Academic Press, Inc.

DOI： 10.1006/abbi.1995.9956

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Bio-Catalyzer alpha . rho No. 11 (Bio-Normalizer), a natural health food product prepared by yeast fermentation of medicinal plants, has been recently reported to posses antioxidant properties. To better define its antioxidant action, we investigated the effects of orally supplemented Bio-Normalizer on oxidative damage in the rat heart. Hearts were isolated from control or Bio-Normalizer supplemented animals and 1) exposed to ischemia-reperfusion using the Langendorff technique, or 2) homogenized and exposed to peroxyl radicals generated from (2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN). During reperfusion following 40 minutes of ischemia, leakage of lactate dehydrogenase from hearts isolated from Bio-Normalizer supplemented rats was significantly lower than from hearts of control animals. Furthermore, lower levels of AMVN-induced accumulation of thiobarbituric acid reactive substances and of protein carbonyl derivatives were measured in homogenates prepared from hearts isolated from Bio-Normalizer supplemented rats than in samples from control animals. Our findings confirm an antioxidant action of Bio-Normalizer and show that it protects the heart against ischemia-reperfusion induced damage.

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Blepharismin is an endogenous photosensitizing pigment found in the protozoan Blepharisma. This pigment inhibited the generation of superoxide anion (O(2)(r)adical anion) in neutrophils not only via a diacylglycerol-induced protein kinase C (PKC)-dependent reaction but also by an arachidonate-induced PKC-independent reaction. The inhibition was light and concentration dependent for both reactions. Light-activated inhibition was strong at wavelengths between 520 and 570 nm but not above 610 nm. PKC activity in neutrophils and from rat brain was inhibited by blepharismin in a light- and concentration-dependent manner. Moreover, arachidonate-activated NADPH oxidase activity in a cell-free system was also inhibited by the pigment in a light- and concentration-dependent manner. These results suggest that blepharismin inhibits NADPH oxidase activation through the non-specific inhibition of Various membrane-bound enzymes and that this inhibition may also be correlated with that of PKC.

DOI： 10.1016/0006-2952(94)00409-F

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Hypericin, a photosensitizing plant pigment, has antiretroviral activity. When exposed to light, the inhibition of Friend leukemia virus (FLV)-induced splenomegaly by hypericin was increased. The ID50 was decreased to less than 2.5 mu g/mouse by exposure to tungsten light (29 X 10(-3) W/cm(2) for 3 min). This pigment inhibited phorbol 12-myristate 13-acetate (PMA)-activated protein kinase C of rat brain in a light- and concentration-dependent manner. The ID50 of hypericin and the light intensity for inhibition of PKC were 0.1 mu M under a constant light of 29 X 10(-3) W/cm(2) for 3 min and 5 X 10(-3) W/cm(2) in the presence of 1 mu M hypericin for 3 min, respectively. The PMA-induced respiratory burst of neutrophils was inhibited in the light but stimulated in the dark by hypericin. The ID50 for inhibition of the respiratory burst was similar to that for inhibition of PKC. These results suggest that hypericin might inhibited PKC-mediated processes of intact cells, including PMA-induced superoxide generation of neutrophils by some light-dependent mechanism, and that this mechanism might underlie its light-dependent inhibition of FLV infection. (C) 1995 Academic Press, Inc.

DOI： 10.1006/abbi.1995.1065

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Alpha-tocopherol but not 2-carboxy-2,5,7,8-tetramethyl-6-chromanol (trolox or CTMC) and 2,2,5,7,8 pentamethyl-6-hydroxy chromane (PMC), derivatives of cx-tocopherol, inhibited the superoxide (O-2(-)) generation of rat peritoneal neutrophils (RPMN) induced by phorbol 12-myristate 13-acetate (PMA). ID50 for neutrophils obtained from the peritoneal cavity of rat and guinea pig was about 1 mu M. This concentration, however, was much lower than that for the inhibition of PMA-activated phospholipid-dependent protein kinase (PKC) (ID50 = 30 mu M). The alpha-tocopherol sensitive O-2(-) generation was also observed in neutrophils induced by dioctanoylglycerol (diC(8)) and calcium ionophore A23187 but not by formylmethionyl-leucyl-phenylalanine (FMLP), opsonized zymosan (OZ) and sodium dodecyl sulfate (SDS). The pattern of inhibition by alpha-tocopherol was quite similar to that of staurosporine, a specific inhibitor of PKC. The alpha-tocopherol content of RPMN was 12 ng/10(6) cells and a linear increase to 200 ng/10(6) cells by addition of alpha-tocopherol to the cell suspension corresponded with an increased inhibition of O-2(-) generation. These results indicate that both the chemical structure and the content of alpha-tocopherol might be important factors in O-2(-) generation by neutrophils.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSIOL CHEM PHYSICS MED NMR  

It is now generally accepted that human tumor necrosis factor-alpha(hTNF-alpha) affects not only tumor cells but also normal cells, providing critical tissue damage, hTNF-alpha also enhanced the response of polymorphonuclear neutrophils (PMN) by its priming action and resulted in the increased generation of active oxygen which in turn may be responsible for the tissue injury. Seeking a conventional drug to attenuate the cytolytic activity of tumor necrosis factor (TNF-alpha) and thereby prevent excessive tissue injury, we focused on the cytolytic action of hTNF-alpha against L929 cells, which are sensitive to TNF-alpha, and found that flecainide acetate [N-(2-piperidylmethyl) 1,5-bis-(2,2,2 trifluoroethoxy) benzamide acetate] inhibited specifically the cytolytic action of hTNF-alpha against L929 cells. Flecainide acetate also specifically inhibited the priming action of hTNF-alpha which enhance the formylmethionyl-leucyl-phenylalanine (FMLP)-induced receptor-mediated superoxide (O-2(.)-) generation of human peripheral polymorphonuclear neutrophils (hPMN). The ID50 values for hTNF-alpha induced cytotoxicity in L929 cells and hTNF-alpha-primed FMLP-induced O-2(.)- generation of hPMN were 30 and 50-60 mu M, respectively. However, the drug does not inhibit the FMLP- or phorbol myristate acetate (PMA)-induced O-2(.)- generation of nonprimed hPMN and has a weak cytotoxic effect on L929 cells. From these results, it is concluded that flecainide acetate suppressed specifically the action of hTNF-alpha.

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Receptor-mediated superoxide (O2-.)-generation in human peripheral neutrophils (HPPMN) is enhanced by various priming agents, such as granulocyte colony stimulating factor (G-CSF) and tumor necrosis factor (TNF-alpha). We previously reported that this enhancement occurred in parallel with the priming agent-induced increase in protein tyrosyl phosphorylation which is sensitive to tyrosine kinase (TK) inhibitors [Akimaru K. et al. Arch. Biochem. Biophys. 298.703, 1992]. We describe here that nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin and aspirin, modulate the priming and tyrosine phosphorylation of HPPMN. The enhancement by TNF-alpha of formylmethionyl-leucyl-phenylalanine (FMLP)-induced O2-. generation was not inhibited by 5 muM azide, whereas that of FMLP-induced luminol chemiluminescence (LCL) was sensitive. Enhancement of FMLP-induced O2-. generation and LCL by priming agents was inhibited by both aspirin and indomethacin in a concentration dependent manner. This inhibition by the NSAIDs was much stronger than that for FMLP-induced O2-. generation without priming. The half-inhibition dose of indomethacin and aspirin were 50 muM and 1.5 mM, respectively. The priming-induced enhancement of tyrosyl phosphorylation of some neutrophil proteins, such as that of 108 and 115 kDa, was also inhibited by aspirin and indomethacin in a dose-dependent manner. However, dose dependent inhibition of the enhanced O2-. generation by the NSAIDs was not completely similar to that of enhanced tyrosyl phosphorylation. However, PKC-mediated O2-. generation, which has little sensitivity to TNF-alpha or G-CSF, was rather stimulated by the NSAIDs. These findings suggest that aspirin and indomethacin inhibit also the early steps of neutrophil activation as reflected by their ability to inhibit priming and the related tyrosyl phosphorylation of neutrophil proteins.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC CELL BIOLOGY  

Receptor-mediated superoxide (O2)-generation and tyrosyl phosphorylation of neutrophil proteins, such as 58, 65, 84, 108 and 115 kDa, were enhanced by priming cells with granulocyte colony stimulating factor (G-CSF) [Akimurs, K. et al. Arch. Biochem. Biophys. 298: 703-709, 1992]. To elucidate the possible involvement of tyrosyl phosphorylation of neutrophil proteins in the enhancing mechanism Of O2 generation, the effect of cepharanthine, a biscoclaurine alkaloid that inhibits phorbol 12-myristate 13-acetate (PMA)- and receptor-mediated 02 generation, on the priming of human peripheral neutrophils (HPPMN) was studied. Both enhancement of formyl-methyonyl-leucyl-phenylalanine (FMLP)-mediated 02 generation and tyrosyl phosphorylation of some neutrophil proteins, i.e., 115, 108 and 84 kDa proteins, by HHPMN after treatment with G-CSF were strongly inhibited by cepharanthine in a concentration- and treatment-time-dependent manner. In contrast, inhibition of PMA-mediated 02 generation by cepharanthine was weak and independent of treatment time. These results suggest that cepharanthine might inhibit the priming step of neutrophil activation concomitantly with its inhibition of the tyrosyl phosphorylation of some neutrophil proteins that might underlie the mechanism for priming of neutrophils with G-CSF.

DOI： 10.1247/csf.17.385

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Upon stimulation by various ligands, freshly isolated human peripheral neutrophils (PMN) respond in a variety of ways, such as superoxide (O2-) generation, phagocytosis, enzyme release, migration etc. Chemotactic peptide formylmethionyl-leucyl-phenylalanine (FMLP) and opsonized zymosan activate neutrophils by a receptor-mediated mechanism, while phorbol myristate acetate and dioctanoylglycerol activate the cells by a mechanism involving Ca2+- and phospholipid-dependent protein kinase (PKC). Receptor-mediated but not PKC-mediated O2- generation in PMN was enhanced by the priming of recombinant human granulocyte colony Stimulating factor (G-CSF). FMLP-dependent luminol chemiluminescence was also enhanced by G-CSF. However, no appreciable enhancement was observed in FMLP-induced intracellular calcium ion concentration ([Ca2+]i). Enhancement of FMLP-induced generation of O2- by G-CSF was inhibited by genistein or alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK), and was stimulated by staurosporine and 1-(5-isoquinolinesulfonyl)-3-methyl-piperazine (H-7), inhibitors of PKC. The ED50 values of genistein and ST 638 for the inhibition of the FMLP-induced O2- generation from G-CSF were 0.5 and 5 muM, respectively. In contrast, O2- generation by PKC activation without G-CSF priming was inhibited by stauroporine and H-7, but was stimulated by genisten and ST 638. These results suggested that the enhancing effect of G-CSF on receptor-mediated generation of the O2- might be regulated by protein kinases, such as TK and PKC, and that the TK inhibitor selectively inhibited the G-CSF-primed receptor-mediated O2- generation of neutrophils.

DOI： 10.1016/0006-2952(92)90366-Q

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Upon stimulation by various ligands, freshly isolated human peripheral neutrophils (PMN) respond in a variety of ways, such as superoxide (O2-) generation, phagocytosis, enzyme release, migration etc. Chemotactic peptide formylmethionyl-leucyl-phenylalanine (FMLP) and opsonized zymosan activate neutrophils by a receptor-mediated mechanism, while phorbol myristate acetate and dioctanoylglycerol activate the cells by a mechanism involving Ca2+- and phospholipid-dependent protein kinase (PKC). Receptor-mediated but not PKC-mediated O2- generation in PMN was enhanced by the priming of recombinant human granulocyte colony Stimulating factor (G-CSF). FMLP-dependent luminol chemiluminescence was also enhanced by G-CSF. However, no appreciable enhancement was observed in FMLP-induced intracellular calcium ion concentration ([Ca2+]i). Enhancement of FMLP-induced generation of O2- by G-CSF was inhibited by genistein or alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK), and was stimulated by staurosporine and 1-(5-isoquinolinesulfonyl)-3-methyl-piperazine (H-7), inhibitors of PKC. The ED50 values of genistein and ST 638 for the inhibition of the FMLP-induced O2- generation from G-CSF were 0.5 and 5 muM, respectively. In contrast, O2- generation by PKC activation without G-CSF priming was inhibited by stauroporine and H-7, but was stimulated by genisten and ST 638. These results suggested that the enhancing effect of G-CSF on receptor-mediated generation of the O2- might be regulated by protein kinases, such as TK and PKC, and that the TK inhibitor selectively inhibited the G-CSF-primed receptor-mediated O2- generation of neutrophils.

DOI： 10.1016/0006-2952(92)90366-Q

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To investigate the role of superoxide dismutase (SOD) in the ovulatory process, SOD isozymes and their mRNAs were determined in the ovary of 22-day-old rat. After treatment with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG), ovarian activity of Mn-SOD decreased markedly while Cu/Zn-SOD remained unchanged. However, the ovarian level of mRNA for Mn-SOD markedly increased after hCG-treatment while that for Cu/Zn-SOD decreased only slightly. Ovulation was inhibited by intravenous injection of a long-acting SOD. These results suggested that superoxide radicals in the ovary might play a critical role in the mechanism for hCG-induced ovulation.

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Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)   Publisher：Kochi University  

We have investigated the effect of tumor necrosis factor-α (TNF-α) and granulocyte colony stimulating factor (G-CSF) on human peripheral neutrophils (HPPMN). TNF-α and G -CSF enhanced fonylmethionyl-1eucyl-phenylalanine (FMLP) -stimiulated O^∸_2 generation of HPPMN in concentration and time dependent manners. The enhancement of 0^∸_2 generation was inhibited by tyrosine kinase inhibitors. These cytokins also enhanced the tyrosyl phosphorylation of neutrophil proteins, such as 115,110,98,83,72,70,60,54 kDa and many of low molecular weight proteins. Both tyrosine kinase and phosphotyr-osine phosphatase might regulate the protein tyrosyl phosphorylation since the phosphorylation inhibited by tyrosine kinase inhibitor, genistein. The TNF-α enhanced tyrosyl phosphorylation of 115 and 108 kDa proteins, which distributed in the membrane fraction, was increased in manners of incubation and concentration dependent. The kinetics of TNF-α enhanced FMLP -dependent O^∸_2 generation was quite similar to that of tyrosyl phosphorylation of neutrophil proteins by TNF-α Furthermore, cepharanthine specifically inhibited either TNF-α or G-CSF enhanced FMLP-stimulated 0^∸_2 generation and tyrosyl phophorylation of some neutrophil proteins, 115 kDa. Taken together with this finding, it is concluded that substrate proteins for tyrosin kinases might act as critical effector molecules in the mechanism for priming in neutrophils.

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Healthy human peripheral neutrophils (HPPMN) are not primed, and have weak responses to stimuli which activate HPPMN through their membrane receptors. Recombinant human tumor necrosis factor-α (rHuTNF) and recombinant granulocyte colony stimulation factor (rG-CSF) primed HPPMN. Superoxide (O^&minusd;_2) generation by formylmethionyl-leucylphenylalanine (FMLP) or opsonized zymosan (OZ) was enhanced by these primers. However, O^&minusd;_2 generation induced by phorbol myristate acetate (PMA) or dioctanoylglycerol (DOG) was not enhanced by the primers. Receptor mediated O^&minusd;_2 generation in rHuTNF primed neutrophils was inhibited by the genistein or alpha-cyan0-3-ethoxy-4-hydroxy-5phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK). But it was enhanced by 1-(5-isoquinoline sulfonyl)-3-methyl-piperazine (H-7) or staurosporine, inhibitors of Ca^<++>_ and phospholipid-dependent protein kinase (PKO, in their concentration dependent manner. On the contrary, O^&minusd;_2 generation of HPPMN at higher concentration of PMA or DOG was rather stimulated by genistein or ST 638 and was inhibited by H-7 or staurosporine. These results suggest that protein kinases participates in the NADPH-oxidase activation of neutrophils and that two pathways exist in the NADPH-oxidase activation : one in PMA- or DOG-stimulated PKC-dependent pathway and the other in FMLP-stimulated TK-dependent pathway. Moreover, it suggests that TK might be involved in the reaction of neutrophil priming with various ligands.

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DOI： 10.1016/0006-2952(90)90271-L

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The present study has been undertaken to examine the effect of cell hybridization of Bloom syndrome (BS) B-lymphoblastoid cell lines (LCLs) and various cell lines from lymphoid malignancies in order to clarify the relationship between sister-chromatid exchange (SCE) and malignant conditions. Cell hybridization studies have shown that though BS high-SCE frequencies were completed by fusion with normal cells, fusion with various malignant cell lines did not result in complete normalization of BS SCEs, with 15-30 SCEs remaining per hybrid cell, demonstrating possibly common defects in DNA of BS and malignant cells. These findings strongly support the idea that the characteristic high SCE frequency in BS cells has some connection with the malignant condition, and that at least one step in carcinogenesis is either accompanied by the production of SCEs, or that SCEs themselves cause such a step to occur. © 1990.

DOI： 10.1016/0165-7992(90)90117-3

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DOI： 10.1016/0014-5793(89)81097-X

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Distribution of EGF receptor/kinase substrates in cytoplasmic proteins of guinea pig various organs was studied. 35kDa and 38kDa proteins in SDS-PAGE were detected as substrates for the enzyme in lung, spleen, stomach, urinary bladder and skin. 35kDa protein is confermed as lipocortin-like 39K protein of neutrophils by the method of immunoblotting using antibody of 39K protein. The Ca^<2+>-dependent membrane binding activity protein was an important character for the protein phosphorylation by this enzyme. A recombinant 39K protein was also phosphorylated by EGF receptor/kinase and the amount of phosphorylated 38kDa detected on SDS-PAGE was increased by the time of incubation.

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CiNii Books

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Event date： 2020.7.18 - 2020.7.20

Language：Japanese  

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Event date： 2019.9.18 - 2019.9.20

Language：English  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap