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Franke C, Nöldner M, Abdel-Kader R, Johnson-Anuna LN, Gibson Wood W, Müller WE, Eckert GP. Bcl-2 upregulation and neuroprotection in guinea pig brain following chronic simvastatin treatment. Neurobiol Dis 2007; 25:438-45. [PMID: 17157514 DOI: 10.1016/j.nbd.2006.10.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 10/05/2006] [Accepted: 10/19/2006] [Indexed: 10/23/2022] Open
Abstract
The present study determined if chronic simvastatin administration in vivo would provide neuroprotection in brain cells isolated from guinea pigs after challenge with the Bcl-2 inhibitor HA 14-1 or the NO donor sodium nitroprusside (SNP). Bcl-2 levels were significantly increased in brains of simvastatin-treated guinea pigs while levels of the pro-apoptotic protein Bax were significantly reduced. The ratio of Bax/Bcl-2, being a critical factor of the apoptotic state of cells, was significantly reduced in simvastatin-treated animals. Cholesterol levels in the brain remained unchanged in the simvastatin group. Brain cells isolated from simvastatin-treated guinea pigs were significantly less vulnerable to mitochondrial dysfunction and caspase-activation. These results provide new insight into potential mechanisms for the protective actions of statins within the CNS where programmed cell death has been implicated.
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Affiliation(s)
- Cornelia Franke
- Department of Pharmacology, ZAFES, Biocenter Niederursel, N260 Max-von-Laue Str. 9, University of Frankfurt, Germany
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Yeow WS, Baras A, Chua A, Nguyen DM, Sehgal SS, Schrump DS, Nguyen DM. Gossypol, a phytochemical with BH3-mimetic property, sensitizes cultured thoracic cancer cells to Apo2 ligand/tumor necrosis factor–related apoptosis-inducing ligand. J Thorac Cardiovasc Surg 2006; 132:1356-62. [PMID: 17140955 DOI: 10.1016/j.jtcvs.2006.07.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 05/19/2006] [Accepted: 07/12/2006] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Chemotherapeutic agents sensitize cancer cells to Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) via recruitment of the mitochondria-dependent activation of caspase and induction of apoptosis. This study was designed to evaluate whether gossypol, a phytochemical compound with BH3-mimetic property that functions as an inhibitor of Bcl2/BclXL, would sensitize cultured thoracic cancer cells to this death-inducing ligand. METHODS Cancer cell lines from the lung (H460, H322), the esophagus (TE2, TE12), and the pleura (H290, H211) or primary normal cells were treated with gossypol+Apo2L/TRAIL combinations. Cell viability and apoptosis were evaluated by (4,5-dimethylthiazo-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) assays, respectively. Caspase 9 and 3 specific proteolytic activity in combination-treated cells was determined by fluorometric enzymatic assay. RESULTS Gossypol, selectively cytotoxic to cancer cells and not primary normal cells, significantly sensitized thoracic cancer cells to Apo2L/TRAIL as indicated by 1.5- to more than 10-fold reduction of Apo2L/TRAIL 50% inhibitory concentration values in cells treated with gossypol+Apo2L/TRAIL combinations. Whereas less than 20% of cancer cells exposed to either gossypol (5 micromol/L) or Apo2L/TRAIL (20 ng/mL) were dead, more than 90% of cells treated with the drug combinations were apoptotic. Combination-induced cytotoxicity and apoptosis was completely abrogated either by overexpression of Bcl2 or by the selective caspase 9 inhibitor. This combination was not toxic to normal cells. CONCLUSION Gossypol profoundly sensitizes thoracic cancer cells to the cytotoxic effect of Apo2L/TRAIL via activation of the mitochondria-dependent death signaling pathway. This study provides evidence for the profound anticancer activity of this drug combination and should be further evaluated as a novel targeted molecular therapeutic for thoracic cancers.
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Affiliation(s)
- Wen-Shuz Yeow
- Section of Thoracic Oncology, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Md, USA
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53
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Shen HM, Pervaiz S. TNF receptor superfamily-induced cell death: redox-dependent execution. FASEB J 2006; 20:1589-98. [PMID: 16873882 DOI: 10.1096/fj.05-5603rev] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Tumor necrosis factor (TNF) superfamily is a group of cytokines with important functions in immunity, inflammation, differentiation, control of cell proliferation, and apoptosis. TNFalpha is the founding member of the 19 different proteins that have so far been identified within this family. TNF family members exert their biological effects through the TNF receptor (TNFR) superfamily of cell surface receptors that share a stretch of approximately 80 amino acids within their cytoplasmic region, the death domain (DD), critical for recruiting the death machinery. Work over the last decade has unraveled critical signaling networks involved in TNFR-induced cell death, specifically using the constitutively expressed TNFR1 as a prototype. Of particular interest is the intermediary role of intracellular reactive oxygen species (ROS) in signal transduction after ligation of the TNFR1. With the increasing understanding of the of death receptor signaling pathways, the exact role of ROS in TNFalpha-induced execution is now believed to be far more complicated than originally thought. Recently, some important discoveries have underscored the critical role of ROS in TNFalpha signaling, notably in TNFalpha-mediated activation of nuclear factor-kappaB (NF-kappaB) and c-Jun N-terminal kinase (c-Jun NH2-terminal kinase, JNK), as well as in cell death (apoptotic and necrotic) pathways. Here we attempt to review the existing knowledge on the involvement of ROS in death receptor signaling using TNFalpha-TNFR1 as the model system, specifically addressing the involvement of intracellular ROS in TNFalpha-induced cell death and in TNFalpha-induced activation of NF-kappaB and JNK and their crosstalk.
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Affiliation(s)
- Han-Ming Shen
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Bldg. MD9, Level 3, Singapore 117597, Singapore
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Park SJ, Wu CH, Choi MR, Najafi F, Emami A, Safa AR. P-glycoprotein enhances TRAIL-triggered apoptosis in multidrug resistant cancer cells by interacting with the death receptor DR5. Biochem Pharmacol 2006; 72:293-307. [PMID: 16753135 DOI: 10.1016/j.bcp.2006.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 04/17/2006] [Accepted: 04/19/2006] [Indexed: 11/17/2022]
Abstract
The death-inducing cytokine TRAIL is a promising agent for anticancer therapy since it preferentially kills cancer versus normal cells; however, some cancer cells are TRAIL-resistant. We initially explored whether overexpression of the MDR1 gene product P-glycoprotein (P-gp), which causes multidrug resistance (MDR) in cancer cells, also contributes to TRAIL-resistance. Surprisingly, our results revealed that P-gp-overexpression enhances TRAIL-induced apoptosis not only in neoplastic cells transfected with the MDR1 gene but also in MDR variants selected with cytotoxic anticancer agents. Mechanistic analysis of TRAIL-induced apoptosis in the MDR1-transfected MCF-7 breast cancer cell line BC-19 revealed that TRAIL-triggered significantly more apoptosis in these cells compared with parental MCF-7 cells by binding to the TRAIL receptor DR5. DR5 but not DR4 engagement by TRAIL attenuated cellular ATP levels by robustly stimulating P-gp ATPase activity, and thus triggered P-gp-dependent apoptosis by depletion of the cellular ATP pool. In addition to hyperactive P-gp-mediated ATP hydrolysis, TRAIL-induced, P-gp-potentiated apoptosis was associated with activation of caspases-6, -7, -8, and -9; Bid cleavage; and mitochondrial depolarization. P-gp interacted with the TRAIL receptors DR4, DR5, and DcR1 in plasma membranes and enhanced TRAIL binding to DR5. Interestingly, the decreased level of the decoy TRAIL receptor, DcR1, in BC-19 cells further sensitized these cells to TRAIL. Therefore, both extrinsic and intrinsic apoptosis pathways are involved in this process. These findings for the first time reveal that TRAIL treatment preferentially causes apoptosis in P-gp-overexpressing MDR cells, and suggests significant clinical implications for the use of TRAIL in treating neoplasms that have failed chemotherapy.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adenosine Triphosphate/metabolism
- Antibodies/pharmacology
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Apoptosis Regulatory Proteins/metabolism
- Apoptosis Regulatory Proteins/pharmacology
- Caspase 8
- Caspases/metabolism
- Cell Line, Tumor
- Cytochromes c/metabolism
- Dose-Response Relationship, Drug
- Doxorubicin/pharmacology
- Drug Resistance, Multiple/genetics
- Drug Resistance, Neoplasm/genetics
- Enzyme Activation/drug effects
- Humans
- Membrane Glycoproteins/metabolism
- Membrane Glycoproteins/pharmacology
- Membrane Potentials/drug effects
- Mitochondrial Membranes/drug effects
- Mitochondrial Membranes/physiology
- Paclitaxel/pharmacology
- Protein Binding
- Receptors, TNF-Related Apoptosis-Inducing Ligand
- Receptors, Tumor Necrosis Factor/immunology
- Receptors, Tumor Necrosis Factor/metabolism
- TNF-Related Apoptosis-Inducing Ligand
- Transfection
- Tumor Necrosis Factor-alpha/metabolism
- Tumor Necrosis Factor-alpha/pharmacology
- Vinblastine/pharmacology
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Affiliation(s)
- Soo-Jung Park
- Department of Pharmacology and Toxicology, Indiana University Cancer Center, 1044 West Walnut R4-119, Indianapolis, 46202, USA
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55
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Separovic D, Wang S, Awad Maitah MY, Hanada K, Kessel D. Ceramide response post-photodamage is absent after treatment with HA14-1. Biochem Biophys Res Commun 2006; 345:803-8. [PMID: 16701558 PMCID: PMC2972543 DOI: 10.1016/j.bbrc.2006.04.131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 04/24/2006] [Indexed: 12/14/2022]
Abstract
The oxidative stress induced by photodynamic therapy using the phthalocyanine Pc 4 (PDT) can lead to apoptosis, and is accompanied by photodamage to Bcl-2 and accumulation of de novo ceramide. Similar to PDT, the oxidative stress inducer and Bcl-2 inhibitor HA14-1 triggers apoptosis. To test the specificity of the ceramide response, Jurkat cells were exposed to an equitoxic dose of HA14-1. Unlike PDT, HA14-1 did not induce accumulation of de novo ceramide, although levels of sphingomyelin, phosphatidylserine and phosphatidylethanolamine were below control values after either treatment. In contrast to PDT, (i) the transient inhibition of serine palmitoyltransferase induced by HA14-1 was associated with the initial decrease in de novo ceramide, and (ii) HA14-1-initiated inhibition of sphingomyelin synthase and glucosylceramide synthase did not result in accumulation of de novo ceramide. These results show that the ceramide response to PDT is not induced by another pro-apoptotic stimulus, and may be unique to PDT as described here.
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Affiliation(s)
- Duska Separovic
- Department of Fundamental and Applied Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
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56
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Manero F, Gautier F, Gallenne T, Cauquil N, Grée D, Cartron PF, Geneste O, Grée R, Vallette FM, Juin P. The small organic compound HA14-1 prevents Bcl-2 interaction with Bax to sensitize malignant glioma cells to induction of cell death. Cancer Res 2006; 66:2757-64. [PMID: 16510597 DOI: 10.1158/0008-5472.can-05-2097] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A functional imbalance between proapoptotic Bax and antiapoptotic Bcl-2 is likely to participate in the resistance of cancer cells to therapy. We show here that ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate (HA14-1), a small organic compound recently proposed to function as an inhibitor of Bcl-2, increases the sensitivity of human glioblastoma cells to radiotherapy and chemotherapy. This sensitizing effect is lost if Bcl-2 expression, but not Bcl-xL expression, is knocked down or if cells only express a mutant of Bax that does not interact with Bcl-2. This points to a specific Bcl-2 inhibitory function of HA14-1 and implies that it selectively involves hindrance of Bcl-2 binding to Bax, which HA14-1 inhibits in cell-free assays and in cells in receipt of an apoptotic stimulation. Moreover, HA14-1, in combination with a cytotoxic treatment, slows down the growth of glioblastoma in vivo. Thus, the inhibition of Bcl-2 achieved by HA14-1 might improve treatment outcome.
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Affiliation(s)
- Florence Manero
- Institut National de la Santé et de la Reserche Médicale U601, Département de Recherche en Cancérologie, Nantes, France
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57
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Milanesi E, Costantini P, Gambalunga A, Colonna R, Petronilli V, Cabrelle A, Semenzato G, Cesura AM, Pinard E, Bernardi P. The Mitochondrial Effects of Small Organic Ligands of BCL-2. J Biol Chem 2006; 281:10066-72. [PMID: 16481323 DOI: 10.1074/jbc.m513708200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the mitochondrial effects of BH3I-2', Chelerythrine, and HA14-1, small organic molecules that share the ability to bind the BH3 domain of BCL-2. All compounds displayed a biphasic effect on mitochondrial respiration with uncoupling at low concentrations and respiratory inhibition at higher concentrations, the relative uncoupling potency being BH3I-2' (half-maximal uncoupling at about 80 nm) > Chelerythrine (half-maximal uncoupling at about 2 microm) > HA14-1 (half-maximal uncoupling at about 20 microm). At concentrations lower than required for uncoupling all compounds sensitized the permeability transition pore (PTP) to opening both in isolated mitochondria and intact cells. To assess whether the effects on BCL-2 binding, PTP induction and respiration could be due to different structural determinants we have tested a set of HA14-1 analogs from the Hoffmann-La Roche chemical library. We have identified 5-(6-chloro-2,4-dioxo-1,3,4,10-tetrahydro-2H-9-oxa-1,3-diaza-anthracen-10-yl)-pyrimidine-2,4,6-trione (EM20-25) as a molecule devoid of effects on respiration that is able to induce PTP opening, to disrupt the BCL-2/BAX interactions in situ and to activate caspase-9 in BCL-2-overexpressing cells. EM20-25 neutralized the antiapoptotic activity of overexpressed BCL-2 toward staurosporine and sensitized BCL-2-expressing cells from leukemic patients to the killing effects of staurosporine, chlorambucil, and fludarabine. These results provide a proof of principle that the potentially toxic effects of BCL-2 ligands on mitochondrial respiration are not essential for their antiapoptotic activity and represent an important step forward in the development of tumor-selective drugs acting on BCL-2.
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Affiliation(s)
- Eva Milanesi
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Institute of Neurosciences, University of Padova, Viale Giuseppe Colombo 3, I-35121 Padua, Italy
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58
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Skommer J, Wlodkowic D, Mättö M, Eray M, Pelkonen J. HA14-1, a small molecule Bcl-2 antagonist, induces apoptosis and modulates action of selected anticancer drugs in follicular lymphoma B cells. Leuk Res 2006; 30:322-31. [PMID: 16213584 DOI: 10.1016/j.leukres.2005.08.022] [Citation(s) in RCA: 187] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Indexed: 12/24/2022]
Abstract
The BCL-2 overexpression is a hallmark of follicular lymphoma (FL). Since patients with FL often suffer from resistant to chemotherapy refractory disease, the development of new regimens is required. Herein, we analyze for the first time the effects of a B-cell lymphoma 2 (Bcl-2) antagonist, HA14-1, alone and in combination with antineoplastic agents commonly used against follicular lymphoma, in human FL cell lines with t(14;18). All cell lines tested were sensitive to HA14-1-induced cytotoxicity and apoptosis, as depicted by morphological changes, SYTO16/PI staining, oligonucleosomal DNA fragmentation and loss of Deltapsi(m). Moreover, HA14-1 significantly enhanced dexamethasone- and doxorubicin-mediated (in schedule independent and dependent manner, respectively), but not vincristine-mediated cytotoxicity and apoptosis.
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Affiliation(s)
- Joanna Skommer
- Department of Clinical Microbiology, University of Kuopio, Harjulantie 1 C, FIN-70211 Kuopio, Finland.
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59
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Caruso J, Mathieu P, Reiners J. Sphingomyelins suppress the targeted disruption of lysosomes/endosomes by the photosensitizer NPe6 during photodynamic therapy. Biochem J 2006; 392:325-34. [PMID: 15943580 PMCID: PMC1316268 DOI: 10.1042/bj20050313] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent studies have described a biochemical pathway whereby lysosome disruption and the released proteases initiate the intrinsic apoptotic pathway. Irradiation of murine hepatoma 1c1c7 cells preloaded with the lysosomal photosensitizer NPe6 (N-aspartyl chlorin e6) caused a rapid loss of Acridine Orange staining of acidic organelles, release of cathepsin D from late endosomes/lysosomes and the activation of procaspase-3. Pretreatment of NPe6-loaded cultures with 10-50 microM 3-O-MeSM (3-O-methylsphingomyelin) caused a concentration-dependent suppression of apoptosis following irradiation. This suppression reflected a stabilization of lysosomes/endosomes, as opposed to an inhibition of the accumulation of photosensitizer in these organelles. Exogenously added sphingomyelin, at comparable concentrations, offered some protection, but less than 3-O-MeSM. Fluorescence microscopy showed that 3-O-MeSM competed with NBD-C6-sphingomyelin (6-{[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]hexanoyl} sphingosyl phosphocholine) for co-localization with LysoTracker Red in acidic organelles. Pre-treatment of 1c1c7 cultures with 3-O-MeSM also suppressed the induction of apoptosis by TNFalpha (tumour necrosis factor alpha), but offered no protection against HA14-1 [ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate], staurosporine, tunicamycin or thapsigargin. These results suggest that exogenously added 3-O-MeSM is trafficked to and stabilizes late endosomes/lysosomes against oxidant-induced damage, and further implicate a role for lysosomal proteases in the apoptotic processes initiated by TNFalpha and lysosomal photosensitizers.
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Affiliation(s)
- Joseph A. Caruso
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, U.S.A
| | - Patricia A. Mathieu
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, U.S.A
| | - John J. Reiners
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, U.S.A
- To whom correspondence should be addressed (email )
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60
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Kim A, Oberley LW, Oberley TD. Induction of apoptosis by adenovirus-mediated manganese superoxide dismutase overexpression in SV-40-transformed human fibroblasts. Free Radic Biol Med 2005; 39:1128-41. [PMID: 16214029 DOI: 10.1016/j.freeradbiomed.2005.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Revised: 05/17/2005] [Accepted: 06/07/2005] [Indexed: 11/23/2022]
Abstract
Although mitochondrial reactive oxygen species (ROS) have been implicated both as an initiator and as an effector of apoptosis, the exact role of mitochondrial ROS has been difficult to establish due to the lack of an appropriate experimental system where ROS could be specifically generated from mitochondria and subsequent effects on cells analyzed. In this study, a manganese superoxide dismutase (MnSOD) activity-mediated apoptosis model was established and characterized. It was shown that despite early increases in the steady-state levels of ROS upon MnSOD overexpression, cellular oxidative damage was decreased significantly at later time points. Alterations in levels of peroxiredoxin (Prxn1) protein preceded the onset of apoptosis after MnSOD overexpression. A time course study demonstrated that increases in MnSOD activity prior to the onset of apoptosis correlated with alterations in the levels of nitration of tyrosine residue(s) of MnSOD protein. A direct correlation between MnSOD activity and the degree of apoptosis was demonstrated using a mutant MnSOD with decreased activity. The current study supports a causative role of mitochondrial ROS leading to the onset of apoptosis. The MnSOD activity-mediated apoptosis model described here could be further utilized to study mitochondrial apoptotic pathways.
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Affiliation(s)
- Aekyong Kim
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA, USA
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61
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Izeradjene K, Douglas L, Tillman DM, Delaney AB, Houghton JA. Reactive Oxygen Species Regulate Caspase Activation in Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand–Resistant Human Colon Carcinoma Cell Lines. Cancer Res 2005; 65:7436-45. [PMID: 16103097 DOI: 10.1158/0008-5472.can-04-2628] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of reactive oxygen species (ROS) on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in solid cancers have yet to be clearly defined. In this study, we found that the classic uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone (CCCP), induced a reduction in DeltaPsim and generation of ROS. This uncoupling effect enhanced TRAIL-induced apoptosis in TRAIL-resistant human colon carcinoma cell lines (RKO, HT29, and HCT8). Sensitization was inhibited by benzyloxycarbonyl-valine-alanine-aspartate fluoromethylketone, indicating the requirement for caspase activation. CCCP per se did not induce apoptosis or release of proapoptotic factors from mitochondria. Generation of ROS by CCCP was responsible for TRAIL-induced Bax and caspase activation because scavenging ROS completely abrogated apical caspase-8 activation and further downstream events leading to cell death. Overexpression of Bcl-2 did not prevent the initial loss of DeltaPsim and ROS generation following CCCP treatment, but did prevent cell death following TRAIL and CCCP exposure. Uncoupling of mitochondria also facilitated TRAIL-induced release of proapoptotic factors. X-linked inhibitor of apoptosis overexpression abrogated TRAIL-induced apoptosis in the presence of CCCP and decreased initiator procaspase-8 processing, indicating that additional processing of caspase-8 required initiation of a mitochondrial amplification loop via effector caspases. Of interest, depletion of caspase-9 in RKO cells did not protect cells from TRAIL/CCCP-induced apoptosis, indicating that apoptosis occurred via a caspase-9-independent pathway. Data suggest that in the presence of mitochondrial-derived ROS, TRAIL induced mitochondrial release of Smac/DIABLO and inactivation of X-linked inhibitor of apoptosis through caspase-9-independent activation of caspase 3.
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Affiliation(s)
- Kamel Izeradjene
- Division of Molecular Therapeutics, Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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62
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Joshi MB, Philippova M, Ivanov D, Allenspach R, Erne P, Resink TJ. T-cadherin protects endothelial cells from oxidative stress-induced apoptosis. FASEB J 2005; 19:1737-9. [PMID: 16099944 DOI: 10.1096/fj.05-3834fje] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In vascular tissue, T-cadherin (T-cad) is up-regulated in vivo under disease conditions associated with oxidative stress and concomitant cell migration, proliferation and apoptosis/survival. Using cultures of human umbilical vein endothelial cells (HUVEC), we examined whether there is a functional relationship between oxidative stress, T-cad expression, and cell survival status. Culture of HUVEC under conditions of oxidative stress (e.g., serum deprivation, inclusion of H2O2) resulted in increased T-cad expression. Oxidative stress-induced increases in T-cad were inhibited by the free radical-scavenging antioxidant, N-acetylcysteine, and the flavin-containing oxidase inhibitor, diphenyleneiodonium. Thus reactive oxygen species (ROS) contribute to stress-induced elevation of T-cad in HUVEC. Compared with control cells, HUVEC overexpressing T-cad (T-cad+-HUVEC) had higher phosphorylation levels for phosphatidylinositol 3-kinase (PI3K) target Akt and mTOR target p70(S6K) (survival pathway regulators), but lower levels for p38MAPK (death pathway regulator). T-cad+-HUVEC exposed to stress (serum-deprivation, TNF-alpha, actinomycin D, staurosporine) exhibited reduced caspase activation together with increased cell survival. Protection against stress-induced apoptosis in T-cad+-HUVEC was abrogated by either PI3K-inhibitor wortmannin or mTOR-inhibitor rapamycin. We conclude that T-cad overexpression in HUVEC protects against stress-induced apoptosis through activation of the PI3K/Akt/mTOR survival signal pathway and concomitant suppression of the p38 MAPK proapoptotic pathway. ROS-induced changes in T-cad expression may play an important role in controlling tissue cellularity during vascular remodeling.
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Affiliation(s)
- Manjunath B Joshi
- Department of Research, Cardiovascular Laboratories, Basel University Hospital, Basel, Switzerland
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63
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Reiners JJ, Kessel D. Susceptibility of myelomonocytic leukemia U937 cells to the induction of apoptosis by the non-peptidic Bcl-2 ligand HA14-1 is cell cycle phase-dependent. Cancer Lett 2005; 221:153-63. [PMID: 15808401 PMCID: PMC2965436 DOI: 10.1016/j.canlet.2004.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Accepted: 09/07/2004] [Indexed: 01/30/2023]
Abstract
Pharmacological approaches employing agents that bind to the Bcl-2 surface pocket have been used successfully to neutralize the activities of anti-apoptotic Bcl-2 family members, and induce apoptosis. Several reports suggest that Bcl-2 expression/function is cell cycle-dependent. Hence, is killing by Bcl-2 surface pocket binding agents also cell cycle-dependent? In the current study, centrifugal elutriation was used to generate cell cycle phase-enriched preparations of the human myelomonocytic leukemia cell line U937. Elutriated fractions were treated with sub-optimal cytotoxic concentrations of the pro-apoptotic, non-peptidic Bcl-2 pocket-binding agent HA14-1. A concentration of HA14-1 sufficient to kill approximately 30-35% of asynchronous cultures minimally affected the progressions of elutriated post-checkpoint G1, S, G2/M phase cells, but completely suppressed the progression of pre-G1 checkpoint G1 cells. Analyses of trypan blue exclusion, morphology, nuclear condensation, mitochondrial membrane potential, sub-diploid DNA contents, and caspase-3 indicated preferential killing and induction of apoptosis in pre-G1 checkpoint G1 and G2/M phase cells.
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Affiliation(s)
- John J Reiners
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA.
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64
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Liu Y, Borchert GL, Donald SP, Surazynski A, Hu CA, Weydert CJ, Oberley LW, Phang JM. MnSOD inhibits proline oxidase-induced apoptosis in colorectal cancer cells. Carcinogenesis 2005; 26:1335-42. [PMID: 15817612 DOI: 10.1093/carcin/bgi083] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Proline oxidase (POX), localized on inner mitochondrial membranes, is encoded by a p53-induced gene and metabolically participates in p53-induced apoptosis. Previously, we showed that POX catalyzed the generation of reactive oxygen species (ROS). We and others have demonstrated that overexpression of POX, independent of p53, causes apoptotic cell death in a variety of cancer cells. But a necessary role for ROS remains uncertain. Therefore, we asked whether superoxide dismutases (SOD) and catalase (CAT), important antioxidant enzymes, might interfere with the POX-dependent induction of apoptosis. In this study, we used DLD-1 colorectal cancer cells stably transfected with the POX gene under the control of a tetracycline-inducible promoter. When doxycycline was removed from the culture medium and the expression of POX was induced, apoptotic cell death was initiated. To examine the importance of the ROS-dependent component of the pathway, we infected DLD-1 POX cells with recombinant adenoviruses containing MnSOD, CuZnSOD, CAT or varying combinations of these adenoviruses followed by induced expression of POX. The expression of MnSOD inhibited POX-induced apoptosis, but others did not. Mechanistically, mitochondria-localized MnSOD dramatically reduced the release of cytochrome c to cytosol by POX. Compared with control cells, MnSOD-expressing DLD-1 POX cells generated a higher concentration of H2O2 owing to dismutation of superoxide radicals, which was elevated by POX. Thus, these data further suggest that the generation of superoxide radicals plays a crucial role in POX-induced apoptosis and the process is partially blocked by MnSOD.
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Affiliation(s)
- Yongmin Liu
- Metabolism and Cancer Susceptibility Section, Laboratory for Comparative Carcinogenesis, National Cancer Institute, Frederick, MD 21702, USA
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O'Neill J, Manion M, Schwartz P, Hockenbery DM. Promises and challenges of targeting Bcl-2 anti-apoptotic proteins for cancer therapy. Biochim Biophys Acta Rev Cancer 2005; 1705:43-51. [PMID: 15585172 DOI: 10.1016/j.bbcan.2004.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cancer cells with elevated levels of BCL-2 and related survival proteins are broadly resistant to cytotoxic agents. Antisense oligodeoxynucleotides, and more recently small molecule ligands for BCL-2 and BCL-XL, are directly cytotoxic or synergistic with standard cytotoxic agents, and in some cases, may demonstrate selectivity for tumor cells. The usual issues for rational drug discovery are writ large upon BCL-2-targeted therapeutics. The molecular functions of BCL-2 are not well understood, such that validation of cytotoxic mechanisms related to BCL-2 as well as identification of surrogate markers for BCL-2 function are significant obstacles for drug development. Despite these problems, a substantial number of small molecules that bind to BCL-2 or BCL-XL are now available for pre-clinical testing; in turn, basic studies with these reagents should yield new insights about optimal strategies to disrupt BCL-2 survival functions.
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Affiliation(s)
- Jason O'Neill
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., D2-190, PO Box 19024, Seattle, Washington 98109-1024, USA
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66
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Konopleva M, Elstner E, McQueen TJ, Tsao T, Sudarikov A, Hu W, Schober WD, Wang RY, Chism D, Kornblau SM, Younes A, Collins SJ, Koeffler HP, Andreeff M. Peroxisome proliferator-activated receptor γ and retinoid X receptor ligands are potent inducers of differentiation and apoptosis in leukemias. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.1249.3.10] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor family that forms heterodimers with retinoid X receptor. These heterodimers bind to DNA and activate the transcription of target genes. Here, we report that the PPARγ receptor protein is expressed in primary myeloid and lymphoid leukemias and in lymphoma and myeloma cell lines. In this study, we compared the activity of several PPARγ ligands including BRL49653 (rosiglitazone), 15-deoxy-Δ12,14-prostaglandin J2, and the novel triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid on leukemia cells. Exposure to these PPARγ ligands induced apoptosis in myeloid (U937 and HL-60) and lymphoid (Su-DHL, Sup-M2, Ramos, Raji, Hodgkin's cell lines, and primary chronic lymphocytic leukemia) cells. A similar exposure to these PPARγ ligands induced the differentiation of myeloid leukemic cells. A combination of PPARγ ligands with a retinoid X receptor agonist (i.e., LG100268) or a retinoic acid receptor agonist (i.e., all trans-retinoic acid) enhanced differentiating and growth-inhibitory effects. 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic acid induced differentiation and apoptosis with much greater potency than the other PPARγ ligands in established cell lines and primary chronic lymphocytic leukemia samples. Exposure to 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid induced mitochondrial depolarization and caspase activation, which was associated with apoptosis induction. In Bcl-2-overexpressing chronic lymphocytic leukemia cells, the small-molecule Bcl-2 inhibitor HA14-1 sensitized these cells to 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid–induced apoptosis. These results suggest that PPARγ ligation alone and in combination with retinoids holds promise as novel therapy for leukemias by activating the transcriptional activity of target genes that control apoptosis and differentiation in leukemias.
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Affiliation(s)
- Marina Konopleva
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Elena Elstner
- 4Department of Medicine (Charité), Division of Hematology/Oncology, Humboldt University, Berlin, Germany
| | - Teresa J. McQueen
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Twee Tsao
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Andrey Sudarikov
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Wei Hu
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Wendy D. Schober
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Rui-Yu Wang
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - David Chism
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | - Steven M. Kornblau
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
| | | | | | - H. Phillip Koeffler
- 6Division of Hematology/Oncology, Cedars-Sinai Medical Center/University of California at Los Angeles School of Medicine, Los Angeles, California
| | - Michael Andreeff
- 1Blood and Marrow Transplantation, Section of Molecular Hematology and Therapy and Departments of
- 3Leukemia, University of Texas M.D. Anderson Cancer Center, Houston, Texas
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