101
|
Abstract
Melatonin, or N-acetyl-5-methoxytryptamine, is a compound derived from tryptophan that is found in all organisms from unicells to vertebrates. This indoleamine may act as a protective agent in disease conditions such as Parkinson's, Alzheimer's, aging, sepsis and other disorders including ischemia/reperfusion. In addition, melatonin has been proposed as a drug for the treatment of cancer. These disorders have in common a dysfunction of the apoptotic program. Thus, while defects which reduce apoptotic processes can exaggerate cancer, neurodegenerative disorders and ischemic conditions are made worse by enhanced apoptosis. The mechanism by which melatonin controls cell death is not entirely known. Recently, mitochondria, which are implicated in the intrinsic pathway of apoptosis, have been identified as a target for melatonin actions. It is known that melatonin scavenges oxygen and nitrogen-based reactants generated in mitochondria. This limits the loss of the intramitochondrial glutathione and lowers mitochondrial protein damage, improving electron transport chain (ETC) activity and reducing mtDNA damage. Melatonin also increases the activity of the complex I and complex IV of the ETC, thereby improving mitochondrial respiration and increasing ATP synthesis under normal and stressful conditions. These effects reflect the ability of melatonin to reduce the harmful reduction in the mitochondrial membrane potential that may trigger mitochondrial transition pore (MTP) opening and the apoptotic cascade. In addition, a reported direct action of melatonin in the control of currents through the MTP opens a new perspective in the understanding of the regulation of apoptotic cell death by the indoleamine.
Collapse
Affiliation(s)
- Josefa León
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
| | | | | | | | | |
Collapse
|
102
|
Korhonen P, Kyrylenko S, Suuronen T, Salminen A. Changes in DNA binding pattern of transcription factor YY1 in neuronal degeneration. Neurosci Lett 2004; 377:121-4. [PMID: 15740849 DOI: 10.1016/j.neulet.2004.11.085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 11/09/2004] [Accepted: 11/25/2004] [Indexed: 10/26/2022]
Abstract
Molecular events under the neuronal degeneration are widely studied but still not defined. Here we compared the effects of both excitotoxic and apoptotic insults on the DNA binding profile of multifunctional transcription factor YY1 protein in cultured cerebellar granule neurons. We report that L-glutamate-induced excitotoxic insult but not ionophore A23187 treatment caused the disappearance of the larger DNA binding complex of YY1 and a simultaneous appearance of the smaller YY1 complex in cerebellar granule neurons. MK-801 (NMDA receptor antagonist) as well as benzamide (PARP inhibitor), MDL 28170 (calpain inhibitor) and roscovitine (cyclin-dependent kinase inhibitor) inhibited the glutamate response to the YY1 complexes. Herbimycin, PD169316, wortmannin, JAK3 inhibitor, KN-93, H-7 and LY294002 were not effective. Apoptosis induced by okadaic acid but not that induced by etoposide or trichostatin A caused a similar excitotoxic reorganization in YY1 complexes. We suggest that despite the different cell death mechanisms, glutamate and okadaic acid activate signalling cascades that affect the formation of YY1 complexes and probably YY1-mediated gene regulation.
Collapse
Affiliation(s)
- Pauliina Korhonen
- Department of Neuroscience and Neurology, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland
| | | | | | | |
Collapse
|
103
|
Tserng KY, Griffin RL. Ceramide metabolite, not intact ceramide molecule, may be responsible for cellular toxicity. Biochem J 2004; 380:715-22. [PMID: 14998372 PMCID: PMC1224207 DOI: 10.1042/bj20031733] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Revised: 02/19/2004] [Accepted: 03/04/2004] [Indexed: 12/14/2022]
Abstract
Ceramides, which are produced from the hydrolysis of sphingomyelin or synthesized from serine and palmitate in a de novo pathway, are regarded as important cellular signals for inducing apoptosis. However, controversy over this proposed role of ceramides exists. Using stable isotope labelling coupled with GC (gas chromatography)-MS and mass isotopomer distribution analysis, we have studied the metabolism of exogenous long-chain ceramides in HL60 cells. Our results do not support the concept of enhanced ceramide transport into cells induced by solvent mixtures of ethanol and hydrocarbons. In addition, cell toxicity does not correlate with the amount of intact ceramide in the cells. Our results are more consistent with a disturbance of sphingomyelin metabolism induced by the solvent mixture. The characteristics of this disturbed sphingolipid disposition are the inhibition of dihydroceramide desaturation and an enhanced degradation of sphingomyelin. As a consequence, dihydroceramides accumulate and the cellular sphingomyelin content decreases. Inhibition of these pathways is most likely to be induced by the increased production of novel ceramide metabolites instead of by intact ceramides. Octadecane-1,2-diol is identified as a possible mediator. Treatments that divert ceramide degradation to the novel pathway are potential strategies in cancer therapy for inducing cell toxicity.
Collapse
Affiliation(s)
- Kou-Yi Tserng
- Veterans Affairs Medical Center, Medical Research Service, Department of Nutrition, Case Western Reserve University, Cleveland, OH 44106, USA.
| | | |
Collapse
|
104
|
de Graaf AO, van den Heuvel LP, Dijkman HBPM, de Abreu RA, Birkenkamp KU, de Witte T, van der Reijden BA, Smeitink JAM, Jansen JH. Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis. Exp Cell Res 2004; 299:533-40. [PMID: 15350550 DOI: 10.1016/j.yexcr.2004.06.024] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 06/14/2004] [Indexed: 11/22/2022]
Abstract
Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity.
Collapse
Affiliation(s)
- Aniek O de Graaf
- Central Hematology Laboratory, Department of Hematology, University Medical Center Nijmegen, Nijmegen 6500 HB, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
105
|
Wang X, Brégégère F, Soroka Y, Frusic-Zlotkin M, Milner Y. Replicative senescence enhances apoptosis induced by pemphigus autoimmune antibodies in human keratinocytes. FEBS Lett 2004; 567:281-6. [PMID: 15178337 DOI: 10.1016/j.febslet.2004.04.083] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Revised: 04/22/2004] [Accepted: 04/29/2004] [Indexed: 10/26/2022]
Abstract
We have recently shown that skin lesions of the autoimmune disease pemphigus vulgaris are associated with Fas-mediated apoptosis. Here, we describe the induction of the Fas-dependent apoptosis pathway in cultured keratinocytes by pemphigus vulgaris autoantibodies (PV-IgG), as seen from a variety of cellular, morphological and biochemical parameters. All apoptotic characters appear stronger and faster in aged cultures than in young, showing increased susceptibility of senescent keratinocytes to PV-IgG-mediated apoptotic death and culture lesions. Together with immunosenescence, this phenomenon may explain the late onset of pemphigus disease.
Collapse
Affiliation(s)
- Xin Wang
- The Myers Skin Biochemistry Laboratory, Department of Biological Chemistry, The Hebrew University, GivatRam, Jerusalem 91904, Israel
| | | | | | | | | |
Collapse
|
106
|
Miyato Y, Ando K. Apoptosis of human melanoma cells by a combination of lonidamine and radiation. JOURNAL OF RADIATION RESEARCH 2004; 45:189-194. [PMID: 15304959 DOI: 10.1269/jrr.45.189] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Human melanoma is the most aggressive form of human skin cancer, and is notoriously resistant to any current modalities of cancer therapy. Here we show that lonidamine (LND), a mitochondria-targeting non-conventional chemotherapeutic agent, markedly induced apoptosis in radioresistant human malignant melanoma C32TG cells. Either LND of up to 250 microM or X-ray irradiation of up to 15 Gy alone induced only a few percent of the apoptosis when administrated separately. When the two agents were combined, the apoptosis prominently increased to 29.3 %. The apoptotic cells thus induced by the combination treatment showed chromatin condensation, a depletion in DeltaPsim, and an activation of caspase-3. A pan-caspase inhibitor Z-Asp-CH(2)DCB completely suppressed the apoptosis. The combination treatment also decreased Bcl-2 and Bad-phosphorylation. These results indicate that the mitochondria pathway of apoptosis would devise a new radiotherapy strategy for treating malignant melanoma.
Collapse
Affiliation(s)
- Yasuyuki Miyato
- Heavy-Ion Radiobiology Research Group, National Institute of Radiological Sciences, Chiba, Japan
| | | |
Collapse
|
107
|
Schrijvers DM, Martinet W, De Meyer GRY, Andries L, Herman AG, Kockx MM. Flow cytometric evaluation of a model for phagocytosis of cells undergoing apoptosis. J Immunol Methods 2004; 287:101-8. [PMID: 15099759 DOI: 10.1016/j.jim.2004.01.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Revised: 11/24/2003] [Accepted: 01/22/2004] [Indexed: 11/24/2022]
Abstract
Phagocyte recognition of cells undergoing apoptosis is a rapid, efficient way of removing unwanted cells from tissue. The uptake of apoptotic cells prevents the release of potentially toxic cell contents that might otherwise damage neighbouring cells and elicit an inflammatory response. The aim of this work was to evaluate a simple cell culture assay to study phagocytosis of cells undergoing apoptosis. Fluorescent negatively charged beads (1 microm) or fluorescently labelled apoptotic cells, derived from etoposide-treated human monocytes (U937), were co-incubated with J774 cells or human peripheral blood macrophages for 1 h. Flow cytometry (FCM) showed an efficient uptake of both beads and apoptotic bodies. Phagocytosis of apoptotic cells but not of beads was significantly inhibited when macrophages were pre-incubated with cytochalasin D, suggesting that an experimental system based on beads is not an appropriate model of phagocytosis of apoptotic cells.
Collapse
Affiliation(s)
- Dorien M Schrijvers
- Division of Pharmacology, University of Antwerp, Universiteitsplein 1, Wilrijk B-2610, Belgium.
| | | | | | | | | | | |
Collapse
|
108
|
Sima AAF, Kamiya H, Kamiya H, Li ZG. Insulin, C-peptide, hyperglycemia, and central nervous system complications in diabetes. Eur J Pharmacol 2004; 490:187-97. [PMID: 15094085 DOI: 10.1016/j.ejphar.2004.02.056] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2004] [Indexed: 11/18/2022]
Abstract
Diabetes is an increasingly common disorder which causes and contributes to a variety of central nervous system (CNS) complications which are often associated with cognitive deficits. There appear to be two types of diabetic encephalopathy. Primary diabetic encephalopathy is caused by hyperglycemia and impaired insulin action, which evolves in a diabetes duration-related fashion and is associated with apoptotic neuronal loss and cognitive decline. This appears to be particularly associated with insulin-deficient diabetes. Secondary diabetic encephalopathy appears to arise from hypoxic-ischemic insults due to underlying microvascular disease or as a consequence of hypoglycemia. This type of cerebral diabetic complication is more common in the type 2 diabetic population. Here, we will review the clinical and experimental data supporting this conceptual division of diabetic CNS complications and discuss the underlying metabolic, molecular, and functional aberrations.
Collapse
Affiliation(s)
- Anders A F Sima
- Department of Pathology, Gordon H. Scott Hall of Basic Medical Sciences, Wayne State University, 540 East Canfield Avenue, Detroit, MI 48201, USA.
| | | | | | | |
Collapse
|
109
|
Hammond CL, Madejczyk MS, Ballatori N. Activation of plasma membrane reduced glutathione transport in death receptor apoptosis of HepG2 cells. Toxicol Appl Pharmacol 2004; 195:12-22. [PMID: 14962501 DOI: 10.1016/j.taap.2003.10.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 10/20/2003] [Indexed: 12/25/2022]
Abstract
Cells undergoing apoptosis release reduced glutathione (GSH) into the extracellular space; however, the physiological significance and the mechanism behind the GSH export remain unclear. The present study demonstrates that GSH is released by HepG2 cells undergoing Fas, tumor necrosis factor alpha (TNFalpha), or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-stimulated cell death. GSH release was observed at times when extracellular lactate dehydrogenase (LDH) activity and propidium iodide (PI) incorporation were low, suggesting that the GSH release does not occur because of nonspecific cell damage, but is occurring through a specific transport system. Caspase 3-like proteases were activated before GSH was released, indicating that protease may be involved in signaling GSH release. To investigate the mechanism of GSH release, studies were performed in the presence of GSH transport inhibitors, as well as 25 mM GSH in the media. Two organic anion transporter inhibitors, probenecid and dibromosulfophthalein (DBSP), were effective in inhibiting Fas-stimulated GSH release. The addition of 25 mM GSH to the extracellular media also prevented the loss of intracellular GSH and delayed cell death. These findings suggest that an organic anion transporter is involved in GSH release during apoptosis, and that maintenance of intracellular GSH levels during apoptosis provides protection for the cell.
Collapse
Affiliation(s)
- Christine L Hammond
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | | | | |
Collapse
|
110
|
Yamamoto T, Nishioka K. Possible role of apoptosis in the pathogenesis of bleomycin-induced scleroderma. J Invest Dermatol 2004; 122:44-50. [PMID: 14962088 DOI: 10.1046/j.0022-202x.2003.22121.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
To elucidate the role of apoptosis in cutaneous sclerosis, we examined the induction of apoptosis and expression of Fas, Fas ligand, as well as caspase-3 in a murine model of bleomycin-induced scleroderma. Dermal sclerosis was induced by local injections of bleomycin (1 mg per mL) in C3H/HeJ mice. Induction of apoptosis was examined by TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling) assay and DNA gel electrophoresis. TUNEL positivity was prominently detected on keratinocytes and infiltrating mononuclear cells, but not endothelial cells and fibroblasts, in the lesional skin. DNA fragmentation revealed laddering at 3 to 4 wk following bleomycin treatment. Immunohistochemistry showed increased expression of Fas in infiltrating mononuclear cells at early phases following bleomycin exposure, whereas constitutive expression in fibroblasts. Fas ligand expression was increased in mononuclear cells as well as fibroblasts in the sclerotic skin. Results of reverse transcription-polymerase chain reaction analysis revealed that expression of Fas ligand mRNA was upregulated and reached a maximum at 3 wk, whereas Fas mRNA was continuously detected. mRNA expression as well as activity of caspase-3 was also enhanced at 3 wk. Administration of neutralizing anti-Fas ligand antibody together with local bleomycin treatment reduced the development of dermal sclerosis, associated with the reduction of TUNEL-positive mononuclear cells and also with the blockade of apoptosis. Caspase-3 activity in the lesional skin was also significantly reduced after anti-Fas ligand treatment. These findings suggest that excessive apoptosis, which is mediated by Fas/Fas ligand pathway and caspase-3 activation, is involved in the pathogenesis of bleomycin-induced scleroderma, possibly by playing an inflammatory role.
Collapse
Affiliation(s)
- Toshiyuki Yamamoto
- Tokyo Medical and Dental University School of Medicine, Department of Dermatology, Tokyo, Japan.
| | | |
Collapse
|
111
|
|
112
|
Vanyushin BF, Bakeeva LE, Zamyatnina VA, Aleksandrushkina NI. Apoptosis in plants: specific features of plant apoptotic cells and effect of various factors and agents. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 233:135-79. [PMID: 15037364 DOI: 10.1016/s0074-7696(04)33004-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Apoptosis is an integral part of plant ontogenesis; it is controlled by cellular oxidative status, phytohormones, and DNA methylation. In wheat plants apoptosis appears at early stages of development in coleoptile and initial leaf of 5- to 6-day-old seedlings. Distinct ultrastructural features of apoptosis observed are (1). compaction and vacuolization of cytoplasm in the apoptotic cell, (2). specific fragmentation of cytoplasm and appearance in the vacuole of unique single-membrane vesicles containing active organelles, (3). cessation of nuclear DNA synthesis, (4). condensation and margination of chromatin in the nucleus, (5). internucleosomal fragmentation of nuclear DNA, and (6). intensive synthesis of mitochondrial DNA in vacuolar vesicles. Peroxides, abscisic acid, ethylene releaser ethrel, and DNA methylation inhibitor 5-azacytidine induce and stimulate apoptosis. Modulation of the reactive oxygen species (ROS) level in seedling by antioxidants and peroxides results in tissue-specific changes in the target date for the appearance and the intensity of apoptosis. Antioxidant butylated hydroxytoluene (BHT) reduces the amount of ROS and prevents apoptosis in etiolated seedlings, prolongs coleoptile life span, and prevents the appearance of all apoptotic features mentioned. Besides, BHT induces large structural changes in the organization of all cellular organelles and the formation of new unusual membrane structures in the cytoplasm. BHT distorts mitosis and this results in the appearance of multiblade polyploid nuclei and multinuclear cells. In roots of etiolated wheat seedlings, BHT induces differentiation of plastids with the formation of chloro(chromo)plasts. Therefore, ROS controlled by BHT seems to regulate mitosis, trigger apoptosis, and control plastid differentiation and the organization of various cellular structures formed by endocytoplasmic reticulum.
Collapse
Affiliation(s)
- B F Vanyushin
- Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia
| | | | | | | |
Collapse
|
113
|
Shih CM, Ko WC, Wu JS, Wei YH, Wang LF, Chang EE, Lo TY, Cheng HH, Chen CT. Mediating of caspase-independent apoptosis by cadmium through the mitochondria-ROS pathway in MRC-5 fibroblasts. J Cell Biochem 2004; 91:384-97. [PMID: 14743397 DOI: 10.1002/jcb.10761] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cadmium (Cd) is an environmental pollutant of global concern with a 10-30-year biological half-life in humans. Accumulating evidence suggests that the lung is one of the major target organs of inhaled Cd compounds. Our previous report demonstrated that 100 microM Cd induces MRC-5 cells, normal human lung fibroblasts, to undergo caspase-independent apoptosis mediated by mitochondrial membrane depolarization and translocation of apoptosis-inducing factor (AIF) from mitochondria into the nucleus. Here, using benzyloxycarbonyl-Val-Ala-Asp-(ome) fluoromethyl ketone (Z-VAD.fmk) as a tool, we further demonstrated that Cd could induce caspase-independent apoptosis at concentrations varied from 25 to 150 microM, which was modulated by reactive oxygen species (ROS) scavengers, such as N-acetylcysteine (NAC), mannitol, and tiron, indicating that ROS play a crucial role in the apoptogenic activity of Cd. Consistent with this notion, the intracellular hydrogen peroxide (H2O2) was 2.9-fold elevated after 3 h of Cd treatment and diminished rapidly within 1 h as detected by flow cytometry with 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Using inhibitors of the mitochondrial electron transport chain (ETC) (oligomycin A and rotenone for complex I and V, respectively) and mitochondrial permeability transition pore (MPTP) (cyclosporin A and aristolochic acid), we coincidently found the ROS production, mitochondrial membrane depolarization, and apoptotic content were almost completely or partially abolished. As revealed by confocal microscopy staining with chloromethyl-X-rosamine (CMXRos) and an anti-AIF antibody, the collapse of mitochondrial membrane potential induced by Cd (3 h-treatment) was a prelude to the translocation of caspase-independent pro-apoptotic factor, AIF, into the nucleus (after 4 h of Cd treatment). In summary, this study demonstrated that, in MRC-5 fibroblasts, Cd induced caspase-independent apoptosis through a mitochondria-ROS pathway. More importantly, we provide several lines of evidence supporting a role of mitochondrial ETC and MPTP in the regulation of caspase-independent cell death triggered by Cd.
Collapse
Affiliation(s)
- Chwen-Ming Shih
- Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei, Taiwan, ROC.
| | | | | | | | | | | | | | | | | |
Collapse
|
114
|
Ahn HJ, Kim YS, Kim JU, Han SM, Shin JW, Yang HO. Mechanism of taxol-induced apoptosis in human SKOV3 ovarian carcinoma cells. J Cell Biochem 2004; 91:1043-52. [PMID: 15034938 DOI: 10.1002/jcb.20006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Taxol is extensively used clinically for chemotherapy of patients with ovarian, breast, and lung cancer. Although taxol induces apoptosis of cancer cells, its exact mechanism of action is not yet known. To determine the mechanism of action of taxol in ovarian cancer, we tested the effects of the drug, on the human ovarian carcinoma cell line, SKOV3. We observed that taxol-induced apoptosis of these cells by phosphatidylserine (PS) externalization and DNA fragmentation. While treatment of cells with taxol resulted in bcl-2 phosphorylation and mitochondrial depolarization, cytochrome c was not released and pro-caspase-3 was not activated. Treatment of SKOV3 cells with taxol, however, resulted in the translocation of AIF from the mitochondria to the nucleus via the cytosol. Taken together, these findings suggest that in SKOV3 cells, taxol induces caspase-independent AIF-dependent apoptosis.
Collapse
Affiliation(s)
- Hak Jun Ahn
- Department of Anesthesiology and Pain Management, College of Medicine, University of Ulsan, Seoul Asan Medical Center, Seoul, Korea
| | | | | | | | | | | |
Collapse
|
115
|
Sook Han M, Shin KJ, Kim YH, Kim SH, Lee T, Kim E, Ho Ryu S, Suh PG. Thiram and ziram stimulate non-selective cation channel and induce apoptosis in PC12 cells. Neurotoxicology 2003; 24:425-34. [PMID: 12782107 DOI: 10.1016/s0161-813x(03)00013-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The neurotoxicity of dithiocarbamates has been previously reported, however, the detailed mechanism underlying the neurotoxicity is still not fully understood. Among the dithiocarbamates, we investigated thiram and ziram in a neuronal-like pheochromocytoma (PC12) cells. Thiram and ziram strongly induced cell death in both dose- and time-dependent manners with the LC(50) of 0.3 and 2 microM, respectively. The cell death showed typical apoptotic features, such as DNA fragmentation and an increase of subdiploidy nuclei. Interestingly, both thiram and ziram induced rapid and sustained increases of intracellular Ca(2+) in PC12 cells, which were almost completely blocked by flufenamic acid (FFA), an inhibitor of non-selective cation channel. BAPTA-AM, an intracellular Ca(2+) chelator, inhibited the thiram- and ziram-induced apoptotic cell death. These results suggest that thiram and ziram induce apoptotic neuronal cell death by Ca(2+) influx through non-selective cation channels. The present study may provide a clue for understanding the mechanism of neurotoxicity of thiram and ziram.
Collapse
Affiliation(s)
- Myoung Sook Han
- Division of Molecular and Life Sciences, Department of Life Science, SIGMOL Institute of Molecular Medicine, SIGMOL Inc., Pohang University of Science and Technology, 790-784, Pohang, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
116
|
Shih CM, Wu JS, Ko WC, Wang LF, Wei YH, Liang HF, Chen YC, Chen CT. Mitochondria-mediated caspase-independent apoptosis induced by cadmium in normal human lung cells. J Cell Biochem 2003; 89:335-47. [PMID: 12704796 DOI: 10.1002/jcb.10488] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cadmium, a well-known environmental hazard, has caused serious health problems in humans and animals. Accumulating evidence suggests the cadmium toxicity is mediated by oxidative stress-induced cell death. However, the molecular signaling underlying cadmium-induced apoptosis remains unclear. In this study, we demonstrate here that cadmium induced mixed types of cell death including primary apoptosis (early apoptosis), secondary necrosis (late apoptosis), and necrosis in normal human lung cells, MRC-5, as revealed by chromatin condensation, phosphatidylserine (PS) externalization, and hypodiploid DNA content. The total apoptotic cells reached a plateau of around 40.0% after 24 h exposure of 100 microM cadmium. Pretreatment with Z-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk), a broad spectrum of caspase inhibitor, could not rescue apoptotic cells from cadmium toxicity. Coincidently, we failed to detect the activation of pro-caspase-3 and cleavage of PARP by immunoblot, which implies the apoptogenic activity of cadmium in MRC-5 cells is caspase-independent. JC-1 staining also indicated that mitochondrial depolarization is a prelude to cadmium-induced apoptosis, which was accompanied by a translocation of caspase-independent pro-apoptotic factor apoptosis-inducing factor (AIF) into the nucleus as revealed by the immunofluorescence assay. In summary, this study demonstrated for the first time that cadmium induced a caspase-independent apoptotic pathway through mitochondria-mediated AIF translocation into the nucleus.
Collapse
Affiliation(s)
- Chwen-Ming Shih
- Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei, Taiwan, ROC.
| | | | | | | | | | | | | | | |
Collapse
|
117
|
Zech B, Köhl R, von Knethen A, Brüne B. Nitric oxide donors inhibit formation of the Apaf-1/caspase-9 apoptosome and activation of caspases. Biochem J 2003; 371:1055-64. [PMID: 12605597 PMCID: PMC1223357 DOI: 10.1042/bj20021720] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2002] [Revised: 02/24/2003] [Accepted: 02/26/2003] [Indexed: 01/24/2023]
Abstract
Caspases are critical for the initiation and execution of apoptosis. Nitric oxide (NO) or derived species can prevent programmed cell death in several cell types, reportedly through S-nitrosation and inactivation of active caspases. Although we find that S-nitrosation of caspases can occur in vitro, our study questions whether this post-translational modification is solely responsible for NO-mediated inhibition of apoptosis. Indeed, using Jurkat cells as a model system, we demonstrate that NO donors block Fas- and etoposide-induced caspase activation and apoptosis (downstream of mitochondrial membrane depolarization) and cytochrome c release. However, caspase activity was not restored by the strong reducing agent dithiothreitol, as predicted for S-nitrosation reactions, thereby excluding active-site-thiol modification of caspases as the only anti-apoptotic mechanism of NO donors in cells. Rather, we observed that processing of procaspases-9, -3 and -8 was decreased due to ineffective formation of the Apaf-1/caspase-9 apoptosome. Gel-filtration and in vitro binding assays indicated that NO donors inhibit correct assembly of Apaf-1 into an active approx. 700 kDa apoptosome complex, and markedly attenuate caspase-recruitment domain (CARD)-CARD interactions between Apaf-1 and procaspase-9. Therefore we suggest that NO or a metabolite acts directly at the level of the apoptosome and inhibits the sequential activation of caspases-9, -3 and -8, which are required for both stress- and receptor-induced death in cells that use the mitochondrial subroute of cell demise.
Collapse
Affiliation(s)
- Birgit Zech
- Department of Cell Biology, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | | | | | | |
Collapse
|
118
|
Abstract
Organisms with renewable tissues use a network of genetic pathways and cellular responses to prevent cancer. The main mammalian tumour-suppressor pathways evolved from ancient mechanisms that, in simple post-mitotic organisms, act predominantly to regulate embryogenesis or to protect the germline. The shift from developmental and/or germline maintenance in simple organisms to somatic maintenance in complex organisms might have evolved at a cost. Recent evidence indicates that some mammalian tumour-suppressor mechanisms contribute to ageing. How might this have happened, and what are its implications for our ability to control cancer and ageing?
Collapse
Affiliation(s)
- Judith Campisi
- Lawrence Berkeley National Laboratory, Life Sciences Division, 1 Cyclotron Road, Berkeley, California 94720, USA.
| |
Collapse
|
119
|
|
120
|
Belov GA, Romanova LI, Tolskaya EA, Kolesnikova MS, Lazebnik YA, Agol VI. The major apoptotic pathway activated and suppressed by poliovirus. J Virol 2003; 77:45-56. [PMID: 12477809 PMCID: PMC140567 DOI: 10.1128/jvi.77.1.45-56.2003] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cells respond to poliovirus infection by switching on the apoptotic program, implementation of which is usually suppressed by viral antiapoptotic functions. We show here that poliovirus infection of HeLa cells or derivatives of MCF-7 cells was accompanied by the efflux of cytochrome c from mitochondria. This efflux occurred during both abortive infection (e.g., interrupted by guanidine-HCl and ending with apoptosis) and productive infection (leading to cytopathic effect). The former type of infection, but not the latter, was accompanied by truncation of the proapoptotic protein Bid. The virus-triggered cytochrome c efflux was suppressed by overexpression of Bcl-2. Both abortive and productive infections also resulted in a decreased level of procaspase-9, as revealed by Western blotting. In the former case, this decrease was accompanied by the accumulation of a protein with the electrophoretic mobility of active caspase-9. In contrast, in the productively infected cells, the latter protein was absent but caspase-9-related polypeptides with altered mobility could be detected. Both caspase-9 and caspase-3 were shown to be essential for the development of such hallmarks of virus-induced apoptosis as chromatin condensation, DNA degradation, and nuclear fragmentation. These and some other results suggest the following scenario. Poliovirus infection activates the apoptotic pathway, involving mitochondrial damage, cytochrome c efflux, and consecutive activation of caspase-9 and caspase-3. The apoptotic signal appears to be amplified by a loop which includes secondary processing of Bid. The implementation of the apoptotic program in productively infected cells may be suppressed, however, by the viral antiapoptotic functions, which act at a step(s) downstream of the cytochrome c efflux. The suppression appears to be caused, at least in part, by aberrant processing and degradation of procaspase-9.
Collapse
Affiliation(s)
- George A Belov
- M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, Moscow Region 142782, Russia
| | | | | | | | | | | |
Collapse
|
121
|
Chen Q, Crosby M, Almasan A. Redox Regulation of Apoptosis before and after Cytochrome C Release. ACTA ACUST UNITED AC 2003; 7:1-9. [PMID: 16467897 PMCID: PMC1343461 DOI: 10.1080/12265071.2003.9647675] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Programmed cell death, or apoptosis, is one of the most studied areas of modern biology. Apoptosis is a genetically regulated process, which plays an essential role in the development and homeostasis of higher organisms. Mitochondria, known to play a central role in regulating cellular metabolism, was found to be critical for regulating apoptosis induced under both physiological and pathological conditions. Mitochondria are a major source of reactive oxygen species (ROS) but they can also serve as its target during the apoptosis process. Release of apoptogenic factors from mitochondria, the best known of which is cytochrome c, leads to assembly of a large apoptosis-inducing complex called the apoptosome. Cysteine proteases (called caspases) are recruited to this complex and, following their activation by proteolytic cleavage, activate other caspases, which in turn target for specific cleavage a large number of cellular proteins. The redox regulation of apoptosis during and after cytochrome c release is an area of intense investigation. This review summarizes what is known about the biological role of ROS and its targets in apoptosis with an emphasis on its intricate connections to mitochondria and the basic components of cell death.
Collapse
Affiliation(s)
- Quan Chen
- *To whom correspondence should be addressed, Tel: 86-10-6252-9232, Fax: +6256-5689, E-mail:
| | | | | |
Collapse
|
122
|
Popov SG, Villasmil R, Bernardi J, Grene E, Cardwell J, Popova T, Wu A, Alibek D, Bailey C, Alibek K. Effect of Bacillus anthracis lethal toxin on human peripheral blood mononuclear cells. FEBS Lett 2002; 527:211-5. [PMID: 12220662 DOI: 10.1016/s0014-5793(02)03228-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lethal toxin (LeTx) plays a central role in anthrax pathogenesis, however a cytotoxicity of LeTx has been difficult to demonstrate in vitro. No cytolytic effect has been reported for human cells, in contrast to murine cell lines, indicating that cell lysis can not be considered as a marker of LeTx activity. We have recently shown that murine macrophage-like RAW 264.7 cells treated with LeTx or infected with anthrax spores underwent changes typical of apoptotic death. Here we demonstrate that cells from human peripheral blood display a proapoptotic behavior similar to murine cells. TUNEL assay detected a nucleosomal degradation typical of apoptosis in peripheral blood mononuclear cells (PBMC) treated with LeTx. Membrane staining with apoptotic dyes was detected in macrophages derived from monocytes in presence of LeTx. The toxin inhibited production of proinflammatory cytokines in PBMC stimulated with a preparation of Bacillus anthracis cell wall. Infection of PBMC with anthrax spores led to the appearance of a large population of cells stained positively for apoptosis, with a reduced capacity to eliminate spores and vegetative bacteria. The aminopeptidase inhibitor, bestatin, capable of protecting cells from LeTx, restored a bactericidal activity of infected cells. These findings may be explained by LeTx expression within phagocytes and support an important role of LeTx as an early intracellular virulence factor contributing to bacterial dissemination and disease progression.
Collapse
Affiliation(s)
- Serguei G Popov
- Advanced Biosystems, Inc., 10900 University Blvd., MSN 1A8, Manassas, VA 20110, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
123
|
Abstract
A family of cysteine proteases, the caspases, plays a central role in the initiation and execution phases of apoptosis. Upon activation, these enzymes cleave specific substrates and thereby mediate many of the typical biochemical and morphological changes in apoptotic cells, such as cell shrinkage, chromatin condensation, DNA fragmentation and plasma membrane blebbing. Hence, the detection of activated caspases can be used as a biochemical marker for apoptosis. Here we review a set of methods available for characterizing and quantifying the activation of caspases, including immunoblotting, cleavage of synthetic substrates, affinity labeling and confocal microscopy. Each method is described in general terms and the advantages and disadvantages of each technique are discussed.
Collapse
Affiliation(s)
- Camilla Köhler
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
| | | | | |
Collapse
|
124
|
Piacentini M, Farrace MG, Piredda L, Matarrese P, Ciccosanti F, Falasca L, Rodolfo C, Giammarioli AM, Verderio E, Griffin M, Malorni W. Transglutaminase overexpression sensitizes neuronal cell lines to apoptosis by increasing mitochondrial membrane potential and cellular oxidative stress. J Neurochem 2002; 81:1061-72. [PMID: 12065619 DOI: 10.1046/j.1471-4159.2002.00898.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
'Tissue' transglutaminase (tTG) selectively accumulates in cells undergoing apoptosis both in vivo and in vitro. Considering the central role played by mitochondria in apoptosis, we investigated the relationships existing amongst tTG expression, apoptosis and mitochondrial function. To this aim we studied the mechanisms of apoptosis in a neuronal cell line (SK-N-BE (2)) in which the tTG-expression was driven by a constitutive promoter. Furthermore, a tet-off inducible promoter was also used in 3T3 fibroblastic cells used as control. Both cell lines, when expressing tTG, appeared 'sensitized' to apoptosis. Strikingly, we found major differences in the morphological features of mitochondria among cell lines in the absence of apoptotic stimuli. In addition, these ultrastructural characteristics were associated with specific functional features: (i) constitutively hyperpolarized mitochondria and (ii) increased reactive oxygen intermediates production. Importantly, after mitochondrial-mediated apoptosis by staurosporine, a rapid loss of mitochondrial membrane potential was found in tTG cells only. Taken together, these results seem to suggest that, via hyperpolarization, tTG might act as a 'sensitizer' towards apoptotic stimuli specifically targeted to mitochondria. These results could also be of pathogenetic relevance for those diseases that are characterized by increased tTG and apoptotic rate together with impaired mitochondrial function, e.g. in some neurodegenerative disease.
Collapse
Affiliation(s)
- Mauro Piacentini
- Department of Biology, University of Rome Tor Vergata Rome, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
125
|
Yuan Q, Ray RM, Johnson LR. Polyamine depletion prevents camptothecin-induced apoptosis by inhibiting the release of cytochrome c. Am J Physiol Cell Physiol 2002; 282:C1290-7. [PMID: 11997243 DOI: 10.1152/ajpcell.00351.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have shown previously that depletion of polyamines delays apoptosis induced by camptothecin in rat intestinal epithelial cells (IEC-6). Mitochondria play an important role in the regulation of apoptosis in mammalian cells because apoptotic signals induce mitochondria to release cytochrome c. The latter interacts with Apaf-1 to activate caspase-9, which in turn activates downstream caspase-3. Bcl-2 family proteins are involved in the regulation of cytochrome c release from mitochondria. In this study, we examined the effects of polyamine depletion on the activation of the caspase cascade, release of cytochrome c from mitochondria, and expression and translocation of Bcl-2 family proteins. We inhibited ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis, with alpha-difluoromethylornithine (DFMO) to deplete cells of polyamines. Depletion of polyamines prevented camptothecin-induced release of cytochrome c from mitochondria and decreased the activity of caspase-9 and caspase-3. The mitochondrial membrane potential was not disrupted when cytochrome c was released. Depletion of polyamines decreased translocation of Bax to mitochondria during apoptosis. The expression of antiapoptotic proteins Bcl-x(L) and Bcl-2 was increased in DFMO-treated cells. Caspase-8 activity and cleavage of Bid were decreased in cells depleted of polyamines. These results suggest that polyamine depletion prevents IEC-6 cells from apoptosis by preventing the translocation of Bax to mitochondria, thus preventing the release of cytochrome c.
Collapse
Affiliation(s)
- Qing Yuan
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | | | | |
Collapse
|
126
|
Gorski S, Marra M. Programmed cell death takes flight: genetic and genomic approaches to gene discovery in Drosophila. Physiol Genomics 2002; 9:59-69. [PMID: 12006672 DOI: 10.1152/physiolgenomics.00114.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Programmed cell death (PCD) is an essential and wide-spread physiological process that results in the elimination of cells. Genes required to carry out this process have been identified, and many of these remain the subjects of intense investigation. Here, we describe PCD, its functions, and some of the consequences when it goes awry. We review PCD in the model system, the fruit fly, Drosophila melanogaster, with a particular emphasis on cell death gene discovery resulting from both genetics and genomics-based approaches.
Collapse
Affiliation(s)
- S Gorski
- Genome Sequence Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada V5Z 4E6.
| | | |
Collapse
|
127
|
Abstract
Apoptosis, also known as programmed cell death, is a ubiquitous mode of cell death known to play an important role during embryogenesis, development, and adult cellular homeostasis. Disruption of this normal physiological cell death process can result in either excessive or insufficient apoptosis, which can lead to various disease states and pathology. Since most cells contain the machinery that brings about apoptosis, it is clear that living cells must contain inherent repressive mechanisms to keep the death process in check. In this review, we examine several modes of repression of apoptosis that exist in cells.
Collapse
Affiliation(s)
- Carl D Bortner
- The Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
| | | |
Collapse
|
128
|
Smith GK, Barrett DG, Blackburn K, Cory M, Dallas WS, Davis R, Hassler D, McConnell R, Moyer M, Weaver K. Expression, preparation, and high-throughput screening of caspase-8: discovery of redox-based and steroid diacid inhibition. Arch Biochem Biophys 2002; 399:195-205. [PMID: 11888206 DOI: 10.1006/abbi.2002.2757] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Because of the intimate role of caspase-8 in apoptosis signaling pathways from FAS, TNFR1, and other death receptors, the enzyme is a potentially important therapeutic target. We have generated an Escherichia coli expression construct for caspase-8 in which a His-tag sequence is inserted ahead of codon 217 of caspase-8. The strain produced a significant amount of soluble His-tagged 31-kDa inactive single-chain enzyme precursor. This 31-kDa protein could be purified to 98% purity. Hydroxyapatite resolved the enzyme into two species, one with the appropriate 31,090 relative mass and the other with 178 units additional mass. The latter proved to result from E. coli-based modification of the His-tag with one equivalent of glucono-1,5-lactone. The purified proteins could be activated by autoproteolysis to the appropriate 19- plus 11-kDa enzyme by the addition of dithiothreitol in appropriate buffer conditions. This yielded an enzyme with specific activity of 4-5 units/mg against 200 microM Ac-IETD-pNA at 25 degrees C. The fully active protein was used in a high-throughput screen for inhibitors of caspase-8. A preliminary robustness screen demonstrated that caspase-8 is susceptible to reactive oxygen-based inactivation in the presence of dithiothreitol (DTT) but not in the presence of cysteine. Investigation into the mechanism of this inactivation showed that quinone-like compounds were reduced by DTT establishing a reactive oxygen generating redox cycle the products of which (likely H(2)O(2)) inactivated the enzyme. A new class of caspase-8 inhibitors, steroid-derived diacids, with affinity in the low micromolar range were discovered in the refined screen. Structure--activity investigation of the inhibitors showed that both the steroid template and the acid moieties were required for activity.
Collapse
Affiliation(s)
- Gary K Smith
- GlaxoSmithKline Research, 5 Moore Drive, Research Triangle Park, North Carolina 27709, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
129
|
Abstract
Nitric oxide and apoptosis in mesangial cells. Radicals such as nitric oxide (NO) or superoxide (O(-)(2)) encompass the ability to initiate morphological and biochemical alterations that are reminiscent of apoptosis. In mesangial cells, death as a result of NO formation is efficiently antagonized by the simultaneous presence of superoxide (O(-)(2)) and vice versa. This article reviews the consequences of a diffusion controlled NO/O(-)(2) interaction with the outcome of redirecting the apoptotic initiating activity of either NO or O(-)(2) toward protection. The crosstalk between cell destructive and protective pathways, and their activation or inhibition under the modulatory influence of NO and/or O(-)(2) are summarized.
Collapse
Affiliation(s)
- Bernhard Brüne
- Department of Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Strasse, 67663 Kaiserslautern, Germany.
| |
Collapse
|
130
|
Kim JS, Kim JM, Jung HC, Song IS. Caspase-3 activity and expression of Bcl-2 family in human neutrophils by Helicobacter pylori water-soluble proteins. Helicobacter 2001; 6:207-15. [PMID: 11683923 DOI: 10.1046/j.1523-5378.2001.00030.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Persistent infiltration of neutrophils is an almost invariable feature of Helicobacter pylori-infected gastric mucosa. A prolongation of neutrophil life-span could contribute to the pathogenesis of H. pylori infection. Recently, we have demonstrated that H. pylori water extracts (HPWE) inhibited neutrophil apoptosis. To elucidate the regulation of intracellular apoptotic signals by HPWE, we examined the activity of caspase-8, -3 and expression of Bcl-2 family in neutrophils. MATERIALS AND METHODS Human neutrophils were obtained from the peripheral blood of healthy volunteers by density gradient separation. HPWE was prepared from a supernatant of the H. pylori suspension in distilled water. After neutrophils were incubated with HPWE, expression of Bcl-2 family [antiapoptotic (Bcl-2, Bcl-XL and Mcl-1) and proapoptotic (Bax, Bak and Bcl-XS)] was determined by RT-PCR and Western blotting, respectively. Western blot for Bcl-2 family also performed in neutrophilic differentiated HL-60 cells by all-trans-retinoic acid. The activity of caspase-8, -3 was measured by the detection of p-nitroanilide after cleavage from labeled substrate. RESULTS HPWE suppressed the activation of caspase-8 and -3, and upregulated the expression of Bcl-XL mRNA and proteins in neutrophils. The expression of Bax and Bak was upregulated and Bcl-2, Bcl-XL and Mcl-1 downregulated in HL-60 cells during neutrophilic differentiation. CONCLUSION Bcl-XL may have an important role in the neutrophilic development and inhibition of neutrophil apoptosis by H. pylori.
Collapse
Affiliation(s)
- J S Kim
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | | | | | | |
Collapse
|
131
|
Abstract
The process of aging and senescence is associated with a decline in several organ functions and ultimately takes away independence and reduces quality of life. The precariously marginal functional reserves of the immune, pulmonary, and cardiovascular systems are among the most important causes of increased hospitalization in the older population. When complicated by chronic diseases, as is often the case, the problem is magnified. Apoptosis, or programmed cell death, is a process that goes on continuously throughout life. It is involved in embryogenesis for proper organ and tissue development. After birth and through adulthood, it helps eliminate unneeded and damaged cells. There is evidence that advanced age is associated with dysregulation of apoptosis. Several studies have shown age-related changes in the levels of proteins and factors that regulate apoptosis. This could explain the age-associated increased prevalence of cancers, certain autoimmune diseases, and neurodegenerative disorders in older people. More studies are needed to further elucidate the process of apoptosis. With this knowledge, the use of gene therapy and apoptosis modulators may someday have therapeutic value in preventing the functional decline we see in the older population.
Collapse
Affiliation(s)
- A M Joaquin
- Division of Geriatrics and Gerontology, Department of Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California 90059, USA
| | | |
Collapse
|
132
|
Alleva R, Tomasetti M, Andera L, Gellert N, Borghi B, Weber C, Murphy MP, Neuzil J. Coenzyme Q blocks biochemical but not receptor-mediated apoptosis by increasing mitochondrial antioxidant protection. FEBS Lett 2001; 503:46-50. [PMID: 11513852 DOI: 10.1016/s0014-5793(01)02694-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Generation of free radicals is often associated with the induction and progression of apoptosis. Therefore, antioxidants can prove anti-apoptotic, and can help to elucidate specific apoptotic pathways. Here we studied whether coenzyme Q, present in membranes in reduced (ubiquinol) or oxidised (ubiquinone) forms, can affect apoptosis induced by various stimuli. Exposure of Jurkat cells to alpha-tocopheryl succinate (alpha-TOS), hydrogen peroxide, anti-Fas IgM or TRAIL led to induction of apoptosis. Cell death due to the chemical agents was suppressed in cells enriched with the reduced form of coenzyme Q. However, coenzyme Q did not block cell death induced by the immunological agents. Ubiquinol-10 inhibited reactive oxygen species (ROS) generation in cells exposed to alpha-TOS, and a mitochondrially targeted coenzyme Q analogue also blocked apoptosis triggered by alpha-TOS or hydrogen peroxide. Therefore, it is plausible that ubiquinol-10 protects cells from chemically-induced apoptosis by acting as an antioxidant in mitochondria. Our results also indicate that generation of free radicals may not be a critical step in induction of apoptosis by immunological agents.
Collapse
Affiliation(s)
- R Alleva
- Rizzoli Orthopaedic Institute, Bologna, Italy
| | | | | | | | | | | | | | | |
Collapse
|
133
|
Hassan Z, Hassan M, Hellström-Lindberg E. The pharmacodynamic effect of busulfan in the P39 myeloid cell line in vitro. Leukemia 2001; 15:1240-7. [PMID: 11480566 DOI: 10.1038/sj.leu.2402193] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Busulfan is an alkylating agent currently used in the myeloablative conditioning regimen before stem cell transplantation. Its mechanism of action is not fully understood, nor the reason for its narrow therapeutic window. We studied the pharmacodynamics of busulfan in an in vitro cell line model, allowing us to evaluate the effects of various doses and exposure times on clonogeneic capacity, proliferation and apoptosis. Cells were incubated with busulfan in concentrations ranging from 10 to 100 microg/ml for 2, 4 or 8 h, then washed and cultured in busulfan-free medium for 72 h. Area under the concentration-time curve (AUC) was estimated by using the trapezoidal rule from different concentrations and times of incubation. In all assays busulfan affected the cells in an AUC-dependent manner. Induced changes in the biological parameters studied appeared at different time points after exposure to busulfan stopped. Thus, the decrease in proliferation and clonogenic capacity preceded cell cycle arrest in G2 phase and development of apoptosis, implying that apoptosis is a secondary event to interruption of vital metabolic processes. Biochemically, apoptotic changes were typical for chemotherapy-induced apoptosis with caspase activation, cleavage of Bcl-2 and PARP proteins, while cleavage of actin was not observed. Cells were rescued from apoptosis with a general caspase inhibitor ZVAD-fmk, but not with granulocyte colony-stimulating factor (G-CSF). Our results add new information about busulfan pharmacodynamics and mechanisms underlying the cytotoxic effect of the drug.
Collapse
Affiliation(s)
- Z Hassan
- Department of Medicine, Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden
| | | | | |
Collapse
|
134
|
Abstract
Normal embryonic development, tissue differentiation and repair in the eukaryote requires a tightly regulated apoptosis, or programmed cell death. Apoptosis also plays an essential role in different pathological processes including atherosclerosis, in which it affects all cell types in the atherosclerotic lesion, including endothelial cells, vascular smooth muscle cells, and macrophages. During atherosclerosis progression, pro- and anti-apoptotic signals abound in the evolving lesion. Apoptosis limits the number of a particular cell type that accumulates in the lesion and slows down the overall progression of the lesion. On the other hand, it contributes to the production of unstable plaques. Many pharmacological agents used to treat cardiovascular and lipid disorders have pro- or/and anti-apoptotic effects. Pharmaceuticals that modulate apoptosis in specific types of cell can potentially serve as anti-atherogenic agents. However, to develop agents for clinical use requires a thorough knowledge of the pathophysiology of apoptosis in atheromatous lesions, a highly cell-specific process. Here we review our current understanding of the process to provide a background for future pharmacological research in the area.
Collapse
Affiliation(s)
- N V Guevara
- Department of Physical Science, University of Texas at Brownsville, Brownsville, TX 78520, USA
| | | | | |
Collapse
|
135
|
Müllauer L, Gruber P, Sebinger D, Buch J, Wohlfart S, Chott A. Mutations in apoptosis genes: a pathogenetic factor for human disease. Mutat Res 2001; 488:211-31. [PMID: 11397650 DOI: 10.1016/s1383-5742(01)00057-6] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cell death by apoptosis is exerted by the coordinated action of many different gene products. Mutations in some of them, acting at different levels in the apoptosis process, have been identified as cause or contributing factor for human diseases. Defects in the transmembrane tumor necrosis factor receptor 1 (TNF-R1) lead to the development of familial periodic fever syndromes. Mutations in the homologous receptor Fas (also named CD95; Apo-1) are observed in malignant lymphomas, solid tumors and the autoimmune lymphoproliferative syndrome type I (ALPS I). A mutation in the ligand for Fas (Fas ligand; CD95 ligand, Apo-1 ligand), which induces apoptosis upon binding to Fas, was described in a patient with systemic lupus erythematodes and lymphadenopathy. Perforin, an other cytotoxic protein employed by T- and NK-cells for target cell killing, is mutated in chromosome 10 linked cases of familial hemophagocytic lymphohistiocytosis. Caspase 10, a representative of the caspase family of proteases, which plays a central role in the execution of apoptosis, is defect in autoimmune lymphoproliferative syndrome type II (ALPS II). The intracellular pro-apoptotic molecule bcl-10 is frequently mutated in mucosa-associated lymphoid tissue (MALT) lymphomas and various non-hematologic malignancies. The p53, an executioner of DNA damage triggered apoptosis, and Bax, a pro-apoptotic molecule with the ability to perturb mitochondrial membrane integrity, are frequently mutated in malignant neoplasms. Anti-apoptotic proteins like bcl-2, cellular-inhibitor of apoptosis protein 2 (c-IAP2) and neuronal apoptosis inhibitory protein 1 (NAIP1) are often altered in follicular lymphomas, MALT lymphomas and spinal muscular atrophy (SMA), respectively. This article reviews the current knowledge on mutations of apoptosis genes involved in the pathogenesis of human diseases and summarises the gradual transformation of discoveries in apoptosis research into benefits for the clinical management of diseases.
Collapse
Affiliation(s)
- L Müllauer
- Institute of Clinical Pathology, University of Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria.
| | | | | | | | | | | |
Collapse
|
136
|
Yuste VJ, Bayascas JR, Llecha N, Sánchez-López I, Boix J, Comella JX. The absence of oligonucleosomal DNA fragmentation during apoptosis of IMR-5 neuroblastoma cells: disappearance of the caspase-activated DNase. J Biol Chem 2001; 276:22323-31. [PMID: 11294834 DOI: 10.1074/jbc.m100072200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caspase-activated DNase is responsible for the oligonucleosomal DNA degradation during apoptosis. DNA degradation is thought to be important for multicellular organisms to prevent oncogenic transformation or as a mechanism of viral defense. It has been reported that certain cells, including some neuroblastoma cell lines such as IMR-5, enter apoptosis without digesting DNA in such a way. We have analyzed the causes for the absence of DNA laddering in staurosporine-treated IMR-5 cells, and we have found that most of the molecular mechanisms controlling apoptosis are well preserved in this cell line. These include degradation of substrates for caspases, blockade of cell death by antiapoptotic genes such as Bcl-2 or Bcl-X(L), or normal levels and adequate activation of caspase-3. Moreover, these cells display normal levels of caspase-activated DNase and its inhibitory protein, inhibitor of caspase-activated DNase, and their cDNA sequences are identical to those reported previously. Nevertheless, IMR-5 cells lose caspase-activated DNase during apoptosis and recover their ability to degrade DNA when human recombinant caspase-activated DNase is overexpressed. Our results lead to the conclusion that caspase-activated DNase is processed during apoptosis of IMR-5 cells, making these cells a good model to study the relevance of this endonuclease in physiological or pathological conditions.
Collapse
Affiliation(s)
- V J Yuste
- Grup de Neurobiologia Molecular, Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, 25198 Lleida, Spain
| | | | | | | | | | | |
Collapse
|
137
|
Fadeel B, Orrenius S, Henter JI. Familial hemophagocytic lymphohistiocytosis: too little cell death can seriously damage your health. Leuk Lymphoma 2001; 42:13-20. [PMID: 11699200 DOI: 10.3109/10428190109097672] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Familial hemophagocytic lymphohistiocytosis (FHL) is a rare and fatal disease of early childhood characterized by a non-malignant accumulation of activated T lymphocytes and histiocytes in the reticuloendothelial system. Moreover, immune system derangement, with prominent hypercytokinemia and low or absent cytotoxic T and natural killer (NK) cell activity, is a consistent feature of this autosomal recessive disorder. Recent work has demonstrated that the degree of spontaneous caspase activation in FHL lymphocytes is attenuated in vitro whereas Fas-mediated caspase activation and apoptosis induction remains unmitigated, and FHL can thus be distinguished from the related chronic disorder of immune regulation termed autoimmune lymphoproliferative syndrome or ALPS. However, subsequent studies have identified mutations in the gene encoding perforin, a cytotoxic granule constituent required for apoptotic killing of target cells, in a number of FHL patients. Hence, the underlying defect in FHL may be conceived of as a lack of apoptosis triggering within the immune system, rather than apoptosis resistance per se. These observations represent an important step in our understanding of the pathogenesis of FHL and also serve to emphasize the pivotal role of cellular (perforin-based) cytotoxicity in the regulation of immune homeostasis.
Collapse
Affiliation(s)
- B Fadeel
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Childhood Cancer Research Unit, Astrid Lindgren Children's Hospital, Karolinska Hospital, Stockholm, Sweden.
| | | | | |
Collapse
|
138
|
Abstract
Caspases are intracellular cysteine proteases that are primarily responsible for the stereotypic morphological and biochemical changes that are associated with apoptosis. Caspases are often activated by the apoptotic protease-activating factor 1 (APAF-1) apoptosome, a complex that is formed following mitochondrial release of cytochrome c in response to many death-inducing stimuli. Both pro- and anti-apoptotic BCL-2 family members regulate apoptosis, primarily by their effects on mitochondria, whereas many inhibitor of apoptosis proteins (IAPs) regulate apoptosis by directly inhibiting distinct caspases. Exposure of cells to chemicals and radiation, as well as loss of trophic stimuli, perturb cellular homeostasis and, depending on the type of cellular stress, particular or multiple organelles appear to 'sense' the damage and signal the cell to undergo apoptosis by stimulating the formation of unique and/or common caspase-activating complexes.
Collapse
Affiliation(s)
- S B Bratton
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, PO Box 138, Lancaster Road, Leicester, UK LE1 9HN.
| | | |
Collapse
|
139
|
Abstract
Cardiac myocyte apoptosis has been extensively studied in the last few years. Increased interest in the field stems from the hope that pharmacological manipulation of apoptosis may become a valuable tool for preventing excessive cell death observed in different pathological conditions. This paper is not intended as a comprehensive overview of current research about life and death in the cardiovascular system, but rather as a concise update on new developments in areas that were highlighted in a recent series of excellent reviews. A short inventory of unsolved issues concerning the significance of cardiac myocyte loss through apoptosis in both physiological and pathological circumstances is addressed.
Collapse
Affiliation(s)
- M E Hinescu
- Department of Cell Biology & Histology, Carol Davila University of Medicine & Pharmacy, Bucharest, Romania.
| |
Collapse
|
140
|
Hellström-Lindberg E, Schmidt-Mende J, Forsblom AM, Christensson B, Fadeel B, Zhivotovsky B. Apoptosis in refractory anaemia with ringed sideroblasts is initiated at the stem cell level and associated with increased activation of caspases. Br J Haematol 2001; 112:714-26. [PMID: 11260077 DOI: 10.1046/j.1365-2141.2001.02581.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Treatment with granulocyte colony-stimulating factor plus erythropoietin may improve haemoglobin levels in patients with ringsideroblastic anaemia (RARS) and reduce bone marrow apoptosis. We studied bone marrow from 10 RARS patients, two of whom were also investigated after successful treatment. Mononuclear, erythroid and CD34+ cells were analysed with regard to proliferation, apoptosis, clonogenic capacity and oncoprotein expression, in the presence or absence of Fas-agonist, Fas-blocking antibody 2 and caspase-3 inhibitor. During culture, RARS bone marrow cells showed higher spontaneous apoptosis (P < 0.05) and caspase activity (P < 0.05)) than bone marrow cells from healthy donors. Eight out of nine patients had reduced growth of erythroid colony-forming units (CFU-E) (< 10% of control) and granulocyte-macrophage CFU (CFU-GM) (< 50% of control) from CD34+ cells. Fas ligation increased apoptosis and decreased colony growth equally in RARS and controls, but caused significantly more caspase activation in RARS (P < 0.01). Fas-blocking antibody showed no significant inhibitory effect on spontaneous apoptosis or ineffective haematopoiesis, as measured using phosphatidylserine exposure, the terminal deoxynucleotide transferase-mediated dUTP-biotin nick-end labelling technique, caspase activity or clonogenic growth. Caspase inhibition reduced apoptosis, increased proliferation and enhanced erythroid colony growth from CD34+ cells in RARS, but showed no effect on normal cells. CFU-E improved > 1000% after successful treatment. Thus, erythroid apoptosis in RARS is initiated at the CD34+ level and growth factor treatment may improve stem cell function. Enhanced caspase activation at the stem cell level, albeit not mediated through endogenous activation of the Fas receptor, contributes to the erythroid apoptosis in RARS.
Collapse
Affiliation(s)
- E Hellström-Lindberg
- Department of Medicine, Division of Haematology, Karolinska Institutet at Huddinge University Hospital, 141 86 Huddinge, Sweden.
| | | | | | | | | | | |
Collapse
|
141
|
Joseph B, Lewensohn R, Zhivotovsky B. Role of apoptosis in the response of lung carcinomas to anti-cancer treatment. Ann N Y Acad Sci 2001; 926:204-16. [PMID: 11193036 DOI: 10.1111/j.1749-6632.2000.tb05613.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Resistance of tumor cells to treatment often accounts for the failure of traditional forms of anti-cancer therapy. It is well known that tumors from the same histological group and stage of development are highly heterogeneous in their sensitivity to therapy. Among the factors that can influence tumor sensitivity are DNA repair capacity, distribution of cells throughout the cell cycle, proliferation potential, etc. In many cases, anti-cancer therapy eliminates tumor cells via apoptosis, an active form of cell death characterized by cell shrinkage and the removal of cells in a neat, orderly fashion. However, this process is not always efficient. In the present review, the precise role that apoptosis plays in the response of lung carcinomas to chemotherapy and radiation treatment is discussed.
Collapse
Affiliation(s)
- B Joseph
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | | | | |
Collapse
|
142
|
Abstract
Recent studies have indicated a role for apoptosis in a variety of human diseases. Suppression of apoptosis contributes to carcinogenesis by several mechanisms, including facilitating the accumulation of gene mutations, permitting growth-factor-independent cell survival, promoting resistance to immune-based cytotoxicity, and allowing bypassing of cell-cycle checkpoints, which would normally induce apoptosis. Defects in apoptotic mechanisms also play an important part in resistance to chemotherapy and radiation. The core machinery of the cell death pathway can be reduced to a few critical types of proteins, which are well conserved across animal evolution. This review gives an update on the key players involved in apoptosis as well as an overview of the involvement of apoptosis in disease, and novel diagnostic and therapeutic options derived from the extensive basic research on this topic carried out over the last decade.
Collapse
Affiliation(s)
- I Tamm
- Medizinische Klinik mit Schwerpunkt Hamatologie, Onkologie, und Tumorimmunologie, Charité, Berlin, Germany.
| | | | | |
Collapse
|
143
|
Li M, Kondo T, Zhao QL, Li FJ, Tanabe K, Arai Y, Zhou ZC, Kasuya M. Apoptosis induced by cadmium in human lymphoma U937 cells through Ca2+-calpain and caspase-mitochondria- dependent pathways. J Biol Chem 2000; 275:39702-9. [PMID: 10970901 DOI: 10.1074/jbc.m007369200] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Apoptosis induced by cadmium has been shown in many tissues in vivo and in cultured cells in vitro. However, its molecular mechanism is not fully understood. When the human histiocytic lymphoma cell line U937 was treated with cadmium for 12 h, evidence of apoptotic features, including change in nuclear morphology, DNA fragmentation, formation of DNA ladder in agarose gel electrophoresis, and phosphatidylserine externalization, were obtained. Moreover, loss of the mitochondrial membrane potential (Deltapsi(m)) was observed in the cadmium-treated cells and was inhibited by a broad caspase inhibitor (Z-VAD-FMK). Caspase inhibitors suppressed the DNA fragmentation in the order of Z-VAD-FMK > caspase-8 inhibitor > caspase-3 inhibitor. Expression of Bcl-x(L) and Bid decreased significantly in the cadmium-treated cells, although no apparent change in Bcl-2 and Bax expression was found. Tetrakis-(2-pyridylmethyl) ethylendiamine, a cell-permeable heavy metal chelator, partially reversed the increase of fluorescence of Fura-2 in the cadmium-treated cells. In addition, verapamil (70 microm), a voltage-dependent Ca(2+) channel blocker, inhibited the DNA fragmentation induced by cadmium less than 100 microm and decreased the fluorescence of Fura-2. Cadmium up-regulated the expression of type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R) but not type 2 or type 3 IP(3)R. Calpain inhibitors I and II partially prevented DNA fragmentation. No effects of Z-VAD-FMK on the expression of type 1 IP(3)R or of calpain inhibitors on the loss of Deltapsi(m) were observed. These results suggest that cadmium possibly induced apoptosis in U937 cells through two independent pathways, the Ca(2+)-calpain-dependent pathway and the caspase-mitochondria-dependent pathway.
Collapse
Affiliation(s)
- M Li
- Department of Public Health, the Department of Radiological Sciences, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Toyama, 930-0194, Japan
| | | | | | | | | | | | | | | |
Collapse
|
144
|
Shin KJ, Bae SS, Hwang YA, Seo JK, Ryu SH, Suh PG. 2,2',4,6,6'-pentachlorobiphenyl induces apoptosis in human monocytic cells. Toxicol Appl Pharmacol 2000; 169:1-7. [PMID: 11076690 DOI: 10.1006/taap.2000.9034] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polychlorinatedbiphenyls (PCBs) are a group of persistent and widely dispersed environmental pollutants, some of which may be immunotoxic. In the present study, we investigated the effect of PCBs on immune system by assessing apoptotic cell death in human monocytic U937 cells. Among the various congeners tested, 2,2',4,6, 6'-pentachlorobiphenyl (PeCB), a highly ortho-substituted congener, specifically induced DNA fragmentation, a hallmark of apoptosis, while the other examined di-, tri-, tetra-, and pentachlorobiphenyls did not. To further study the 2,2',4,6,6'-PeCB-induced cell death, various features of apoptosis were examined. 2,2',4,6,6'-PeCB caused a decrease in cell viability and induced cellular morphologic features characteristic of apoptosis such as chromatin aggregation and apoptotic bodies. In addition, caspase-3, an executioner of apoptosis, was activated and its substrate, poly(ADP-ribose) polymerase (PARP), was cleaved during 2,2',4,6,6'-PeCB-induced apoptosis. In contrast, 3,3',4,4',5-PeCB, a congener of coplanar structure, as well as 2,3,7,8-TCDD did not induce apoptosis in these human monocytic cells, although they potently induced CYP 1A1 in human hepatoma Hep G2 cells. Taken together, the data indicate that 2,2',4,6,6'-PeCB induces apoptosis in human monocytic cells through a mechanism that is independent of the arylhydrocarbon receptor. This suggests a possibly separate mechanism by which PCBs cause immunosuppression.
Collapse
Affiliation(s)
- K J Shin
- School of Environmental Engineering, Pohang University of Science and Technology, Pohang, 790-784 Kyungbuk, Republic of Korea
| | | | | | | | | | | |
Collapse
|
145
|
Toescu EC, Myronova N, Verkhratsky A. Age-related structural and functional changes of brain mitochondria. Cell Calcium 2000; 28:329-38. [PMID: 11115372 DOI: 10.1054/ceca.2000.0167] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Normal ageing is associated with a gradual decline in the capacity of various cell types, including neurones, to respond to metabolic stress and return to the resting state. An important factor in the decrease of this 'homeostatic reserve' is the gradual, age-dependent impairment of mitochondrial function. In this article we review some of the major structural and functional changes in mitochondria associated with ageing. Apart from the increased mutations in mitochondrial DNA and the evidence for increased oxidative stress with ageing, we also discuss, in some detail, the importance of the mitochondrial membrane structure and composition (in particular lipid composition) for mitochondrial function in general and during ageing. Although some of the neurodegenerative diseases are also associated with some degree of mitochondrial dysfunction, it is not yet clear if these changes are due to the underlining process of normal, physiological ageing or due to the specific pathophysiologic agents responsible for the neurodegenerative processes. Furthermore, we are proposing that there are important differences between normal ageing and neurodegeneration.
Collapse
Affiliation(s)
- E C Toescu
- Department of Physiology, Division Medical Sciences, The University of Birmingham, Edgbaston, UK.
| | | | | |
Collapse
|
146
|
Yu A, Byers DM, Ridgway ND, McMaster CR, Cook HW. Preferential externalization of newly synthesized phosphatidylserine in apoptotic U937 cells is dependent on caspase-mediated pathways. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1487:296-308. [PMID: 11018481 DOI: 10.1016/s1388-1981(00)00100-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Externalization of phosphatidylserine (PtdSer) is a common feature of programmed cell death and plays an important role in the recognition and removal of apoptotic cells. In this study with U937 cells, PtdSer synthesis from [(3)H]serine was stimulated and newly synthesized PtdSer was transferred preferentially to cell-free medium vesicles (CFMV) from cells when apoptosis was induced with a topoisomerase I inhibitor, camptothecin (CAM). When CAM-induced apoptosis was blocked by a caspase inhibitor, z-VAD-fmk, stimulation of PtdSer synthesis and movement to CFMV were abolished. In contrast, changes in synthesis and transport of sphingomyelin (SM) or phosphatidylethanolamine (PtdEtn) were minor; total phosphatidylcholine (PtdCho) synthesis was below control levels. All phospholipids appeared in CFMV but PtdSer displayed a 6-fold increase relative to controls compared to 3-fold for SM, 2-fold for PtdCho and 1.8-fold for PtdEtn. Even greater effects on specificity of PtdSer synthesis, movement to CFMV and inhibition by z-VAD-fmk were observed in apoptotic cells induced by UV irradiation or tumor necrosis factor-alpha/cycloheximide treatment. Thus, PtdSer biosynthesis stimulated during apoptosis in U937 cells was specific for this phospholipid and was correlated with caspase-mediated exposure of PtdSer at the cell surface and preferential movement to vesicles during apoptosis.
Collapse
Affiliation(s)
- A Yu
- Atlantic Research Centre, Departments of Pediatrics and Biochemistry and Molecular Biology, 5849 University Avenue, Dalhousie University, B3H 4H7, Halifax, NS, Canada
| | | | | | | | | |
Collapse
|
147
|
Abstract
Though the term apoptosis was originated in pathology and developmental biology as an alternative to necrosis, the tissue necrosis with inflammation is irrelevant to cell culture conditions where apoptosis is mostly studied. Furthermore, no one single morphological feature is either necessary or sufficient to define apoptosis. The emerging biochemical definition, a cell death with caspase activation, allows the distinction of alternative forms of cell death. Thus, inhibition of caspases delays but does not prevent cell death. Slow cell death without caspase activation may nevertheless be associated with DNA fragmentation. Oncogenic Ras, Raf, and mitogen-activated kinases inhibit apoptosis by affecting the cytochrome C/caspase-9 pathway but may arrest growth and cause slow cell death with delayed DNA fragmentation. Such 'slow' cell death without caspase activation is often caused by chemotherapeutic drugs. Whether a cell will undergo apoptosis or slow death depends not only on a chemotherapeutic agent but also on the readiness of cellular caspases. Therefore, one can distinguish apoptosis-prone (eg leukemia) vs apoptosis-resistant cells. Cell susceptibilities to spontaneous, starvation-induced and drug-induced apoptosis are correlated and characterize an apoptosis-prone phenotype. Finally, distinction of slow cell death allows rephrasing of a question regarding the goal of cancer therapy: apoptosis vs slow cell death, or cancer cell-selectivity regardless of the mode of cell death.
Collapse
Affiliation(s)
- M V Blagosklonny
- Medicine Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| |
Collapse
|
148
|
Fadeel B, Orrenius S, Zhivotovsky B. The most unkindest cut of all: on the multiple roles of mammalian caspases. Leukemia 2000; 14:1514-25. [PMID: 10942252 DOI: 10.1038/sj.leu.2401871] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The caspases, first discovered almost a decade ago, are intracellular cysteine proteases which have been shown to play an essential role in the initiation and execution phases of apoptotic cell death. Numerous strategies for the activation and inhibition of these 'killer' proteases have evolved, including the regulation of caspase expression and function at the transcriptional and post-translational level, as well as the expression of viral and cellular inhibitors of caspases. Emerging evidence in recent years has also implicated the caspases in various, nonapoptotic aspects of cellular physiology, such as cytokine processing during inflammation, differentiation of progenitor cells during erythropoiesis and lens fiber development, and proliferation of T lymphocytes, thus attesting to the pleiotropic functions of these proteases. The present review aims to discuss the multiple roles of the mammalian caspases with particular emphasis on their activation and regulation in cells of leukemic origin and the attendant possibilities of therapeutic intervention.
Collapse
Affiliation(s)
- B Fadeel
- Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | |
Collapse
|
149
|
Mather M, Rottenberg H. Aging enhances the activation of the permeability transition pore in mitochondria. Biochem Biophys Res Commun 2000; 273:603-8. [PMID: 10873652 DOI: 10.1006/bbrc.2000.2994] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aging is associated with mitochondrial dysfunction in several tissues. However, it is not known how the observed mitochondrial dysfunction is related to aging-associated tissue degeneration. We have shown previously that the activation of the permeability transition pore (PTP), which is believed to play a critical role in cell necrosis and apoptosis, is enhanced in spleen lymphocytes from old mice. Here we show that the threshold for calcium-induced, cyclosporin-sensitive, calcium release was significantly lower in isolated brain and liver mitochondria from aging mice. Thus, aging mice exhibit enhanced PTP activation in lymphocytes, brain, and liver. These results suggest that aging increases the susceptibility to calcium-dependent cell death (e.g., excitotoxicity, ischemia-reperfusion damage) in the brain, liver, and possibly other tissues. In addition, other pathways to apoptosis or necrosis that depend on PTP activation are also likely to be enhanced by aging.
Collapse
Affiliation(s)
- M Mather
- MCP Hahnemann University, Philadelphia, Pennsylvania 19102, USA
| | | |
Collapse
|