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Murphy ÁC, Weyhenmeyer B, Noonan J, Kilbride SM, Schimansky S, Loh KP, Kögel D, Letai AG, Prehn JHM, Murphy BM. Modulation of Mcl-1 sensitizes glioblastoma to TRAIL-induced apoptosis. Apoptosis 2015; 19:629-42. [PMID: 24213561 PMCID: PMC3938842 DOI: 10.1007/s10495-013-0935-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Glioblastoma (GBM) is the most aggressive form of primary brain tumour, with dismal patient outcome. Treatment failure is associated with intrinsic or acquired apoptosis resistance and the presence of a highly tumourigenic subpopulation of cancer cells called GBM stem cells. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has emerged as a promising novel therapy for some treatment-resistant tumours but unfortunately GBM can be completely resistant to TRAIL monotherapy. In this study, we identified Mcl-1, an anti-apoptotic Bcl-2 family member, as a critical player involved in determining the sensitivity of GBM to TRAIL-induced apoptosis. Effective targeting of Mcl-1 in TRAIL resistant GBM cells, either by gene silencing technology or by treatment with R-roscovitine, a cyclin-dependent kinase inhibitor that targets Mcl-1, was demonstrated to augment sensitivity to TRAIL, both within GBM cells grown as monolayers and in a 3D tumour model. Finally, we highlight that two separate pathways are activated during the apoptotic death of GBM cells treated with a combination of TRAIL and R-roscovitine, one which leads to caspase-8 and caspase-3 activation and a second pathway, involving a Mcl-1:Noxa axis. In conclusion, our study demonstrates that R-roscovitine in combination with TRAIL presents a promising novel strategy to trigger cell death pathways in glioblastoma.
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Affiliation(s)
- Á C Murphy
- Centre for Systems Medicine, Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, York House, St. Stephen's Green, Dublin, 2, Ireland
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Weisová P, Alvarez SP, Kilbride SM, Anilkumar U, Baumann B, Jordán J, Bernas T, Huber HJ, Düssmann H, Prehn JHM. Latrepirdine is a potent activator of AMP-activated protein kinase and reduces neuronal excitability. Transl Psychiatry 2013; 3:e317. [PMID: 24150226 PMCID: PMC3818013 DOI: 10.1038/tp.2013.92] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/09/2013] [Indexed: 12/18/2022] Open
Abstract
Latrepirdine/Dimebon is a small-molecule compound with attributed neurocognitive-enhancing activities, which has recently been tested in clinical trials for the treatment of Alzheimer's and Huntington's disease. Latrepirdine has been suggested to be a neuroprotective agent that increases mitochondrial function, however the molecular mechanisms underlying these activities have remained elusive. We here demonstrate that latrepirdine, at (sub)nanomolar concentrations (0.1 nM), activates the energy sensor AMP-activated protein kinase (AMPK). Treatment of primary neurons with latrepirdine increased intracellular ATP levels and glucose transporter 3 translocation to the plasma membrane. Latrepirdine also increased mitochondrial uptake of the voltage-sensitive probe TMRM. Gene silencing of AMPKα or its upstream kinases, LKB1 and CaMKKβ, inhibited this effect. However, studies using the plasma membrane potential indicator DisBAC2(3) demonstrated that the effects of latrepirdine on TMRM uptake were largely mediated by plasma membrane hyperpolarization, precluding a purely 'mitochondrial' mechanism of action. In line with a stabilizing effect of latrepirdine on plasma membrane potential, pretreatment with latrepirdine reduced spontaneous Ca(2+) oscillations as well as glutamate-induced Ca(2+) increases in primary neurons, and protected neurons against glutamate toxicity. In conclusion, our experiments demonstrate that latrepirdine is a potent activator of AMPK, and suggest that one of the main pharmacological activities of latrepirdine is a reduction in neuronal excitability.
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Affiliation(s)
- P Weisová
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - S P Alvarez
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Dpto Ciencias Médicas-Farmacología, Faculdad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - S M Kilbride
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - U Anilkumar
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - B Baumann
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - J Jordán
- Dpto Ciencias Médicas-Farmacología, Faculdad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - T Bernas
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Institute of Experimental Biology PAS, Warsaw, Poland
| | - H J Huber
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - H Düssmann
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - J H M Prehn
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin, 2, Ireland. E-mail:
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Abstract
Mitochondria have been classically characterized as organelles with responsibility for cellular energy production in the form of ATP, but they are also the organelles through which apoptotic signaling occurs. Cell stress stimuli can result in outer membrane permeabilization, after which mitochondria release numerous proteins involved in apoptotic signaling, including cytochrome c, apoptosis-inducing factor, endonuclease G, Smac/DIABLO and Omi/HtrA2. Cell fate is determined by signaling through apoptotic proteins within the Bcl-2 (B-cell lymphoma 2) protein family, which converges on mitochondria. Many cancerous cells display abnormal levels of Bcl-2 protein family member expression that results in defective apoptotic signaling. Alterations in bioenergetic function also contribute to cancer as well as numerous other disorders. Recent evidence indicates that several pro-apoptotic proteins localized within mitochondria, as well as proteins within the Bcl-2 protein family, can influence mitochondrial bioenergetic function. This review focuses on the emerging roles of these proteins in the control of mitochondrial activity.
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Affiliation(s)
- S M Kilbride
- Department of Physiology and Medical Physics, Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin 2, Ireland
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