1101
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Shikonin directly targets mitochondria and causes mitochondrial dysfunction in cancer cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:726025. [PMID: 23118796 PMCID: PMC3478753 DOI: 10.1155/2012/726025] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 09/07/2012] [Indexed: 01/18/2023]
Abstract
Chemotherapy is a mainstay of cancer treatment. Due to increased drug resistance and the severe side effects of currently used therapeutics, new candidate compounds are required for improvement of therapy success. Shikonin, a natural naphthoquinone, was used in traditional Chinese medicine for the treatment of different inflammatory diseases and recent studies revealed the anticancer activities of shikonin. We found that shikonin has strong cytotoxic effects on 15 cancer cell lines, including multidrug-resistant cell lines. Transcriptome-wide mRNA expression studies showed that shikonin induced genetic pathways regulating cell cycle, mitochondrial function, levels of reactive oxygen species, and cytoskeletal formation. Taking advantage of the inherent fluorescence of shikonin, we analyzed its uptake and distribution in live cells with high spatial and temporal resolution using flow cytometry and confocal microscopy. Shikonin was specifically accumulated in the mitochondria, and this accumulation was associated with a shikonin-dependent deregulation of cellular Ca2+ and ROS levels. This deregulation led to a breakdown of the mitochondrial membrane potential, dysfunction of microtubules, cell-cycle arrest, and ultimately induction of apoptosis. Seeing as both the metabolism and the structure of mitochondria show marked differences between cancer cells and normal cells, shikonin is a promising candidate for the next generation of chemotherapy.
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1102
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Fulda S. Shifting the balance of mitochondrial apoptosis: therapeutic perspectives. Front Oncol 2012; 2:121. [PMID: 23061040 PMCID: PMC3465793 DOI: 10.3389/fonc.2012.00121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 09/03/2012] [Indexed: 01/25/2023] Open
Abstract
Signaling via the intrinsic (mitochondrial) pathway of apoptosis represents one of the critical signal transduction cascades that control the regulation of cell death. This pathway is typically altered in human cancers, thereby providing a suitable target for therapeutic intervention. Members of the Bcl-2 family of proteins as well as cell survival signaling cascades such as the PI3K/Akt/mTOR pathway are involved in the regulation of mitochondria-mediated apoptosis. Therefore, further insights into the molecular mechanisms that form the basis for the control of mitochondria-mediated apoptosis will likely open new perspectives to bypass evasion of apoptosis and treatment resistance in human cancers.
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Affiliation(s)
- Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Germany
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1103
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Catalina-Rodriguez O, Kolukula VK, Tomita Y, Preet A, Palmieri F, Wellstein A, Byers S, Giaccia AJ, Glasgow E, Albanese C, Avantaggiati ML. The mitochondrial citrate transporter, CIC, is essential for mitochondrial homeostasis. Oncotarget 2012; 3:1220-35. [PMID: 23100451 PMCID: PMC3717962 DOI: 10.18632/oncotarget.714] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 10/18/2012] [Indexed: 12/25/2022] Open
Abstract
Dysregulation of the pathways that preserve mitochondrial integrity hallmarks many human diseases including diabetes, neurodegeration, aging and cancer. The mitochondrial citrate transporter gene, SLC25A1 or CIC, maps on chromosome 22q11.21, a region amplified in some tumors and deleted in developmental disorders known as velo-cardio-facial- and DiGeorge syndromes. We report here that in tumor cells CIC maintains mitochondrial integrity and bioenergetics, protects from mitochondrial damage and circumvents mitochondrial depletion via autophagy, hence promoting proliferation. CIC levels are increased in human cancers and its inhibition has anti-tumor activity, albeit with no toxicity on adult normal tissues. The knock-down of the CIC gene in zebrafish leads to mitochondria depletion and to proliferation defects that recapitulate features of human velo-cardio-facial syndrome, a phenotype rescued by blocking autophagy. Our findings reveal that CIC maintains mitochondrial homeostasis in metabolically active, high proliferating tissues and imply that this protein is a therapeutic target in cancer and likely, in other human diseases.
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Affiliation(s)
- Olga Catalina-Rodriguez
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Vamsi K. Kolukula
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - York Tomita
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Anju Preet
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | | | - Anton Wellstein
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Stephen Byers
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Amato J. Giaccia
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Eric Glasgow
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Chris Albanese
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Maria Laura Avantaggiati
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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1104
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Mitochondria-targeted antioxidants and metabolic modulators as pharmacological interventions to slow ageing. Biotechnol Adv 2012; 31:563-92. [PMID: 23022622 DOI: 10.1016/j.biotechadv.2012.09.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 02/07/2023]
Abstract
Populations in many nations today are rapidly ageing. This unprecedented demographic change represents one of the main challenges of our time. A defining property of the ageing process is a marked increase in the risk of mortality and morbidity with age. The incidence of cancer, cardiovascular and neurodegenerative diseases increases non-linearly, sometimes exponentially with age. One of the most important tasks in biogerontology is to develop interventions leading to an increase in healthy lifespan (health span), and a better understanding of basic mechanisms underlying the ageing process itself may lead to interventions able to delay or prevent many or even all age-dependent conditions. One of the putative basic mechanisms of ageing is age-dependent mitochondrial deterioration, closely associated with damage mediated by reactive oxygen species (ROS). Given the central role that mitochondria and mitochondrial dysfunction play not only in ageing but also in apoptosis, cancer, neurodegeneration and other age-related diseases there is great interest in approaches to protect mitochondria from ROS-mediated damage. In this review, we explore strategies of targeting mitochondria to reduce mitochondrial oxidative damage with the aim of preventing or delaying age-dependent decline in mitochondrial function and some of the resulting pathologies. We discuss mitochondria-targeted and -localized antioxidants (e.g.: MitoQ, SkQ, ergothioneine), mitochondrial metabolic modulators (e.g. dichloroacetic acid), and uncouplers (e.g.: uncoupling proteins, dinitrophenol) as well as some alternative future approaches for targeting compounds to the mitochondria, including advances from nanotechnology.
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1105
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Abstract
The current status of peptides that target the mitochondria in the context of cancer is the focus of this review. Chemotherapy and radiotherapy used to kill tumor cells are principally mediated by the process of apoptosis that is governed by the mitochondria. The failure of anticancer therapy often resides at the level of the mitochondria. Therefore, the mitochondrion is a key pharmacological target in cancer due to many of the differences that arise between malignant and healthy cells at the level of this ubiquitous organelle. Additionally, targeting the characteristics of malignant mitochondira often rely on disruption of protein--protein interactions that are not generally amenable to small molecules. We discuss anticancer peptides that intersect with pathological changes in the mitochondrion.
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1106
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Thomas KJ, Jacobson MR. Defects in mitochondrial fission protein dynamin-related protein 1 are linked to apoptotic resistance and autophagy in a lung cancer model. PLoS One 2012; 7:e45319. [PMID: 23028930 PMCID: PMC3447926 DOI: 10.1371/journal.pone.0045319] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 08/20/2012] [Indexed: 11/22/2022] Open
Abstract
Evasion of apoptosis is implicated in almost all aspects of cancer progression, as well as treatment resistance. In this study, resistance to apoptosis was identified in tumorigenic lung epithelial (A549) cells as a consequence of defects in mitochondrial and autophagic function. Mitochondrial function is determined in part by mitochondrial morphology, a process regulated by mitochondrial dynamics whereby the joining of two mitochondria, fusion, inhibits apoptosis while fission, the division of a mitochondrion, initiates apoptosis. Mitochondrial morphology of A549 cells displayed an elongated phenotype–mimicking cells deficient in mitochondrial fission protein, Dynamin-related protein 1 (Drp1). A549 cells had impaired Drp1 mitochondrial recruitment and decreased Drp1-dependent fission. Cytochrome c release and caspase-3 and PARP cleavage were impaired both basally and with apoptotic stimuli in A549 cells. Increased mitochondrial mass was observed in A549 cells, suggesting defects in mitophagy (mitochondrial selective autophagy). A549 cells had decreased LC3-II lipidation and lysosomal inhibition suggesting defects in autophagy occur upstream of lysosomal degradation. Immunostaining indicated mitochondrial localized LC3 punctae in A549 cells increased after mitochondrial uncoupling or with a combination of mitochondrial depolarization and ectopic Drp1 expression. Increased inhibition of apoptosis in A549 cells is correlated with impeded mitochondrial fission and mitophagy. We suggest mitochondrial fission defects contribute to apoptotic resistance in A549 cells.
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Affiliation(s)
- Kelly Jean Thomas
- Biological Sciences Department, Colorado Mesa University, Grand Junction, Colorado, United States of America.
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1107
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Liu JX, Zhang JH, Li HH, Lai FJ, Chen KJ, Chen H, Luo J, Guo HC, Wang ZH, Lin SZ. Emodin induces Panc-1 cell apoptosis via declining the mitochondrial membrane potential. Oncol Rep 2012; 28:1991-6. [PMID: 22992976 DOI: 10.3892/or.2012.2042] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/12/2012] [Indexed: 11/06/2022] Open
Abstract
In this study, we investigated the apoptotic effect of emodin on human pancreatic cancer cell line Panc-1 in vitro and in vivo as well as the possible mechanisms involved. In vitro, human pancreatic cancer cell line Panc-1 was exposed to varying concentrations of emodin (0, 10, 20, 40 or 80 µmol/l). Then the mitochondrial membrane potential (MMP) was analyzed by JC-1 staining, cell apoptosis was analyzed by flow cytometry (FCM) and cell proliferation was analyzed by MTT. In vivo, nude mice orthotopically implanted were randomly divided into five groups to receive treatments by different doses of emodin: control group (normal saline 0.2 ml), E10 group (emodin 10 mg/kg), E20 group (emodin 20 mg/kg), E40 group (emodin 40 mg/kg) and E80 group (emodin 80 mg/kg). Each mouse was treated 5 times by intraperitoneal injection of emodin every 3 days. During the treatment, the feeding stuff was recorded. One week after the last treatment, we recorded the body weight and the maximum diameter of tumor in each group before the mice were sacrificed. Then the cell apoptosis of the tumor was tested by TUNEL assay. The results in vitro showed that the MMP of the cells declined and the apoptosis rate increased with the emodin concentration increasing and the cell proliferation of each group was inhibited in a dose- and time-dependent manner by emodin. The feeding stuff curve did not decline significantly in E40 group and the apoptosis rate of the tumor cells in this group was higher than the lower-dose groups. Taken together, our results demonstrate that emodin may induce the pancreatic cancer cell apoptosis via declining the MMP and a moderate dose of emodin improved the living state of the model mice.
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Affiliation(s)
- Jin-Xiang Liu
- Department of Hepatobiliary-Pancreatic Surgery, The Second Affiliated Hospital of Wenzhou Medical College,Wenzhou 325027, PR China
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1108
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Enzenmüller S, Gonzalez P, Karpel-Massler G, Debatin KM, Fulda S. GDC-0941 enhances the lysosomal compartment via TFEB and primes glioblastoma cells to lysosomal membrane permeabilization and cell death. Cancer Lett 2012; 329:27-36. [PMID: 23000516 DOI: 10.1016/j.canlet.2012.09.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/17/2012] [Accepted: 09/10/2012] [Indexed: 12/20/2022]
Abstract
Since phosphatidylinositol-3-kinase (PI3K) inhibitors are primarily cytostatic against glioblastoma, we searched for new drug combinations. Here, we discover that the PI3K inhibitor GDC-0941 acts in concert with the natural compound B10, a glycosylated derivative of betulinic acid, to induce cell death in glioblastoma cells. Importantly, parallel experiments in primary glioblastoma cultures similarly show that GDC-0941 and B10 cooperate to trigger cell death, underscoring the clinical relevance of this finding. Molecular studies revealed that treatment with GDC-0941 stimulates the expression and nuclear translocation of Transcription Factor EB (TFEB), a master regulator of lysosomal biogenesis, the lysosomal membrane marker LAMP-1 and the mature form of cathepsin B. Also, GDC-0941 triggers a time-dependent increase of the lysosomal compartment in a TFEB-dependent manner, since knockdown of TFEB significantly reduces this GDC-0941-stimulated lysosomal enhancement. Importantly, GDC-0941 cooperates with B10 to trigger lysosomal membrane permeabilization, leading to increased activation of Bax, loss of mitochondrial membrane potential (MMP), caspase-3 activation and cell death. Addition of the cathepsin B inhibitor CA-074me reduces Bax activation, loss of MMP, caspase-3 activation and cell death upon treatment with GDC-0941/B10. By comparison, knockdown of caspase-3 or the broad-range caspase inhibitor zVAD.fmk inhibits GDC-0941/B10-induced DNA fragmentation, but does not prevent cell death, thus pointing to both caspase-dependent and -independent pathways. By identifying the combination of GDC-0941 and B10 as a new, potent strategy to trigger cell death in glioblastoma cells, our findings have important implications for the development of novel treatment approaches for glioblastoma.
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1109
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Engineering of blended nanoparticle platform for delivery of mitochondria-acting therapeutics. Proc Natl Acad Sci U S A 2012; 109:16288-93. [PMID: 22991470 DOI: 10.1073/pnas.1210096109] [Citation(s) in RCA: 352] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial dysfunctions cause numerous human disorders. A platform technology based on biodegradable polymers for carrying bioactive molecules to the mitochondrial matrix could be of enormous potential benefit in treating mitochondrial diseases. Here we report a rationally designed mitochondria-targeted polymeric nanoparticle (NP) system and its optimization for efficient delivery of various mitochondria-acting therapeutics by blending a targeted poly(d,l-lactic-co-glycolic acid)-block (PLGA-b)-poly(ethylene glycol) (PEG)-triphenylphosphonium (TPP) polymer (PLGA-b-PEG-TPP) with either nontargeted PLGA-b-PEG-OH or PLGA-COOH. An optimized formulation was identified through in vitro screening of a library of charge- and size-varied NPs, and mitochondrial uptake was studied by qualitative and quantitative investigations of cytosolic and mitochondrial fractions of cells treated with blended NPs composed of PLGA-b-PEG-TPP and a triblock copolymer containing a fluorescent quantum dot, PLGA-b-PEG-QD. The versatility of this platform was demonstrated by studying various mitochondria-acting therapeutics for different applications, including the mitochondria-targeting chemotherapeutics lonidamine and α-tocopheryl succinate for cancer, the mitochondrial antioxidant curcumin for Alzheimer's disease, and the mitochondrial uncoupler 2,4-dinitrophenol for obesity. These biomolecules were loaded into blended NPs with high loading efficiencies. Considering efficacy, the targeted PLGA-b-PEG-TPP NP provides a remarkable improvement in the drug therapeutic index for cancer, Alzheimer's disease, and obesity compared with the nontargeted construct or the therapeutics in their free form. This work represents the potential of a single, programmable NP platform for the diagnosis and targeted delivery of therapeutics for mitochondrial dysfunction-related diseases.
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1110
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Alberghina L, Gaglio D, Gelfi C, Moresco RM, Mauri G, Bertolazzi P, Messa C, Gilardi MC, Chiaradonna F, Vanoni M. Cancer cell growth and survival as a system-level property sustained by enhanced glycolysis and mitochondrial metabolic remodeling. Front Physiol 2012; 3:362. [PMID: 22988443 PMCID: PMC3440026 DOI: 10.3389/fphys.2012.00362] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/23/2012] [Indexed: 12/14/2022] Open
Abstract
Systems Biology holds that complex cellular functions are generated as system-level properties endowed with robustness, each involving large networks of molecular determinants, generally identified by “omics” analyses. In this paper we describe four basic cancer cell properties that can easily be investigated in vitro: enhanced proliferation, evasion from apoptosis, genomic instability, and inability to undergo oncogene-induced senescence. Focusing our analysis on a K-ras dependent transformation system, we show that enhanced proliferation and evasion from apoptosis are closely linked, and present findings that indicate how a large metabolic remodeling sustains the enhanced growth ability. Network analysis of transcriptional profiling gives the first indication on this remodeling, further supported by biochemical investigations and metabolic flux analysis (MFA). Enhanced glycolysis, down-regulation of TCA cycle, decoupling of glucose and glutamine utilization, with increased reductive carboxylation of glutamine, so to yield a sustained production of growth building blocks and glutathione, are the hallmarks of enhanced proliferation. Low glucose availability specifically induces cell death in K-ras transformed cells, while PKA activation reverts this effect, possibly through at least two mitochondrial targets. The central role of mitochondria in determining the two investigated cancer cell properties is finally discussed. Taken together the findings reported herein indicate that a system-level property is sustained by a cascade of interconnected biochemical pathways that behave differently in normal and in transformed cells.
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Affiliation(s)
- Lilia Alberghina
- SysBio Centre for Systems Biology Milano and Rome, Italy ; Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza Milano, Italy
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1111
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Heller A, Brockhoff G, Goepferich A. Targeting drugs to mitochondria. Eur J Pharm Biopharm 2012; 82:1-18. [DOI: 10.1016/j.ejpb.2012.05.014] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/21/2012] [Accepted: 05/23/2012] [Indexed: 12/20/2022]
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1112
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Caro AA, Adlong LW, Crocker SJ, Gardner MW, Luikart EF, Gron LU. Effect of garlic-derived organosulfur compounds on mitochondrial function and integrity in isolated mouse liver mitochondria. Toxicol Lett 2012; 214:166-74. [PMID: 22960305 DOI: 10.1016/j.toxlet.2012.08.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/21/2012] [Accepted: 08/22/2012] [Indexed: 11/19/2022]
Abstract
The objectives of this work were to evaluate the direct effects of diallysulfide (DAS) and diallyldisulfide (DADS), two major organosulfur compounds of garlic oil, on mitochondrial function and integrity, by using isolated mouse liver mitochondria in a cell-free system. DADS produced concentration-dependent mitochondrial swelling over the range 125-1000μM, while DAS was ineffective. Swelling experiments performed with de-energized or energized mitochondria showed similar maximal swelling amplitudes. Cyclosporin A (1μM), or ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA, 1mM) were ineffective in inhibiting DADS-induced mitochondrial swelling. DADS produced a minor (12%) decrease in mitochondrial membrane protein thiols, but did not induce clustering of mitochondrial membrane proteins. Incubation of mitochondria with DADS (but not DAS) produced an increase in the oxidation rate of 2',7' dichlorofluorescein diacetate (DCFH-DA), together with depletion of reduced glutathione (GSH) and increased lipid peroxidation. DADS (but not DAS) produced a concentration-dependent dissipation of the mitochondrial membrane potential, but did not induce cytochrome c release. DADS-dependent effects, including mitochondrial swelling, DCFH-DA oxidation, lipid peroxidation and loss of mitochondrial membrane potential, were inhibited by antioxidants and iron chelators. These results suggest that DADS causes direct impairment of mitochondrial function as the result of oxidation of the membrane lipid phase initiated by the GSH- and iron-dependent generation of oxidants.
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Affiliation(s)
- Andres A Caro
- Chemistry Department, Hendrix College, Conway, AR, United States.
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1113
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Basit F, Humphreys R, Fulda S. RIP1 protein-dependent assembly of a cytosolic cell death complex is required for inhibitor of apoptosis (IAP) inhibitor-mediated sensitization to lexatumumab-induced apoptosis. J Biol Chem 2012; 287:38767-77. [PMID: 22927431 DOI: 10.1074/jbc.m112.398966] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Searching for new strategies to trigger apoptosis in rhabdomyosarcoma (RMS), we investigated the effect of two novel classes of apoptosis-targeting agents, i.e. monoclonal antibodies against TNF-related apoptosis-inducing ligand (TRAIL) receptor 1 (mapatumumab) and TRAIL receptor 2 (lexatumumab) and small-molecule inhibitors of inhibitor of apoptosis (IAP) proteins. Here, we report that IAP inhibitors synergized with lexatumumab, but not with mapatumumab, to reduce cell viability and to induce apoptosis in several RMS cell lines in a highly synergistic manner (combination index <0.1). Cotreatment-induced apoptosis was accompanied by enhanced activation of caspase-8, -9, and -3; loss of mitochondrial membrane potential; and caspase-dependent apoptosis. In addition, IAP inhibitor and lexatumumab cooperated to stimulate the assembly of a cytosolic complex containing RIP1, FADD, and caspase-8. Importantly, knockdown of RIP1 by RNA interference prevented the formation of the RIP1·FADD·caspase-8 complex and inhibited subsequent activation of caspase-8, -9, and -3; loss of mitochondrial membrane potential; and apoptosis upon treatment with IAP inhibitor and lexatumumab. In addition, RIP1 silencing rescued clonogenic survival of cells treated with the combination of lexatumumab and IAP inhibitor, thus underscoring the critical role of RIP1 in cotreatment-induced apoptosis. By comparison, the TNFα-blocking antibody Enbrel had no effect on IAP inhibitor/lexatumumab-induced apoptosis, indicating that an autocrine TNFα loop is dispensable. By demonstrating that IAP inhibitors and lexatumumab synergistically trigger apoptosis in a RIP1-dependent but TNFα-independent manner in RMS cells, our findings substantially advance our understanding of IAP inhibitor-mediated regulation of TRAIL-induced cell death.
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Affiliation(s)
- Farhan Basit
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, 60528 Frankfurt, Germany
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1114
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RIP1 is required for IAP inhibitor-mediated sensitization for TRAIL-induced apoptosis via a RIP1/FADD/caspase-8 cell death complex. Oncogene 2012; 32:3263-73. [PMID: 22890322 DOI: 10.1038/onc.2012.337] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 01/09/2023]
Abstract
Inhibitor of apoptosis (IAP) proteins represent promising therapeutic targets due to their high expression in many cancers. Here, we report that small-molecule IAP inhibitors at subtoxic concentrations cooperate with monoclonal antibodies against TRAIL receptor 1 (Mapatumumab) or TRAIL-R2 (Lexatumumab) to induce apoptosis in neuroblastoma cells in a highly synergistic manner (combination index <0.1). Importantly, we identify receptor-activating protein 1 (RIP1) as a critical mediator of this synergism. RIP1 is required for the formation of a RIP1/FADD/caspase-8 complex that drives caspase-8 activation, cleavage of Bid into tBid, mitochondrial outer membrane permeabilization, full activation of caspase-3 and caspase-dependent apoptosis. Indeed, knockdown of RIP1 abolishes formation of the RIP1/FADD/caspase-8 complex, caspase activation and apoptosis upon combination treatment. Similarly, inhibition of RIP1 kinase activity by Necrostatin-1 inhibits IAP inhibitor- and TRAIL receptor-triggered apoptosis. In contrast, overexpression of the dominant-negative superrepressor IκBα-SR or addition of the tumor necrosis factor (TNF)α-blocking antibody Enbrel do not interfere with cotreatment-induced apoptosis, pointing to a nuclear factor-κB- and TNFα-independent mechanism. Of note, IAP inhibitor also sensitizes primary cultured neuroblastoma cells for TRAIL receptor-mediated loss of viability, underscoring the clinical relevance. By identifying RIP1 as a critical mediator of IAP inhibitor-mediated sensitization for Mapatumumab- or Lexatumumab-induced apoptosis, our findings provide new insights into the synergistic interaction of IAP inhibitors together with TRAIL receptor agonists.
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1115
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Ciocca DR, Arrigo AP, Calderwood SK. Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update. Arch Toxicol 2012; 87:19-48. [PMID: 22885793 DOI: 10.1007/s00204-012-0918-z] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/25/2012] [Indexed: 12/20/2022]
Abstract
Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participate in many of the traits that permit the malignant phenotype. Thus, cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1/HSP in malignant transformation and (3) discovering approaches to therapy based on disrupting the influence of the HSF1-controlled transcriptome in cancer.
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Affiliation(s)
- Daniel R Ciocca
- Oncology Laboratory, Institute of Experimental Medicine and Biology of Cuyo (IMBECU), Scientific and Technological Center (CCT), CONICET, 5500 Mendoza, Argentina.
| | - Andre Patrick Arrigo
- Apoptosis Cancer and Development, Cancer Research Center of Lyon (CRCL), UMR INSERM 1052-CNRS 5286, Claude Bernard University, Lyon-1, Cheney A Building, Centre Regional Léon Bérard, 28, rue Laennec 69008 LYON, France. ;
| | - Stuart K Calderwood
- Molecular and Cellular Radiation Oncology, Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, MA02215
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1116
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Neuzil J, Dong LF, Rohlena J, Truksa J, Ralph SJ. Classification of mitocans, anti-cancer drugs acting on mitochondria. Mitochondrion 2012; 13:199-208. [PMID: 22846431 DOI: 10.1016/j.mito.2012.07.112] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/15/2012] [Accepted: 07/22/2012] [Indexed: 12/13/2022]
Abstract
Mitochondria have emerged as an intriguing target for anti-cancer drugs, inherent to vast majority if not all types of tumours. Drugs that target mitochondria and exert anti-cancer activity have become a focus of recent research due to their great clinical potential (which has not been harnessed thus far). The exceptional potential of mitochondria as a target for anti-cancer agents has been reinforced by the discouraging finding that even tumours of the same type from individual patients differ in a number of mutations. This is consistent with the idea of personalised therapy, an elusive goal at this stage, in line with the notion that tumours are unlikely to be treated by agents that target only a single gene or a single pathway. This endows mitochondria, an invariant target present in all tumours, with an exceptional momentum. This train of thoughts inspired us to define a class of anti-cancer drugs acting by way of mitochondrial 'destabilisation', termed 'mitocans'. In this communication, we define mitocans (many of which have been known for a long time) and classify them into several classes based on their molecular mode of action. We chose the targets that are of major importance from the point of view of their role in mitochondrial destabilisation by small compounds, some of which are now trialled as anti-cancer agents. The classification starts with targets at the surface of mitochondria and ending up with those in the mitochondrial matrix. The purpose of this review is to present in a concise manner the classification of compounds that hold a considerable promise as potential anti-cancer drugs.
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Affiliation(s)
- Jiri Neuzil
- School of Medical Science, Griffith University, Southport, Qld, Australia.
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1117
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Schimmer AD, Skrtić M. Therapeutic potential of mitochondrial translation inhibition for treatment of acute myeloid leukemia. Expert Rev Hematol 2012; 5:117-9. [PMID: 22475277 DOI: 10.1586/ehm.12.8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1118
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Mitocans, Mitochondria-Targeting Anticancer Drugs. ACTA ACUST UNITED AC 2012. [DOI: 10.1201/b12308-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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1119
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Mo R, Sun Q, Xue J, Li N, Li W, Zhang C, Ping Q. Multistage pH-responsive liposomes for mitochondrial-targeted anticancer drug delivery. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:3659-3665. [PMID: 22678851 DOI: 10.1002/adma.201201498] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Indexed: 06/01/2023]
Abstract
Zwitterionic oligopeptide liposomes (HHG2C(18)-L) containing a smart lipid (1,5-dioctadecyl-L-glutamyl 2-histidyl-hexahydrobenzoic acid, HHG2C(18)) are developed to overcome the barriers faced by anticancer drugs on the route from the site of injection into the body to the final antitumor target within transport steps with multiple physiological and biological barriers. HHG2C(18)-L show the multistage pH-responsive to the tumor cell (the mitochondria in this case). Their multistage pH response leads to more effective entry of the tumor cell, improved escape from the endolysosomes, and accumulation at the mitochondria (see picture).
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Affiliation(s)
- Ran Mo
- Center of Drug Discovery, State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, PR China
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1120
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Oxidative stress in genetic mouse models of Parkinson's disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:624925. [PMID: 22829959 PMCID: PMC3399377 DOI: 10.1155/2012/624925] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/12/2012] [Accepted: 04/12/2012] [Indexed: 02/07/2023]
Abstract
There is extensive evidence in Parkinson's disease of a link between oxidative stress and some of the monogenically inherited Parkinson's disease-associated genes. This paper focuses on the importance of this link and potential impact on neuronal function. Basic mechanisms of oxidative stress, the cellular antioxidant machinery, and the main sources of cellular oxidative stress are reviewed. Moreover, attention is given to the complex interaction between oxidative stress and other prominent pathogenic pathways in Parkinson's disease, such as mitochondrial dysfunction and neuroinflammation. Furthermore, an overview of the existing genetic mouse models of Parkinson's disease is given and the evidence of oxidative stress in these models highlighted. Taken into consideration the importance of ageing and environmental factors as a risk for developing Parkinson's disease, gene-environment interactions in genetically engineered mouse models of Parkinson's disease are also discussed, highlighting the role of oxidative damage in the interplay between genetic makeup, environmental stress, and ageing in Parkinson's disease.
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1121
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Kang BH. TRAP1 regulation of mitochondrial life or death decision in cancer cells and mitochondria-targeted TRAP1 inhibitors. BMB Rep 2012; 45:1-6. [PMID: 22281005 DOI: 10.5483/bmbrep.2012.45.1.1] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hsp90 is one of the most conserved molecular chaperones ubiquitously expressed in normal cells and over-expressed in cancer cells. A pool of Hsp90 was found in cancer mitochondria and the expression of the mitochondrial Hsp90 homolog, TRAP1, was also elevated in many cancers. The mitochondrial pool of chaperones plays important roles in regulating mitochondrial integrity, protecting against oxidative stress, and inhibiting cell death. Pharmacological inactivation of the chaperones induced mitochondrial dysfunction and concomitant cell death selectively in cancer cells, suggesting they can be target proteins for the development of cancer therapeutics. Several drug candidates targeting TRAP1 and Hsp90 in the mitochondria have been developed and have shown strong cytotoxic activity in many cancers, but not in normal cells in vitros and in vivo. In this review, recent developments in the study of mitochondrial chaperones and the mitochondria-targeted chaperone inhibitors are discussed.
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Affiliation(s)
- Byoung Heon Kang
- Graduate Program of Life Science, School of Nano-Bioscience and Chemical Engineering, UNIST, Ulsan, Korea.
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1122
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Fulda S. Histone deacetylase (HDAC) inhibitors and regulation of TRAIL-induced apoptosis. Exp Cell Res 2012; 318:1208-12. [DOI: 10.1016/j.yexcr.2012.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 02/06/2012] [Accepted: 02/06/2012] [Indexed: 10/28/2022]
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1123
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Phospho-sulindac (OXT-328) inhibits the growth of human lung cancer xenografts in mice: enhanced efficacy and mitochondria targeting by its formulation in solid lipid nanoparticles. Pharm Res 2012; 29:3090-101. [PMID: 22723123 DOI: 10.1007/s11095-012-0801-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 06/06/2012] [Indexed: 12/27/2022]
Abstract
PURPOSE To evaluate the antitumor efficacy of solid lipid nanoparticle-encapsulated phospho-sulindac (SLN-PS) in human lung cancer. METHODS PS was incorporated into SLNs using the emulsion evaporation technique. We determined the antitumor activity of SLN-PS in cultured lung cancer cells. The performance of SLN-PS was further evaluated by pharmacokinetic studies in mice and in a model of human lung cancer xenografts in nude mice. RESULTS SLN-PS was >4-fold more potent than PS in inhibiting the growth of A549 and H510 cells in vitro. SLN-PS enhanced cellular uptake and facilitated PS accumulation in mitochondria, leading to oxidative stress and apoptosis via the mitochondrial-apoptosis pathway. SLN-PS was highly effective in suppressing the growth of A549 xenografts (78% inhibition compared to control, p < 0.01); while PS had no significant effect. Formulation of PS in SLNs resulted in improved pharmacokinetics in mice and an enhanced (≈ 14-fold) accumulation of PS and its metabolites in A549 xenografts. Finally, SLN-PS enhanced urinary F2-isoprostane uniquely in mice bearing A549 xenografts compared to untreated controls, suggesting that SLN-PS specifically induced oxidative stress in tumors. CONCLUSIONS Our results show that SLN-PS is efficacious in suppressing the growth of lung cancer and merits further evaluation.
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1124
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Abstract
With about 22,000 new cases estimated in 2012 in the US and 15,500 related deaths, ovarian cancer is a heterogeneous and aggressive disease. Even though most of patients are sensitive to chemotherapy treatment following surgery, recurring disease is almost always lethal, and only about 30% of the women affected will be cured. Thanks to a better understanding of the molecular mechanisms underlying ovarian cancer malignancy, new therapeutic options with molecular-targeted agents have become available. This review discusses the rationale behind molecular-targeted therapies and examines how newly identified molecular targets may enhance personalized therapies for ovarian cancer patients.
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1125
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Rodriguez N, Yang J, Hasselblatt K, Liu S, Zhou Y, Rauh-Hain JA, Ng SK, Choi PW, Fong WP, Agar NYR, Welch WR, Berkowitz RS, Ng SW. Casein kinase I epsilon interacts with mitochondrial proteins for the growth and survival of human ovarian cancer cells. EMBO Mol Med 2012; 4:952-63. [PMID: 22707389 PMCID: PMC3491827 DOI: 10.1002/emmm.201101094] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 05/07/2012] [Accepted: 05/11/2012] [Indexed: 01/04/2023] Open
Abstract
Epithelial ovarian cancer is the leading cause of death among gynaecologic cancers in Western countries. Our studies have shown that casein kinase I-epsilon (CKIε), a Wnt pathway protein, is significantly overexpressed in ovarian cancer tissues and is associated with poor survival. Ectopic expression of CKIε in normal human ovarian surface epithelial cells and inhibition of CKIε in ovarian cancer cells and in xenografts demonstrated the importance of CKIε in regulating cell proliferation and migration. Interestingly, CKIε function did not seem to involve β-catenin activity. Instead, CKIε was found to interact with several mitochondrial proteins including adenine nucleotide translocase 2 (ANT2). Inhibition of CKIε in ovarian cancer cells resulted in suppression of ANT2, downregulation of cellular ATP and the resulting cancer cells were more susceptible to chemotherapy. Our studies indicate that, in the context of ovarian cancer, the interaction between CKIε and ANT2 mediates pathogenic signalling that is distinct from the canonical Wnt/β-catenin pathway and is essential for cell proliferation and is clinically associated with poor survival.
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Affiliation(s)
- Noah Rodriguez
- Department of Obstetrics/Gynecology and Reproductive Biology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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1126
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Disruption of the VDAC2-Bak interaction by Bcl-x(S) mediates efficient induction of apoptosis in melanoma cells. Cell Death Differ 2012; 19:1928-38. [PMID: 22705850 DOI: 10.1038/cdd.2012.71] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The proapoptotic B-cell lymphoma (Bcl)-2 protein Bcl-x(S) encloses the Bcl-2 homology (BH) domains BH3 and BH4 and triggers apoptosis via the multidomain protein Bak, however, the mechanism remained elusive. For investigating Bcl-x(S) efficacy and pathways, an adenoviral vector was constructed with its cDNA under tetracycline-off control. Bcl-x(S) overexpression resulted in efficient apoptosis induction and caspase activation in melanoma cells. Indicative of mitochondrial apoptosis pathways, Bcl-x(S) translocated to the mitochondria, disrupted the mitochondrial membrane potential and induced release of cytochrome c, apoptosis-inducing factor and second mitochondria-derived activator of caspases. In melanoma cells, Bcl-x(S) resulted in significant Bak activation, and Bak knockdown as well as Bcl-x(L) overexpression abrogated Bcl-x(S)-induced apoptosis, whereas Mcl-1 (myeloid cell leukemia-1) knockdown resulted in a sensitization. With regard to the particular role of voltage-dependent anion channel 2 (VDAC2) for inhibition of Bak, we identified here a notable interaction between Bcl-x(S) and VDAC2 in melanoma cells, which was proven in reciprocal coimmunoprecipitation analyses. On the other hand, Bcl-x(S) showed no direct interaction with Bak, and its binding to VDAC2 appeared as also independent of Bak expression. Suggesting a new proapoptotic mechanism, Bcl-x(S) overexpression resulted in disruption of the VDAC2-Bak interaction leading to release of Bak. Further supporting this pathway, overexpression of VDAC2 strongly decreased apoptosis by Bcl-x(S). New proapoptotic pathways are of principle interest for overcoming apoptosis deficiency of melanoma cells.
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1127
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Mazumder S, Choudhary GS, Al-Harbi S, Almasan A. Mcl-1 Phosphorylation defines ABT-737 resistance that can be overcome by increased NOXA expression in leukemic B cells. Cancer Res 2012; 72:3069-79. [PMID: 22525702 PMCID: PMC3377792 DOI: 10.1158/0008-5472.can-11-4106] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
ABT-737 is a small molecule Bcl-2 homology (BH)-3 domain mimetic that binds to the Bcl-2 family proteins Bcl-2 and Bcl-xL and is currently under investigation in the clinic. In this study, we investigated potential mechanisms of resistance to ABT-737 in leukemia cell lines. Compared with parental cells, cells that have developed acquired resistance to ABT-737 showed increased expression of Mcl-1 in addition to posttranslational modifications that facilitated both Mcl-1 stabilization and its interaction with the BH3-only protein Bim. To sensitize resistant cells, Mcl-1 was targeted by two pan-Bcl-2 family inhibitors, obatoclax and gossypol. Although gossypol was effective only in resistant cells, obatoclax induced cell death in both parental and ABT-737-resistant cells. NOXA levels were increased substantially by treatment with gossypol and its expression was critical for the gossypol response. Mechanistically, the newly generated NOXA interacted with Mcl-1 and displaced Bim from the Mcl-1/Bim complex, freeing Bim to trigger the mitochondrial apoptotic pathway. Together, our findings indicate that NOXA and Mcl-1 are critical determinants for gossypol-mediated cell death in ABT-737-resistant cells. These data therefore reveal novel insight into mechanisms of acquired resistance to ABT-737.
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Affiliation(s)
- Suparna Mazumder
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Ohio 44195, USA
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1128
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Davis RE, Williams M. Mitochondrial function and dysfunction: an update. J Pharmacol Exp Ther 2012; 342:598-607. [PMID: 22700430 DOI: 10.1124/jpet.112.192104] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
With the current explosion of knowledge on the role of mitochondrial dysfunction in the genesis of various human disease states, there is an increased interest in targeting mitochondrial processes, pathways, and proteins for drug discovery efforts in cancer and cardiovascular, metabolic, and central nervous system diseases, the latter including autism and neurodegenerative diseases. We provide an update on understanding the central role of the mitochondrion in ATP and reactive oxygen species production and in controlling cell death pathways.
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Affiliation(s)
- Robert E Davis
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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1129
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Lin MW, Lin AS, Wu DC, Wang SSW, Chang FR, Wu YC, Huang YB. Euphol from Euphorbia tirucalli selectively inhibits human gastric cancer cell growth through the induction of ERK1/2-mediated apoptosis. Food Chem Toxicol 2012; 50:4333-9. [PMID: 22634261 DOI: 10.1016/j.fct.2012.05.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 04/09/2012] [Accepted: 05/16/2012] [Indexed: 01/09/2023]
Abstract
Gastric cancer is one of the most common malignancies worldwide, and the main cause of cancer-related death in Asia. The present study assessed the anticancer effects of euphol, a triterpene alcohol with anti-inflammatory and antiviral activities on human gastric cancer cells. Euphol showed higher cytotoxicity activity against human gastric CS12 cancer cells than against noncancer CSN cells. In addition, it up-regulated the pro-apoptotic protein BAX and down-regulated the prosurvival protein Bcl-2, causing mitochondrial dysfunction, possibly by caspase-3 activation. The anti-proliferative effects of euphol were associated with the increased p27(kip1) levels and decreased cyclin B1 levels. Inhibition of ERK1/2 activation by PD98059 reversed euphol-induced pro-apoptotic protein expression and cell death. Taken together, these findings suggest that euphol selectively induced gastric cancer cells apoptosis by modulation of ERK signaling, and could thus be of value for cancer therapy.
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Affiliation(s)
- Ming-Wei Lin
- Graduate Institute of Clinical Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan, ROC
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1130
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Zhou F, Wu S, Yuan Y, Chen WR, Xing D. Mitochondria-targeting photoacoustic therapy using single-walled carbon nanotubes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:1543-1550. [PMID: 22422554 DOI: 10.1002/smll.201101892] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/13/2011] [Indexed: 05/31/2023]
Abstract
In vitro photoacoustic therapy using modified single-walled carbon nanotubes (SWNTs) as "bomb" agents is a newly reported approach for cancer. Herein, a mitochondria-targeting photoacoustic modality using unmodified SWNTs and its in vitro and in vivo antitumor effect are reported. Unmodified SWNTs can be taken up into cancer cells due to a higher mitochondrial transmembrane potential in cancerous cells than normal cells. Under the irradiation of a 1064 nm pulse laser, 79.4% of cancer cells with intracellular SWNTs die within 20 s, while 82.3% of normal cells without SWNTs remain alive. This modality kills cancer cells mainly by triggering cell apoptosis that initiates from mitochondrial damage, through the depolarization of mitochondria and the subsequent release of cytochrome c after photoacoustic therapy. It is very effective in suppressing tumor growth by selectively destroying tumor tissue without causing epidermis injury. Taken together, these discoveries provide a new method using mitochondria-localized SWNTs as photoacoustic transducers for cancer treatment.
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Affiliation(s)
- Feifan Zhou
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
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1131
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Lin X, Wu G, Huo WQ, Zhang Y, Jin FS. Resveratrol induces apoptosis associated with mitochondrial dysfunction in bladder carcinoma cells. Int J Urol 2012; 19:757-64. [PMID: 22607368 DOI: 10.1111/j.1442-2042.2012.03024.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Resveratrol shows chemopreventive activity in a variety of human cancers by targeting mitochondria and triggering apoptosis. The purpose of this study was to investigate the antitumor action of resveratrol in bladder cancer and its underlying mechanism. METHODS Using two different bladder cell lines, BTT739 and T24, the cytotoxicity of resveratrol were determined by MTT assay. The apoptosis induced by resveratrol was assayed by transferase dUTP nick end labeling staining. To show whether the mitochondrial dysfunction involved in the effects of resveratrol, mitochondrial function was detected by mitochondrial membrane potential, reactive oxygen species production and adenosine 5'-triphosphate content. In addition, the markers of apoptosis in the intrinsic mitochondrial-dependent pathway were analyzed by the release of cytochrome c and the activities of caspase-9 and caspase-3. RESULTS Resveratrol effectively decreased cell viability and induced apoptosis in a concentration- and time-dependent manner. In addition, resveratrol significantly disrupted the mitochondrial membrane potential in both intact cells and isolated mitochondria. Resveratrol also increased reactive oxygen species production and reduced adenosine 5'-triphosphate concentrations. Western blot analysis showed that resveratrol provoked the release of cytochrome c from mitochondria to the cytosol. Furthermore, resveratrol significantly promoted the activation of caspase-9 and caspase-3. CONCLUSIONS These findings suggest that resveratrol efficiently triggers apoptosis in bladder cancer cells through the intrinsic mitochondrial-dependent pathway, which is associated with mitochondrial dysfunction. Resveratrol might have great pharmacological promise in the treatment of bladder cancer.
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Affiliation(s)
- Xi Lin
- Department of Urology, Daping Hospital, The Third Military Medical University, Chongqing, China
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1132
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Zhang YY, Zhou LM. Sirt3 inhibits hepatocellular carcinoma cell growth through reducing Mdm2-mediated p53 degradation. Biochem Biophys Res Commun 2012; 423:26-31. [PMID: 22609775 DOI: 10.1016/j.bbrc.2012.05.053] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 05/10/2012] [Indexed: 11/18/2022]
Abstract
Sirt3 is a member of the mammalian sirtuin family that is localized to mitochondria and plays a role in the control of the metabolic activity. Recently, Sirt3 has been reported to be associated with the deregulating metabolism of cancer cells. However, the role of Sirt3 in hepatocellular carcinoma (HCC) has never been studied. In this study, we found that Sirt3 protein expression was downregulated in human HCC tissue. We also showed that overexpression of Sirt3 using adenovirus inhibited HCC cell growth (two cell lines: HepG2 and HuH-7 cells) and induced apoptosis, which was evidenced by the increase of LDH leakage, enhancement of TUNEL-positive cells number and promotion of AIF translocation to nuclei. Sirt3 overexpression reduced the intracellular NAD(+) level, repressed the ERK1/2 signaling pathway, and activated the Akt and JNK signaling pathways. Furthermore, Sirt3 overexpression upregulated p53 protein level through downregulating Mdm2 and thereby slowing p53 degradation. Collectively, our data suggests that Sirt3 may play an important role in HCC development and progression and may be a promising therapeutic target for HCC.
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Affiliation(s)
- Yuan-Yuan Zhang
- Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, PR China
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1133
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Roslie H, Chan KM, Rajab NF, Velu SS, Kadir SAIASA, Bunyamin I, Weber JFF, Thomas NF, Majeed ABA, Myatt G, Inayat-Hussain SH. 3,5-dibenzyloxy-4'-hydroxystilbene induces early caspase-9 activation during apoptosis in human K562 chronic myelogenous leukemia cells. J Toxicol Sci 2012; 37:13-21. [PMID: 22293408 DOI: 10.2131/jts.37.13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A series of 22 stilbene derivatives based on resveratrol were synthesized incorporating acetoxy-, benzyloxy-, carboxy-, chloro-, hydroxy- and methoxy functional groups. We examined the cytotoxicity of these 22 stilbenes in human K562 chronic myelogenous leukemia cells. Only four compounds were cytotoxic namely 4'-hydroxy-3-methoxystilbene (15), 3'-acetoxy-4-chlorostilbene (19), 4'-hydroxy-3,5-dimethoxystilbene or pterostilbene (3) and 3,5-dibenzyloxy-4'-hydroxystilbene (28) with IC(50)s of 78 µM, 38 µM, 67 µM and 19.5 µM respectively. Further apoptosis assessment on the most potent compound, 28, confirmed that the cells underwent apoptosis based on phosphatidylserine externalization and loss of mitochondrial membrane potential. Importantly, we observed a concentration-dependent activation of caspase-9 as early as 2 hr with resultant caspase-3 cleavage in 28-induced apoptosis. Additionally, a structure-activity relationship (SAR) study proposed a possible mechanism of action for compound 28. Taken together, our data suggests that the pro-apoptotic effects of 28 involve the intrinsic mitochondrial pathway characterized by an early activation of caspase-9.
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Affiliation(s)
- Haslan Roslie
- Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, 42300 Selangor, Malaysia
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1134
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Nagai M, Vo NH, Shin Ogawa L, Chimmanamada D, Inoue T, Chu J, Beaudette-Zlatanova BC, Lu R, Blackman RK, Barsoum J, Koya K, Wada Y. The oncology drug elesclomol selectively transports copper to the mitochondria to induce oxidative stress in cancer cells. Free Radic Biol Med 2012; 52:2142-50. [PMID: 22542443 DOI: 10.1016/j.freeradbiomed.2012.03.017] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/16/2012] [Accepted: 03/20/2012] [Indexed: 01/08/2023]
Abstract
Elesclomol is an investigational drug that exerts potent anticancer activity through the elevation of reactive oxygen species (ROS) levels and is currently under clinical evaluation as a novel anticancer therapeutic. Here we report the first description of selective mitochondrial ROS induction by elesclomol in cancer cells based on the unique physicochemical properties of the compound. Elesclomol preferentially chelates copper (Cu) outside of cells and enters as elesclomol-Cu(II). The elesclomol-Cu(II) complex then rapidly and selectively transports the copper to mitochondria. In this organelle Cu(II) is reduced to Cu(I), followed by subsequent ROS generation. Upon dissociation from the complex, elesclomol is effluxed from cells and repeats shuttling elesclomol-Cu complexes from the extracellular to the intracellular compartments, leading to continued copper accumulation within mitochondria. An optimal range of redox potentials exhibited by copper chelates of elesclomol and its analogs correlated with the elevation of mitochondrial Cu(I) levels and cytotoxic activity, suggesting that redox reduction of the copper triggers mitochondrial ROS induction. Importantly the mitochondrial selectivity exhibited by elesclomol is a distinct characteristic of the compound that is not shared by other chelators, including disulfiram. Together these findings highlight a unique mechanism of action with important implications for cancer therapy.
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1135
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Fulda S. Modulation of mitochondrial apoptosis by PI3K inhibitors. Mitochondrion 2012; 13:195-8. [PMID: 22580303 DOI: 10.1016/j.mito.2012.05.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/23/2012] [Accepted: 05/02/2012] [Indexed: 12/15/2022]
Abstract
Most anticancer therapies exert their action by triggering programmed cell death (apoptosis) in cancer cells. The mitochondrial pathway of apoptosis is initiated by mitochondrial outer membrane permeabilization, leading to the release of apoptogenic factors such as cytochrome c or Smac from the mitochondrial intermembrane space into the cytosol. Mitochondrial outer membrane permeabilization is tightly controlled, for example by pro- and anti-apoptotic proteins of the Bcl-2 family. Recent evidence indicates that inhibition of the PI3K/Akt/mTOR pathway by small-molecule PI3K inhibitors primes cancer cells to mitochondrial apoptosis by tipping the balance towards pro-apoptotic Bcl-2 proteins, resulting in increased mitochondrial outer membrane permeabilization. Thus, mitochondrial apoptotic events play an important role in PI3K inhibitor-mediated sensitization for apoptosis.
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Affiliation(s)
- Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Komturstr. 3a, 60528 Frankfurt, Germany.
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1136
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Zhang Y, Xu Z, Wang H, Dong Y, Shi HN, Culley DJ, Crosby G, Marcantonio ER, Tanzi RE, Xie Z. Anesthetics isoflurane and desflurane differently affect mitochondrial function, learning, and memory. Ann Neurol 2012; 71:687-98. [PMID: 22368036 PMCID: PMC3942786 DOI: 10.1002/ana.23536] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 11/28/2011] [Accepted: 01/06/2012] [Indexed: 12/16/2022]
Abstract
OBJECTIVE There are approximately 8.5 million Alzheimer disease (AD) patients who need anesthesia and surgery care every year. The inhalation anesthetic isoflurane, but not desflurane, has been shown to induce caspase activation and apoptosis, which are part of AD neuropathogenesis, through the mitochondria-dependent apoptosis pathway. However, the in vivo relevance, underlying mechanisms, and functional consequences of these findings remain largely to be determined. METHODS We therefore set out to assess the effects of isoflurane and desflurane on mitochondrial function, cytotoxicity, learning, and memory using flow cytometry, confocal microscopy, Western blot analysis, immunocytochemistry, and the fear conditioning test. RESULTS Here we show that isoflurane, but not desflurane, induces opening of mitochondrial permeability transition pore (mPTP), increase in levels of reactive oxygen species, reduction in levels of mitochondrial membrane potential and adenosine-5'-triphosphate, activation of caspase 3, and impairment of learning and memory in cultured cells, mouse hippocampus neurons, mouse hippocampus, and mice. Moreover, cyclosporine A, a blocker of mPTP opening, attenuates isoflurane-induced mPTP opening, caspase 3 activation, and impairment of learning and memory. Finally, isoflurane may induce the opening of mPTP via increasing levels of reactive oxygen species. INTERPRETATION These findings suggest that desflurane could be a safer anesthetic for AD patients as compared to isoflurane, and elucidate the potential mitochondria-associated underlying mechanisms, and therefore have implications for use of anesthetics in AD patients, pending human study confirmation.
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Affiliation(s)
- Yiying Zhang
- Geriatric Anesthesia Research Unit, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, USA
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1137
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Ahmad R, Alam M, Rajabi H, Kufe D. The MUC1-C oncoprotein binds to the BH3 domain of the pro-apoptotic BAX protein and blocks BAX function. J Biol Chem 2012; 287:20866-75. [PMID: 22544745 DOI: 10.1074/jbc.m112.357293] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The pro-apoptotic BAX protein contains a BH3 domain that is necessary for its dimerization and for activation of the intrinsic apoptotic pathway. The MUC1 (mucin 1) heterodimeric protein is overexpressed in diverse human carcinomas and blocks apoptosis in the response to stress. In this study, we demonstrate that the oncogenic MUC1-C subunit associates with BAX in human cancer cells. MUC1-C·BAX complexes are detectable in the cytoplasm and mitochondria and are induced by genotoxic and oxidative stress. The association between MUC1-C and BAX is supported by the demonstration that the MUC1-C cytoplasmic domain is sufficient for the interaction with BAX. The results further show that the MUC1-C cytoplasmic domain CQC motif binds directly to the BAX BH3 domain at Cys-62. Consistent with binding to the BAX BH3 domain, MUC1-C blocked BAX dimerization in response to (i) truncated BID in vitro and (ii) treatment of cancer cells with DNA-damaging agents. In concert with these results, MUC1-C attenuated localization of BAX to mitochondria and the release of cytochrome c. These findings indicate that the MUC1-C oncoprotein binds directly to the BAX BH3 domain and thereby blocks BAX function in activating the mitochondrial death pathway.
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Affiliation(s)
- Rehan Ahmad
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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1138
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Barbosa IA, Machado NG, Skildum AJ, Scott PM, Oliveira PJ. Mitochondrial remodeling in cancer metabolism and survival: potential for new therapies. Biochim Biophys Acta Rev Cancer 2012; 1826:238-54. [PMID: 22554970 DOI: 10.1016/j.bbcan.2012.04.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 02/09/2023]
Abstract
Mitochondria are semi-autonomous organelles that play essential roles in cellular metabolism and programmed cell death pathways. Genomic, functional and structural mitochondrial alterations have been associated with cancer. Some of those alterations may provide a selective advantage to cells, allowing them to survive and grow under stresses created by oncogenesis. Due to the specific alterations that occur in cancer cell mitochondria, these organelles may provide promising targets for cancer therapy. The development of drugs that specifically target metabolic and mitochondrial alterations in tumor cells has become a matter of interest in recent years, with several molecules undergoing clinical trials. This review focuses on the most relevant mitochondrial alterations found in tumor cells, their contribution to cancer progression and survival, and potential usefulness for stratification and therapy.
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Affiliation(s)
- Inês A Barbosa
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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1139
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Du W, Zhou JR, Wang DL, Gong K, Zhang QJ. Vitamin K1 enhances sorafenib-induced growth inhibition and apoptosis of human malignant glioma cells by blocking the Raf/MEK/ERK pathway. World J Surg Oncol 2012; 10:60. [PMID: 22520038 PMCID: PMC3482596 DOI: 10.1186/1477-7819-10-60] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/21/2012] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The combined effects of anticancer drugs with nutritional factors against tumor cells have been reported previously. This study characterized the efficacy and possible mechanisms of the combination of sorafenib and vitamin K1 (VK1) on glioma cell lines. METHODS We examined the effects of sorafenib, VK1 or their combination on the proliferation and apoptosis of human malignant glioma cell lines (BT325 and U251) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry and 4',6-diamidino-2-phenylindole (DAPI) assay. The signaling pathway changes were detected by western blotting. RESULTS Sorafenib, as a single agent, showed antitumor activity in a dose-dependent manner in glioma cells, but the effects were more pronounced when used in combination with VK1 treatment. Sorafenib in combination with VK1 treatment produced marked potentiation of growth inhibition and apoptosis, and reduced expression of phospho-mitogen-activated protein kinase kinase (MEK) and phospho-extracellular signal-regulated kinase (ERK). Furthermore, the expression levels of antiapoptotic proteins Bcl-2 and Mcl-1 were significantly reduced. CONCLUSIONS Our findings indicated that VK1 enhanced the cytotoxicity effect of sorafenib through inhibiting the Raf/MEK/ERK signaling pathway in glioma cells, and suggested that sorafenib in combination with VK1 maybe a new therapeutic option for patients with gliomas.
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Affiliation(s)
- Wei Du
- Department of Neurosurgery, Peking University People's Hospital, No 11 Xizhimen South Street, Beijing 100044, China
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1140
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Smith RAJ, Hartley RC, Cochemé HM, Murphy MP. Mitochondrial pharmacology. Trends Pharmacol Sci 2012; 33:341-52. [PMID: 22521106 DOI: 10.1016/j.tips.2012.03.010] [Citation(s) in RCA: 360] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/28/2012] [Accepted: 03/13/2012] [Indexed: 12/13/2022]
Abstract
Mitochondria are being recognized as key factors in many unexpected areas of biomedical science. In addition to their well-known roles in oxidative phosphorylation and metabolism, it is now clear that mitochondria are also central to cell death, neoplasia, cell differentiation, the innate immune system, oxygen and hypoxia sensing, and calcium metabolism. Disruption to these processes contributes to a range of human pathologies, making mitochondria a potentially important, but currently seemingly neglected, therapeutic target. Mitochondrial dysfunction is often associated with oxidative damage, calcium dyshomeostasis, defective ATP synthesis, or induction of the permeability transition pore. Consequently, therapies designed to prevent these types of damage are beneficial and can be used to treat many diverse and apparently unrelated indications. Here we outline the biological properties that make mitochondria important determinants of health and disease, and describe the pharmacological strategies being developed to address mitochondrial dysfunction.
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Affiliation(s)
- Robin A J Smith
- Department of Chemistry, University of Otago, Box 56, Dunedin, New Zealand
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1141
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Smac mimetic sensitizes glioblastoma cells to Temozolomide-induced apoptosis in a RIP1- and NF-κB-dependent manner. Oncogene 2012; 32:988-97. [PMID: 22469979 DOI: 10.1038/onc.2012.108] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inhibitor of apoptosis (IAP) proteins are expressed at high levels in many cancers and therefore represent attractive targets for therapeutic intervention. Here, we report for the first time that the second mitochondria-derived activator of caspases (Smac) mimetic BV6 sensitizes glioblastoma cells toward Temozolomide (TMZ), the first-line chemotherapeutic agent in the treatment of glioblastoma. BV6 and TMZ synergistically reduce cell viability and trigger apoptosis in glioblastoma cells (combination index <0.4-0.8), which is accompanied by increased loss of mitochondrial-membrane potential, cytochrome c release, caspase activation and caspase-dependent apoptosis. Analysis of the molecular mechanisms reveals that BV6 causes rapid degradation of cIAP1, leading to stabilization of NF-κB-inducing kinase and NF-κB activation. BV6-stimulated NF-κB activation is critically required for sensitization toward TMZ, as inhibition of NF-κB by overexpression of the mutant IκBα super-repressor profoundly reduces loss of mitochondrial membrane potential, cytochrome c release, caspase activation and apoptosis. Of note, BV6-mediated sensitization to TMZ is not associated with increased tumor necrosis factor alpha (TNFα) production. Also, TNFα, CD95 or TRAIL-blocking antibodies or knockdown of TNFR1 have no or little effect on combination treatment-induced apoptosis. Interestingly, BV6 and TMZ cooperate to trigger the formation of a RIP1 (receptor activating protein 1)/caspase-8/FADD complex. Knockdown of RIP1 by small interfering RNA significantly reduces BV6- and TMZ-induced caspase-8 activation and apoptosis, showing that RIP1 is necessary for apoptosis induction. By demonstrating that BV6 primes glioblastoma cells for TMZ in a NF-κB- and RIP1-dependent manner, these findings build the rationale for further (pre)clinical development of Smac mimetics in combination with TMZ.
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1142
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Surface conjugation of triphenylphosphonium to target poly(amidoamine) dendrimers to mitochondria. Biomaterials 2012; 33:4773-82. [PMID: 22469294 DOI: 10.1016/j.biomaterials.2012.03.032] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 03/10/2012] [Indexed: 11/23/2022]
Abstract
Dendrimers have emerged as promising carriers for the delivery of a wide variety of pay-loads including therapeutic drugs, imaging agents and nucleic acid materials into biological systems. The current work aimed to develop a novel mitochondria-targeted generation 5 poly(amidoamine) (PAMAM) dendrimer (G(5)-D). To achieve this goal, a known mitochondriotropic ligand triphenylphosphonium (TPP) was conjugated on the surface of the dendrimer. A fraction of the cationic surface charge of G(5)-D was neutralized by partial acetylation of the primary amine groups. Next, the mitochondria-targeted dendrimer was synthesized via the acid-amine-coupling conjugation reaction between the acid group of (3-carboxypropyl)triphenyl-phosphonium bromide and the primary amines of the acetylated dendrimer (G(5)-D-Ac). These dendrimers were fluorescently labeled with fluorescein isothiocyanate (FITC) to quantify cell association by flow cytometry and for visualization under confocal laser scanning microscopy to assess the mitochondrial targeting in vitro. The newly developed TPP-anchored dendrimer (G(5)-D-Ac-TPP) was efficiently taken up by the cells and demonstrated good mitochondrial targeting. In vitro cytotoxicity experiments carried out on normal mouse fibroblast cells (NIH-3T3) had greater cell viability in the presence of the G(5)-D-Ac-TPP compared to the parent unmodified G(5)-D. This mitochondria-targeted dendrimer-based nanocarrier could be useful for imaging as well as for selective delivery of bio-actives to the mitochondria for the treatment of diseases associated with mitochondrial dysfunction.
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1143
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Quirós PM, Ramsay AJ, Sala D, Fernández-Vizarra E, Rodríguez F, Peinado JR, Fernández-García MS, Vega JA, Enríquez JA, Zorzano A, López-Otín C. Loss of mitochondrial protease OMA1 alters processing of the GTPase OPA1 and causes obesity and defective thermogenesis in mice. EMBO J 2012; 31:2117-33. [PMID: 22433842 DOI: 10.1038/emboj.2012.70] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 02/17/2012] [Indexed: 01/06/2023] Open
Abstract
Mitochondria are dynamic subcellular organelles that convert nutrient intermediates into readily available energy equivalents. Optimal mitochondrial function is ensured by a highly evolved quality control system, coordinated by protein machinery that regulates a process of continual fusion and fission. In this work, we provide in vivo evidence that the ATP-independent metalloprotease OMA1 plays an essential role in the proteolytic inactivation of the dynamin-related GTPase OPA1 (optic atrophy 1). We also show that OMA1 deficiency causes a profound perturbation of the mitochondrial fusion-fission equilibrium that has important implications for metabolic homeostasis. Thus, ablation of OMA1 in mice results in marked transcriptional changes in genes of lipid and glucose metabolic pathways and substantial alterations in circulating blood parameters. Additionally, Oma1-mutant mice exhibit an increase in body weight due to increased adipose mass, hepatic steatosis, decreased energy expenditure and impaired thermogenenesis. These alterations are especially significant under metabolic stress conditions, indicating that an intact OMA1-OPA1 system is essential for developing the appropriate adaptive response to different metabolic stressors such as a high-fat diet or cold-shock. This study provides the first description of an unexpected role in energy metabolism for the metalloprotease OMA1 and reinforces the importance of mitochondrial quality control for normal metabolic function.
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Affiliation(s)
- Pedro M Quirós
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología, Universidad de Oviedo, Oviedo, Spain
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1144
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Fulda S. Regulation of apoptosis pathways in cancer stem cells. Cancer Lett 2012; 338:168-73. [PMID: 22429999 DOI: 10.1016/j.canlet.2012.03.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 03/06/2012] [Accepted: 03/08/2012] [Indexed: 12/18/2022]
Abstract
Cancer stem cell are considered to represent a population within the bulk tumor that share many similarities to normal stem cells as far as their capacities to self-renew, differentiate, proliferate and to reconstitute the entire tumor upon serial transplantation are concerned. Since cancer stem cells have been shown to be critical for maintaining tumor growth and have been implicated in treatment resistance and tumor progression, they constitute relevant targets for therapeutic intervention. Indeed, it has been postulated that eradication of cancer stem cells will be pivotal in order to achieve long-term relapse-free survival. However, one of the hallmarks of cancer stem cells is their high resistance to undergo cell death including apoptosis in response to environmental cues or cytotoxic stimuli. Since activation of apoptosis programs in tumor cells underlies the antitumor activity of most currently used cancer therapeutics, it will be critical to develop strategies to overcome the intrinsic resistance to apoptosis of cancer stem cells. Thus, a better understanding of the molecular mechanisms that are responsible for the ability of cancer stem cells to evade apoptosis will likely open new avenues to target this critical pool of cells within the tumor in order to develop more efficient treatment options for patients suffering from cancer.
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Affiliation(s)
- Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Komturstr. 3a, 60528 Frankfurt, Germany.
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1145
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Yan C, Ding X, Dasgupta N, Wu L, Du H. Gene profile of myeloid-derived suppressive cells from the bone marrow of lysosomal acid lipase knock-out mice. PLoS One 2012; 7:e30701. [PMID: 22383970 PMCID: PMC3288004 DOI: 10.1371/journal.pone.0030701] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 12/28/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Lysosomal acid lipase (LAL) controls development and homeostasis of myeloid lineage cells. Loss of the lysosomal acid lipase (LAL) function leads to expansion of myeloid-derived suppressive cells (MDSCs) that cause myeloproliferative neoplasm. METHODOLOGY/PRINCIPAL FINDINGS Affymetrix GeneChip microarray analysis identified detailed intrinsic defects in Ly6G(+) myeloid lineage cells of LAL knock-out (lal-/-) mice. Ingenuity Pathway Analysis revealed activation of the mammalian target of rapamycin (mTOR) signaling, which functions as a nutrient/energy/redox sensor, and controls cell growth, cell cycle entry, cell survival, and cell motility. Loss of the LAL function led to major alteration of large GTPase and small GTPase signal transduction pathways. lal-/- Ly6G(+) myeloid cells in the bone marrow showed substantial increase of cell proliferation in association with up-regulation of cyclin and cyclin-dependent kinase (cdk) genes. The epigenetic microenvironment was significantly changed due to the increased expression of multiple histone cluster genes, centromere protein genes and chromosome modification genes. Gene expression of bioenergetic pathways, including glycolysis, aerobic glycolysis, mitochondrial oxidative phosphorylation, and respiratory chain proteins, was also increased, while the mitochondrial function was impaired in lal-/- Ly6G(+) myeloid cells. The concentration of reactive oxygen species (ROS) was significantly increased accompanied by up-regulation of nitric oxide/ROS production genes in these cells. CONCLUSIONS/SIGNIFICANCE This comprehensive gene profile study for the first time identifies and defines important gene pathways involved in the myeloid lineage cells towards MDSCs using lal-/- mouse model.
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Affiliation(s)
- Cong Yan
- The Center for Immunobiology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- IU Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Xinchun Ding
- The Center for Immunobiology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- IU Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Nupur Dasgupta
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Lingyan Wu
- The Center for Immunobiology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- IU Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Hong Du
- IU Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
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Inhibitor of Apoptosis (IAP) proteins as therapeutic targets for radiosensitization of human cancers. Cancer Treat Rev 2012; 38:760-6. [PMID: 22342104 DOI: 10.1016/j.ctrv.2012.01.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 01/17/2012] [Accepted: 01/23/2012] [Indexed: 01/22/2023]
Abstract
Radiotherapy initiates a variety of signaling events in cancer cells that eventually lead to cell death in case the DNA damage cannot be repaired. However, the signal transduction pathways that mediate cell death in response to radiation-inflicted DNA damage are frequently disturbed in human cancers, contributing to radioresistance. For example, aberrant activation of antiapoptotic programs such as high expression of Inhibitor of Apoptosis (IAP) proteins has been shown to interfere with the efficacy of radiotherapy. Since IAP proteins have been linked to radioresistance in several malignancies, therapeutic targeting of IAP proteins may open new perspectives to overcome radioresistance. Therefore, molecular targeting of IAP proteins may provide novel opportunities to reactivate cell death pathways that mediate radiation-induced cytotoxicity. A number of strategies have been developed in recent years to antagonize IAP proteins for the treatment of cancers. Some of these approaches have already been translated into a clinical application. While IAP protein-targeting agents are currently being evaluated in early clinical trials alone or in combination with conventional chemotherapy, they have not yet been tested in combination with radiation therapy. Therefore, it is a timely subject to discuss the opportunities of antagonizing IAP proteins for radiosensitization. Preclinical studies demonstrating the potential of this concept in relevant in vitro and in vivo models underscore that this combination approach warrants further clinical investigation. Thus, combination protocols using IAP antagonists together with radiotherapy may pave the avenue to more effective radiation-based treatment options for cancer patients.
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1147
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Xue X, You S, Zhang Q, Wu Y, Zou GZ, Wang PC, Zhao YL, Xu Y, Jia L, Zhang X, Liang XJ. Mitaplatin increases sensitivity of tumor cells to cisplatin by inducing mitochondrial dysfunction. Mol Pharm 2012; 9:634-44. [PMID: 22289032 DOI: 10.1021/mp200571k] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tumor resistance to chemotherapy is the major obstacle to employ cisplatin, one of the broadly used chemotherapeutic drugs, for effective treatment of various tumors in the clinic. Most acknowledged mechanisms of cancer resistance to cisplatin focus on increased nuclear DNA repair or detoxicity of cisplatin. We previously demonstrated that there was a unique metabolic profile in cisplatin-resistant (CP-r) human epidermoid adenocarcinoma KB-CP 20 and hepatoma BEL 7404-CP 20 cancer cells. In this study, we further defined hyperpolarized mitochondrial membrane potentials (Δψ(m)) in CP-r KB-CP 20 and BEL 7404-CP 20 cells compared to the cisplatin-sensitive (CP-s) KB-3-1 and BEL 7404 cells. Based on the mitochondrial dysfunction, mitaplatin was designed with two mitochondrial-targeting moieties [dichloroacetate (DCA) units] to the axial positions of a six-coordinate Pt(IV) center to sensitize cisplatin resistance. It was found that mitaplatin induced more apoptosis in CP-r KB-CP 20 and BEL 7404-CP 20 cells than that of cisplatin, DCA and cisplatin/DCA compared on an equal molar basis. There was more platinum accumulation in mitaplatin-treated CP-r cells due to enhanced transmembrane permeability of lipophilicity, and mitaplatin also showed special targeting to mitochondria. Moreover, in the case of treatment with mitaplatin, the dramatic collapse of Δψ(m) was shown in a dose-dependent manner, which was confirmed by FACS and confocal microscopic measurements. Reduced glucose utilization of CP-r cells was detected with specifically inhibited phosphorylation of pyruvate dehydrogenase (PDH) at Ser-232, Ser-293, and Ser-300 of the E1α subunit when treated with mitaplatin, which was indicated to modulate the abnormal glycolysis of resistant cells. The present study suggested novel mitochondrial mechanism of mitaplatin circumventing cisplatin resistance toward CP-r cells as a carrier across membrane to produce CP-like cytotoxicity and DCA-like mitochondria-dependent apoptosis. Therefore, mitochondria targeting compounds would be more vulnerable and selective to overcome cisplatin resistance due to the unique metabolic properties of CP-r cancer cells.
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Affiliation(s)
- Xue Xue
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, PR China
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Dong LF, Grant G, Massa H, Zobalova R, Akporiaye E, Neuzil J. α-Tocopheryloxyacetic acid is superior to α-tocopheryl succinate in suppressing HER2-high breast carcinomas due to its higher stability. Int J Cancer 2012; 131:1052-8. [PMID: 22038845 DOI: 10.1002/ijc.26489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 09/27/2011] [Indexed: 01/13/2023]
Abstract
Breast cancer is the number one neoplastic disease of women, with the HER2-high carcinomas presenting a considerable challenge for efficient treatment. Therefore, a search for novel agents active against this type of cancer is warranted. We tested two vitamin E (VE) analogs, the esterase-hydrolyzable α-tocopheryl succinate (α-TOS) and the non-hydrolyzable ether α-tocopheryloxyacetic acid (α-TEA) for their effects on HER2-positive breast carcinomas using a breast tumor mouse model and breast cancer cell lines. Ultrasound imaging documented that α-TEA suppressed breast carcinomas in the transgenic animals more efficiently than found for its ester counterpart. However, both agents exerted a comparable apoptotic effect on the NeuTL breast cancer cells derived from the FVB/N c-neu mice as well as in the human MBA-MD-453 and MCF7HER2-18 cells with high level of HER2. The superior anti-tumor effect of α-TEA over α-TOS in vivo can be explained by longer persistence of the former in mice, possibly due to the enhanced plasma and hepatic processing of α-TOS in comparison to the esterase-non-cleavable α-TEA. Indeed, the stability of α-TOS in plasma was inferior to that of α-TEA. We propose that α-TEA is a promising drug efficient against breast cancer, as documented by its effect on experimental HER2-positive breast carcinomas that present a considerable problem in cancer management.
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Affiliation(s)
- Lan-Feng Dong
- School of Medical Science, Griffith Health Institute, Griffith University, Southport, QLD, Australia.
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Abstract
Frequently, low doses of toxins and other stressors not only are harmless but also activate an adaptive stress response that raise the resistance of the organism against high doses of the same agent. This phenomenon, which is known as "hormesis", is best represented by ischemic preconditioning, the situation in which short ischemic episodes protect the brain and the heart against prolonged shortage of oxygen and nutrients. Many molecules that cause cell death also elicit autophagy, a cytoprotective mechanism relying on the digestion of potentially harmful intracellular structures, notably mitochondria. When high doses of these agents are employed, cells undergo mitochondrial outer membrane permeabilization and die. In contrast, low doses of such cytotoxic agents can activate hormesis in several paradigms, and this may explain the lifespan-prolonging potential of autophagy inducers including resveratrol and caloric restriction.
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Fulda S, Vucic D. Targeting IAP proteins for therapeutic intervention in cancer. Nat Rev Drug Discov 2012; 11:109-24. [PMID: 22293567 DOI: 10.1038/nrd3627] [Citation(s) in RCA: 627] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Evasion of apoptosis is one of the crucial acquired capabilities used by cancer cells to fend off anticancer therapies. Inhibitor of apoptosis (IAP) proteins exert a range of biological activities that promote cancer cell survival and proliferation. X chromosome-linked IAP is a direct inhibitor of caspases - pro-apoptotic executioner proteases - whereas cellular IAP proteins block the assembly of pro-apoptotic protein signalling complexes and mediate the expression of anti-apoptotic molecules. Furthermore, mutations, amplifications and chromosomal translocations of IAP genes are associated with various malignancies. Among the therapeutic strategies that have been designed to target IAP proteins, the most widely used approach is based on mimicking the IAP-binding motif of second mitochondria-derived activator of caspase (SMAC), which functions as an endogenous IAP antagonist. Alternative strategies include transcriptional repression and the use of antisense oligonucleotides. This Review provides an update on IAP protein biology as well as current and future perspectives on targeting IAP proteins for therapeutic intervention in human malignancies.
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Affiliation(s)
- Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe University Frankfurt, Komturstr. 3a, 60528 Frankfurt, Germany.
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