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Abstract
Melanogenesis is a highly regulated process through which the pigment melanin is produced in skin cells. Irregularities in the molecular events that govern the process of skin pigmentation can cause disorders like vitiligo. In order to understand the biology of disease progression, it is important to have an in depth understanding of intracellular events. Mathematical models provide an integrated view of intracellular signalling. There are very few models to date that incorporate intracellular processes relevant to melanogenesis and only one to our knowledge that simulates the dynamics of response to varying levels of input. Here, we report the formulation of the largest Boolean model (265 nodes) for melanogenesis to date. The model was built on the basis of a detailed interaction network graph published by Raghunath et al. Through additional manual curation of the reported interactions, we converted the graph into a set of Boolean rules, following the procedure of the first Boolean model (62 nodes) for melanogenesis published by Lee et al. Simulations show that the predicted response to varying UV levels for most of the nodes is similar to the predictions of the existing model. The greater complexity allows investigation of the sensitivity of melanin to additional nodes. We carried out perturbation analysis of the network through node deletion and constitutive activation to identify sensitivity of outcomes, and compared the nodes identified as sensitive to previous reports.
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Affiliation(s)
- Pooja Dnyane
- Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune 411008, India. Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad 201002, India
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The Enigmatic Protein Kinase C-eta. Cancers (Basel) 2019; 11:cancers11020214. [PMID: 30781807 PMCID: PMC6406448 DOI: 10.3390/cancers11020214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/04/2019] [Accepted: 02/10/2019] [Indexed: 01/02/2023] Open
Abstract
Protein kinase C (PKC), a multi-gene family, plays critical roles in signal transduction and cell regulation. Protein kinase C-eta (PKCη) is a unique member of the PKC family since its regulation is distinct from other PKC isozymes. PKCη was shown to regulate cell proliferation, differentiation and cell death. It was also shown to contribute to chemoresistance in several cancers. PKCη has been associated with several cancers, including renal cell carcinoma, glioblastoma, breast cancer, non-small cell lung cancer, and acute myeloid leukemia. However, mice lacking PKCη were more susceptible to tumor formation in a two-stage carcinogenesis model, and it is downregulated in hepatocellular carcinoma. Thus, the role of PKCη in cancer remains controversial. The purpose of this review article is to discuss how PKCη regulates various cellular processes that may contribute to its contrasting roles in cancer.
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Hong YH, Kim D, Nam G, Yoo S, Han SY, Jeong SG, Kim E, Jeong D, Yoon K, Kim S, Park J, Cho JY. Photoaging protective effects of BIOGF1K, a compound-K-rich fraction prepared from Panax ginseng. J Ginseng Res 2018; 42:81-89. [PMID: 29348726 PMCID: PMC5766695 DOI: 10.1016/j.jgr.2017.01.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/25/2016] [Accepted: 01/02/2017] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND BIOGF1K, a compound-K-rich fraction, has been shown to display anti-inflammatory activity. Although Panax ginseng is widely used for the prevention of photoaging events induced by UVB irradiation, the effect of BIOGF1K on photoaging has not yet been examined. In this study, we investigated the effects of BIOGF1K on UVB-induced photoaging events. METHODS We analyzed the ability of BIOGF1K to prevent UVB-induced apoptosis, enhance matrix metalloproteinase (MMP) expression, upregulate anti-inflammatory activity, reduce sirtuin 1 expression, and melanin production using reverse transcription-polymerase chain reaction, melanin content assay, tyrosinase assay, and flow cytometry. We also evaluated the effects of BIOGF1K on the activator protein-1 signaling pathway, which plays an important role in photoaging, by immunoblot analysis and luciferase reporter gene assays. RESULTS Treatment of UVB-irradiated NIH3T3 fibroblasts with BIOGF1K prevented UVB-induced cell death, inhibited apoptosis, suppressed morphological changes, reduced melanin secretion, restored the levels of type I procollagen and sirtuin 1, and prevented mRNA upregulation of MMP-1, MMP-2, and cyclo-oxygenase-2; these effects all occurred in a dose-dependent manner. In addition, BIOGF1K markedly reduced activator-protein-1-mediated luciferase activity and decreased the activity of mitogen-activated protein kinases (extracellular response kinase, p38, and C-Jun N-terminal kinase). CONCLUSION Our results strongly suggest that BIOGF1K has anti-photoaging activity and that BIOGF1K could be used in anti-aging cosmeceutical preparations.
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Affiliation(s)
- Yo Han Hong
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Donghyun Kim
- Amorepacific Research and Development Unit, Yongin, Republic of Korea
| | - Gibaeg Nam
- Amorepacific Research and Development Unit, Yongin, Republic of Korea
| | - Sulgi Yoo
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sang Yun Han
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Seong-Gu Jeong
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Eunji Kim
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Deok Jeong
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Keejung Yoon
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sunggyu Kim
- Research and Business Foundation, Sungkyunkwan University, Suwon, Republic of Korea
| | - Junseong Park
- Amorepacific Research and Development Unit, Yongin, Republic of Korea
| | - Jae Youl Cho
- Department of Genetic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
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Janjanam J, Chandaka GK, Kotla S, Rao GN. PLCβ3 mediates cortactin interaction with WAVE2 in MCP1-induced actin polymerization and cell migration. Mol Biol Cell 2015; 26:4589-606. [PMID: 26490115 PMCID: PMC4678017 DOI: 10.1091/mbc.e15-08-0570] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/13/2015] [Indexed: 12/24/2022] Open
Abstract
Monocyte chemotactic protein 1 (MCP1) stimulates vascular smooth muscle cell (VSMC) migration in vascular wall remodeling. However, the mechanisms underlying MCP1-induced VSMC migration have not been understood. Here we identify the signaling pathway associated with MCP1-induced human aortic smooth muscle cell (HASMC) migration. MCP1, a G protein-coupled receptor agonist, activates phosphorylation of cortactin on S405 and S418 residues in a time-dependent manner, and inhibition of its phosphorylation attenuates MCP1-induced HASMC G-actin polymerization, F-actin stress fiber formation, and migration. Cortactin phosphorylation on S405/S418 is found to be critical for its interaction with WAVE2, a member of the WASP family of cytoskeletal regulatory proteins required for cell migration. In addition, the MCP1-induced cortactin phosphorylation is dependent on PLCβ3-mediated PKCδ activation, and siRNA-mediated down-regulation of either of these molecules prevents cortactin interaction with WAVE2, affecting G-actin polymerization, F-actin stress fiber formation, and HASMC migration. Upstream, MCP1 activates CCR2 and Gαq/11 in a time-dependent manner, and down-regulation of their levels attenuates MCP1-induced PLCβ3 and PKCδ activation, cortactin phosphorylation, cortactin-WAVE2 interaction, G-actin polymerization, F-actin stress fiber formation, and HASMC migration. Together these findings demonstrate that phosphorylation of cortactin on S405 and S418 residues is required for its interaction with WAVE2 in MCP1-induced cytoskeleton remodeling, facilitating HASMC migration.
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Affiliation(s)
- Jagadeesh Janjanam
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163
| | - Giri Kumar Chandaka
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163
| | - Sivareddy Kotla
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163
| | - Gadiparthi N Rao
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163
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PKCη is an anti-apoptotic kinase that predicts poor prognosis in breast and lung cancer. Biochem Soc Trans 2015; 42:1519-23. [PMID: 25399563 DOI: 10.1042/bst20140182] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The successful treatment of cancer in a disseminated stage using chemotherapy is limited by the occurrence of drug resistance, often mediated by anti-apoptotic mechanisms. Thus the challenge is to pinpoint the underlying key factors and to develop therapies for their direct targeting. Protein kinase C (PKC) enzymes are promising candidates, as some PKCs were shown to be involved in regulation of apoptosis. Our studies and others have shown that PKCη is an anti-apoptotic kinase, able to confer protection on tumour cells against stress and chemotherapy. We have demonstrated that PKCη shuttles between the cytoplasm and the nucleus and that upon DNA damage is tethered at the nuclear membrane. The C1b domain mediates translocation of PKCη to the nuclear envelope and, similar to the full-length protein, could also confer protection against cell death. Furthermore, its localization in cell and nuclear membranes in breast cancer biopsies of neoadjuvant-treated breast cancer patients was an indicator for poor survival and a predictor for the effectiveness of treatment. PKCη is also a novel biomarker for poor prognosis in non-small-cell lung cancer (NSCLC). Thus PKCη presents a potential target for therapy where inhibition of its activity and/or translocation to membranes could interfere with the resistance to chemotherapy.
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Park GB, Choi Y, Kim YS, Lee HK, Kim D, Hur DY. Silencing of PKCη induces cycle arrest of EBV(+) B lymphoma cells by upregulating expression of p38-MAPK/TAp73/GADD45α and increases susceptibility to chemotherapeutic agents. Cancer Lett 2014; 350:5-14. [PMID: 24784886 DOI: 10.1016/j.canlet.2014.04.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 03/28/2014] [Accepted: 04/21/2014] [Indexed: 01/01/2023]
Abstract
PKCη is involved in proliferation, differentiation, and drug resistance. However, PKCη function in EBV(+) B lymphoma remains poorly understood. Gene silencing of PKCη through siRNA knockdown inhibited cellular proliferation, induced cell cycle arrest in G0/G1 and G2/M phases, and sensitized cells to chemotherapeutic drugs. Upon PKCη knockdown, expression levels of p21, GADD45α, and TAp73 were all increased, whereas expression levels of CDK2, CDK4, CDK6, cyclin E, cyclin B1, and cdc2 were all downregulated. PKCη silencing also activated p38-MAPK, which in turn contributed to the expression of cell cycle arrest-related molecules. These results suggest that siRNA-mediated silencing of PKCη can be a potent tool to complement existing chemotherapy regimens for treating EBV(+) B lymphoma.
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Affiliation(s)
- Ga Bin Park
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea
| | - Yunock Choi
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea
| | - Yeong-Seok Kim
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea
| | - Hyun-Kyung Lee
- Department of Internal Medicine, Inje University Busan Paik Hospital, Busan 614-735, Republic of Korea
| | - Daejin Kim
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea
| | - Dae Young Hur
- Department of Anatomy and Research Center for Tumor Immunology, Inje University College of Medicine, Busan 614-735, Republic of Korea.
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Chattopadhyay R, Dyukova E, Singh NK, Ohba M, Mobley JA, Rao GN. Vascular endothelial tight junctions and barrier function are disrupted by 15(S)-hydroxyeicosatetraenoic acid partly via protein kinase C ε-mediated zona occludens-1 phosphorylation at threonine 770/772. J Biol Chem 2013; 289:3148-63. [PMID: 24338688 DOI: 10.1074/jbc.m113.528190] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Disruption of tight junctions (TJs) perturbs endothelial barrier function and promotes inflammation. Previously, we have shown that 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), the major 15-lipoxygenase 1 (15-LO1) metabolite of arachidonic acid, by stimulating zona occludens (ZO)-2 tyrosine phosphorylation and its dissociation from claudins 1/5, induces endothelial TJ disruption and its barrier dysfunction. Here, we have studied the role of serine/threonine phosphorylation of TJ proteins in 15(S)-HETE-induced endothelial TJ disruption and its barrier dysfunction. We found that 15(S)-HETE enhances ZO-1 phosphorylation at Thr-770/772 residues via PKCε-mediated MEK1-ERK1/2 activation, causing ZO-1 dissociation from occludin, disrupting endothelial TJs and its barrier function, and promoting monocyte transmigration; these effects were reversed by T770A/T772A mutations. In the arteries of WT mice ex vivo, 15(S)-HETE also induced ZO-1 phosphorylation and endothelial TJ disruption in a PKCε and MEK1-ERK1/2-dependent manner. In line with these observations, in WT mice high fat diet feeding induced 12/15-lipoxygenase (12/15-LO) expression in the endothelium and caused disruption of its TJs and barrier function. However, in 12/15-LO(-/-) mice, high fat diet feeding did not cause disruption of endothelial TJs and barrier function. These observations suggest that the 12/15-LO-12/15(S)-HETE axis, in addition to tyrosine phosphorylation of ZO-2, also stimulates threonine phosphorylation of ZO-1 in the mediation of endothelial TJ disruption and its barrier dysfunction.
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Affiliation(s)
- Rima Chattopadhyay
- From the Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163
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Karp G, Abu-Ghanem S, Novack V, Mermershtain W, Ariad S, Sion-Vardy N, Livneh E. Localization of PKCη in cell membranes as a predictor for breast cancer response to treatment. ACTA ACUST UNITED AC 2012; 35:260-6. [PMID: 22868505 DOI: 10.1159/000338443] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Successful treatment of breast cancer is frequently limited by the resistance of tumors to chemotherapy. Recent studies suggested a role for protein kinase C (PKC) in the resistance to chemotherapy. Here we used retrospective analysis of breast cancer biopsies of neoadjuvantly treated patients to investigate the correlation of PKC expression with aggressiveness and resistance to chemotherapy. PATIENTS AND METHODS Our cohort (n = 25) included patients with advanced and aggressive breast cancers, who underwent neoadjuvant therapy with the CAF regimen (cyclophosphamide, doxorubicin, fluorouracil). Core biopsies (pre-chemotherapy) and surgical biopsies of primary tumors and lymph node metastases (post-chemotherapy) were scored for PKCeta (PKCh) and PKCepsilon (PKCe) expression in the cytoplasm, cell membrane, nuclear membrane, and the nucleus. RESULTS Our results showed increased expression of PKCh (not PKCe) in the cytoplasm and cell membranes of post-chemotherapy biopsies (p = 0.03). PKCh presence in cell membranes, indicating activation, was in correlation with poor survival (p = 0.007). CONCLUSION PKCh staining in cell and nuclear membranes is an indicator for poor survival and a predictor for the effectiveness of neoadjuvant treatment. Other avenues of treatment should be considered for these patients. PKCh presents a target for therapy where inhibition of its activity and/or translocation to membranes could interfere with the resistance to chemotherapy.
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Affiliation(s)
- Galia Karp
- The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion University, Beer Sheva, Israel
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Shahaf G, Rotem-Dai N, Koifman G, Raveh-Amit H, Frost SA, Livneh E. PKCη is a negative regulator of AKT inhibiting the IGF-I induced proliferation. Exp Cell Res 2012; 318:789-99. [PMID: 22305966 DOI: 10.1016/j.yexcr.2012.01.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 10/14/2022]
Abstract
The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKCη isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKCη-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKCη-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKCη exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKCη and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKCη expression, suggesting that PKCη acts through a different route to increase cell survival. Hence, our studies show that PKCη provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.
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Affiliation(s)
- Galit Shahaf
- The Shraga Segal department of Microbiology and Immunology, Faculty of Health Science and the Cancer Research Center, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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Activation of VEGFR-2 signaling in response to moderate dose of ultraviolet B promotes survival of normal human keratinocytes. Int J Biochem Cell Biol 2012; 44:246-56. [DOI: 10.1016/j.biocel.2011.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 09/24/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
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Luparello C, Sirchia R, Longo A. Type V collagen and protein kinase C η down-regulation in 8701-BC breast cancer cells. Mol Carcinog 2011; 52:348-58. [PMID: 22213077 DOI: 10.1002/mc.21856] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 09/21/2011] [Accepted: 11/16/2011] [Indexed: 01/23/2023]
Abstract
We previously reported that ductal infiltrating carcinomas (d.i.c.) of the human breast display profound modifications of the stromal architecture, associated with anomalous collagen composition. Among the major alterations observed in the interstitial collagen, the relative increase of type V collagen content was detected. When type V collagen was used as an "in vitro" substrate for 8701-BC d.i.c. cells, it appeared able to restrain cell growth, inhibit cell motility and invasion "in vitro", and modify the expression levels of genes coding for apoptosis factors, caspases and stress response proteins. In the present paper we demonstrate that type V collagen induces the down-regulation of protein kinase C η, an event that may be, at least in part, responsible of the previously-reported modifications of cell morphology and growth rate, and that appears to be involved in the already-observed changes of expression levels of genes encoding for anti- (Bcl-2) and pro-apoptotic factors (Bad, Dapk, Bcl-Xs) and enzymes (caspase 5 and 8).
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Affiliation(s)
- Claudio Luparello
- Dipartimento di Scienze e Tecnologie Molecolari e Biomolecolari, STEMBIO, Università di Palermo, Palermo, Italy
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Protein kinase Cη activates NF-κB in response to camptothecin-induced DNA damage. Biochem Biophys Res Commun 2011; 412:313-7. [PMID: 21820409 DOI: 10.1016/j.bbrc.2011.07.090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 07/21/2011] [Indexed: 11/20/2022]
Abstract
The nuclear factor κB (NF-κB) family of transcription factors participates in the regulation of genes involved in innate- and adaptive-immune responses, cell death and inflammation. The involvement of the Protein kinase C (PKC) family in the regulation of NF-κB in inflammation and immune-related signaling has been extensively studied. However, not much is known on the role of PKC in NF-κB regulation in response to DNA damage. Here we demonstrate for the first time that PKC-eta (PKCη) regulates NF-κB upstream signaling by activating the IκB kinase (IKK) and the degradation of IκB. Furthermore, PKCη enhances the nuclear translocation and transactivation of NF-κB under non-stressed conditions and in response to the anticancer drug camptothecin. We and others have previously shown that PKCη confers protection against DNA damage-induced apoptosis. Our present study suggests that PKCη is involved in NF-κB signaling leading to drug resistance.
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DNA damage targets PKCη to the nuclear membrane via its C1b domain. Exp Cell Res 2011; 317:1465-75. [PMID: 21514295 DOI: 10.1016/j.yexcr.2011.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 03/10/2011] [Accepted: 03/31/2011] [Indexed: 11/23/2022]
Abstract
Translocation to cellular membranes is one of the hallmarks of PKC activation, occurring as a result of the generation of lipid secondary messengers in target membrane compartments. The activation-induced translocation of PKCs and binding to membranes is largely directed by their regulatory domains. We have previously reported that PKCη, a member of the novel subfamily and an epithelial specific isoform, is localized at the cytoplasm and ER/Golgi and is translocated to the plasma membrane and the nuclear envelope upon short-term activation by PMA. Here we show that PKCη is shuttling between the cytoplasm and the nucleus and that upon etoposide induced DNA damage is tethered at the nuclear envelope. Although PKCη expression and its phosphorylation on the hydrophobic motif (Ser675) are increased by etoposide, this phosphorylation is not required for its accumulation at the nuclear envelope. Moreover, we demonstrate that the C1b domain is sufficient for translocation to the nuclear envelope. We further show that, similar to full-length PKCη, the C1b domain could also confer protection against etoposide-induced cell death. Our studies demonstrate translocation of PKCη to the nuclear envelope, and suggest that its spatial regulation could be important for its cellular functions including effects on cell death.
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Ultraviolet B irradiation and activation of protein kinase D in primary mouse epidermal keratinocytes. Oncogene 2010; 30:1586-96. [PMID: 21132013 PMCID: PMC3069139 DOI: 10.1038/onc.2010.540] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Our previous studies demonstrated that protein kinase D (PKD), a serine/threonine kinase implicated in various cell processes, is up-regulated in basal cell carcinoma (BCC), supporting a possible tumorigenic role for PKD in skin. Since the greatest risk factor for BCC is sun exposure, the ability of ultraviolet B (UVB) irradiation to activate PKD in primary mouse keratinocytes was investigated. Using western analysis with two autophosphorylation-specific antibodies, we show for the first time that UVB activated PKD in a time- and dose-dependent manner. UVB-induced PKD activation was verified using an in vitro kinase assay. Furthermore, activation was reduced by antioxidant pretreatment, suggesting a link with oxidative stress. UVB-induced PKD activation was mediated primarily by Src family tyrosine kinases rather than protein kinase C (PKC), and in fact, UVB did not alter PKC-mediated transphosphorylation. UVB induced apoptosis dose-dependently, and this death could be prevented by overexpression of wild-type PKD, but not mutant PKD or the empty adenovirus. Indeed, a mutant that cannot be phosphorylated by Src kinases exacerbated UVB-elicited apoptosis. Thus, our data indicate that UVB irradiation of keratinocytes induces Src-mediated activation of PKD, which protects cells from UVB-stimulated apoptosis, providing a possible explanation for the observed up-regulation of PKD in BCC.
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Bertrand-Vallery V, Belot N, Dieu M, Delaive E, Ninane N, Demazy C, Raes M, Salmon M, Poumay Y, Debacq-Chainiaux F, Toussaint O. Proteomic profiling of human keratinocytes undergoing UVB-induced alternative differentiation reveals TRIpartite Motif Protein 29 as a survival factor. PLoS One 2010; 5:e10462. [PMID: 20454669 PMCID: PMC2862717 DOI: 10.1371/journal.pone.0010462] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 04/06/2010] [Indexed: 02/01/2023] Open
Abstract
Background Repeated exposures to UVB of human keratinocytes lacking functional p16INK-4a and able to differentiate induce an alternative state of differentiation rather than stress-induced premature senescence. Methodology/Principal Findings A 2D-DIGE proteomic profiling of this alternative state of differentiation was performed herein at various times after the exposures to UVB. Sixty-nine differentially abundant protein species were identified by mass spectrometry, many of which are involved in keratinocyte differentiation and survival. Among these protein species was TRIpartite Motif Protein 29 (TRIM29). Increased abundance of TRIM29 following UVB exposures was validated by Western blot using specific antibody and was also further analysed by immunochemistry and by RT-PCR. TRIM29 was found very abundant in keratinocytes and reconstructed epidermis. Knocking down the expression of TRIM29 by short-hairpin RNA interference decreased the viability of keratinocytes after UVB exposure. The abundance of involucrin mRNA, a marker of late differentiation, increased concomitantly. In TRIM29-knocked down reconstructed epidermis, the presence of picnotic cells revealed cell injury. Increased abundance of TRIM29 was also observed upon exposure to DNA damaging agents and PKC activation. The UVB-induced increase of TRIM29 abundance was dependent on a PKC signaling pathway, likely PKCδ. Conclusions/Significance These findings suggest that TRIM29 allows keratinocytes to enter a protective alternative differentiation process rather than die massively after stress.
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Affiliation(s)
| | | | - Marc Dieu
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Edouard Delaive
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Noëlle Ninane
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Catherine Demazy
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Martine Raes
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | | | - Yves Poumay
- Cell and Tissue Laboratory, URPHYM, University of Namur (FUNDP), Namur, Belgium
| | | | - Olivier Toussaint
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
- * E-mail:
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Protein kinase C delta and eta differently regulate the expression of loricrin and Jun family proteins in human keratinocytes. Biochem Biophys Res Commun 2010; 394:106-11. [PMID: 20184865 DOI: 10.1016/j.bbrc.2010.02.125] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 02/19/2010] [Indexed: 01/25/2023]
Abstract
Barrier function of the epidermis is maintained by precise expression of keratinocyte-specific structural proteins to form the cornified cell envelope (CE). Loricrin, a major component of the CE, is expressed at the late stage of keratinocyte differentiation. In this study, we reveal the isoform-specific function of protein kinase C (PKC) in the regulation of loricrin expression. Both PKCdelta and PKCeta have been recognized as differentiation-promoting isoforms. However, loricrin expression was inversely controlled by PKCdelta and PKCeta in cultured keratinocytes and 3D skin culture; i.e. loricrin expression was decreased by PKCdelta and increased by PKCeta. To clarify the mechanisms that PKCdelta and PKCeta oppositely regulate the loricrin expression, we examined the expression of activator protein-1 (AP-1) family proteins, which modulate the transcription of loricrin and are downstream molecules of PKC. PKCdelta decreased c-Jun expression, whereas PKCeta increased JunD, which are positive regulators of loricrin transcription. These findings suggest that inverse effects of PKCdelta and PKCeta on loricrin expression attributes to the expression of c-Jun and JunD.
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Translational control of protein kinase Ceta by two upstream open reading frames. Mol Cell Biol 2009; 29:6140-8. [PMID: 19797084 DOI: 10.1128/mcb.01044-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Protein kinase C (PKC) represents a family of serine/threonine kinases that play a central role in the regulation of cell growth, differentiation, and transformation. Posttranslational control of the PKC isoforms and their activation have been extensively studied; however, not much is known about their translational regulation. Here we report that the expression of one of the PKC isoforms, PKCeta, is regulated at the translational level both under normal growth conditions and during stress imposed by amino acid starvation, the latter causing a marked increase in its protein levels. The 5' untranslated region (5' UTR) of PKCeta is unusually long and GC rich, characteristic of many oncogenes and growth regulatory genes. We have identified two conserved upstream open reading frames (uORFs) in its 5' UTR and show their effect in suppressing the expression of PKCeta in MCF-7 growing cells. While the two uORFs function as repressive elements that maintain low basal levels of PKCeta in growing cells, they are required for its enhanced expression upon amino acid starvation. We show that the translational regulation during stress involves leaky scanning and is dependent on eIF-2alpha phosphorylation by GCN2. Our work further suggests that translational regulation could provide an additional level for controlling the expression of PKC family members, being more common than currently recognized.
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18
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Rotem-Dai N, Oberkovitz G, Abu-Ghanem S, Livneh E. PKCη confers protection against apoptosis by inhibiting the pro-apoptotic JNK activity in MCF-7 cells. Exp Cell Res 2009; 315:2616-23. [DOI: 10.1016/j.yexcr.2009.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 05/31/2009] [Accepted: 06/04/2009] [Indexed: 12/17/2022]
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Elnakat H, Gonit M, D’Alincourt Salazar M, Zhang J, Basrur V, Gunning W, Kamen B, Ratnam M. Regulation of Folate Receptor Internalization by Protein Kinase C α. Biochemistry 2009; 48:8249-60. [DOI: 10.1021/bi900565t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Hala Elnakat
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
| | - Mesfin Gonit
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
| | - Marcela D’Alincourt Salazar
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
| | - Juan Zhang
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
- Crown BioScience, Inc., Beijing, China
| | - Venkatesha Basrur
- Division of Pathology Informatics, Department of Pathology, University of Michigan Medical School, 1301 Catherine Road, Ann Arbor, Michigan 48109
| | - William Gunning
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
| | - Barton Kamen
- UMDNJ-R. W. Johnson Medical School, Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, New Jersey 08901
| | - Manohar Ratnam
- Department of Biochemistry and Cancer Biology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614
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Marrot L, Belaïdi JP, Jones C, Perez P, Meunler JR. Molecular Responses to Stress Induced in Normal Human Caucasian Melanocytes in Culture by Exposure to Simulated Solar UV¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb00196.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Kraft CA, Efimova T, Eckert RL. Activation of PKCδ and p38δ MAPK during okadaic acid dependent keratinocyte apoptosis. Arch Dermatol Res 2007; 299:71-83. [PMID: 17256148 DOI: 10.1007/s00403-006-0727-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 10/18/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
There is substantial interest in identifying agents that differentially activate keratinocyte differentiation versus apoptosis. Okadaic acid (OA) is a tumor promoter in mouse skin that also stimulates apoptosis of murine keratinocytes. OA also enhances human keratinocyte differentiation; however, the impact of OA treatment on apoptosis in these cells has not been examined. We show that OA promotes normal human keratinocyte apoptosis as evidenced by increased accumulation of cells having sub-G1/S DNA content, decreased mitochondrial integrity, increased annexin V binding, increased cytoplasmic cytochrome c level, and increased procaspase 3 and PARP cleavage. Cyclin A, cyclin D1, cdk2, cdk4, p53 and p21 levels are reduced. These changes are associated with release of the PKCdelta catalytic domain and increased phosphorylation of PKCdelta-T(505)-responses consistent with PKCdelta activation. In contrast, phosphorylation of PKCdelta-Y(311) is not increased. The apoptotic response is enhanced in OA treated cells in the presence of p38delta, a PKCdelta target. OA treatment selectively activated p38delta, and OA-dependent apoptosis is not inhibited by treatment with the p38alpha/beta inhibitor, SB203580. These findings are consistent with the idea that the response is mediated by p38delta. Our data indicate that OA is an agent that regulates both keratinocyte differentiation and apoptosis, and that this regulation is mediated via activation of a PKCdelta/p38delta signaling cascade.
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Affiliation(s)
- Catherine A Kraft
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106-4970, USA
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22
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Kubo M, Hata J, Ninomiya T, Matsuda K, Yonemoto K, Nakano T, Matsushita T, Yamazaki K, Ohnishi Y, Saito S, Kitazono T, Ibayashi S, Sueishi K, Iida M, Nakamura Y, Kiyohara Y. A nonsynonymous SNP in PRKCH (protein kinase C eta) increases the risk of cerebral infarction. Nat Genet 2007; 39:212-7. [PMID: 17206144 DOI: 10.1038/ng1945] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Accepted: 11/27/2006] [Indexed: 01/02/2023]
Abstract
Cerebral infarction is the most common type of stroke and often causes long-term disability. To investigate the genetic contribution to cerebral infarction, we conducted a case-control study using 52,608 gene-based tag SNPs selected from the JSNP database. Here we report that a nonsynonymous SNP in a member of protein kinase C (PKC) family, PRKCH, was significantly associated with lacunar infarction in two independent Japanese samples (P = 5.1 x 10(-7), crude odds ratio of 1.40). This SNP is likely to affect PKC activity. Furthermore, a 14-year follow-up cohort study in Hisayama (Fukuoka, Japan) supported involvement of this SNP in the development of cerebral infarction (P = 0.03, age- and sex-adjusted hazard ratio of 2.83). We also found that PKCeta was expressed mainly in vascular endothelial cells and foamy macrophages in human atherosclerotic lesions, and its expression increased as the lesion type progressed. Our results support a role for PRKCH in the pathogenesis of cerebral infarction.
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Affiliation(s)
- Michiaki Kubo
- Department of Environmental Medicine, Kyushu University, Fukuoka 812-8582, Japan.
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Mattiangeli V, Ryan AW, McManus R, Bradley DG. A genome-wide approach to identify genetic loci with a signature of natural selection in the Irish population. Genome Biol 2006; 7:R74. [PMID: 16904005 PMCID: PMC1779589 DOI: 10.1186/gb-2006-7-8-r74] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 05/26/2006] [Accepted: 08/11/2006] [Indexed: 11/24/2022] Open
Abstract
A single population test applied in a genomic context reveals evidence of selection on three biologically interesting genes in the Irish population. Background In this study we present a single population test (Ewens-Waterson) applied in a genomic context to investigate the presence of recent positive selection in the Irish population. The Irish population is an interesting focus for the investigation of recent selection since several lines of evidence suggest that it may have a relatively undisturbed genetic heritage. Results We first identified outlier single nucleotide polymorphisms (SNPs), from previously published genome-wide data, with high FST branch specification in a European-American population. Eight of these were chosen for further analysis. Evidence for selective history was assessed using the Ewens-Watterson's statistic calculated using Irish genotypes of microsatellites flanking the eight outlier SNPs. Evidence suggestive of selection was detected in three of these by comparison with a population-specific genome-wide empirical distribution of the Ewens-Watterson's statistic. Conclusion The cystic fibrosis gene, a disease that has a world maximum frequency in Ireland, was among the genes showing evidence of selection. In addition to the demonstrated utility in detecting a signature of natural selection, this approach has the particular advantage of speed. It also illustrates concordance between results drawn from alternative methods implemented in different populations.
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Affiliation(s)
- Valeria Mattiangeli
- Smurfit Institute of Genetics, Trinity College, Dublin 2, Ireland
- Department of Clinical Medicine, Trinity Centre for Health Science; Institute of Molecular Medicine, Dublin Molecular Medicine Centre, St James's Hospital, Dublin, Ireland
| | - Anthony W Ryan
- Department of Clinical Medicine, Trinity Centre for Health Science; Institute of Molecular Medicine, Dublin Molecular Medicine Centre, St James's Hospital, Dublin, Ireland
- Trinity College, Dublin, Ireland
| | - Ross McManus
- Department of Clinical Medicine, Trinity Centre for Health Science; Institute of Molecular Medicine, Dublin Molecular Medicine Centre, St James's Hospital, Dublin, Ireland
- Trinity College, Dublin, Ireland
| | - Daniel G Bradley
- Smurfit Institute of Genetics, Trinity College, Dublin 2, Ireland
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Abstract
Gliomas are the most common major subgroup of primary CNS tumours. Approximately 17,000 new cases are reported each year and, of these, 11,500 patients die. Glioblastoma multiforme (GBM) is highly proliferative and typically invades distal portions of the brain, thereby making complete surgical resection of these tumours nearly impossible. Moreover, GBMs are often resistant to current chemotherapy and radiation regimens. Therefore, there is a need for better therapeutic interventions. One class of proteins that is involved in the formation of malignant brain tumours is protein kinase C (PKC) and these kinases have not been thoroughly explored for their chemotherapeutic value in GBMs. The PKC isozyme, PKCeta (PKC-eta) increases cell proliferation and resistance to radiation of GBM cell lines. These properties make PKCeta an attractive target for chemotherapeutic intervention in the management of GBMs.
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Affiliation(s)
- Patrick M Martin
- Department of Pathology, University of Virginia, Charlottesville, VA, USA.
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25
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Maissel A, Marom M, Shtutman M, Shahaf G, Livneh E. PKCeta is localized in the Golgi, ER and nuclear envelope and translocates to the nuclear envelope upon PMA activation and serum-starvation: C1b domain and the pseudosubstrate containing fragment target PKCeta to the Golgi and the nuclear envelope. Cell Signal 2005; 18:1127-39. [PMID: 16242915 DOI: 10.1016/j.cellsig.2005.09.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 09/09/2005] [Indexed: 11/27/2022]
Abstract
Protein kinase C (PKC) represents a family of serin/threonine kinases, playing a central role in the regulation of cell growth, differentiation and transformation. These enzymes differ in their primary structure, biochemical properties, tissue distribution and subcellular localization. The specific cellular functions of PKC isoforms are largely controlled by their localization. PKCeta, a member of the novel subfamily, is expressed predominantly in epithelial tissues. However, not much is known with respect to its mechanism of activation and regulation. Our recent studies suggest its role in cell cycle control. Here we show that PKCeta is localized at the Golgi apparatus, ER and the nuclear envelope. Furthermore, using GFP-fusion proteins of the different functional domains of PKCeta we deciphered the specific structural domains of the protein responsible for its apparent localization. We show that the cysteine-rich repeat C1b is responsible for its Golgi localization, while for its presence at the ER/nuclear envelope the pseudosubstrate containing fragment coupled to the C1 domain is required. In response to short-term activation by PMA we show translocation of PKCeta to the plasma membrane and the nuclear envelope. We demonstrate that the C1b is sufficient for its translocation to the plasma membrane. Interestingly, accumulation of PKCeta at the nuclear envelope also occurred in response to serum-starvation. It should be noted that interaction of PKCeta with the cyclin E/Cdk2 complex at the perinuclear region was recently reported by us in response to serum-starvation. Thus, our studies demonstrate translocation of PKCeta to the nuclear envelope, and suggest that the spatial regulation of PKCeta could be important for its cellular functions including effects on cell cycle control and involvement in tumor promotion.
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Affiliation(s)
- Adva Maissel
- Department of Microbiology and Immunology, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University, Beer Sheva 84105, Israel
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26
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Assefa Z, Van Laethem A, Garmyn M, Agostinis P. Ultraviolet radiation-induced apoptosis in keratinocytes: on the role of cytosolic factors. Biochim Biophys Acta Rev Cancer 2005; 1755:90-106. [PMID: 15964692 DOI: 10.1016/j.bbcan.2005.04.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 04/04/2005] [Accepted: 04/19/2005] [Indexed: 01/14/2023]
Abstract
Epidemiological and experimental evidences have established solar ultraviolet (UV) radiation as the leading cause of skin cancers. Specifically, the frequency of non-melanoma skin cancer, one of the malignancies with the most rapidly increasing incidence, is directly related to the total exposure to solar UV light. As part of a general effort to elucidate the components of cellular signal transduction pathways, the mechanisms of cellular responses to UV radiation have received considerable attention over the last few years. These efforts were driven mainly by the conviction that understanding how normal cells respond to extracellular stimuli such as exposure to UV radiation will undoubtedly help in deciphering what goes wrong in a variety of clinical disorders including skin cancers and will assist in the development of novel therapeutic strategies. Studies over the last decade have established that UV radiation induces a bewildering array of signal transduction pathways, some of which could lead to apoptotic cell death. UV-induced cell death by apoptosis is considered to be a natural protective mechanism that removes damaged keratinocytes and circumvents the risk of malignant transformation. In this review, we summarize some of the most important findings regarding the response and role of mitogen-activated protein kinases in UVA and UVB radiation-induced signaling to apoptosis in keratinocytes. We will also briefly discuss what is known about the role of the BCL-2 family of proteins, the emerging role of lysosomal proteases and other important cytosolic signaling proteins in UV-induced apoptosis.
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Affiliation(s)
- Zerihun Assefa
- Department of Molecular Cell Biology, Division of Physiology, Faculty of Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
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27
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Won YK, Ong CN, Shen HM. Parthenolide sensitizes ultraviolet (UV)-B-induced apoptosis via protein kinase C-dependent pathways. Carcinogenesis 2005; 26:2149-56. [PMID: 16051639 DOI: 10.1093/carcin/bgi194] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Parthenolide (PN) is the principal sesquiterpene lactone in feverfew (Tanacetum parthenium) with proven anti-inflammatory properties. We have previously reported that PN possesses strong anticancer activity in ultraviolet B (UVB)-induced skin cancer in SKH-1 hairless mice. In order to further understand the mechanism(s) involved in the anticancer activity of PN, we investigated the role of protein kinase C (PKC) in the sensitization activity of PN on UVB-induced apoptosis. Several subtypes of PKC have been reported to be involved in UVB-induced signaling cascade with both pro- and anti-apoptotic activities. Here we focused on two isoforms of PKC: novel PKCdelta and atypical PKCzeta. In JB6 murine epidermal cells, UVB induces the membrane translocations of both PKCs, and PN pre-treatment enhances the membrane translocation of PKCdelta, but inhibits the translocation of PKCzeta. Similar results were also detected when the activities of these PKCs were tested with the PKC kinase assay. Moreover, pre-treatment with a specific PKCdelta inhibitor, rotterlin, completely diminishes the sensitization effect of PN on UVB-induced apoptosis. When cells were transiently transfected with dominant negative PKCdelta or wild-type PKCzeta, the sensitization effect of PN on UVB-induced apoptosis was also drastically reduced. Further mechanistic study revealed that PKCzeta, but not PKCdelta, is required for UVB-induced p38 MAPK activation and PN is likely to act through PKCzeta to suppress p38 activation in UVB-treated JB6 cells. In conclusion, we demonstrated that PN sensitizes UVB-induced apoptosis via PKC-dependent pathways.
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Affiliation(s)
- Yen-Kim Won
- Department of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore
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Niederberger N, Buehler LK, Ampudia J, Gascoigne NRJ. Thymocyte stimulation by anti-TCR-beta, but not by anti-TCR-alpha, leads to induction of developmental transcription program. J Leukoc Biol 2005; 77:830-841. [PMID: 15661827 DOI: 10.1189/jlb.1004608] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 12/15/2004] [Accepted: 12/29/2004] [Indexed: 12/19/2022] Open
Abstract
Anti-T cell receptor (aTCR) antibody (Ab) stimulation of T cells results in TCR down-modulation and T cell activation. Differences in the effect of anti-alpha-chain and beta-chain Ab have been reported on thymocytes. Anti-beta-chain Ab but not anti-alpha-chain reagents cause long-term TCR down-modulation. However, both types of Ab result in TCR cross-linking and activate early steps in signal transduction. In this study, we show that TCR internalization and calcium flux, hallmarks of T cell activation, are similar with aValpha and aVbeta treatment. Therefore, we have compared the gene expression profiles of preselection thymocytes stimulated with these reagents. We find that aValpha treatment does not cause any significant change in gene expression compared with control culture conditions. In contrast, aVbeta stimulation results in numerous changes in gene expression. The alterations of expression of genes known to be expressed in thymocytes are similar to changes caused by positive thymic selection, suggesting that the expression of some of the genes without known roles in thymocyte development and of novel genes whose expression is found to be altered may also be involved in this process.
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Affiliation(s)
- Nathalie Niederberger
- Department of Immunology, IMM1, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA
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Marrot L, Belaïdi JP, Jones C, Perez P, Meunier JR. Molecular Responses to Stress Induced in Normal Human Caucasian Melanocytes in Culture by Exposure to Simulated Solar UV¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-10-13-ra-343.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Efimova T, Broome AM, Eckert RL. Protein kinase Cdelta regulates keratinocyte death and survival by regulating activity and subcellular localization of a p38delta-extracellular signal-regulated kinase 1/2 complex. Mol Cell Biol 2004; 24:8167-83. [PMID: 15340077 PMCID: PMC515052 DOI: 10.1128/mcb.24.18.8167-8183.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Protein kinase Cdelta (PKCdelta) is an important regulator of apoptosis in epidermal keratinocytes. However, little information is available regarding the downstream kinases that mediate PKCdelta-dependent keratinocyte death. This study implicates p38delta mitogen-activated protein kinase (MAPK) as a downstream carrier of the PKCdelta-dependent death signal. We show that coexpression of PKCdelta with p38delta produces profound apoptosis-like morphological changes. These morphological changes are associated with increased sub-G(1) cell population, cytochrome c release, loss of mitochondrial membrane potential, caspase activation, and PARP cleavage. This death response is specific for the combination of PKCdelta and p38delta and is not produced by replacing PKCdelta with PKCalpha or p38delta with p38alpha. A constitutively active form of MEK6, an upstream activator of p38delta, can also produce cell death when coupled with p38delta. In addition, concurrent p38delta activation and extracellular signal-regulated kinase 1/2 (ERK1/2) inactivation are required for apoptosis. Regarding this inverse regulation, we describe a p38delta-ERK1/2 complex that may coordinate these changes in activity. We further show that this p38delta-ERK1/2 complex relocates into the nucleus in response to PKCdelta expression. This regulation appears to be physiological, since H(2)O(2), a known inducer of keratinocyte apoptosis, promotes identical PKCdelta and p38delta-ERK1/2 activity changes, leading to similar morphological changes.
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Affiliation(s)
- Tatiana Efimova
- Department of Physiology, Case Western Reserve University School of Medicine, 2109 Adelbert Rd., Cleveland, OH 44106-4970, USA
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Sitailo LA, Tibudan SS, Denning MF. Bax Activation and Induction of Apoptosis in Human Keratinocytes by the Protein Kinase C δ Catalytic Domain. J Invest Dermatol 2004; 123:434-43. [PMID: 15304079 DOI: 10.1111/j.0022-202x.2004.23403.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The constitutively active catalytic domain of protein kinase C (PKC)delta is an apoptotic effector generated by caspase-3 cleavage of full-length PKCdelta in response to a wide variety of apoptotic stimuli, including UV radiation. The PKCdelta catalytic domain induces apoptosis when ectopically expressed, however, the mechanism of apoptosis induction is unclear. We constructed a chimeric protein encoding the PKCdelta catalytic domain fused to a mutated estrogen receptor ligand-binding domain in order to selectively activate the PKCdelta catalytic domain. The enzymatic activity of the PKCdelta catalytic domain fusion protein was induced in human keratinocytes treated with 4-hydroxytamoxifen, and its activation triggered loss of mitochondrial membrane potential and apoptosis. The apoptosis was associated with release of cytochrome c from the mitochondria and caspase activation, and was blocked by caspase inhibitors and the anti-apoptotic proteins Bcl-2, and Bcl-x(L), suggesting a role for mitochondrial pore formation. Consistent with this, the activated PKCdelta catalytic domain triggered the redistribution and activation of Bax, a Bcl-2 family protein that can directly induce cytochrome c release. In summary, despite being an apoptotic effector activated late in the apoptotic cascade, PKCdelta also activates upstream components of the death effector pathway to insure the demise of cells committed to apoptosis.
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Affiliation(s)
- Leonid A Sitailo
- Department of Pathology and the Oncology Institute, Skin Cancer Research Program, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL 60153, USA
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Sonnemann J, Gekeler V, Ahlbrecht K, Brischwein K, Liu C, Bader P, Müller C, Niethammer D, Beck JF. Down-regulation of protein kinase Ceta by antisense oligonucleotides sensitises A549 lung cancer cells to vincristine and paclitaxel. Cancer Lett 2004; 209:177-85. [PMID: 15159020 DOI: 10.1016/j.canlet.2004.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 02/03/2004] [Accepted: 02/05/2004] [Indexed: 10/26/2022]
Abstract
Previous studies point to protein kinase C (PKC) isozyme eta as a resistance factor in cancer cells. Therefore, we investigated whether down-regulation of PKCeta with second generation antisense oligonucleotides (ODNs) would sensitise A549 human lung carcinoma cells to cytostatics. The effects were compared to the outcome of Bcl-xL down-regulation. Upon treatment with antisense ODNs, PKCeta and Bcl-xL were both significantly reduced on mRNA and protein level. Down-regulation of either PKCeta or Bcl-xL in combination with vincristine or paclitaxel resulted in a significant increase in caspase-3 activity compared to that in the control oligonucleotide treated cells. In addition, PKCeta down-regulation augmented vincristine-induced dissipation of mitochondrial transmembrane potential. In conclusion, these results confirm that PKCeta might represent a considerable resistance factor and an interesting target to improve anticancer chemotherapy.
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Affiliation(s)
- Jürgen Sonnemann
- Peter Holtz Research Center of Pharmacology and Experimental Therapeutics, Ernst Moritz Arndt University, Greifswald, Germany
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Sonnemann J, Gekeler V, Sagrauske A, Müller C, Hofmann HP, Beck JF. Down-regulation of protein kinase Cη potentiates the cytotoxic effects of exogenous tumor necrosis factor–related apoptosis-inducing ligand in PC-3 prostate cancer cells. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.773.3.7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is a highly promising candidate for the treatment of cancer because it elicits cell death in the majority of tumor cells while sparing most normal cells. Some cancers, however, display resistance to TRAIL, suggesting that treatment with TRAIL alone may be insufficient for cancer therapy. In the present study, we explored whether the apoptotic responsiveness of PC-3 prostate cancer cells to TRAIL could be enhanced by targeting the novel protein kinase C (PKC) isoform η. Transfection of PC-3 cells with second-generation chimeric antisense oligonucleotides against PKCη caused a time- and dose-dependent knockdown of PKCη, as revealed by real-time RT-PCR and Western blot analyses. Knockdown of PKCη resulted in a marked amplification of TRAIL's cytotoxic activity. Cell killing could be substantially prevented by the pan-caspase inhibitor z-VAD-fmk. In addition, PKCη knockdown and administration of TRAIL significantly synergized in activation of caspase-3 and internucleosomal DNA fragmentation. Knockdown of PKCη augmented TRAIL-induced dissipation of the mitochondrial transmembrane potential and release of cytochrome c from mitochondria into the cytosol, indicating that PKCη acts upstream of mitochondria. We conclude that PKCη represents a considerable resistance factor with respect to TRAIL and a promising target to exploit the therapeutic potential of TRAIL.
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Affiliation(s)
- Jürgen Sonnemann
- 1Peter Holtz Research Center of Pharmacology and Experimental Therapeutics,
| | - Volker Gekeler
- 3Department of Pharmacology-Oncology, Altana Pharma AG, Konstanz, Germany
| | - Antje Sagrauske
- 1Peter Holtz Research Center of Pharmacology and Experimental Therapeutics,
| | - Cornelia Müller
- 2Department of Pediatric Oncology/Hematology, Ernst Moritz Arndt University, Greifswald, Germany; and
| | - Hans-Peter Hofmann
- 3Department of Pharmacology-Oncology, Altana Pharma AG, Konstanz, Germany
| | - James F. Beck
- 2Department of Pediatric Oncology/Hematology, Ernst Moritz Arndt University, Greifswald, Germany; and
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Denning MF. Epidermal keratinocytes: regulation of multiple cell phenotypes by multiple protein kinase C isoforms. Int J Biochem Cell Biol 2004; 36:1141-6. [PMID: 15109560 DOI: 10.1016/j.biocel.2003.12.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Revised: 12/05/2003] [Accepted: 12/10/2003] [Indexed: 10/26/2022]
Abstract
Squamous cells form the outermost layers of the epidermis, and though they are readily discarded from the tissue, they serve a vital water barrier function while in the stratum corneum. The generation of cornified or squamous keratinocytes involves a complex, multi-step differentiation process that insures the proper physical and immunological barrier functions of the epidermis are maintained. The regulation of keratinocyte terminal differentiation is influenced by a large number of signaling pathways. This article will review some recent findings regarding the roles of the protein kinase C (PKC) family in normal keratinocyte differentiation, as well as their involvement in skin diseases, especially skin cancer.
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Affiliation(s)
- Mitchell F Denning
- Skin Cancer Research Program, Department of Pathology and the Cardinal Bernardin Cancer Center, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL 60153, USA.
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Alpini G, Kanno N, Phinizy JL, Glaser S, Francis H, Taffetani S, LeSage G. Tauroursodeoxycholate inhibits human cholangiocarcinoma growth via Ca2+-, PKC-, and MAPK-dependent pathways. Am J Physiol Gastrointest Liver Physiol 2004; 286:G973-82. [PMID: 14701718 DOI: 10.1152/ajpgi.00270.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Tauroursodeoxychate (TUDCA) is used for the treatment of cholangiopathies including primary sclerosing cholangitis, which is considered the primary risk factor for cholangiocarcinoma. The effect of TUDCA on cholangiocarcinoma growth is unknown. We evaluated the role of TUDCA in the regulation of growth of the cholangiocarcinoma cell line Mz-ChA-1. TUDCA inhibited the growth of Mz-ChA-1 cells in concentration- and time-dependent manners. TUDCA inhibition of cholangiocarcinoma growth was blocked by BAPTA-AM, an intracellular Ca(2+) concentration ([Ca(2+)](i)) chelator, and H7, a PKC-alpha inhibitor. TUDCA increased [Ca(2+)](i) and membrane translocation of the Ca(2+)-dependent PKC-alpha in Mz-ChA-1 cells. TUDCA inhibited the activity of MAPK, and this inhibitory effect of TUDCA was abrogated by BAPTA-AM and H7. TUDCA did not alter the activity of Raf-1 and B-Raf and the phosphorylation of MAPK p38 and JNK/stress-activated protein kinase. TUDCA inhibits Mz-ChA-1 growth through a signal-transduction pathway involving MAPK p42/44 and PKC-alpha but independent from Raf proteins and MAPK p38 and JNK/stress-activated protein kinases. TUDCA may be important for the treatment of cholangiocarcinoma.
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Affiliation(s)
- Gianfranco Alpini
- Department of Internal Medicine, Scott & White Hospital and The Texas A & M University System Health Science Center, College of Medicine, and Central Texas Veterans Health Care System, Temple, USA
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