151
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Lorenzo HK, Susin SA. Therapeutic potential of AIF-mediated caspase-independent programmed cell death. Drug Resist Updat 2008; 10:235-55. [PMID: 18180198 DOI: 10.1016/j.drup.2007.11.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 11/01/2007] [Indexed: 01/15/2023]
Abstract
Resistance to anticancer drugs is often related to deficient cell death execution pathways in cancer cells. Apoptosis, which denotes a form of cell death executed by caspases, was traditionally considered as the only physiological and programmed form of cell death. However, recent evidence indicates that programmed cell death (PCD) can occur in complete absence of caspase activation. Indeed, a large number of caspase-independent models are now defined and a key protein implicated in this type of PCD, apoptosis-inducing factor (AIF), has been identified. AIF is a mitochondrial protein with two faces looking in opposite life/death directions. Recently, the identification of five different isoforms allowed a better characterization of AIFs life/mitochondrial versus death/nuclear functions, as well as definition of its pro-apoptotic region and some of its nuclear partners. Importantly, much work on caspase-independent PCD has revealed that AIF participates in more PCD systems than initially thought. A wider molecular knowledge of AIF, and of the caspase-independent PCDs in which it is involved, are key to provide new insights into the role of PCD. There is no doubt that these insights will lead to the development of more selective and efficient drugs against cancer, degenerative diseases, and other pathological disorders implicating AIF.
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Affiliation(s)
- Hans K Lorenzo
- INSERM U542, Institut André Lwoff, Lavoisier Building, 94803 Villejuif, France.
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152
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Malik F, Kumar A, Bhushan S, Khan S, Bhatia A, Suri KA, Qazi GN, Singh J. Reactive oxygen species generation and mitochondrial dysfunction in the apoptotic cell death of human myeloid leukemia HL-60 cells by a dietary compound withaferin A with concomitant protection by N-acetyl cysteine. Apoptosis 2007; 12:2115-33. [PMID: 17874299 DOI: 10.1007/s10495-007-0129-x] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Induction of apoptosis in cancer cells has become the major focus of anti-cancer therapeutics development. WithaferinA, a major chemical constituent of Withania somnifera, reportedly shows cytotoxicity in a variety of tumor cell lines while its molecular mechanisms of action are not fully understood. We observed that withaferinA primarily induces oxidative stress in human leukemia HL-60 cells and in several other cancer cell lines. The withanolide induced early ROS generation and mitochondrial membrane potential (Deltapsi(mt)) loss, which preceded release of cytochrome c, translocation of Bax to mitochondria and apoptosis inducing factor to cell nuclei. These events paralleled activation of caspases -9, -3 and PARP cleavage. WA also activated extrinsic pathway significantly as evidenced by time dependent increase in caspase-8 activity vis-à-vis TNFR-1 over expression. WA mediated decreased expression of Bid may be an important event for cross talk between intrinsic and extrinsic signaling. Furthermore, withaferinA inhibited DNA binding of NF-kappaB and caused nuclear cleavage of p65/Rel by activated caspase-3. N-acetyl-cysteine rescued all these events suggesting thereby a pro-oxidant effect of withaferinA. The results of our studies demonstrate that withaferinA induced early ROS generation and mitochondrial dysfunction in cancer cells trigger events responsible for mitochondrial -dependent and -independent apoptosis pathways.
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Affiliation(s)
- Fayaz Malik
- Division of Pharmacology, Indian Institute of Integrative Medicine, Council of Scientific and Industrial Research, Canal Road, Jammu-Tawi 180001, India
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153
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Heeres JT, Hergenrother PJ. Poly(ADP-ribose) makes a date with death. Curr Opin Chem Biol 2007; 11:644-53. [DOI: 10.1016/j.cbpa.2007.08.038] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 08/30/2007] [Indexed: 01/23/2023]
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154
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Hail N, Carter BZ, Konopleva M, Andreeff M. Apoptosis effector mechanisms: a requiem performed in different keys. Apoptosis 2007; 11:889-904. [PMID: 16547589 DOI: 10.1007/s10495-006-6712-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Apoptosis is the regulated form of cell death utilized by metazoans to remove unneeded, damaged, or potentially deleterious cells. Certain manifestations of apoptosis may be associated with the proteolytic activity of caspases. These changes are often held as hallmarks of apoptosis in dying cells. Consequently, many regard caspases as the central effectors or executioners of apoptosis. However, this "caspase-centric" paradigm of apoptotic cell death does not appear to be as universal as once believed. In fact, during apoptosis the efficacy of caspases may be highly dependent on the cytotoxic stimulus as well as genetic and epigenetic factors. An ever-increasing number of studies strongly suggest that there are effectors in addition to caspases, which are important in generating apoptotic signatures in dying cells. These seemingly caspase-independent effectors may represent evolutionarily redundant or failsafe mechanisms for apoptotic cell elimination. In this review, we will discuss the molecular regulation of caspases and various caspase-independent effectors of apoptosis, describe the potential context and/or limitations of these mechanisms, and explore why the understanding of these processes may have relevance in cancer where treatment is believed to engage apoptosis to destroy tumor cells.
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Affiliation(s)
- N Hail
- Department of Clinical Pharmacy, School of Pharmacy, Denver and Health Sciences Center, The University of Colorado, Denver, CO 80262, USA
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155
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Srivastava S, Banerjee H, Chaudhry A, Khare A, Sarin A, George A, Bal V, Durdik JM, Rath S. Apoptosis-inducing factor regulates death in peripheral T cells. THE JOURNAL OF IMMUNOLOGY 2007; 179:797-803. [PMID: 17617569 DOI: 10.4049/jimmunol.179.2.797] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Apoptosis-inducing factor (Aif) is a mitochondrial flavoprotein with multiple roles in apoptosis as well as in cellular respiration and redox regulation. The harlequin (Hq) mouse strain carries an aif locus modification causing reduced Aif expression. We demonstrate that activated CD4(+) and CD8(+) peripheral T cells from Hq mice show resistance to neglect-induced death (NID) triggered by growth factor withdrawal, but not to death induced by multiple agents that trigger DNA damage. Aif translocates to the nucleus in cells undergoing NID, and, in Hq T cell blasts, resistance to NID is associated with reduced cytosolic release of mitochondrial cytochrome c, implicating Aif in this event. In contrast, Hq T cell blasts express higher levels of CD95L, demonstrating increased susceptibility to activation-induced cell death (AICD) and apoptosis triggered by hydrogen peroxide. Superoxide scavenging protects from AICD in wild-type, but not Hq, T cell blasts, suggesting that Aif plays a crucial superoxide-scavenging role to regulate T cell AICD. Finally, the altered pattern of death susceptibility is reproduced by siRNA-mediated reduction of Aif expression in normal T cells. Thus, Aif serves nonredundant roles, both proapoptotic and antiapoptotic, in activated peripheral T cells.
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156
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Collingwood TS, Smirnova EV, Bogush M, Carpino N, Annan RS, Tsygankov AY. T-cell ubiquitin ligand affects cell death through a functional interaction with apoptosis-inducing factor, a key factor of caspase-independent apoptosis. J Biol Chem 2007; 282:30920-8. [PMID: 17709377 DOI: 10.1074/jbc.m706870200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The lymphoid protein T-cell ubiquitin ligand (TULA)/suppressor of T-cell receptor signaling (Sts)-2 is associated with c-Cbl and ubiquitylated proteins and has been implicated in the regulation of signaling mediated by protein-tyrosine kinases. The results presented in this report indicate that TULA facilitates T-cell apoptosis independent of either T-cell receptor/CD3-mediated signaling or caspase activity. Mass spectrometry-based analysis of protein-protein interactions of TULA demonstrates that TULA binds to the apoptosis-inducing protein AIF, which has previously been shown to function as a key factor of caspase-independent apoptosis. Using RNA interference, we demonstrate that AIF is essential for the apoptotic effect of TULA. Analysis of the subcellular localization of TULA and AIF together with the functional analysis of TULA mutants is consistent with the idea that TULA enhances the apoptotic effect of AIF by facilitating the interactions of AIF with its apoptotic co-factors, which remain to be identified. Overall, our results shed new light on the biological functions of TULA, a recently discovered protein, describing its role as one of very few known functional interactors of AIF.
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Affiliation(s)
- Therese S Collingwood
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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157
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Zhu C, Wang X, Deinum J, Huang Z, Gao J, Modjtahedi N, Neagu MR, Nilsson M, Eriksson PS, Hagberg H, Luban J, Kroemer G, Blomgren K. Cyclophilin A participates in the nuclear translocation of apoptosis-inducing factor in neurons after cerebral hypoxia-ischemia. ACTA ACUST UNITED AC 2007; 204:1741-8. [PMID: 17635954 PMCID: PMC2118669 DOI: 10.1084/jem.20070193] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Upon cerebral hypoxia-ischemia (HI), apoptosis-inducing factor (AIF) can move from mitochondria to nuclei, participate in chromatinolysis, and contribute to the execution of cell death. Previous work (Cande, C., N. Vahsen, I. Kouranti, E. Schmitt, E. Daugas, C. Spahr, J. Luban, R.T. Kroemer, F. Giordanetto, C. Garrido, et al. 2004. Oncogene. 23:1514–1521) performed in vitro suggests that AIF must interact with cyclophilin A (CypA) to form a proapoptotic DNA degradation complex. We addressed the question as to whether elimination of CypA may afford neuroprotection in vivo. 9-d-old wild-type (WT), CypA+/−, or CypA−/− mice were subjected to unilateral cerebral HI. The infarct volume after HI was reduced by 47% (P = 0.0089) in CypA−/− mice compared with their WT littermates. Importantly, CypA−/− neurons failed to manifest the HI-induced nuclear translocation of AIF that was observed in WT neurons. Conversely, CypA accumulated within the nuclei of damaged neurons after HI, and this nuclear translocation of CypA was suppressed in AIF-deficient harlequin mice. Immunoprecipitation of AIF revealed coprecipitation of CypA, but only in injured, ischemic tissue. Surface plasmon resonance revealed direct molecular interactions between recombinant AIF and CypA. These data indicate that the lethal translocation of AIF to the nucleus requires interaction with CypA, suggesting a model in which two proteins that normally reside in separate cytoplasmic compartments acquire novel properties when moving together to the nucleus.
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Affiliation(s)
- Changlian Zhu
- Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Göteborg University, 405 30 Göteborg, Sweden.
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158
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Herr I, Gassler N, Friess H, Büchler MW. Regulation of differential pro- and anti-apoptotic signaling by glucocorticoids. Apoptosis 2007; 12:271-91. [PMID: 17191112 DOI: 10.1007/s10495-006-0624-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
More than a quarter of a century ago, the phenomenon of glucocorticoid-induced apoptosis in the majority of hematological cells was first recognized. More recently, glucocorticoid-induced antiapoptotic signaling associated with apoptosis resistance has been identified in cells of epithelial origin, most of malignant solid tumors and some other tissues. Despite these huge amount of data demonstrating differential pro- and anti-apoptotic effects of glucocorticoids, the underlying mechanisms of cell type specific glucocorticoid signaling are just beginning to be described. This review summarizes our present understanding of cell type-specific pro- and anti-apoptotic signaling induced by glucocorticoids. In the first section we give a summary and update of known glucocorticoid-induced pathways mediating apoptosis in hematological cells. We shortly introduce mechanisms of glucocorticoid resistance of hematological cells. We highlight and discuss the emerging molecular evidence of a general induction of survival signaling in epithelial cells and carcinoma cells by glucocorticoids. We provide a model for glucocorticoid-induced resistance in cells growing in a tissue formation. Thus, attachment to the extracellular matrix and cell-cell contacts typical for e.g. epithelial and tumor cells may be crucially involved in switching the balance of several interacting pathways to survival upon treatment with glucocorticoids.
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Affiliation(s)
- Ingrid Herr
- Department of Surgery, University of Heidelberg, Heidelberg, Germany.
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159
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Fröhlich KU, Fussi H, Ruckenstuhl C. Yeast apoptosis—From genes to pathways. Semin Cancer Biol 2007; 17:112-21. [PMID: 17207637 DOI: 10.1016/j.semcancer.2006.11.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 11/25/2006] [Indexed: 11/23/2022]
Abstract
Yeast are eukaryotic unicellular organisms that are easy to cultivate and offer a wide spectrum of genetic and cytological tools for research. Yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have successfully been used as models for human cell division cycle. Stress conditions, cellular ageing, failed mating, certain mutations or heterologous expression of proapoptotic genes induce yeast cell death with the characteristic markers of apoptosis. Several crucial regulators of apoptosis are conserved between metazoans and yeast. This simple model organism offers the possibility to identify conserved and new components of the apoptotic machinery and to elucidate the regulatory pathways beyond.
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160
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Zhang L, Wei LJ. ACTX-8, a cytotoxic l-amino acid oxidase isolated from Agkistrodon acutus snake venom, induces apoptosis in Hela cervical cancer cells. Life Sci 2007; 80:1189-97. [PMID: 17275856 DOI: 10.1016/j.lfs.2006.12.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 12/03/2006] [Accepted: 12/12/2006] [Indexed: 01/11/2023]
Abstract
ACTX-8 is a protein isolated from Agkistrodon acutus snake venom in our laboratory. It demonstrates cytotoxic activity on various carcinoma cell lines in vitro. However, the mechanism by which ACTX-8 inhibits cell proliferation remains poorly understood. In this study the influence of ACTX-8 on the activation of apoptotic pathway in Hela cells was investigated. We demonstrated that cell death induced by ACTX-8 was concentration- and time-dependent. Apoptotic changes such as phosphatidyl serine externalization and DNA fragmentation were detected in ACTX-8-treated cells. Caspase activation and reactive oxygen species (ROS) production were involved in ACTX-8-induced apoptosis, but pan caspase inhibitor, z-VAD-fmk, could not inhibit cell death induced by ACTX-8 completely, which proved the existence of another pathway for ACTX-8-induced cell death. We found cytochrome c release into cytosol and mitochondrial membrane potential (MMP) dissipation in ACTX-8-treated cells, which indicated that mitochondrial pathway played a role in ACTX-8-induced cell apoptosis. The ratio of expression levels of pro- and anti-apoptotic Bcl-2 family members was not changed by ACTX-8 treatment. However Bad and Bax were translocated from cytosol into mitochondria, and the coimmunoprecipitation result indicated that in mitochondria Bak and Bcl-xL dissociation was followed by the binding of Bad and Bcl-xL. Taken together, the study indicated mitochondrial pathway played an important role in the ACTX-8-induced apoptosis, which was regulated by Bcl-2 family members.
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Affiliation(s)
- Liang Zhang
- School of Pharmacy, Soochow University, Soochow, Jiangsu Province, 215123, China.
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161
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Abstract
Irrespective of the morphological features of end-stage cell death (that may be apoptotic, necrotic, autophagic, or mitotic), mitochondrial membrane permeabilization (MMP) is frequently the decisive event that delimits the frontier between survival and death. Thus mitochondrial membranes constitute the battleground on which opposing signals combat to seal the cell's fate. Local players that determine the propensity to MMP include the pro- and antiapoptotic members of the Bcl-2 family, proteins from the mitochondrialpermeability transition pore complex, as well as a plethora of interacting partners including mitochondrial lipids. Intermediate metabolites, redox processes, sphingolipids, ion gradients, transcription factors, as well as kinases and phosphatases link lethal and vital signals emanating from distinct subcellular compartments to mitochondria. Thus mitochondria integrate a variety of proapoptotic signals. Once MMP has been induced, it causes the release of catabolic hydrolases and activators of such enzymes (including those of caspases) from mitochondria. These catabolic enzymes as well as the cessation of the bioenergetic and redox functions of mitochondria finally lead to cell death, meaning that mitochondria coordinate the late stage of cellular demise. Pathological cell death induced by ischemia/reperfusion, intoxication with xenobiotics, neurodegenerative diseases, or viral infection also relies on MMP as a critical event. The inhibition of MMP constitutes an important strategy for the pharmaceutical prevention of unwarranted cell death. Conversely, induction of MMP in tumor cells constitutes the goal of anticancer chemotherapy.
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Affiliation(s)
- Guido Kroemer
- Institut Gustave Roussy, Institut National de la Santé et de la Recherche Médicale Unit "Apoptosis, Cancer and Immunity," Université de Paris-Sud XI, Villejuif, France
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162
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Krantic S, Mechawar N, Reix S, Quirion R. Apoptosis-inducing factor: A matter of neuron life and death. Prog Neurobiol 2007; 81:179-96. [PMID: 17267093 DOI: 10.1016/j.pneurobio.2006.12.002] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2006] [Revised: 10/29/2006] [Accepted: 12/07/2006] [Indexed: 01/17/2023]
Abstract
The mitochondrial flavoprotein apoptosis-inducing factor (AIF) is the main mediator of caspase-independent apoptosis-like programmed cell death. Upon pathological permeabilization of the outer mitochondrial membrane, AIF is translocated to the nucleus, where it participates in chromatin condensation and is associated to large-scale DNA fragmentation. Heavy down-regulation of AIF expression in mutant mice or reduced AIF expression achieved with small interfering RNA (siRNA) provides neuroprotection against acute neurodegenerative insults. Paradoxically, in addition to its pro-apoptotic function, AIF likely plays an anti-apoptotic role by regulating the production of reactive oxygen species (ROS) via its putative oxidoreductase and peroxide scavenging activities. In this review, we discuss accumulating evidence linking AIF to both acute and chronic neurodegenerative processes by emphasising mechanisms underlying the dual roles apparently played by AIF in these processes.
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Affiliation(s)
- Slavica Krantic
- Institut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale, Parc Scientifique Luminy, BP13, 13 273 Marseille, France
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163
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Leverrier S, Bergamaschi D, Ghali L, Ola A, Warnes G, Akgül B, Blight K, García-Escudero R, Penna A, Eddaoudi A, Storey A. Role of HPV E6 proteins in preventing UVB-induced release of pro-apoptotic factors from the mitochondria. Apoptosis 2006; 12:549-60. [PMID: 17195958 DOI: 10.1007/s10495-006-0004-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Accepted: 10/30/2006] [Indexed: 12/14/2022]
Abstract
Apoptotic elimination of UV-damaged cells from the epidermis is an important step in preventing both the emergence and expansion of cells with carcinogenic potential. A pivotal event in apoptosis is the release of apoptogenic factors from the mitochondria, although the mechanisms by which the different proteins are released are not fully understood. Here we demonstrate that UV radiation induced the mitochondrial to nuclear translocation of apoptosis inducing factor (AIF) in normal skin. The human papillomavirus (HPV) E6 protein prevented release of AIF and other apoptotic factors such as cytochrome c and Omi from mitochondria of UV-damaged primary epidermal keratinocytes and preserved mitochondrial integrity. shRNA silencing of Bak, a target for E6-mediated proteolysis, demonstrated the requirement of Bak for UV-induced AIF release and mitochondrial fragmentation. Furthermore, screening non-melanoma skin cancer biopsies revealed an inverse correlation between HPV status and AIF nuclear translocation. Our results indicate that the E6 activity towards Bak is a key factor that promotes survival of HPV-infected cells that facilitates tumor development.
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Affiliation(s)
- Sabrina Leverrier
- CR-UK, Skin Tumour Laboratory, Centre for Cutaneous Research, London, UK
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164
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McGrath LB, Onnis V, Campiani G, Williams DC, Zisterer DM, Mc Gee MM. Caspase-activated DNase (CAD)-independent oligonucleosomal DNA fragmentation in chronic myeloid leukaemia cells; a requirement for serine protease and Mn2+-dependent acidic endonuclease activity. Apoptosis 2006; 11:1473-87. [PMID: 16820964 DOI: 10.1007/s10495-006-8968-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
We have previously reported that the pro-apoptotic pyrrolobenzoxazepine, PBOX-6, induces apoptosis in chronic myelogenous leukaemia (CML) cells which is accompanied by oligonucleosomal DNA fragmentation. In this study we show that PBOX-6-induced oligonucleosomal DNA fragmentation occurs in the absence of caspase and CAD activation in CML cells. Dissection of the signalling pathway has revealed that induction of apoptosis requires the upstream activation of a trypsin-like serine protease that promotes the phosphorylation and inactivation of anti-apoptotic Bcl-2. In addition, in this system chymotrypsin-like serine proteases are dispensable for high molecular weight DNA fragmentation, however are required for the activation of a relatively small manganese-dependent acidic endonuclease that is responsible for oligonucleosomal fragmentation of DNA. Furthermore, we demonstrate mitochondrial involvement during PBOX-6-induced apoptosis and suggest the existence of unidentified mitochondrial effectors of apoptosis.
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Affiliation(s)
- L B McGrath
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland,
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165
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Sanges D, Marigo V. Cross-talk between two apoptotic pathways activated by endoplasmic reticulum stress: differential contribution of caspase-12 and AIF. Apoptosis 2006; 11:1629-41. [PMID: 16820963 DOI: 10.1007/s10495-006-9006-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Co-activation and cross-talk of different apoptotic pathways have been described in several systems however, the differential contributions of the different executors have not been well characterized. Here we report the co-translocation to the nucleus of caspase-12 and AIF in response to two endoplasmic reticulum (ER) stresses: protein misfolding and disruption of calcium homeostasis. As seen by treatment with pan-caspase inhibitor and calpain inhibitors, apoptosis is not mediated by executor caspases but by calpains. By reduction of AIF or caspase-12 expression we unraveled that AIF primarily controls apoptosis caused by changes in calcium homeostasis while caspase-12 has a main role in programmed cell death induced by protein misfolding. Nevertheless, the two apoptotic factors appear to reinforce each other during the apoptotic process, confirming that while the first response primarily involves one organelle, mitochondria and ER can influence each other in the apoptotic event.
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Affiliation(s)
- Daniela Sanges
- Telethon Institute of Genetics and Medicine, TIGEM, via P. Castellino, Naples, 111 80131, Italy
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166
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Kim JT, Kim KD, Song EY, Lee HG, Kim JW, Kim JW, Chae SK, Kim E, Lee MS, Yang Y, Lim JS. Apoptosis-inducing factor (AIF) inhibits protein synthesis by interacting with the eukaryotic translation initiation factor 3 subunit p44 (eIF3g). FEBS Lett 2006; 580:6375-83. [PMID: 17094969 DOI: 10.1016/j.febslet.2006.10.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/25/2006] [Accepted: 10/25/2006] [Indexed: 11/23/2022]
Abstract
Apoptosis-inducing factor (AIF) is a ubiquitous FAD-binding flavoprotein comprised of 613 amino acids and plays an important role in caspase-independent apoptosis. During apoptotic induction, AIF is translocated from the mitochondrial intermembrane space to the nucleus, where it interacts with DNA and activates a nuclear endonuclease. By performing a yeast two-hybrid screen with mature AIF, we have isolated the eukaryotic translation initiation factor 3 subunit p44 (eIF3g). Our deletion mutant analysis revealed that the eIF3g N-terminus interacts with the C-terminal region of AIF. The direct interaction between AIF and eIF3g was confirmed in a GST pull-down assay and also verified by the results of co-immunoprecipitation and confocal microscopy studies. Using an in vitro TNT coupled transcription-translation system, we found that mature AIF could inhibit newly-translated protein synthesis and this inhibition was significantly blocked by eIF3g competitively. These results were also confirmed in cells. In addition, mature AIF overexpression specifically resulted in the activation of caspase-7, thereby amplifying the inhibition of protein synthesis including eIF3g cleavage. Our data suggest that eIF3g is one of the cytosolic targets that interacts with mature AIF, and provide insight into the AIF's cellular functions of the inhibition of protein synthesis during apoptosis.
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Affiliation(s)
- Jong-Tae Kim
- Department of Biological Sciences, Research Center for Women's Diseases, Sookmyung Women's University, Chungpa-Dong, Yongsan-Gu, Seoul 140-742, Republic of Korea
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167
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Cheung ECC, Joza N, Steenaart NAE, McClellan KA, Neuspiel M, McNamara S, MacLaurin JG, Rippstein P, Park DS, Shore GC, McBride HM, Penninger JM, Slack RS. Dissociating the dual roles of apoptosis-inducing factor in maintaining mitochondrial structure and apoptosis. EMBO J 2006; 25:4061-73. [PMID: 16917506 PMCID: PMC1560366 DOI: 10.1038/sj.emboj.7601276] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 07/19/2006] [Indexed: 11/09/2022] Open
Abstract
The mitochondrial protein apoptosis-inducing factor (AIF) translocates to the nucleus and induces apoptosis. Recent studies, however, have indicated the importance of AIF for survival in mitochondria. In the absence of a means to dissociate these two functions, the precise roles of AIF remain unclear. Here, we dissociate these dual roles using mitochondrially anchored AIF that cannot be released during apoptosis. Forebrain-specific AIF null (tel. AifDelta) mice have defective cortical development and reduced neuronal survival due to defects in mitochondrial respiration. Mitochondria in AIF deficient neurons are fragmented with aberrant cristae, indicating a novel role of AIF in controlling mitochondrial structure. While tel. AifDelta Apaf1(-/-) neurons remain sensitive to DNA damage, mitochondrially anchored AIF expression in these cells significantly enhanced survival. AIF mutants that cannot translocate into nucleus failed to induce cell death. These results indicate that the proapoptotic role of AIF can be uncoupled from its physiological function. Cell death induced by AIF is through its proapoptotic activity once it is translocated to the nucleus, not due to the loss of AIF from the mitochondria.
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Affiliation(s)
- Eric C C Cheung
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicholas Joza
- IMBA, Institute of Molecular Biotechnology of the Austria Academy of Sciences, Vienna, Austria
| | | | - Kelly A McClellan
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Margaret Neuspiel
- Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Stephen McNamara
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jason G MacLaurin
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Peter Rippstein
- Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - David S Park
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Gordon C Shore
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Heidi M McBride
- Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Josef M Penninger
- IMBA, Institute of Molecular Biotechnology of the Austria Academy of Sciences, Vienna, Austria
| | - Ruth S Slack
- Ottawa Health Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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168
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Counis MF, Torriglia A. Acid DNases and their interest among apoptotic endonucleases. Biochimie 2006; 88:1851-8. [PMID: 16989934 DOI: 10.1016/j.biochi.2006.07.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 07/05/2006] [Indexed: 01/11/2023]
Abstract
Apoptosis is characterized by cell shrinkage, nuclear condensation and internucleosomal DNA cleavage. Besides the central role of caspases and other proteases, cell death triggers DNA degradation so that DNases have an active role in apoptotic cell death. The best-characterized apoptotic DNase is CAD, a neutral Mg-dependent endonuclease. Its activity is regulated by its inhibitor, ICAD, which is cleaved by caspases. Other neutral DNases have been shown to cleave nuclear DNA in apoptotic conditions: endonuclease G, GADD. In cells, the cytosolic pH is maintained to 7.2, mostly due to the activity of the Na(+)/H(+) exchanger. In many apoptotic conditions, a decrease of the intracellular pH has been shown. This decrease may activate different acid DNases, mostly when pH decreases below 6.5. Three acidic DNases II are so far known: DNase II alpha, DNase II beta and L-DNase II, a DNase II, derived from the serpin LEI (Leukocyte Elastase Inhibitor). Their activation during cell death is discussed in this review.
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Affiliation(s)
- Marie-France Counis
- INSERM U 598, Centre de Recherches Biomédicales des Cordeliers, Paris, France.
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169
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Malugin A, Kopeèková P, Kopeèek J. HPMA copolymer-bound doxorubicin induces apoptosis in ovarian carcinoma cells by the disruption of mitochondrial function. Mol Pharm 2006; 3:351-61. [PMID: 16749867 PMCID: PMC2544630 DOI: 10.1021/mp050065e] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer-bound doxorubicin has showed greater potency than free doxorubicin in the treatment of ovarian cancer in vivo and in vitro. The promising activity of the conjugate demonstrated in clinical trials has generated considerable interest in understanding the mechanism of action of this macromolecular therapeutic. In this study, the involvement of the mitochondrial pathway in HPMA copolymer-bound doxorubicin-induced apoptosis in the human ovarian cancer cell line A2780 was investigated. Through a series of in vitro assays, including confocal microscopy, flow cytometry, and spectrofluorimetry, a significant decrease in mitochondrial membrane potential in A2780 cells treated with HPMA copolymer-bound doxorubicin was found. The most dramatic changes in mitochondrial membrane potential were observed between 2 and 12 h of continuous drug exposure. The potential of the mitochondrial membrane remained collapsed when drug treatment continued up to 24 h. For the first time, it was shown that HPMA copolymer-bound doxorubicin induces apoptosis in ovarian cancer cells by simultaneous activation of both caspase-dependent and caspase-independent pathways of DNA damage. This was determined by monitoring the translocation of the mitochondrial proteins cytochrome c and apoptosis-inducing factor to cytosol. The altered balance between anti-apoptotic and pro-apoptotic members of the Bcl-2 family of proteins was responsible for the mitochondrial function distraction. HPMA copolymer-bound doxorubicin induced a time-dependent decrease in the expression of the anti-apoptotic Bcl-2 and Bcl-xL proteins, which control cell survival. At the same time, the expression level of pro-apoptotic members (Bax, Bad) of the Bcl-2 family was increased under the chosen experimental conditions. Altogether, these results indicate that HPMA copolymer-bound doxorubicin induced apoptosis in ovarian cancer cells through the mitochondrial pathway.
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Affiliation(s)
- Alexander Malugin
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, U.S.A
| | - Pavla Kopeèková
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, U.S.A
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112, U.S.A
| | - Jindøich Kopeèek
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, U.S.A
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112, U.S.A
- *To whom correspondence should be addressed: Jindøich Kopeèek, Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 30 S., 2000 E., Rm. 201, Salt Lake City, Utah 84112, U.S.A., Phone:(801)581-7211, Fax:(801)581-7848, E-mail:
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170
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Abstract
Apoptosis or programmed cell death is a key regulator of physiological growth control and regulation of tissue homeostasis. One of the most important advances in cancer research in recent years is the recognition that cell death mostly by apoptosis is crucially involved in the regulation of tumor formation and also critically determines treatment response. Killing of tumor cells by most anticancer strategies currently used in clinical oncology, for example, chemotherapy, gamma-irradiation, suicide gene therapy or immunotherapy, has been linked to activation of apoptosis signal transduction pathways in cancer cells such as the intrinsic and/or extrinsic pathway. Thus, failure to undergo apoptosis may result in treatment resistance. Understanding the molecular events that regulate apoptosis in response to anticancer chemotherapy, and how cancer cells evade apoptotic death, provides novel opportunities for a more rational approach to develop molecular-targeted therapies for combating cancer.
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Affiliation(s)
- S Fulda
- University Children's Hospital, Ulm, Germany.
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171
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Galluzzi L, Larochette N, Zamzami N, Kroemer G. Mitochondria as therapeutic targets for cancer chemotherapy. Oncogene 2006; 25:4812-30. [PMID: 16892093 DOI: 10.1038/sj.onc.1209598] [Citation(s) in RCA: 259] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondria are vital for cellular bioenergetics and play a central role in determining the point-of-no-return of the apoptotic process. As a consequence, mitochondria exert a dual function in carcinogenesis. Cancer-associated changes in cellular metabolism (the Warburg effect) influence mitochondrial function, and the invalidation of apoptosis is linked to an inhibition of mitochondrial outer membrane permeabilization (MOMP). On theoretical grounds, it is tempting to develop specific therapeutic interventions that target the mitochondrial Achilles' heel, rendering cancer cells metabolically unviable or subverting endogenous MOMP inhibitors. A variety of experimental therapeutic agents can directly target mitochondria, causing apoptosis induction. This applies to a heterogeneous collection of chemically unrelated compounds including positively charged alpha-helical peptides, agents designed to mimic the Bcl-2 homology domain 3 of Bcl-2-like proteins, ampholytic cations, metals and steroid-like compounds. Such MOMP inducers or facilitators can induce apoptosis by themselves (monotherapy) or facilitate apoptosis induction in combination therapies, bypassing chemoresistance against DNA-damaging agents. In addition, it is possible to design molecules that neutralize inhibitor of apoptosis proteins (IAPs) or heat shock protein 70 (HSP70). Such IAP or HSP70 inhibitors can mimic the action of mitochondrion-derived mediators (Smac/DIABLO, that is, second mitochondria-derived activator of caspases/direct inhibitor of apoptosis-binding protein with a low isoelectric point, in the case of IAPs; AIF, that is apoptosis-inducing factor, in the case of HSP70) and exert potent chemosensitizing effects.
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Affiliation(s)
- L Galluzzi
- CNRS-FRE 2939, Institut Gustave Roussy, Villejuif, France
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172
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Dall'Agnol M, Bernstein C, Bernstein H, Garewal H, Payne CM. Identification of S-nitrosylated proteins after chronic exposure of colon epithelial cells to deoxycholate. Proteomics 2006; 6:1654-62. [PMID: 16404723 DOI: 10.1002/pmic.200500240] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Apoptosis resistance, a condition favoring genomic instability, is associated with higher risk of colorectal cancer. Deoxycholate (DOC) is a hydrophobic bile salt found in high concentrations in colon cancer patients, and induces apoptosis in cultured colonic cells and ex vivo in colonic biopsies. We showed previously that the chronic exposure of colon cancer cells to increasing concentrations of DOC leads to apoptosis resistance, and the suggested mechanism involves oxidative/nitrosative stress. Nitric oxide (NO) is a key signaling molecule that regulates cell function in a variety of physiologic and pathophysiologic states. In part, NO exerts its actions by S-nitrosylation of target thiols, and several proteins are regulated through this PTM, including the caspases, the main effectors of apoptosis. Here, we performed a proteomics study in the DOC-induced apoptosis-resistant colon cell line, HCT-116RC. Its profile of S-nitrosylated proteins was compared to a control cell line not exposed to DOC. Eighteen differentially S-nitrosylated proteins were identified in the HCT-116RC cell line, 14 of these are novel targets of S-nitrosylation not previously reported. These proteins include cytoskeletal and signaling proteins, metabolic enzymes, chaperones, and redox- and differentiation-related proteins. These results broaden our knowledge of potential signal transduction pathways that may lead to the development of new biomarkers and therapy targets.
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Affiliation(s)
- Monique Dall'Agnol
- Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, AZ, USA
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173
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Vahsen N, Candé C, Dupaigne P, Giordanetto F, Kroemer RT, Herker E, Scholz S, Modjtahedi N, Madeo F, Le Cam E, Kroemer G. Physical interaction of apoptosis-inducing factor with DNA and RNA. Oncogene 2006; 25:1763-74. [PMID: 16278674 DOI: 10.1038/sj.onc.1209206] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein, which upon apoptosis induction translocates to the nucleus where it interacts with DNA by virtue of positive charges clustered on the AIF surface. Here we show that the AIF interactome, as determined by mass spectroscopy, contains a large panel of ribonucleoproteins, which apparently bind to AIF through the RNA moiety. However, AIF is devoid of any detectable RNAse activity both in vitro and in vivo. Recombinant AIF can directly bind to DNA as well as to RNA. This binding can be visualized by electron microscopy, revealing that AIF can condense DNA, showing a preferential binding to single-stranded over double-stranded DNA. AIF also binds and aggregates single-stranded and structured RNA in vitro. Single-stranded poly A, poly G and poly C, as well double-stranded A/T and G/C RNA competed with DNA for AIF binding with a similar efficiency, thus corroborating a computer-calculated molecular model in which the binding site within AIF is the same for distinct nucleic acid species, without a clear sequence specificity. Among the preferred electron donors and acceptors of AIF, nicotine adenine dinucleotide phosphate (NADP) was particularly efficient in enhancing the generation of higher-order AIF/DNA and AIF/RNA complexes. Altogether, these data support a model in which a direct interaction of AIF contributes to the compaction of nucleic acids within apoptotic cells.
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Affiliation(s)
- N Vahsen
- Centre National de la Recherche Scientifique, UMR8125, Institut Gustave Roussy, 39 rue Camille-Desmoulins, F-94805 Villejuif, France
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174
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Besada V, Diaz M, Becker M, Ramos Y, Castellanos-Serra L, Fichtner I. Proteomics of xenografted human breast cancer indicates novel targets related to tamoxifen resistance. Proteomics 2006; 6:1038-48. [PMID: 16385476 DOI: 10.1002/pmic.200500151] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Tamoxifen is the most frequently used drug for hormone therapy of breast cancer patients, even though a high percentage of women are (or become) refractory to this treatment. The proteins involved in tamoxifen resistance of breast tumor cells as well as the mechanisms by which they interact, are still unknown. Some years ago, we established the xenograft breast tumor 3366, sensitive to tamoxifen and the 3366/TAM, resistant to tamoxifen, derived after two years of in vivo passages of the parental 3366 under tamoxifen treatment. Here, we compare the protein expression levels of both xenografts. 2-DE of proteins from total cell extracts showed very high reproducibility among tumors from each group (tamoxifen sensitive and tamoxifen resistant). The heuristic clustering analysis of these gels pooled them correctly in both groups. Twelve proteins were found up-regulated in the tamoxifen-resistant line, while nine were down-regulated. The proteins differentially expressed were identified by MS and sequence database analysis. Biological functions of these proteins are related to cell-cell adhesion and interaction, signal transduction, DNA and protein synthesis machinery, mitochondrial respiratory chain, oxidative stress processes and apoptosis. Three of the identified proteins (ALG-2 interacting protein and two GDP-dissociation inhibitors) could be directly involved in the resistance phenomenon.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antineoplastic Agents, Hormonal/therapeutic use
- Biomarkers, Tumor/metabolism
- Breast Neoplasms/drug therapy
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cluster Analysis
- Drug Resistance, Neoplasm
- Electrophoresis, Gel, Two-Dimensional
- Female
- Humans
- Mice
- Mice, Nude
- Molecular Sequence Data
- Proteomics
- Sequence Homology, Amino Acid
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Tamoxifen/therapeutic use
- Transplantation, Heterologous
- Tumor Cells, Cultured
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Affiliation(s)
- Vladimir Besada
- Department for Proteome Analysis, Centre for Genetic Engineering and Biotechnology, Havana, Cuba
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175
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Jack GD, Mead EA, Garst JF, Cabrera MC, DeSantis AM, Slaughter SM, Jervis J, Brooks AI, Potts M, Helm RF. Long term metabolic arrest and recovery of HEK293 spheroids involves NF-kappaB signaling and sustained JNK activation. J Cell Physiol 2006; 206:526-36. [PMID: 16155929 DOI: 10.1002/jcp.20499] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Understanding how cells withstand a depletion of intracellular water is relevant to the study of longevity, aging, and quiescence because one consequence of air-drying is metabolic arrest. After removal of medium, HEK293 spheroids with intracellular water content of approximately 65% survived partial vacuum, with antistatic control, for weeks in the dark at 25 degrees C. In contrast, only a limited exposure of monolayers to air was lethal; the mitochondrion being a target of this stress. The pathways activated during the long-term arrest and recovery of spheroids depended on both NF-kappaB signaling and sustained JNK activation. A cyclical cascade, presumably originating from an intercellular stress signal, led to endogenous cytokine production (TNF-alpha, IL-1b, and IL-8) and propagation of the cellular stress signal through the co-activation of NF-kappaB and JNK. Increased levels of downstream pathway signaling members, specifically Gadd45beta, c-jun, and ATF3 were observed, as was activation of c-jun (phosphorylation). Activation of these pathways permit cells to survive long-term storage and recovery because chemical inhibition of both NF-kappaB nuclear translocation and JNK phosphorylation led to cell death. The capacity of an immortalized cell to enter, and then exit, a state of long-term quiescence, without genetic or chemical intervention, has implications for the study of cell transformation. In addition, the ability to monitor the relevant signaling pathways at endogenous levels, from effector to transcriptional regulator, emphasizes the utility of multicellular aggregate models in delineating stress response pathways.
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Affiliation(s)
- Graham D Jack
- Department of Biochemistry, Virginia Tech Center for Genomics, Virginia Tech, Blacksburg, Virginia, USA
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176
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Obama K, Kato T, Hasegawa S, Satoh S, Nakamura Y, Furukawa Y. Overexpression of peptidyl-prolyl isomerase-like 1 is associated with the growth of colon cancer cells. Clin Cancer Res 2006; 12:70-6. [PMID: 16397026 DOI: 10.1158/1078-0432.ccr-05-0588] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE AND EXPERIMENTAL DESIGN To discover novel therapeutic targets for colon cancers, we previously surveyed expression patterns among 23,000 genes in colon cancer tissues using a cDNA microarray. Among the genes that were up-regulated in the tumors, we selected for this study peptidyl-prolyl isomerase-like 1 (PPIL1) encoding PPIL1, a cyclophilin-related protein. RESULTS Western blot analysis and immunohistochemical staining using PPIL1-specific antibody showed that PPIL1 protein was frequently overexpressed in colon cancer cells compared with noncancerous epithelial cells of the colon mucosa. Colony formation assay showed a growth-promoting effect of wild-type PPIL1 on NIH3T3 and HEK293 cells. Consistently, transfection of short-interfering RNA specific to PPIL1 into SNUC4 and SNUC5 cells effectively reduced expression of the gene and retarded growth of the colon cancer cells. We further identified two PPIL1-interacting proteins, SNW1/SKIP (SKI-binding protein) and stathmin. SNW1/SKIP is involved in the regulation of transcription and mRNA splicing, whereas stathmin is involved in stabilization of microtubules. Therefore, elevated expression of PPIL1 may play an important role in proliferation of cancer cells through the control of SNW1/SKIP and/or stathmin. CONCLUSION The findings reported here may offer new insight into colonic carcinogenesis and contribute to the development of new molecular strategies for treatment of human colorectal tumors.
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Affiliation(s)
- Kazutaka Obama
- Laboratory of Molecular Medicine, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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177
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Yu CJ, Jia LT, Meng YL, Zhao J, Zhang Y, Qiu XC, Xu YM, Wen WH, Yao LB, Fan DM, Jin BQ, Chen SY, Yang AG. Selective proapoptotic activity of a secreted recombinant antibody/AIF fusion protein in carcinomas overexpressing HER2. Gene Ther 2006; 13:313-20. [PMID: 16267568 DOI: 10.1038/sj.gt.3302672] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 07/19/2005] [Accepted: 08/25/2005] [Indexed: 11/09/2022]
Abstract
Apoptosis-inducing factor (AIF) represents a caspase-independent apoptotic pathway in the cell, and a mitochondrial localization sequence-truncated AIF (AIFDelta1-120) can be relocated from the cytoplasm to the nucleus and exhibit a constitutive proapoptotic activity. Here, we generated a chimeric immuno-AIF protein, which comprised an HER2 antibody, a Pseudomonas exotoxin translocation domain and AIFDelta1-120. Human Jurkat cells transfected with the immuno-AIF gene could express and secrete the chimeric protein, which selectively recognized HER2-overexpressing tumor cells and was endocytosed. Subsequent cleavage of truncated AIF from immuno-AIF and its release from the internalized vesicles resulted in apoptosis of tumor cells. Intramuscular injection of the immuno-AIF gene caused significant suppression of tumors and substantially prolonged mice survival in an HER2-overexpressing xenograft tumor model. Our study demonstrates the feasibility of the immuno-AIF gene as a novel approach to treating cancers that overexpress HER2.
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Affiliation(s)
- C-J Yu
- State Key Laboratory of Cancer Biology, Department of Immunology, Fourth Military Medical University, Xi'an, China
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178
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Byun K, Kim J, Cho SY, Hutchinson B, Yang SR, Kang KS, Cho M, Hwang K, Michikawa M, Jeon YW, Paik YK, Lee B. Alteration of the glutamate and GABA transporters in the hippocampus of the Niemann-Pick disease, type C mouse using proteomic analysis. Proteomics 2006; 6:1230-6. [PMID: 16429462 DOI: 10.1002/pmic.200500412] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Niemann-Pick disease type C (NPC) is a fatal autosomal recessive cholesterol disorder characterized by severe progressive neurodegeneration. To unveil the mechanism of neurodegeneration, proteomic and morphological approaches were applied to the hippocampus in NPC -/- mouse. Two-DE was utilized to resolve the hippocampal protein expression profiles of 4- and 8-week-old NPC +/+ and -/- mice. Differentially expressed protein spots were identified by MALDI-TOF MS and database searching. At 4 weeks of age, there was no significant difference in protein profiles between NPC +/+ and -/- mice. However, at the age of 8 weeks, NPC +/+ and -/- mice showed marked difference in protein expressions. Among these, glutamate receptor 2 precursor was identified. The immunohistochemical study on neurotransporters showed that glial GABA transporter (GAT-3) increased in both 4- and 8-week-old NPC -/- mouse and glutamic acid decarboxylase (GAD-6) increased in 8-week-old NPC -/- mouse. Glial glutamate transporter, excitatory amino acids carrier-1 (EAAC1), decreased in 8-week-old NPC -/- mouse. In conclusion, our data may provide insight into the understanding of the basic mechanism through perturbation of protein networks and neurotransporter systems in a single gene knockout model of NPC disease.
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Affiliation(s)
- Kyunghee Byun
- Department of Anatomy and Neurobiology, College of Medicine, Institute of Medical Science, Cheju National University, Jeju City, Jeju, South Korea
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179
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Parrish JZ, Xue D. Cuts can kill: the roles of apoptotic nucleases in cell death and animal development. Chromosoma 2006; 115:89-97. [PMID: 16418867 DOI: 10.1007/s00412-005-0038-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 11/28/2005] [Accepted: 11/28/2005] [Indexed: 12/28/2022]
Abstract
Chromosome fragmentation is one of the major biochemical hallmarks of apoptosis. However, until recently, its roles in apoptosis and mechanisms of action remained elusive. Recent biochemical and genetic studies have shown that chromosome fragmentation is a complex biochemical process that involves a plethora of conserved nucleases with distinct nuclease activities and substrate specificities. These apoptotic nucleases act cooperatively among themselves and with other nonnuclease cofactors to promote stepwise chromosome fragmentation and DNA degradation. Importantly, in addition to its direct contribution to the dismantling of the dying cell, apoptotic DNA degradation can facilitate cell killing and other apoptotic events such as clearance of apoptotic cells. Furthermore, some apoptotic nucleases apparently affect other aspects of animal development, including immune responses. The identification of new apoptotic nucleases and analysis of their functions in apoptosis and animal development should pave the way for future studies to uncover new functions for apoptotic nucleases and shed light on the hidden links between apoptotic DNA degradation and human diseases.
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Affiliation(s)
- Jay Z Parrish
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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180
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Porter AG, Urbano AGL. Does apoptosis-inducing factor (AIF) have both life and death functions in cells? Bioessays 2006; 28:834-43. [PMID: 16927311 DOI: 10.1002/bies.20444] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Apoptosis-inducing factor (AIF) is expelled from mitochondria after some apoptotic stimuli and translocates to the nucleus, which may contribute to DNA and nuclear fragmentation in some non-physiological mammalian cell deaths. Conversely, the requirement for mitochondrial AIF in oxidative phosphorylation and energy generation provides a plausible explanation for the embryonic lethality or neurodegeneration that has been found in different AIF-deficient mouse models. These findings may help illuminate the ability of mitochondrial AIF to suppress cytoplasmic stress granule formation and to promote the tumorigenic growth of cancer cells. AIF is ideally located in the mitochondrion to perform a vital normal function in energy production. Once it translocates to the nucleus, however, the cell might die either of energy failure or nuclear fragmentation (or both). We propose that the main function of AIF is to support energy production in both normal and transformed cell physiology, whereas nuclear-translocated AIF might contribute to stress-induced or pathological cell death in certain scenarios.
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Affiliation(s)
- Alan G Porter
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore.
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181
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Pemberton TJ, Kay JE. The cyclophilin repertoire of the fission yeast Schizosaccharomyces pombe. Yeast 2005; 22:927-45. [PMID: 16134115 DOI: 10.1002/yea.1288] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The cyclophilin repertoire of the fission yeast Schizosaccharomyces pombe is comprised of nine members that are distributed over all three of its chromosomes and range from small single-domain to large multi-domain proteins. Each cyclophilin possesses only a single prolyl-isomerase domain, and these vary in their degree of consensus, including at positions that are likely to affect their drug-binding ability and catalytic activity. The additional identified motifs are involved in putative protein or RNA interactions, while a novel domain that is specific to SpCyp7 and its orthologues may have functions that include an interaction with hnRNPs. The Sz. pombe cyclophilins are found throughout the cell but appear to be absent from the mitochondria, which is unique among the characterized eukaryotic repertoires. SpCyp5, SpCyp6 and SpCyp8 have exhibited significant upregulation of their expression during the meiotic cycle and SpCyp5 has exhibited significant upregulation of its expression during heat stress. All nine have identified members in the repertoires of H. sapiens, D. melanogaster and A. thaliana. However, only three identified members in the cyclophilin repertoire of S. cerevisiae with SpCyp7 identifying a fourth protein that is not a member of the recognized repertoire due to its possession of a degenerate prolyl-isomerase domain. The cyclophilin repertoire of Sz. pombe therefore represents a better model group for the study of cyclophilin function in the higher eukaryotes.
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Affiliation(s)
- Trevor J Pemberton
- The Brighton and Sussex Medical School, University of Sussex, Falmer, Brighton, East Sussex BN1 9PX, UK.
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182
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Delettre C, Yuste VJ, Moubarak RS, Bras M, Lesbordes-Brion JC, Petres S, Bellalou J, Susin SA. AIFsh, a novel apoptosis-inducing factor (AIF) pro-apoptotic isoform with potential pathological relevance in human cancer. J Biol Chem 2005; 281:6413-27. [PMID: 16365034 DOI: 10.1074/jbc.m509884200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIF is a main mediator of caspase-independent cell death. It is encoded by a single gene located on chromosome X, region q25-26 and A6 in humans and mice, respectively. Previous studies established that AIF codes for two isoforms of the protein, AIF and AIF-exB. Here, we identify a third AIF isoform resulting from an alternate transcriptional start site located at intron 9 of AIF. The resulting mRNA encodes a cytosolic protein that corresponds to the C-terminal domain of AIF (amino acids 353-613). We named this new isoform AIFshort (AIFsh). AIFsh overexpression in HeLa cells results in nuclear translocation and caspase-independent cell death. Once in the nucleus, AIFsh provokes the same effects than AIF, namely chromatin condensation and large scale (50 kb) DNA fragmentation. In contrast, these apoptogenic effects are not precluded by the AIF-inhibiting protein Hsp70. These findings identify AIFsh as a new pro-apoptotic isoform of AIF, and also reveal that the first N-terminal 352 amino acids of AIF are not required for its apoptotic activity. In addition, we demonstrate that AIFsh is strongly down-regulated in tumor cells derived from kidney, vulva, skin, thyroid, and pancreas, whereas, gamma-irradiation treatment provokes AIFsh up-regulation. Overall, our results identify a novel member of the AIF-dependent pathway and shed new light on the role of caspase-independent cell death in tumor formation/suppression.
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Affiliation(s)
- Cécile Delettre
- Apoptose et Système Immunitaire, CNRS-URA 1961 and Plateforme 5-Production de Protéines Recombinantes et d'Anticorps, Institut Pasteur, 25, rue du Dr. Roux, 75015 Paris, France
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183
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Krantic S, Mechawar N, Reix S, Quirion R. Molecular basis of programmed cell death involved in neurodegeneration. Trends Neurosci 2005; 28:670-6. [PMID: 16216345 DOI: 10.1016/j.tins.2005.09.011] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 08/25/2005] [Accepted: 09/27/2005] [Indexed: 01/07/2023]
Abstract
Rapid progress in understanding the molecular basis of neurodegeneration has been tightly linked with recent discoveries in the field of programmed cell death (PCD). Analysis of PCD in neuronal demise has led to identification of several associated phenomena, such as re-initiation of the cell cycle and the key role of oxidative stress, although putative causal relationships between these events are still debatable. These issues are reviewed here in the context of acute and chronic neurodegenerative processes. In addition, newly emerging concepts concerning cell-cycle re-initiation are discussed in terms of their potential impact on the development of more effective therapeutic strategies.
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Affiliation(s)
- Slavica Krantic
- Institut de Neurobiologie de la Méditerranée (INMED), Institut National de la Santé et de la Recherche Médicale (INSERM), Parc Scientifique Luminy, BP13, 13 273 Marseille, France.
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184
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Samejima K, Earnshaw WC. Trashing the genome: the role of nucleases during apoptosis. Nat Rev Mol Cell Biol 2005; 6:677-88. [PMID: 16103871 DOI: 10.1038/nrm1715] [Citation(s) in RCA: 224] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Two classes of nucleases degrade the cellular DNA during apoptosis. Cell-autonomous nucleases cleave DNA within the dying cell. They are not essential for apoptotic cell death or the life of the organism, but they might affect the efficiency of the process. By contrast, waste-management nucleases are essential for the life of the organism. In post-engulfment DNA degradation, the DNA of apoptotic cells is destroyed in lysosomes of the cells that have phagocytosed the corpses. Waste-management nucleases also destroy DNA that is released into the extracellular compartment. Here, we describe the complex group of nucleases that are involved in DNA destruction during apoptotic cell death.
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Affiliation(s)
- Kumiko Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Swann Building, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
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185
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Howard BA, Furumai R, Campa MJ, Rabbani ZN, Vujaskovic Z, Wang XF, Patz EF. Stable RNA Interference–Mediated Suppression of Cyclophilin A Diminishes Non–Small-Cell Lung Tumor Growth In vivo. Cancer Res 2005; 65:8853-60. [PMID: 16204056 DOI: 10.1158/0008-5472.can-05-1219] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cyclophilin A (CypA) was recently reported to be overexpressed in non-small-cell lung cancer, and represents a potentially novel therapeutic target. To determine the role of CypA in oncogenesis, stable RNA interference (RNAi)-mediated knockdown of CypA was established in two non-small-cell lung cancer cell lines (ADLC-5M2 and LC-103H), and these cells were grown as xenografts in severe combined immunodeficient mice. Tumor cell proliferation, apoptosis, and angiogenesis were measured by Ki67, terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling, and CD31 immunohistochemistry, respectively. Tumor glucose metabolism was assessed by fluorodeoxyglucose positron emission tomography imaging. Knockdown of CypA correlated in vivo with slower growth, less fluorodeoxyglucose uptake, decreased proliferation, and a greater degree of apoptosis in the tumors. These results establish the relevance of CypA to tumor growth in vivo, specifically to proliferation and apoptosis. Elucidation of the precise role of CypA in these pathways may lead to new targeted therapies for lung cancer.
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Affiliation(s)
- Brandon A Howard
- Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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186
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Liu ZM, Chen GG, Vlantis AC, Liang NC, Deng YF, van Hasselt CA. Cell death induced by ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic-acid in anaplastic thyroid carcinoma cells is via a mitochondrial-mediated pathway. Apoptosis 2005; 10:1345-56. [PMID: 16215682 DOI: 10.1007/s10495-005-1730-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemical compound ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F), isolated from the Chinese herbal medicine plant Pteris semipinnata L, has been known to exert antitumor activity. However, the molecular mechanism of the action is not understood. In this study we demonstrated that apoptotic cell death induced by 5F in FRO cells was concentration- and time-dependent. The rapid increase in intracellular reactive oxygen species (ROS) levels was involved in the mechanism of cell death. c-Jun N-terminal kinase (JNK) activation and G2 block were related to cell death induced by 5F. Extracellular signal-related kinase (ERK) and p38 were also activated, but as survival signals in response to 5F treatment to counteract the induction of cell death. In the process of the induction of apoptotic cell death, Bax translocated into mitochondria, a reduction in Delta psi(m) was observed and a release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria into the cytosol occurred, indicating that cell death induced by 5F was through a mitochondrial-mediated pathway.
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Affiliation(s)
- Z M Liu
- Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China
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187
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Apostolova N, Cervera AM, Victor VM, Cadenas S, Sanjuan-Pla A, Alvarez-Barrientos A, Esplugues JV, McCreath KJ. Loss of apoptosis-inducing factor leads to an increase in reactive oxygen species, and an impairment of respiration that can be reversed by antioxidants. Cell Death Differ 2005; 13:354-7. [PMID: 16195738 DOI: 10.1038/sj.cdd.4401776] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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188
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Seth R, Yang C, Kaushal V, Shah SV, Kaushal GP. p53-dependent caspase-2 activation in mitochondrial release of apoptosis-inducing factor and its role in renal tubular epithelial cell injury. J Biol Chem 2005; 280:31230-9. [PMID: 15983031 DOI: 10.1074/jbc.m503305200] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We demonstrate the role of p53-mediated caspase-2 activation in the mitochondrial release of apoptosis-inducing factor (AIF) in cisplatin-treated renal tubular epithelial cells. Gene silencing of AIF with its small interfering RNA (siRNA) suppressed cisplatin-induced AIF expression and provided a marked protection against cell death. Subcellular fractionation and immunofluorescence studies revealed cisplatin-induced translocation of AIF from the mitochondria to the nuclei. Pancaspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone or p53 inhibitor pifithrin-alpha markedly prevented mitochondrial release of AIF, suggesting that caspases and p53 are involved in this release. Caspase-2 and -3 that were predominantly activated in response to cisplatin provided a unique model to study the role of these caspases in AIF release. Cisplatin-treated caspase-3 (+/+) and caspase-3 (-/-) cells exhibited similar AIF translocation to the nuclei, suggesting that caspase-3 does not affect AIF translocation, and thus, caspase-2 may be involved in the translocation. Caspase-2 inhibitor benzyloxycarbonyl-Val-Asp-Val-Ala-Asp-fluoromethylketone or down-regulation of caspase-2 by its siRNA significantly prevented translocation of AIF. Caspase-2 activation was a critical response from p53, which was markedly induced and phosphorylated in cisplatin-treated cells. Overexpression of p53 not only resulted in caspase-2 activation but also mitochondrial release of AIF. The p53 inhibitor pifithrin-alpha or p53 siRNA prevented both cisplatin-induced caspase-2 activation and mitochondrial release of AIF. Caspase-2 activation was dependent on the p53-responsive gene, PIDD, a death domain-containing protein that was induced by cisplatin in a p53-dependent manner. These results suggest that caspase-2 activation mediated by p53 is an important pathway involved in the mitochondrial release of AIF in response to cisplatin injury.
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Affiliation(s)
- Rohit Seth
- Department of Medicine, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, Arkansas 72205, USA
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189
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Marshall KR, Gong M, Wodke L, Lamb JH, Jones DJL, Farmer PB, Scrutton NS, Munro AW. The human apoptosis-inducing protein AMID is an oxidoreductase with a modified flavin cofactor and DNA binding activity. J Biol Chem 2005; 280:30735-40. [PMID: 15958387 DOI: 10.1074/jbc.m414018200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMID (apoptosis-inducing factor-homologous mitochondrion-associated inducer of death; also known as PRG3 (p53-responsive gene 3)) is a human caspase-independent pro-apoptotic protein with some similarity to apoptosis-inducing factor. AMID was purified from a recombinant bacterial host, enabling biochemical analysis of the protein. AMID is a flavoprotein; possesses NAD(P)H oxidase activity; and catalyzes NAD(P)H-dependent reduction of cytochrome c and other electron acceptors, including molecular oxygen. NADPH binds approximately 10-fold tighter than NADH. AMID binds 6-hydroxy-FAD (a cofactor that accumulates only adventitiously and at low abundance in other flavoprotein enzymes) to form a stoichiometric cofactor.protein complex. AMID has a distinctive electronic spectrum due to the modified flavin. NAD(P)+ binding perturbed the spectrum, enabling determination of K(d) values for these coenzymes. 6-Hydroxy-FAD could be removed from AMID and the apoprotein reconstituted with FAD. FAD was converted to 6-hydroxy-FAD in reconstituted AMID during aerobic turnover with NADPH. AMID is a DNA-binding protein that lacks apparent DNA sequence specificity. Formation of the protein.DNA complex (i) effected a major protein conformational change and (ii) was prevented in the presence of nicotinamide coenzyme. Apo-AMID retains DNA binding activity. Our studies establish a link between coenzyme and DNA binding that likely impacts on the physiological role of AMID in cellular apoptosis.
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Affiliation(s)
- Ker R Marshall
- Department of Biochemistry, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9NH, United Kingdom.
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190
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Abstract
Caspase activation has been frequently viewed as synonymous with apoptotic cell death; however, caspases can also contribute to processes that do not culminate in cell demise. Moreover, inhibition of caspases can have cytoprotective effects. In a number of different models, caspase inhibition does not maintain cellular viability and instead shifts the morphology of death from apoptosis to nonapoptotic pathways. Here, we explore the contribution of caspases to cell death, either as upstream signals or as downstream effectors contributing to apoptotic morphology, as well as alternative strategies for cell death inhibition. Such alternative strategies may either target catabolic hydrolases or be aimed at preventing mitochondrial membrane permeabilization and its upstream triggers.
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Affiliation(s)
- Guido Kroemer
- Centre National de la Recherche Scientifique, UMR8125, Institut Gustave Roussy, 39 rue Camille-Desmoulins, F-94805 Villejuif, France.
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191
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Urbano A, Lakshmanan U, Choo PH, Kwan JC, Ng PY, Guo K, Dhakshinamoorthy S, Porter A. AIF suppresses chemical stress-induced apoptosis and maintains the transformed state of tumor cells. EMBO J 2005; 24:2815-26. [PMID: 16001080 PMCID: PMC1182241 DOI: 10.1038/sj.emboj.7600746] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 06/16/2005] [Indexed: 11/09/2022] Open
Abstract
Apoptosis-inducing factor (AIF) exhibits reactive oxygen species (ROS)-generating NADH oxidase activity of unknown significance, which is dispensable for apoptosis. We knocked out the aif gene in two human colon carcinoma cell lines that displayed lower mitochondrial complex I oxidoreductase activity and produced less ROS, but showed increased sensitivity to peroxide- or drug-induced apoptosis. AIF knockout cells failed to form tumors in athymic mice or grow in soft agar. Only AIF with intact NADH oxidase activity restored complex I activity and anchorage-independent growth of aif knockout cells, and induced aif-transfected mouse NIH3T3 cells to form foci. AIF knockdown in different carcinoma cell types resulted in lower superoxide levels, enhanced apoptosis sensitivity and loss of tumorigenicity. Antioxidants sensitized AIF-expressing cells to apoptosis, but had no effect on tumorigenicity. In summary, AIF-mediated resistance to chemical stress involves ROS and probably also mitochondrial complex I. AIF maintains the transformed state of colon cancer cells through its NADH oxidase activity, by mechanisms that involve complex I function. On both counts, AIF represents a novel type of cancer drug target.
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Affiliation(s)
- Alexander Urbano
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | - Umayal Lakshmanan
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | - Poh Heok Choo
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | - Jair Chau Kwan
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | - Poh Yong Ng
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | - Ke Guo
- Histology Unit, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
| | | | - Alan Porter
- Cell Death and Human Disease Group, Institute of Molecular and Cell Biology, Proteos, Singapore, Republic of Singapore
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192
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Yuste VJ, Sánchez-López I, Solé C, Moubarak RS, Bayascas JR, Dolcet X, Encinas M, Susin SA, Comella JX. The contribution of apoptosis-inducing factor, caspase-activated DNase, and inhibitor of caspase-activated DNase to the nuclear phenotype and DNA degradation during apoptosis. J Biol Chem 2005; 280:35670-83. [PMID: 16049016 DOI: 10.1074/jbc.m504015200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have assessed the contribution of apoptosis-inducing factor (AIF) and inhibitor of caspase-activated DNase (ICAD) to the nuclear morphology and DNA degradation pattern in staurosporine-induced apoptosis. Expression of D117E ICAD, a mutant that is resistant to caspase cleavage at residue 117, prevented low molecular weight (LMW) DNA fragmentation, stage II nuclear morphology, and detection of terminal deoxynucleotidyl transferase staining. However, high molecular weight (HMW) DNA fragmentation and stage I nuclear morphology remained unaffected. On the other hand, expression of either D224E or wild type ICAD had no effect on DNA fragmentation or nuclear morphology. In addition, both HMW and LMW DNA degradation required functional executor caspases. Interestingly, silencing of endogenous AIF abolished type I nuclear morphology without any effect on HMW or LMW DNA fragmentation. Together, these results demonstrate that AIF is responsible for stage I nuclear morphology and suggest that HMW DNA degradation is a caspase-activated DNase and AIF-independent process.
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Affiliation(s)
- Victor J Yuste
- Department of Ciències Mèdiques Bàsiques, Cell Signalling and Apoptosis Group, Facultat de Medicina, Universitat de Lleida, Montserrat Roig, 2, E-25008 Lleida, Spain
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193
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Castedo M, Perfettini JL, Piacentini M, Kroemer G. p53-A pro-apoptotic signal transducer involved in AIDS. Biochem Biophys Res Commun 2005; 331:701-6. [PMID: 15865925 DOI: 10.1016/j.bbrc.2005.03.188] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Indexed: 11/20/2022]
Abstract
P53 is a well-characterized tumor suppressor protein, which can induce apoptosis, either by inducing transcription of pro-apoptotic genes or by direct effects on mitochondrial membranes. Roughly 50% of human cancers are affected by the genetic or epigenetic inactivation of p53. Recently, p53 has been incriminated to play a cardinal role in the destruction of the immune system by human immunodeficiency virus (HIV-1) infection. This suspicion is based on several lines of evidence: (i) p53 exhibits activating phosphorylations in a subset of peripheral blood mononuclear cells and lymph node cells from HIV-1 carriers; (ii) some p53 target genes (e.g., PUMA, a pro-apoptotic member of the Bcl-2 family) are overexpressed in HIV-1 carriers; (iii) in vitro, p53 and/or PUMA are rate-limiting for the induction of cell death by HIV-1 infection or, in particular, by the HIV-1 Envelope (Env), in a variety of model systems, including the apoptosis of syncytia elicited by Env or cell death induced by the Env constituent gp120. Thus, p53 may constitute a novel therapeutic target for the treatment of AIDS.
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Affiliation(s)
- Maria Castedo
- CNRS-UMR8125, Institut Gustave Roussy, 39 rue Camille-Desmoulins, F-94805 Villejuif, France
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194
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Schneider MD. Cyclophilin D: knocking on death's door. SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2005; 2005:pe26. [PMID: 15942033 DOI: 10.1126/stke.2872005pe26] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two recent genetic studies have identified a critical role for cyclophilin D, a component of the mitochondrial membrane permeability transition pore, in cell death induced by calcium, reactive oxygen species, and cardiac ischemia-reperfusion injury. Transgenic mice lacking cyclophilin D developed normally but showed reduced infarct size after coronary artery ligation and reperfusion. Cells from the knockout mice were resistant to death imposed by excess calcium and H2O2, but not to death from x-irradiation, staurosporine, tumor necrosis factor-alpha, or forced expression of proapoptotic proteins. These data raise questions about the relationship between apoptotic and necrotic cell death, and they also highlight cyclophilin D as a potential therapeutic target in myocardial infarction.
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Affiliation(s)
- Michael D Schneider
- Department of Medicine, Center for Cardiovascular Development, Baylor College of Medicine, Houston, TX 77030, USA.
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195
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Abstract
Apoptosis has been causally linked to the pathogenesis of myocardial infarction and heart failure in rodent models. This death process is mediated by two central pathways, an extrinsic pathway involving cell surface receptors and an intrinsic pathway using mitochondria and the endoplasmic reticulum. Each of these pathways has been implicated in myocardial pathology. In this review, we summarize recent advances in the understanding of the intrinsic pathway and how it relates to cardiac myocyte death and heart disease.
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Affiliation(s)
- Michael T Crow
- Department of Medicine, Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Rm 5A.58, Baltimore, MD 21224, USA.
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196
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Garrido C, Kroemer G. Life's smile, death's grin: vital functions of apoptosis-executing proteins. Curr Opin Cell Biol 2005; 16:639-46. [PMID: 15530775 DOI: 10.1016/j.ceb.2004.09.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Apoptosis is executed by caspases as well as caspase-independent death effectors. Caspases are expressed as inactive zymogens in virtually all animal cells and are activated in cells destined to undergo apoptosis. However, there are many examples where caspase activation is actually required for cellular processes not related to cell death, namely terminal differentiation, activation, proliferation, and cytoprotection. Several caspase-independent death effectors including apoptosis-inducing factor, endonuclease G and a serine protease (Omi/HtrA2) are released from the mitochondrial intermembrane space upon permeabilization of the outer membrane. Such proteins also have important roles in cellular redox metabolism and/or mitochondrial biogenesis. As a general rule, it thus appears that cell-death-relevant proteins, especially those involved in the core of the executing machinery, have a dual function in life and death. This has important implications for pathophysiology. The fact that the building blocks of the apoptotic machinery have normal functions not related to cell death may mean that essential parts of the apoptotic executioner cannot be lost and thus reduces the possibility of oncogenic mutations that block the apoptotic program. Moreover, therapeutic suppression of unwarranted cell death must be designed to target only the lethal (and not the vital) role of death effectors.
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Affiliation(s)
- Carmen Garrido
- INSERM U-517, Faculty of Medicine and Pharmacy, 7 Boulevard Jeanne d'Arc, 21033 Dijon, France.
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197
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Lovell MA, Xiong S, Markesbery WR, Lynn BC. Quantitative proteomic analysis of mitochondria from primary neuron cultures treated with amyloid beta peptide. Neurochem Res 2005; 30:113-22. [PMID: 15756939 DOI: 10.1007/s11064-004-9692-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Increasing evidence supports a role for altered mitochondrial function in the pathogenesis of neuron degeneration in Alzheimer's disease (AD). Although several studies have examined the effect of amyloid beta peptide (Abeta), on activities of individual proteins in primary neuron cultures, there have been no studies of the effects of Abeta on the mitochondrial proteome. Here, we quantitatively measured changes in mitochondrial proteins of primary rat cortical neuron cultures exposed to 25 microM Abeta(25-35) for 16 h using isotope coded affinity tag (ICAT) labeling and 2-dimensional liquid chromatography/tandem mass spectrometry (2D-LC/MS/MS) which allows simultaneous identification and quantification of cysteine-containing proteins. The analysis of enriched mitochondrial fractions identified 10 proteins including sodium/potassium-transporting ATPase, cofilin, dihydropyrimidinase, pyruvate kinase and voltage dependent anion channel 1 that were statistically significantly (P < 0.05) altered in Abeta-treated cultures. Elevations of proteins associated with energy production suggest that cells undergoing Abeta-mediated apoptosis increase synthesis of proteins essential for ATP production and efflux in an attempt to maintain metabolic function.
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Affiliation(s)
- Mark A Lovell
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA.
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198
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Xie Q, Lin T, Zhang Y, Zheng J, Bonanno JA. Molecular cloning and characterization of a human AIF-like gene with ability to induce apoptosis. J Biol Chem 2005; 280:19673-81. [PMID: 15764604 DOI: 10.1074/jbc.m409517200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we cloned and characterized a human gene homologous to the apoptosis-inducing factor (AIF), which is named AIF-like (AIFL). Human AIFL has 598 amino acids, with a characteristic Rieske domain and a pyridine nucleotide-disulfide oxidoreductase domain (Pyr_redox). AIFL shares 35% homology with AIF, mainly in the Pyr_redox domain. Reverse transcriptase-PCR analysis showed the expression of AIFL mRNA in all tissues tested, i.e. brain, colon, heart, kidney, liver, lung, muscle, ovary, pancreas, placenta, small intestine, and testis. We developed antibodies against human AIFL using fusion proteins as antigens. The antibodies specifically recognized the antigen and heterologously expressed AIFL proteins. The expression of AIFL proteins in human tissues was also ubiquitous, demonstrated by immunohistochemistry in tissue array slides. Subcellular fractionation and immunofluorescence staining studies revealed that AIFL is predominantly localized to the mitochondria. Similar to AIF, overexpression of AIFL induced apoptosis, as shown by increased cytoplasmic nucleosomes and subdiploid cell populations in AIFL-transfected cells. The segment 1-190 containing the Rieske domain induced apoptosis, whereas the segment containing the Pyr_redox domain did not contribute to the pro-apoptotic function. The mitochondrial membrane potential of cells transfected with AIFL was significantly more depolarized than that of the control. AIFL transfection-induced cytochrome c release and cleavage of caspase 3. Furthermore, the pan-caspase inhibitor Z-VAD-fmk inhibited AIFL induced apoptosis. In summary, AIFL induces apoptosis in a caspase-dependent manner when heterologously expressed.
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Affiliation(s)
- Qiang Xie
- Indiana University School of Optometry, Bloomington, 47405, USA
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199
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Polster BM, Basañez G, Etxebarria A, Hardwick JM, Nicholls DG. Calpain I induces cleavage and release of apoptosis-inducing factor from isolated mitochondria. J Biol Chem 2005; 280:6447-54. [PMID: 15590628 DOI: 10.1074/jbc.m413269200] [Citation(s) in RCA: 309] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus has been implicated in the mechanism of glutamate excitotoxicity in cortical neurons and has been observed in vivo following acute rodent brain injuries. However, the mechanism and time course of AIF redistribution to the nucleus is highly controversial. Because elevated intracellular calcium is one of the most ubiquitous features of neuronal cell death, this study tested the hypothesis that cleavage of AIF by the calcium-activated protease calpain mediates its release from mitochondria. Both precursor and mature forms of recombinant AIF were cleaved near the amino terminus by calpain I in vitro. Mitochondrial outer membrane permeabilization by truncated Bid induced cytochrome c release from isolated liver or brain mitochondria but only induced AIF release in the presence of active calpain. Enzymatic inhibition of calpain by calpeptin precluded AIF release, demonstrating that proteolytic activity was required for release. Calpeptin and the mitochondrial permeability transition pore antagonist cyclosporin A also inhibited calcium-induced AIF release from mouse liver mitochondria, implicating the involvement of an endogenous mitochondrial calpain in release of AIF during permeability transition. Cleavage of AIF directly decreased its association with pure lipid vesicles of mitochondrial inner membrane composition. Taken together, these results define a novel mechanism of AIF release involving calpain processing and identify a potential molecular checkpoint for cytoprotective interventions.
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Affiliation(s)
- Brian M Polster
- The Buck Institute for Age Research, Novato, California 94945, USA.
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200
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Hu H, Huang CQ, Liu HL, Han Y, Yu L, Bi RC. Crystallization and preliminary X-ray crystallographic studies of human cyclophilin J. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:216-8. [PMID: 16510998 PMCID: PMC1952245 DOI: 10.1107/s1744309105000643] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 01/07/2005] [Indexed: 11/10/2022]
Abstract
Human cyclophilin J, a new member of the cyclophilin family, has been expressed and crystallized. Diffraction data have been collected to 2.0 A resolution and preliminary crystallographic studies have been completed. The space group of the crystals is P3(1)21, with unit-cell parameters a = b = 40.597, c = 170.732 A, alpha = beta = 90, gamma = 120 degrees.
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Affiliation(s)
- Hao Hu
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Chao-Qun Huang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, People’s Republic of China
| | - He-Li Liu
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Yi Han
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Long Yu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, People’s Republic of China
| | - Ru-Chang Bi
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
- Correspondence e-mail:
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