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Skalka GL, Tsakovska M, Murphy DJ. Kinase signalling adaptation supports dysfunctional mitochondria in disease. Front Mol Biosci 2024; 11:1354682. [PMID: 38434478 PMCID: PMC10906720 DOI: 10.3389/fmolb.2024.1354682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/15/2024] [Indexed: 03/05/2024] Open
Abstract
Mitochondria form a critical control nexus which are essential for maintaining correct tissue homeostasis. An increasing number of studies have identified dysregulation of mitochondria as a driver in cancer. However, which pathways support and promote this adapted mitochondrial function? A key hallmark of cancer is perturbation of kinase signalling pathways. These pathways include mitogen activated protein kinases (MAPK), lipid secondary messenger networks, cyclic-AMP-activated (cAMP)/AMP-activated kinases (AMPK), and Ca2+/calmodulin-dependent protein kinase (CaMK) networks. These signalling pathways have multiple substrates which support initiation and persistence of cancer. Many of these are involved in the regulation of mitochondrial morphology, mitochondrial apoptosis, mitochondrial calcium homeostasis, mitochondrial associated membranes (MAMs), and retrograde ROS signalling. This review will aim to both explore how kinase signalling integrates with these critical mitochondrial pathways and highlight how these systems can be usurped to support the development of disease. In addition, we will identify areas which require further investigation to fully understand the complexities of these regulatory interactions. Overall, this review will emphasize how studying the interaction between kinase signalling and mitochondria improves our understanding of mitochondrial homeostasis and can yield novel therapeutic targets to treat disease.
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Affiliation(s)
- George L. Skalka
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mina Tsakovska
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Daniel J. Murphy
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
- CRUK Scotland Institute, Glasgow, United Kingdom
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Justet A, Ghanem M, Boghanim T, Hachem M, Vasarmidi E, Jaillet M, Vadel A, Joannes A, Mordant P, Bonniaud P, Kolb M, Ling L, Cazes A, Mal H, Mailleux A, Crestani B. FGF19 is Downregulated in Idiopathic Pulmonary Fibrosis and Inhibits Lung Fibrosis in Mice. Am J Respir Cell Mol Biol 2022; 67:173-187. [PMID: 35549849 DOI: 10.1165/rcmb.2021-0246oc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
IPF is a devastating lung disease with limited therapeutic possibilities. FGF19, an endocrine FGF, was recently shown to decrease liver fibrosis. To ask whether FGF19 had anti-fibrotic properties in the lung and decipher its effects on common features associated with lung fibrogenesis. We assessed, by Elisa, FGF19 levels in plasma and bronchoalveolar lavage fluids (BALF)obtained from controls and IPF patients. In vivo, using an intravenously administered adeno11 associated virus (AAV), we overexpressed FGF19 at the fibrotic phase of two experimental models of murine lung fibrosis and assessed its effect on lung morphology, lung collagen content, fibrosis markers and pro fibrotic mediator expression, at mRNA and protein levels. In vitro, we investigated whether FGF19 could modulate the TGFβ-induced differentiation of primary human lung fibroblast into myofibroblast and the apoptosis of murine alveolar type II cell. While FGF19 was not detected in BALF, FGF19 concentration was decreased in the plasma of IPF patients compared to controls. In vivo, the overexpression of FGF19 was associated with a marked decrease of lung fibrosis and fibrosis markers, with a decrease of pro fibrotic mediator expression and lung collagen content. In vitro, FGF19 decreased alveolar type 2 epithelial cell apoptosis through the decrease of the proapoptotic BIM protein expression and prevented TGF-ß induced myofibroblast differentiation through the inhibition of JNK phosphorylation. Altogether these data identify FGF19 as an anti-fibrotic molecule with a potential therapeutic interest in fibrotic lung disorders.
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Affiliation(s)
| | | | | | | | | | | | | | - Audrey Joannes
- INSERM U1085, IRSET Institut de Recherche sur la Santé, l'Environnement et le Travail, Université de Rennes-1, Rennes, France
| | - Pierre Mordant
- Assistance Publique - Hopitaux de Paris, 26930, Bichat Hospital, Department of Vascular and Thoracic Sugery, Paris, France.,INSERM, U1152, Paris, France.,Universite Paris Diderot UFR de Medecine Site Xavier-Bichat, 60152, Paris, France
| | - Philippe Bonniaud
- CHU Dijon-Bourgogne, Service de Pneumologie et Soins Intensifs Respiratoires, Dijon, France
| | - Martin Kolb
- McMaster University, Hamilton, Ontario, Canada
| | - Lei Ling
- NGM Biopharmaceuticals Inc, 200841, San Francisco, California, United States
| | | | | | - Arnaud Mailleux
- Inserm U700, Faculté de Médecine Paris 7, site X. Bichat, Paris, France
| | - Bruno Crestani
- AP-HP, Hôpital Bichat, Service de Pneumologie A, DHU FIRE, Université Paris Diderot, Paris, France;
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Karbon G, Haschka MD, Hackl H, Soratroi C, Rocamora-Reverte L, Parson W, Fiegl H, Villunger A. The BH3-only protein NOXA serves as an independent predictor of breast cancer patient survival and defines susceptibility to microtubule targeting agents. Cell Death Dis 2021; 12:1151. [PMID: 34903710 PMCID: PMC8668920 DOI: 10.1038/s41419-021-04415-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/11/2021] [Accepted: 11/22/2021] [Indexed: 12/21/2022]
Abstract
Breast cancer (BC) treatment frequently involves microtubule-targeting agents (MTAs), such as paclitaxel, that arrest cells in mitosis. Sensitivity to MTAs is defined by a subset of pro- and anti-apoptotic BCL2 family proteins controlling mitochondrial apoptosis. Here, we aimed to determine their prognostic value in primary tumour samples from 92 BC patients. Our analysis identified high NOXA/PMAIP mRNA expression levels as an independent prognostic marker for improved relapse-free survival (RFS) and overall survival (OS) in multivariate analysis in BC patients, independent of their molecular subtype. Analysis of available TCGA datasets of 1060 BC patients confirmed our results and added a clear predictive value of NOXA mRNA levels for patients who received MTA-based therapy. In this TCGA cohort, 122 patients received MTA-treatment and high NOXA mRNA levels correlated with their progression-free interval (PFI) and OS. Our follow-up analyses in a panel of BC cell lines of different molecular subtypes identified NOXA protein expression as a key determinant of paclitaxel sensitivity in triple-negative breast cancer (TNBC) cells. Moreover, we noted highest additive effects between paclitaxel and chemical inhibition of BCLX, but not BCL2 or MCL1, documenting dependence of TNBC cells on BCLX for survival and paclitaxel sensitivity defined by NOXA expression levels.
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Affiliation(s)
- Gerlinde Karbon
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Manuel D Haschka
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Hubert Hackl
- Insitute for Bioinformatics, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Claudia Soratroi
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Lourdes Rocamora-Reverte
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
| | - Walther Parson
- Institute of Legal Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Heidelinde Fiegl
- Department for Obstetrics & Gynecology, Medical University of Innsbruck, Innsbruck, Austria
| | - Andreas Villunger
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
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Fava LL, Haschka MD, Villunger A. Bim vanishes in the light of a mitotic Aurora. Cell Death Differ 2014; 20:1597-8. [PMID: 24212928 DOI: 10.1038/cdd.2013.140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- L L Fava
- Division of Developmental Immunology, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
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He X, Khurana A, Roy D, Kaufmann S, Shridhar V. Loss of HSulf-1 expression enhances tumorigenicity by inhibiting Bim expression in ovarian cancer. Int J Cancer 2014; 135:1783-9. [PMID: 24596063 DOI: 10.1002/ijc.28818] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 02/17/2014] [Indexed: 01/01/2023]
Abstract
The expression of human Sulfatase1 (HSulf-1) is downregulated in the majority of primary ovarian cancer tumors, but the functional consequence of this downregulation remains unclear. Using two different shRNAs (Sh1 and Sh2), HSulf-1 expression was stably downregulated in ovarian cancer OV202 cells. We found that HSulf-1-deficient OV202 Sh1 and Sh2 cells formed colonies in soft agar. In contrast, nontargeting control (NTC) shRNA-transduced OV202 cells did not form any colonies. Moreover, subcutaneous injection of OV202 HSulf-1-deficient cells resulted in tumor formation in nude mice, whereas OV202 NTC cells did not. Also, ectopic expression of HSulf-1 in ovarian cancer SKOV3 cells significantly suppressed tumor growth in nude mice. Here, we show that HSulf-1-deficient OV202 cells have markedly decreased expression of proapoptotic Bim protein, which can be rescued by restoring HSulf-1 expression in OV202 Sh1 cells. Enhanced expression of HSulf-1 in HSulf-1-deficient SKOV3 cells resulted in increased Bim expression. Decreased Bim levels after loss of HSulf-1 were due to increased p-ERK, because inhibition of ERK activity with PD98059 resulted in increased Bim expression. However, treatment with a PI3 kinase/AKT inhibitor, LY294002, failed to show any change in Bim protein level. Importantly, rescuing Bim expression in HSulf-1 knockdown cells significantly retarded tumor growth in nude mice. Collectively, these results suggest that loss of HSulf-1 expression promotes tumorigenicity in ovarian cancer through regulating Bim expression.
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Affiliation(s)
- Xiaoping He
- Department of Laboratory Medicine and Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN
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Moustafa-Kamal M, Gamache I, Lu Y, Li S, Teodoro JG. BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1. Cell Death Differ 2013; 20:1393-403. [PMID: 23912711 DOI: 10.1038/cdd.2013.93] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 05/15/2013] [Accepted: 06/17/2013] [Indexed: 01/09/2023] Open
Abstract
Bcl-2-interacting mediator of cell death (Bim) is a pro-apoptotic B-cell lymphoma 2 family member implicated in numerous apoptotic stimuli. In particular, Bim is required for cell death mediated by antimitotic agents, however, mitotic regulation of Bim remains poorly understood. Here, we show that the major splice variant of Bim, BimEL, is regulated during mitosis by the Aurora A kinase and protein phosphatase 2A (PP2A). We observed that BimEL is phosphorylated by Aurora A early in mitosis and reversed by PP2A after mitotic exit. Aurora A phosphorylation stimulated binding of BimEL to the F-box protein beta-transducin repeat containing E3 ubiquitin protein ligase and promoted ubiquitination and degradation of BimEL. These findings describe a novel mechanism by which the oncogenic kinase Aurora A promotes cell survival during mitosis by downregulating proapoptotic signals. Notably, we observed that knockdown of Bim significantly increased resistance of cells to the Aurora A inhibitor MLN8054. Inhibitors of Aurora A are currently under investigation as cancer chemotherapeutics and our findings suggest that efficacy of this class of drugs may function in part by enhancing apoptotic activity of BimEL.
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Affiliation(s)
- M Moustafa-Kamal
- Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
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Gilley R, Lochhead PA, Balmanno K, Oxley D, Clark J, Cook SJ. CDK1, not ERK1/2 or ERK5, is required for mitotic phosphorylation of BIMEL. Cell Signal 2012; 24:170-80. [DOI: 10.1016/j.cellsig.2011.08.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 08/29/2011] [Indexed: 01/05/2023]
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Bunk EC, König HG, Bernas T, Engel T, Henshall DC, Kirby BP, Prehn JHM. BH3-only proteins BIM and PUMA in the regulation of survival and neuronal differentiation of newly generated cells in the adult mouse hippocampus. Cell Death Dis 2011; 1:e15. [PMID: 21364616 PMCID: PMC3039291 DOI: 10.1038/cddis.2009.13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neurogenesis persists in the adult hippocampus, where several thousand neurons are born every day. Most of the newly generated cells are eliminated by apoptosis, possibly because of their failure to integrate properly into neural networks. The BH3-only proteins Bim and Puma have been shown to mediate trophic factor withdrawal- and anoikis-induced apoptosis in various systems. We therefore determined their impact on proliferation, survival, and differentiation of adult-generated cells in the mouse hippocampus using gene-deficient mice. Wild-type, bim-, and puma-deficient mice showed similar rates of precursor cell proliferation, as evidenced by 5-bromo-2-deoxyuridine (BrdU)-incorporation. Deficiency in either bim or puma significantly increased the survival of adult-born cells in the dentate gyrus (DG) after 7 days. Consistently, we detected increased numbers of doublecortin (DCX)-positive and fewer terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelled-positive cells in the DG of bim- and puma-deficient mice. Bim and puma deficiency did not change early markers of neuronal differentiation, as evidenced by BrdU/DCX double-labelling. However, BrdU/NeuN double-labelling revealed that deficiency of bim, but not puma, accelerated the differentiation of newly generated cells into a neuronal phenotype. Our data show that Bim and Puma are prominently involved in the regulation of neuronal progenitor cell survival in the adult DG, but also suggest that Bim has an additional role in neuronal differentiation of adult-born neural precursor cells.
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Affiliation(s)
- E C Bunk
- Department of Physiology and Medical Physics, RCSI Neuroscience Research Centre, Dublin, Ireland
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O'Reilly LA, Kruse EA, Puthalakath H, Kelly PN, Kaufmann T, Huang DCS, Strasser A. MEK/ERK-mediated phosphorylation of Bim is required to ensure survival of T and B lymphocytes during mitogenic stimulation. THE JOURNAL OF IMMUNOLOGY 2009; 183:261-9. [PMID: 19542438 DOI: 10.4049/jimmunol.0803853] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Survival and death of lymphocytes are regulated by the balance between pro- and antiapoptotic members of the Bcl-2 family; this is coordinated with the control of cell cycling and differentiation. Bim, a proapoptotic BH3-only member of the Bcl-2 family, can be regulated by MEK/ERK-mediated phosphorylation, which affects its binding to pro-survival Bcl-2 family members and its turnover. We investigated Bim modifications in mouse B and T lymphoid cells after exposure to apoptotic stimuli and during mitogenic activation. Treatment with ionomycin or cytokine withdrawal caused an elevation in Bim(EL), the most abundant Bim isoform. In contrast, in mitogenically stimulated T and B cells, Bim(EL) was rapidly phosphorylated, and its levels declined. Pharmacological inhibitors of MEK/ERK signaling prevented both of these changes in Bim, reduced proliferation, and triggered apoptosis of mitogen-stimulated T and B cells. Loss of Bim prevented this cell killing but did not restore cell cycling. These results show that during mitogenic stimulation of T and B lymphocytes MEK/ERK signaling is critical for two distinct processes, cell survival, mediated (at least in part) through phosphorylation and consequent inhibition of Bim, and cell cycling, which proceeds independently of Bim inactivation.
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Affiliation(s)
- Lorraine A O'Reilly
- Water and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
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Abstract
INTRODUCTION Osteoblasts depend on a constant supply of prosurvival signals from their microenvironment. When trophic factors become limited by injury or disease, cells undergo apoptosis. This study establishes the regulation and function of Bim, Bak, and Bax in this response. MATERIALS AND METHODS MBA-15.4 murine osteoblasts and primary human bone marrow stromal cells (hBMSCs) were subjected to growth factor depletion by serum starvation (1% FCS or serum withdrawal). Protein phosphorylation, activation, or expression was quantified by Western blotting and gene expression by real-time PCR. Regulation of apoptosis in response to serum depletion was determined using siRNA specific for Bim, Bak, or Bax, followed by TUNEL staining. Statistical significance was determined by one-way ANOVA after multiple experimental repeats. RESULTS Serum depletion strongly induced expression of the proapoptotic protein Bim in both hBMSC and MBA-15.4 osteoblasts. Detailed analysis of the mouse line showed that both mRNA and protein levels rose from 2 h to peak between 16 and 24 h, in conjunction with activation of caspase 3 and rising levels of apoptosis. Both actinomycin D and cycloheximide prevented this increase in Bim, indicating transcriptional regulation. Serum deprivation caused immediate and sustained decreases in phosphorylation of prosurvival kinases, ERK and PKB, preceding upregulation of Bim. Pathway inhibitors, U0126 or LY294002, strongly increased both Bim mRNA and protein, confirming that both kinases regulate Bim. These inhibitors also induced osteoblast apoptosis within 24-72 h. JC-1 tracer detected mitochondrial potential disruption after serum deprivation, indicating involvement of the intrinsic pathway. Moreover, activation-associated conformational changes were detected in the channel-formers, Bax and Bak. Selective knockdown of Bim or Bak by siRNA protected osteoblasts from serum depletion-induced apoptosis by 50%, whereas knockdown of Bax alone or Bak and Bax together reduced apoptosis by 90%. CONCLUSIONS Our data indicate that Bim, Bak, and Bax actively mediate osteoblast apoptosis induced by trophic factor withdrawal. The complex upstream regulation of Bim may provide targets for therapeutic enhancement of osteoblast viability.
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Gírio A, Montero JC, Pandiella A, Chatterjee S. Erk5 is activated and acts as a survival factor in mitosis. Cell Signal 2007; 19:1964-72. [PMID: 17624732 DOI: 10.1016/j.cellsig.2007.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 04/24/2007] [Accepted: 05/18/2007] [Indexed: 01/19/2023]
Abstract
Erk5 is a recently discovered MAPK claimed to be responsible for some of the roles attributed to Erk1/2; here we report that it is activated in mitosis in comparison to G1/S. When Erk5 is inactivated pharmacologically or largely ablated by RNAi, cell survival in mitosis is diminished. We have previously shown Bim, a BH3-only protein of the Bcl-2 family, to be phosphorylated in mitosis, in a MEK-dependent manner (M. Grãos, A. D. Almeida, S. Chatterjee, Biochem. J. 388 (2005) 185). Inactivation of Erk5 in mitosis causes dephosphorylation of Bim. Bim is in the mitochondria in mitosis and when dephosphorylated interacts with Bax, inducing caspase activation. We also show that in mitosis Bim co-immunoprecipitates with Erk5 and Erk5 phosphorylates GST-Bim in in vitro kinase reaction. Taken together, our results identify a new target of the still largely mysterious Erk5 and suggest that Erk5 in mitosis may be a decisive step for the survival of proliferating cells.
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Affiliation(s)
- Ana Gírio
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal
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Li Z, Zhang J, Liu Z, Woo CW, Thiele CJ. Downregulation of Bim by brain-derived neurotrophic factor activation of TrkB protects neuroblastoma cells from paclitaxel but not etoposide or cisplatin-induced cell death. Cell Death Differ 2006; 14:318-26. [PMID: 16778834 DOI: 10.1038/sj.cdd.4401983] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chemoresistance and increased expression of TrkB and brain-derived neurotrophic factor (BDNF) are biomarkers of poor prognosis in tumors from patients with neuroblastoma (NB). Previously, we found BDNF activation of TrkB through PI3K/Akt protects NB from etoposide/cisplatin-induced cell death. In this study, the role of Bim, a proapoptotic protein, was investigated. Bim was involved in paclitaxel but not etoposide or cisplatin-induced cell death in NB cells. Pharmacological and genetic studies showed that BDNF-induced decreases in Bim were regulated by MAPK and not PI3K/Akt pathway. Both MAPK and PI3K pathways were involved in BDNF protection of NB cells from paclitaxel-induced cell death, while PI3K predominantly mediated BDNF protection of NB cells from etoposide or cisplatin-induced cell death. These data indicate that different chemotherapeutic drugs induce distinct death pathways and growth factors utilize different signal transduction pathways to modulate the effects of chemotherapy on cells.
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Affiliation(s)
- Z Li
- Cell & Molecular Biology Section, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Teraishi F, Wu S, Inoue S, Zhang L, Davis JJ, Guo W, Dong F, Fang B. Antitumor activity and downregulation of pro-angiogenic molecules in human prostate cancer cells by a novel thiazolidione compound. Prostate 2006; 66:430-8. [PMID: 16302260 PMCID: PMC1351358 DOI: 10.1002/pros.20373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Current treatments for prostate cancer are effective in many patients with locally advanced disease, but many of these patients eventually have recurrence. It is therefore important to develop alternative therapeutic agents with improved efficacy and tolerability. We recently identified a synthetic thiazolidin compound, 5-(2,4-dihydroxybenzylidene)-2-(phenylimino)-1,3-thiazolidione (DBPT), that induces apoptosis in human colon cancer cells, independent of p53 and P-glycoprotein status. Here, we investigated the antitumor properties and mechanisms of action of this compound in human prostate cancer cell lines. METHODS The effect of DBPT on cell-cycle progression and apoptosis in LNCaP and DU145 cells was examined by flow cytometry and Western blotting. The effect of DBPT on pro-angiogenic molecules was analyzed by Western blotting and by an enzyme-linked immunosorbent assay. RESULTS DBPT inhibited the growth of LNCaP and DU145 cells with 50% inhibitory concentrations ranging from 1.6 to 5.9 microM. Treating LNCaP and DU145 cells with DBPT led to a time-dependent cell-cycle arrest in the G(2)/M phase and increased levels of G(2)/M checkpoint proteins, such as cyclin B1, cdc25C, phosphorylated histone H(3), and MPM-2. DBPT induced the phosphorylation of Bcl-xL and Bim, and induced apoptosis, as evidenced by cleavage of caspase and poly (ADP-ribose) polymerase. DBPT also effectively induced apoptosis in Bcl-2-overexpressing DU145 cells. Furthermore, DBPT decreased hypoxia-inducible factor 1 alpha and vascular endothelial growth factor expression in LNCaP cells under both normoxia and hypoxia. CONCLUSIONS DBPT can suppress proliferation, induce apoptosis, and down regulate pro-angiogenic molecules in prostate cancer cells, and might be useful in treating prostate cancer.
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Affiliation(s)
| | | | | | | | | | | | | | - Bingliang Fang
- *Correspondence to: Bingliang Fang, Department of Thoracic and Cardiovascular Surgery, Unit 445, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030. Phone: 713-563-9147; Fax: 713-794-4901;
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