1
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PKCeta Promotes Stress-Induced Autophagy and Senescence in Breast Cancer Cells, Presenting a Target for Therapy. Pharmaceutics 2022; 14:pharmaceutics14081704. [PMID: 36015330 PMCID: PMC9413313 DOI: 10.3390/pharmaceutics14081704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 12/22/2022] Open
Abstract
The emergence of chemoresistance in neoplastic cells is one of the major obstacles in cancer therapy. Autophagy was recently reported as one of the mechanisms that promote chemoresistance in cancer cells by protecting against apoptosis and driving senescence. Thus, understanding the role of autophagy and its underlying signaling pathways is crucial for the development of new therapeutic strategies to overcome chemoresistance. We have previously reported that PKCη is a stress-induced kinase that confers resistance in breast cancer cells against chemotherapy by inducing senescence. Here, we show that PKCη promotes autophagy induced by ER and oxidative stress and facilitates the transition from autophagy to senescence. We demonstrate that PKCη knockdown reduces both the autophagic flux and markers of senescence. Additionally, using autophagy inhibitors such as chloroquine and 3-methyladenine, we show that PKCη and autophagy are required for establishing senescence in MCF-7 in response to oxidative stress. Different drugs used in the clinic are known to induce autophagy and senescence in breast cancer cells. Our study proposes PKCη as a target for therapeutic intervention, acting in synergy with autophagy-inducing drugs to overcome resistance and enhance cell death in breast cancer.
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2
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Unraveling the hidden role of a uORF-encoded peptide as a kinase inhibitor of PKCs. Proc Natl Acad Sci U S A 2021; 118:2018899118. [PMID: 34593629 PMCID: PMC8501901 DOI: 10.1073/pnas.2018899118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 02/01/2023] Open
Abstract
Approximately 40% of human messenger RNAs (mRNAs) contain upstream open reading frames (uORFs) in their 5' untranslated regions. Some of these uORF sequences, thought to attenuate scanning ribosomes or lead to mRNA degradation, were recently shown to be translated, although the function of the encoded peptides remains unknown. Here, we show a uORF-encoded peptide that exhibits kinase inhibitory functions. This uORF, upstream of the protein kinase C-eta (PKC-η) main ORF, encodes a peptide (uPEP2) containing the typical PKC pseudosubstrate motif present in all PKCs that autoinhibits their kinase activity. We show that uPEP2 directly binds to and selectively inhibits the catalytic activity of novel PKCs but not of classical or atypical PKCs. The endogenous deletion of uORF2 or its overexpression in MCF-7 cells revealed that the endogenously translated uPEP2 reduces the protein levels of PKC-η and other novel PKCs and restricts cell proliferation. Functionally, treatment of breast cancer cells with uPEP2 diminished cell survival and their migration and synergized with chemotherapy by interfering with the response to DNA damage. Furthermore, in a xenograft of MDA-MB-231 breast cancer tumor in mice models, uPEP2 suppressed tumor progression, invasion, and metastasis. Tumor histology showed reduced proliferation, enhanced cell death, and lower protein expression levels of novel PKCs along with diminished phosphorylation of PKC substrates. Hence, our study demonstrates that uORFs may encode biologically active peptides beyond their role as translation regulators of their downstream ORFs. Together, we point to a unique function of a uORF-encoded peptide as a kinase inhibitor, pertinent to cancer therapy.
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3
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de Miranda MC, Rodrigues MA, de Angelis Campos AC, Faria JAQA, Kunrath-Lima M, Mignery GA, Schechtman D, Goes AM, Nathanson MH, Gomes DA. Epidermal growth factor (EGF) triggers nuclear calcium signaling through the intranuclear phospholipase Cδ-4 (PLCδ4). J Biol Chem 2019; 294:16650-16662. [PMID: 31537645 DOI: 10.1074/jbc.ra118.006961] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 09/10/2019] [Indexed: 02/06/2023] Open
Abstract
Calcium (Ca2+) signaling within the cell nucleus regulates specific cellular events such as gene transcription and cell proliferation. Nuclear and cytosolic Ca2+ levels can be independently regulated, and nuclear translocation of receptor tyrosine kinases (RTKs) is one way to locally activate signaling cascades within the nucleus. Nuclear RTKs, including the epidermal growth factor receptor (EGFR), are important for processes such as transcriptional regulation, DNA-damage repair, and cancer therapy resistance. RTKs can hydrolyze phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) within the nucleus, leading to Ca2+ release from the nucleoplasmic reticulum by inositol 1,4,5-trisphosphate receptors. PI(4,5)P2 hydrolysis is mediated by phospholipase C (PLC). However, it is unknown which nuclear PLC isoform is triggered by EGFR. Here, using subcellular fractionation, immunoblotting and fluorescence, siRNA-based gene knockdowns, and FRET-based biosensor reporter assays, we investigated the role of PLCδ4 in epidermal growth factor (EGF)-induced nuclear Ca2+ signaling and downstream events. We found that EGF-induced Ca2+ signals are inhibited when translocation of EGFR is impaired. Nuclear Ca2+ signals also were reduced by selectively buffering inositol 1,4,5-trisphosphate (InsP3) within the nucleus. EGF induced hydrolysis of nuclear PI(4,5)P2 by the intranuclear PLCδ4, rather than by PLCγ1. Moreover, protein kinase C, a downstream target of EGF, was active in the nucleus of stimulated cells. Furthermore, PLCδ4 and InsP3 modulated cell cycle progression by regulating the expression of cyclins A and B1. These results provide evidence that EGF-induced nuclear signaling is mediated by nuclear PLCδ4 and suggest new therapeutic targets to modulate the proliferative effects of this growth factor.
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Affiliation(s)
- Marcelo Coutinho de Miranda
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Michele Angela Rodrigues
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Ana Carolina de Angelis Campos
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | | | - Marianna Kunrath-Lima
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil
| | - Gregory A Mignery
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153
| | - Deborah Schechtman
- Department of Biochemistry, University of São Paulo, Av. Professor Lineu Prestes, 748, São Paulo-SP 05508-900, Brazil
| | - Alfredo Miranda Goes
- Department of Pathology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil
| | - Michael H Nathanson
- Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Dawidson A Gomes
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil .,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
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4
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Basu A, Pal D, Blaydes R. Differential effects of protein kinase C-eta on apoptosis versus senescence. Cell Signal 2019; 55:1-7. [DOI: 10.1016/j.cellsig.2018.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/07/2018] [Accepted: 12/07/2018] [Indexed: 12/17/2022]
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5
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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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6
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Zhang J, Liu J, Ren L, Wei J, Zhang F, Li Y, Guo C, Duan J, Sun Z, Zhou X. Silica nanoparticles induce abnormal mitosis and apoptosis via PKC-δ mediated negative signaling pathway in GC-2 cells of mice. CHEMOSPHERE 2018; 208:942-950. [PMID: 30068038 DOI: 10.1016/j.chemosphere.2018.05.178] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
The potential health hazards of silica nanoparticles (SiNPs) have attracted more and more attentions. Researches had shown that SiNPs could damage seminiferous epithelium and reduce the quantity and quality of sperms, however the specific mechanism of male reproductive toxicity induced by SiNPs still unclear. So we designed to investigate the mechanism of SiNPs on male mice using spermatocyte lines (GC-2spd cells) after exposure to SiNPs (6.25, 12.5, 25 and 50 μg/mL) for 24 h. The present study showed that SiNPs entered GC-2 cells and mainly localized in the cytoplasm and lysosome. And internalized SiNPs damaged mitochondria structures. As a result, SiNPs not only induced a dose-dependent reduction in cell viability, but also increased the LDH release and apoptosis rate in GC-2 cells. Furthermore, SiNPs induced DNA strand breaks and abnormal mitosis, and arrested GC-2 cells at the G0/G1 phase. Besides, SiNPs could simultaneously activate both PKC-mediated negative signaling pathway (PKC-δ/p53/p21cip1) and positive signaling pathway (PKC-α/MAPK). However, the lower expressions of cyclin E and cyclin-dependent kinases 2 (CDK2) indicated that PKC-δ signaling pathway played a major role in cell cycle process. These results suggested internalized SiNPs in GC-2 cells induced DNA strand breaks and activated PKC-mediated signaling pathway. While the activation of PKC-δ signaling pathway led to cell cycle arrest and apoptosis, thereby resulting in abnormal mitosis. The present study may provide a new evidence to elucidate the toxic mechanisms of male reproductive system, and will be beneficial for safety assessment of SiNPs products.
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Affiliation(s)
- Jin Zhang
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Jianhui Liu
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Lihua Ren
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Jialiu Wei
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Feng Zhang
- Colleges of Life Science, Qilu Normal University, Jinan, 250013, China
| | - Yanbo Li
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Caixia Guo
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Junchao Duan
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Zhiwei Sun
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China
| | - Xianqing Zhou
- Department of Toxicology and Hygienic Chemistry, School of Public Health, Capital Medical University, Beijing, 100069, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 100069, China.
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7
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Ji F, Liu Q, Feng Z, Han X, Li Z. Genetic association between 1425G/A SNP in PRKCH and hypertrophic cardiomyopathy in a Chinese population. Oncotarget 2017; 8:114839-114844. [PMID: 29383124 PMCID: PMC5777736 DOI: 10.18632/oncotarget.22214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 09/23/2017] [Indexed: 12/21/2022] Open
Abstract
Hypertrophic cardiomyopathy is a heterogeneous myocardial disorder with a broad spectrum of clinical presentation and morphologic features. Previous reports indicated that protein kinase C pathway as a major determinant of cardiac hypertrophy and heart failure. Population-based analyses of the association between PRKCH gene (encoded PKCη) and HCM has not been performed yet. The purpose of this study is to investigate the association of the nonsynonymous SNP (1425G/A) in PRKCH gene and hypertrophic cardiomyopathy in a Chinese population. 323 patients with HCM and 326 controls were examined using a case-control methodology. The 1425G/A SNP in PRKCH was genotyped by allele-specific real-time PCR assay. The 1425G/A SNP in PRKCH increased the risk of HOCM (hypertrophic obstructive cardiomyopathy) (OR=1.427, 95% confidence interval, 1.013 to 2.012, P=0.046) under a dominant model. After age- and sex-adjustment, the significant associations remained in HOCM (for GG +AG versus AA, OR= 2.497, 95% confidence interval, 1.01 to 6.17; P=0.047). The 1425G/A SNP in PRKCH increases the risk of hypertrophic obstructive cardiomyopathy in the Chinese population.
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Affiliation(s)
- Feng Ji
- Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Qun Liu
- Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Zeyu Feng
- Medical School of Nantong University, Nantong 226001, China
| | - Xinwei Han
- Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Zhitong Li
- Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
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8
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Guo FZ, Xu Y, Ren LH, Zhang J, Zhang F, Duan J, Zhou XQ, Sun ZW. Endosulfan induces apoptosis by activating the negative regulation pathway of cell cycle and death receptor pathway in spermatogenic cells. Toxicol Res (Camb) 2017; 6:223-231. [PMID: 30090493 DOI: 10.1039/c6tx00315j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/05/2017] [Indexed: 01/17/2023] Open
Abstract
The male reproductive toxicity of endosulfan has been proved. Nevertheless, the underlying molecular mechanisms of the apoptosis caused by endosulfan in spermatogenic cells remains poorly understood. In order to investigate the reproductive toxicity mechanism caused by endosulfan, there were four groups, which had eight Wistar male rats randomly assigned to them, and the rats in different groups received different doses of endosulfan for a period of 21 days. GC-1 spermatogenic cell lines were divided into four groups, and each group was exposed to different doses of endosulfan for 24 hours. The results of this research showed that endosulfan decreased the cell viability, damaged cell membranes and induced apoptosis in spermatogenic cells. Endosulfan had obviously activated the protein expression of PKC-δ, p53, p21cip1, p27kip1, Fas, FasL, Caspase-8, Caspase-3, and inhibited the expression of E2F-1. Endosulfan also induced oxidative stress and DNA damage in spermatogenic cells. The results of this research suggested that endosulfan could lead to E2F-1-induced apoptosis of spermatogenic cells by activating the negative regulation factors of the cell cycle, and endosulfan might cause apoptosis by death receptor pathway, causing oxidative stress.
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Affiliation(s)
- Fang-Zi Guo
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Ying Xu
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Li-Hua Ren
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Jin Zhang
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Feng Zhang
- College of Life Science , Qilu Normal University , Jinan 250013 , China
| | - Junchao Duan
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Xian-Qing Zhou
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
| | - Zhi-Wei Sun
- Department of Toxicology and Hygienic Chemistry , School of Public Health , Capital Medical University , Beijing , 100069 , China . ; ; Tel: +8610-83911775.,Beijing Key Laboratory of Environmental Toxicology , Capital Medical University , Beijing 100069 , China
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9
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Torisu K, Zhang X, Nonaka M, Kaji T, Tsuchimoto D, Kajitani K, Sakumi K, Torisu T, Chida K, Sueishi K, Kubo M, Hata J, Kitazono T, Kiyohara Y, Nakabeppu Y. PKCη deficiency improves lipid metabolism and atherosclerosis in apolipoprotein E-deficient mice. Genes Cells 2016; 21:1030-1048. [PMID: 27545963 DOI: 10.1111/gtc.12402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 07/13/2016] [Indexed: 12/21/2022]
Abstract
Genomewide association studies have shown that a nonsynonymous single nucleotide polymorphism in PRKCH is associated with cerebral infarction and atherosclerosis-related complications. We examined the role of PKCη in lipid metabolism and atherosclerosis using apolipoprotein E-deficient (Apoe-/- ) mice. PKCη expression was augmented in the aortas of mice with atherosclerosis and exclusively detected in MOMA2-positive macrophages within atherosclerotic lesions. Prkch+/+ Apoe-/- and Prkch-/- Apoe-/- mice were fed a high-fat diet (HFD), and the dyslipidemia observed in Prkch+/+ Apoe-/- mice was improved in Prkch-/- Apoe-/- mice, with a particular reduction in serum LDL cholesterol and phospholipids. Liver steatosis, which developed in Prkch+/+ Apoe-/- mice, was improved in Prkch-/- Apoe-/- mice, but glucose tolerance, adipose tissue and body weight, and blood pressure were unchanged. Consistent with improvements in LDL cholesterol, atherosclerotic lesions were decreased in HFD-fed Prkch-/- Apoe-/- mice. Immunoreactivity against 3-nitrotyrosine in atherosclerotic lesions was dramatically decreased in Prkch-/- Apoe-/- mice, accompanied by decreased necrosis and apoptosis in the lesions. ARG2 mRNA and protein levels were significantly increased in Prkch-/- Apoe-/- macrophages. These data show that PKCη deficiency improves dyslipidemia and reduces susceptibility to atherosclerosis in Apoe-/- mice, showing that PKCη plays a role in atherosclerosis development.
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Affiliation(s)
- Kumiko Torisu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. .,Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Xueli Zhang
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Mari Nonaka
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takahide Kaji
- Translational Research Department, Sohyaku, Innovative Research Division, Mitsubishi Tanabe Pharma Corporation, 17-10 Nihonbashi, Koami-cho, Chuo-ku, Tokyo, 103-8405, Japan
| | - Daisuke Tsuchimoto
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Research Center for Nucleotide Pool, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Kosuke Kajitani
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Counseling and Health Center, Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kunihiko Sakumi
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Research Center for Nucleotide Pool, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takehiro Torisu
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Kazuhiro Chida
- Department of Animal Resource Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Katsuo Sueishi
- Department of Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Michiaki Kubo
- Laboratory for Genotyping Development, Center for Genomic Medicine, RIKEN 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Jun Hata
- Department of Epidemiology and Public Health, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yutaka Kiyohara
- Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Research Center for Nucleotide Pool, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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10
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Zhang MX, Zhang J, Zhang H, Tang H. miR-24-3p Suppresses Malignant Behavior of Lacrimal Adenoid Cystic Carcinoma by Targeting PRKCH to Regulate p53/p21 Pathway. PLoS One 2016; 11:e0158433. [PMID: 27351203 PMCID: PMC4924841 DOI: 10.1371/journal.pone.0158433] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/15/2016] [Indexed: 12/11/2022] Open
Abstract
MicroRNA (miRNA) may function as an oncogene or a tumor suppressor in tumorigenesis. However, the mechanism of miRNAs in adenoid cystic carcinoma (ACC) is unclear. Here, we provide evidence that miR-24-3p was downreglated and functions as a tumor suppressor in human lacrimal adenoid cystic carcinoma by suppressing proliferation and migration/invasion while promoting apoptosis. miR-24-3p down-regulated protein kinase C eta (PRKCH) by binding to its untranslated region (3’UTR). PRKCH increased the of the cell growth and migration/invasion in ACC cells and suppressed the expression of p53 and p21 in both mRNA and protein level. The overexpression of miR-24-3p decreased its malignant phenotype. Ectopic expression of PRKCH counteracted the suppression of malignancy induced by miR-24-3p, as well as ectopic expression of miR-24-3p rescued the suppression of PRKCH in the p53/p21 pathway. These results suggest that miR-24-3p promotes the p53/p21 pathway by down-regulating PRKCH expression in lacrimal adenoid cystic carcinoma cells.
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Affiliation(s)
- Ming-xue Zhang
- Department of Ophthalmology, The Second Hospital of TianJin Medical University, Tianjin, China
| | - Jie Zhang
- Department of Ophthalmology, The Second Hospital of TianJin Medical University, Tianjin, China
| | - Hong Zhang
- Department of Ophthalmology, The Second Hospital of TianJin Medical University, Tianjin, China
- * E-mail: (HZ); (HT)
| | - Hua Tang
- Tianjin Life Science Research Center and Department of Microbiology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- * E-mail: (HZ); (HT)
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11
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The role of protein kinase C alpha translocation in radiation-induced bystander effect. Sci Rep 2016; 6:25817. [PMID: 27165942 PMCID: PMC4863171 DOI: 10.1038/srep25817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/22/2016] [Indexed: 01/24/2023] Open
Abstract
Ionizing radiation is a well known human carcinogen. Evidence accumulated over the past decade suggested that extranuclear/extracellular targets and events may also play a critical role in modulating biological responses to ionizing radiation. However, the underlying mechanism(s) of radiation-induced bystander effect is still unclear. In the current study, AL cells were irradiated with alpha particles and responses of bystander cells were investigated. We found out that in bystander AL cells, protein kinase C alpha (PKCα) translocated from cytosol to membrane fraction. Pre-treatment of cells with PKC translocation inhibitor chelerythrine chloride suppressed the induced extracellular signal-regulated kinases (ERK) activity and the increased cyclooxygenase 2 (COX-2) expression as well as the mutagenic effect in bystander cells. Furthermore, tumor necrosis factor alpha (TNFα) was elevated in directly irradiated but not bystander cells; while TNFα receptor 1 (TNFR1) increased in the membrane fraction of bystander cells. Further analysis revealed that PKC activation caused accelerated internalization and recycling of TNFR1. Our data suggested that PKCα translocation may occur as an early event in radiation-induced bystander responses and mediate TNFα-induced signaling pathways that lead to the activation of ERK and up-regulation of COX-2.
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12
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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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13
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Zurgil U, Ben-Ari A, Atias K, Isakov N, Apte R, Livneh E. PKCη promotes senescence induced by oxidative stress and chemotherapy. Cell Death Dis 2014; 5:e1531. [PMID: 25412309 PMCID: PMC4260739 DOI: 10.1038/cddis.2014.481] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 10/06/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Senescence is characterized by permanent cell-cycle arrest despite continued viability and metabolic activity, in conjunction with the secretion of a complex mixture of extracellular proteins and soluble factors known as the senescence-associated secretory phenotype (SASP). Cellular senescence has been shown to prevent the proliferation of potentially tumorigenic cells, and is thus generally considered a tumor suppressive process. However, some SASP components may act as pro-tumorigenic mediators on premalignant cells in the microenvironment. A limited number of studies indicated that protein kinase C (PKC) has a role in senescence, with different isoforms having opposing effects. It is therefore important to elucidate the functional role of specific PKCs in senescence. Here we show that PKCη, an epithelial specific and anti-apoptotic kinase, promotes senescence induced by oxidative stress and DNA damage. We further demonstrate that PKCη promotes senescence through its ability to upregulate the expression of the cell cycle inhibitors p21Cip1 and p27Kip1 and enhance transcription and secretion of interleukin-6 (IL-6). Moreover, we demonstrate that PKCη creates a positive loop for reinforcing senescence by increasing the transcription of both IL-6 and IL-6 receptor, whereas the expression of IL-8 is specifically suppressed by PKCη. Thus, the presence/absence of PKCη modulates major components of SASP. Furthermore, we show that the human polymorphic variant of PKCη, 374I, that exhibits higher kinase activity in comparison to WT-374V, is also more effective in IL-6 secretion, p21Cip1 expression and the promotion of senescence, further supporting a role for PKCη in senescence. As there is now considerable interest in senescence activation/elimination to control tumor progression, it is first crucial to reveal the molecular regulators of senescence. This will improve our ability to develop new strategies to harness senescence as a potential cancer therapy in the future.
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Affiliation(s)
- U Zurgil
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - A Ben-Ari
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - K Atias
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - N Isakov
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - R Apte
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - E Livneh
- The Shraga Segal Department of Microbiology Immunology and Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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Pal D, Basu A. The unique protein kinase Cη: implications for breast cancer (review). Int J Oncol 2014; 45:493-8. [PMID: 24841225 DOI: 10.3892/ijo.2014.2443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 02/18/2014] [Indexed: 11/05/2022] Open
Abstract
Deregulation of key signal transduction pathways that govern important cellular processes leads to cancer. The development of effective therapeutics for cancer warrants a comprehensive understanding of the signaling pathways that are deregulated in cancer. The protein kinase C (PKC) family has served as an attractive target for cancer therapy for decades owing to its crucial roles in several cellular processes. PKCη is a novel member of the PKC family that plays critical roles in various cellular processes such as growth, proliferation, differentiation and cell death. The regulation of PKCη appears to be unique compared to other PKC isozymes, and there are conflicting reports regarding its role in cancer. This review focuses on the unique aspects of PKCη in terms of its structure, regulation and subcellular distribution and speculates on how these features could account for its distinct functions. We have also discussed the functional implications of PKCη in cancer with particular emphasis on breast cancer.
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Affiliation(s)
- Deepanwita Pal
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center and Institute for Cancer Research, Fort Worth, TX 76107, USA
| | - Alakananda Basu
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center and Institute for Cancer Research, Fort Worth, TX 76107, USA
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15
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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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16
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Evaluating the potential bioactivity of a novel compound ER1626. PLoS One 2014; 9:e86509. [PMID: 24475135 PMCID: PMC3903524 DOI: 10.1371/journal.pone.0086509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 12/10/2013] [Indexed: 12/21/2022] Open
Abstract
Background ER1626, a novel compound, is a derivate of indeno-isoquinoline ketone. This study was designed to evaluate the biological activity and potential anti-tumor mechanism of ER1626. Method MTT assay, scratch assay and flow cytometry were used to determine cell proliferation, cell migration and cell cycle distribution as well as cell apoptosis on human breast cancer MCF-7 cells and endometrial cancer Ishikawa cells. We also explored the antiangiogenic effect of ER1626 on HUVEC cells and chicken embryos. The expression of estrogen receptor protein was investigated with western-blot analysis. Results ER1626 down-regulated the expression of estrogen receptor α protein and up-regulated β protein in MCF-7 and Ishikawa cells. The value of IC50 of ER1626 on MCF-7 and Ishikawa cells were respectively 8.52 and 3.08 µmol/L. Meanwhile, ER1626 decreased VEGF secretion of MCF-7 and Ishikawa cells, disturbed the formation of VEGF-stimulated tubular structure in HUVEC cells, and inhibited the angiogenesis on the chicken chorioallantoic membrane. Scratch assay revealed that ER1626 suppressed the migration of MCF-7, Ishikawa and HUVEC cells. In addition to induction tumor cell apoptosis, ER1626 arrested cell cycle in G1/G0 phase in MCF-7 cells and G2/M phase in Ishikawa cells. Conclusion In conclusion, our results demonstrated that ER1626 has favorable bioactivities to be a potential candidate against breast cancer and angiogenesis.
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do Carmo A, Balça-Silva J, Matias D, Lopes MC. PKC signaling in glioblastoma. Cancer Biol Ther 2013; 14:287-94. [PMID: 23358475 PMCID: PMC3667867 DOI: 10.4161/cbt.23615] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 01/11/2023] Open
Abstract
Glioblastoma Multiforme (GBM) is the most aggressive brain tumor characterized by intratumoral heterogeneity at cytopathological, genomic and transcriptional levels. Despite the efforts to develop new therapeutic strategies the median survival of GBM patients is 12-14 months. Results from large-scale gene expression profile studies confirmed that the genetic alterations in GBM affect pathways controlling cell cycle progression, cellular proliferation and survival and invasion ability, which may explain the difficulty to treat GBM patients. One of the signaling pathways that contribute to the aggressive behavior of glioma cells is the protein kinase C (PKC) pathway. PKC is a family of serine/threonine-specific protein kinases organized into three groups according the activating domains. Due to the variability of actions controlled by PKC isoforms, its contribution to the development of GBM is poorly understood. This review intends to highlight the contribution of PKC isoforms to proliferation, survival and invasive ability of glioma cells.
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Affiliation(s)
- Anália do Carmo
- Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
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18
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Suzuki M, Iio Y, Saito N, Fujimoto T. Protein kinase Cη is targeted to lipid droplets. Histochem Cell Biol 2013; 139:505-11. [PMID: 23436195 DOI: 10.1007/s00418-013-1083-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 12/11/2022]
Abstract
Protein kinase C (PKC) is a family of kinases that regulate numerous cellular functions. They are classified into three subfamilies, i.e., conventional PKCs, novel PKCs, and atypical PKCs, that have different domain structures. Generally, PKCs exist as a soluble protein in the cytosol in resting cells and they are recruited to target membranes upon stimulation. In the present study, we found that PKCη tagged with EGFP distributed in lipid droplets (LD) and induced a significant reduction in LD size. Two other novel PKCs, PKCδ and PKCε, also showed some concentration around LDs, but it was less distinct and less frequent than that of PKCη. Conventional and atypical PKCs (α, βII, γ, and ζ) did not show any preferential distribution around LDs. 1,2-Diacylglycerol, which can activate novel PKCs without an increase of Ca(2+) concentration, is the immediate precursor of triacylglycerol and exists in LDs. The present results suggest that PKCη modifies lipid metabolism by phosphorylating unidentified targets in LDs.
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Affiliation(s)
- Michitaka Suzuki
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, 466-8550, Japan
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19
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Black AR, Black JD. Protein kinase C signaling and cell cycle regulation. Front Immunol 2013; 3:423. [PMID: 23335926 PMCID: PMC3547298 DOI: 10.3389/fimmu.2012.00423] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 12/21/2012] [Indexed: 12/20/2022] Open
Abstract
A link between T cell proliferation and the protein kinase C (PKC) family of serine/threonine kinases has been recognized for about 30 years. However, despite the wealth of information on PKC-mediated control of, T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. The outcome of PKC activation is highly context-dependent, with the precise cell cycle target(s) and overall effects determined by the specific isozyme involved, the timing of PKC activation, the cell type, and the signaling environment. Although PKCs can regulate all stages of the cell cycle, they appear to predominantly affect G0/G1 and G2. PKCs can modulate multiple cell cycle regulatory molecules, including cyclins, cyclin-dependent kinases (cdks), cdk inhibitors and cdc25 phosphatases; however, evidence points to Cip/Kip cdk inhibitors and D-type cyclins as key mediators of PKC-regulated cell cycle-specific effects. Several PKC isozymes can target Cip/Kip proteins to control G0/G1 → S and/or G2 → M transit, while effects on D-type cyclins regulate entry into and progression through G1. Analysis of PKC signaling in T cells has largely focused on its roles in T cell activation; thus, observed cell cycle effects are mainly positive. A prominent role is emerging for PKCθ, with non-redundant functions of other isozymes also described. Additional evidence points to PKCδ as a negative regulator of the cell cycle in these cells. As in other cell types, context-dependent effects of individual isozymes have been noted in T cells, and Cip/Kip cdk inhibitors and D-type cyclins appear to be major PKC targets. Future studies are anticipated to take advantage of the similarities between these various systems to enhance understanding of PKC-mediated cell cycle regulation in T cells.
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Affiliation(s)
- Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center Omaha, NE, USA
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20
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Pal D, Outram SP, Basu A. Novel regulation of protein kinase C-η. Biochem Biophys Res Commun 2012; 425:836-41. [PMID: 22892130 DOI: 10.1016/j.bbrc.2012.07.163] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
Protein kinase C (PKC) is the receptor for tumor promoting phorbol esters, which are potent activators of conventional and novel PKCs, but persistent treatment with phorbol esters leads to downregulation of these PKCs. However, PKCη, a novel PKC isozyme, resists downregulation by tumor-promoting phorbol esters, but little is known about how PKCη level is regulated. Phosphorylation and dephosphorylation play an important role in regulating activity and stability of PKCs. In the present study, we have investigated the molecular mechanism of PKCη regulation. Several PKC activators, including phorbol 12,13-dibutyrate, 12-O-tetradecanoylphorbol-13-acetate and indolactam V caused upregulation of PKCη, whereas the general PKC inhibitor Gö 6983, but not the conventional PKC inhibitor Gö 6976 led to the downregulation of PKCη. Upregulation of PKCη was associated with an increase in phosphorylation of PKCη. Silencing of phosphoinositide-dependent kinase-1, which phosphorylates PKCη at the activation loop, failed to prevent PKC activator-induced upregulation of PKCη. Knockdown of PKCε but not PKCα inhibited PKC activator-induced upregulation of PKCη. Thus, our results suggest that the regulation of PKCη is unique and PKCε is required for the PKC activator-induced upregulation of PKCη.
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Affiliation(s)
- Deepanwita Pal
- Department of Molecular Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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21
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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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22
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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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25
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Goto Y, Hishida A, Matsuo K, Tajima K, Morita E, Naito M, Wakai K, Hamajima N. PRKCH gene polymorphism is associated with the risk of severe gastric atrophy. Gastric Cancer 2010; 13:90-4. [PMID: 20602195 DOI: 10.1007/s10120-009-0542-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 12/25/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND Individuals infected with Helicobacter pylori do not necessarily develop gastric atrophy (GA) and gastric cancer (GC). Several factors, including genetic polymorphism, can regulate the development of GA and GC. A G/A single nucleotide polymorphism (rs3783799) of the PRKCH gene, which encodes the eta isozyme of protein kinase C (PKCeta), has been reported to be a tag single nucleotide polymorphism (SNP) of the PRKCH gene linked to a functional 1425G/A SNP in exon 9 (rs2230500). To elucidate its applicability in the development of GA and GC, this study aimed to investigate the associations of the PRKCH polymorphism with the risks of GA and GC. METHODS The subjects consisted of 583 patients (cases) from first-visit outpatients at Aichi Cancer Center Hospital, aged 27 to 80 years, who were diagnosed as having GC from 2001 to 2005, and 1742 controls, frequency-matched for age and sex. Anti-H. pylori IgG antibodies and pepsinogens (PGs) in serum were measured for 1638 controls. RESULTS Of the 1638 controls, 57.3% were seropositive and 33.0% had GA (PG1 < or = 70 ng/dl and PG1/PG2 < or = 3). When compared to the seronegative controls without GA, the AA genotype was significantly associated with severe GA (PG1 < or = 30 ng/dl and PG1/PG2 < or = 2); odds ratio (OR), 2.37 (95% confidence interval, 1.11-5.05) relative to the GG genotype. The genotype was not associated with the risk of GC. CONCLUSION This was the first study to examine the associations of the PRKCH polymorphism with GA and GC, and suggested that the AA genotype, relative to the G/G genotype, may be a higher risk genotype for severe GA.
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Affiliation(s)
- Yasuyuki Goto
- Department of Preventive Medicine / Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, 466-8550, Japan
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26
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Gustafsson N, Zhao C, Gustafsson JÅ, Dahlman-Wright K. RBCK1 Drives Breast Cancer Cell Proliferation by Promoting Transcription of Estrogen Receptor α and Cyclin B1. Cancer Res 2010; 70:1265-74. [DOI: 10.1158/0008-5472.can-09-2674] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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27
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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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Baskar R, Hande MP. A comparative study of protein kinase C activation in gamma-irradiated proliferating and confluent human lung fibroblast cells. JOURNAL OF RADIATION RESEARCH 2009; 50:415-423. [PMID: 19602851 DOI: 10.1269/jrr.08125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposure to low doses of radiation has been recently proven to be much more mutagenic and carcinogenic than previously thought. Since radiation sensitivity varies with different phases of cell cycle, we have investigated the activation of protein kinase C (PKC) after low doses (0.10-1 Gy) of gamma-irradiation on proliferating (log) and non-proliferating (confluent/plateau) human normal lung fibroblast (MRC-5) cells. PKC isoforms have been shown to play key roles in the regulation of proliferation, differentiation, migration and survival. In this study, we have examined the activation of phosphorylated forms of PKC isoforms (PKC-betaII, PKC-alpha/beta, PKC-theta) and non-phosphorylated PKC-alpha in an attempt to understand its kinases in total and subcellular (cytosolic and nuclear) fractions. Cytosolic fraction of the log phase cells showed an increase in activity of PKC-betaII, PKC-alpha/beta and PKC-theta with the radiation dose. However, in the nuclear fraction, PKC-betaII and PKC-theta showed higher activity than the PKC-alpha/beta. In the plateau phase cells of the cytosolic fraction, PKC-betaII showed higher activity than the PKC-alpha/beta and PKC-theta isoforms. Furthermore, in the nuclear fraction PKC-betaII and PKC-alpha/beta isoforms showed higher activity than the PKC-theta. In total cellular protein of the log phase cells, a dose dependent increase in PKC-betaII activity followed by PKC-alpha/ beta was observed and in the plateau phase of cells, PKC-betaII showed higher activity than the PKC-alpha/ beta. The specific activation of PKC isoforms in the plateau phase cells, as demonstrated for the first time, may help us to understand the radiation induced initiation of cellular transformation like hyper-proliferative phenotype, if any.
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Affiliation(s)
- Rajamanickam Baskar
- Department of Clinical Research, Singapore General Hospital, Outram Road, Singapore-169608.
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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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Ezrin-radixin-moesin family proteins are involved in parvovirus replication and spreading. J Virol 2009; 83:5854-63. [PMID: 19321616 DOI: 10.1128/jvi.00039-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The propagation of autonomous parvoviruses is strongly dependent on the phosphorylation of the major nonstructural protein NS1 by members of the protein kinase C (PKC) family. Minute virus of mice (MVM) replication is accompanied by changes in the overall phosphorylation pattern of NS1, which is newly modified at consensus PKC sites. These changes result, at least in part, from the ability of MVM to modulate the PDK-1/PKC pathway, leading to activation and redistribution of both PDK-1 and PKCeta. We show that proteins of the ezrin-radixin-moesin (ERM) family are essential for virus propagation and spreading through their functions as adaptors for PKCeta. MVM infection led to redistribution of radixin and moesin in the cell, resulting in increased colocalization of these proteins with PKCeta. Radixin was found to control the PKCeta-driven phosphorylation of NS1 and newly synthesized capsids in vivo. Conversely, radixin phosphorylation and activation were driven by the NS1/CKIIalpha complex. Altogether, these data argue for ERM proteins being both targets and modulators of parvovirus infection.
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Narita S, So A, Ettinger S, Hayashi N, Muramaki M, Fazli L, Kim Y, Gleave ME. GLI2 knockdown using an antisense oligonucleotide induces apoptosis and chemosensitizes cells to paclitaxel in androgen-independent prostate cancer. Clin Cancer Res 2008; 14:5769-77. [PMID: 18794086 DOI: 10.1158/1078-0432.ccr-07-4282] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE GLI transcription factors mediate hedgehog signaling and have been implicated in several human malignancies, including prostate cancer. The objectives of this study were to characterize GLI2 expression levels in human prostate cancer cell lines and tissues to test the effect of antisense oligonucleotide (ASO) targeting GLI2 on androgen-independent (AI) prostate cancer cell lines. EXPERIMENTAL DESIGN A tissue microarray was used to characterize differences in GLI2 expression in benign prostate hyperplasia, prostate cancer treated by neoadjuvant hormonal therapy and AI prostate cancer. The effects of GLI2 ASO on PC-3 cell growth and paclitaxel chemosensitivity were assessed in vitro and in vivo. Oligonucleotide spotted microarray analysis was used to determine alteration in GLI2 coregulated genes after ASO treatment. RESULTS The expression of GLI2 was significantly higher in prostate cancer than in benign prostate hyperplasia, decreased after androgen ablation in a time-dependent fashion, but became highly expressed again in AI prostate cancer. GLI2 ASO treatment of PC-3 cells reduced GLI2 mRNA and protein levels in a dose-dependent manner. GLI2 knockdown increased PC-3 cell apoptotic rates and significantly decreased cell growth and modulated levels of apoptosis-related genes, such as Bcl2, Bcl-xL, and clusterin. GLI2 knockdown also changed levels of several cell cycle regulators, such as cyclin D1, p27, and PKC-eta. Systematic administration of GLI2 ASO in athymic mice significantly delayed PC-3 tumor progression and enhanced paclitaxel chemosensitivity. CONCLUSIONS These findings suggest that increased levels of GLI2 correlates with AI progression and that GLI2 may be a therapeutic target in castrate-resistant prostate cancer.
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Affiliation(s)
- Shintaro Narita
- The Prostate Center, Vancouver General Hospital, British Columbia, Canada
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Basu A, Persaud SD, Sivaprasad U. Manipulation of PKC isozymes by RNA interference and inducible expression of PKC constructs. Methods Enzymol 2008; 446:141-57. [PMID: 18603120 DOI: 10.1016/s0076-6879(08)01608-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein kinase C (PKC), a family of serine/threonine kinases, plays an important role in apoptosis. Several members of the PKC family act as substrates for caspases. In addition, PKCs can also regulate caspase activation and cell death by apoptosis. The cleavage of PKCs separates the regulatory domain from the catalytic domain. The full-length, the catalytic domain, and the regulatory domain of PKC family members may have distinct function in apoptosis. Delineating the role of protein kinase C (PKC) isozymes in apoptosis has been challenging because of the lack of selective inhibitors of PKC isozymes and difficulty in generating stable cell lines expressing pro-apoptotic PKC isozymes. In this chapter, we describe the use of RNA interference (siRNA) technology and tetracycline-inducible expression of PKC isozymes to study their function in apoptosis.
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Affiliation(s)
- Alakananda Basu
- Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Breitkreutz D, Braiman-Wiksman L, Daum N, Denning MF, Tennenbaum T. Protein kinase C family: on the crossroads of cell signaling in skin and tumor epithelium. J Cancer Res Clin Oncol 2007; 133:793-808. [PMID: 17661083 DOI: 10.1007/s00432-007-0280-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Accepted: 07/03/2007] [Indexed: 12/28/2022]
Abstract
The protein kinase C (PKC) family represents a large group of phospholipid dependent enzymes catalyzing the covalent transfer of phosphate from ATP to serine and threonine residues of proteins. Phosphorylation of the substrate proteins induces a conformational change resulting in modification of their functional properties. The PKC family consists of at least ten members, divided into three subgroups: classical PKCs (alpha, betaI, betaII, gamma), novel PKCs (delta, epsilon, eta, theta), and atypical PKCs (zeta, iota/lambda). The specific cofactor requirements, tissue distribution, and cellular compartmentalization suggest differential functions and fine tuning of specific signaling cascades for each isoform. Thus, specific stimuli can lead to differential responses via isoform specific PKC signaling regulated by their expression, localization, and phosphorylation status in particular biological settings. PKC isoforms are activated by a variety of extracellular signals and, in turn, modify the activities of cellular proteins including receptors, enzymes, cytoskeletal proteins, and transcription factors. Accordingly, the PKC family plays a central role in cellular signal processing. Accumulating data suggest that various PKC isoforms participate in the regulation of cell proliferation, differentiation, survival and death. These findings have enabled identification of abnormalities in PKC isoform function, as they occur in several cancers. Specifically, the initiation of squamous cell carcinoma formation and progression to the malignant phenotype was found to be associated with distinct changes in PKC expression, activation, distribution, and phosphorylation. These studies were recently further extended to transgenic and knockout animals, which allowed a more direct analysis of individual PKC functions. Accordingly, this review is focused on the involvement of PKC in physiology and pathology of the skin.
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Affiliation(s)
- D Breitkreutz
- Division of Differentiation and Carcinogenesis (A080/A110), German Cancer Research Center (DKFZ), POB 101949, Im Neuenheimer Feld 280, 69009, Heidelberg, Germany.
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Karp G, Maissel A, Livneh E. Hormonal regulation of PKC: Estrogen up-regulates PKCη expression in estrogen-responsive breast cancer cells. Cancer Lett 2007; 246:173-81. [PMID: 16580129 DOI: 10.1016/j.canlet.2006.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 02/08/2006] [Accepted: 02/17/2006] [Indexed: 11/24/2022]
Abstract
Protein kinase C (PKC) is involved in several major signal transduction pathways that control gene expression cell growth and differentiation. The PKCeta isoform appears as a candidate regulator of mammary gland proliferation or differentiation, as its expression is up-regulated in the mammary gland in the transit from resting to the pregnant state. The purpose of this study was to examine the hormonal regulation of PKCeta. Here we show that estradiol specifically up-regulates the expression of PKCeta in the estrogen-responsive lines MCF-7 and T47D but not in the estrogen non-responsive line MDA-MB 231. Interestingly, the presence of progesterone, involved in the differentiation of the mammary gland, reduced the estrogen-induced PKCeta expression in a time-dependent manner. Thus, our studies suggest that PKCeta has an important role in signalling pathways regulating mammary gland proliferation and its development.
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Affiliation(s)
- Galia Karp
- Department of Microbiology and Immunology, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University, 84105 Beer Sheva, Israel
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35
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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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Cerda SR, Mustafi R, Little H, Cohen G, Khare S, Moore C, Majumder P, Bissonnette M. Protein kinase C delta inhibits Caco-2 cell proliferation by selective changes in cell cycle and cell death regulators. Oncogene 2006; 25:3123-38. [PMID: 16434969 DOI: 10.1038/sj.onc.1209360] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PKC-delta is a serine/threonine kinase that mediates diverse signal transduction pathways. We previously demonstrated that overexpression of PKC-delta slowed the G1 progression of Caco-2 colon cancer cells, accelerated apoptosis, and induced cellular differentiation. In this study, we further characterized the PKC-delta dependent signaling pathways involved in these tumor suppressor actions in Caco-2 cells overexpressing PKC-delta using a Zn2+ inducible expression vector. Consistent with a G1 arrest, increased expression of PKC-delta caused rapid and significant downregulation of cyclin D1 and cyclin E proteins (50% decreases, P<0.05), while mRNA levels remained unchanged. The PKC agonist, phorbol 12-myristate 13-acetate (TPA, 100 nM, 4 h), induced two-fold higher protein and mRNA levels of p21(Waf1), a cyclin-dependent kinase (cdk) inhibitor in PKC-delta transfectants compared with empty vector (EV) transfected cells, whereas the PKC-delta specific inhibitor rottlerin (3 microM) or knockdown of this isoenzyme with specific siRNA oligonucleotides blocked p21(Waf1) expression. Concomitantly, compared to EV control cells, PKC-delta upregulation decreased cyclin D1 and cyclin E proteins co-immunoprecipitating with cdk6 and cdk2, respectively. In addition, overexpression of PKC-delta increased binding of cdk inhibitor p27(Kip1) to cdk4. These alterations in cyclin-cdks and their inhibitors are predicted to decrease G1 cyclin kinase activity. As an independent confirmation of the direct role PKC-delta plays in cell growth and cell cycle regulation, we knocked down PKC-delta using specific siRNA oligonucleotides. PKC-delta specific siRNA oligonucleotides, but not irrelevant control oligonucleotides, inhibited PKC-delta protein by more than 80% in Caco-2 cells. Moreover, PKC-delta knockdown enhanced cell proliferation ( approximately 1.4-2-fold, P<0.05) and concomitantly increased cyclin D1 and cyclin E expression ( approximately 1.7-fold, P<0.05). This was a specific effect, as nontargeted PKC-zeta was not changed by PKC-delta siRNA oligonucleotides. Consistent with accelerated apoptosis in PKC-delta transfectants, compared to EV cells, PKC-delta upregulation increased proapoptotic regulator Bax two-fold at mRNA and protein levels, while antiapoptotic Bcl-2 protein was decreased by 50% at a post-transcriptional level. PKC-delta specific siRNA oligonucleotides inhibited Bax protein expression by more than 50%, indicating that PKC-delta regulates apoptosis through Bax. Taken together, these results elucidate two critical mechanisms regulated by PKC-delta that inhibit cell cycle progression and enhance apoptosis in colon cancer cells. We postulate these antiproliferative pathways mediate an important tumor suppressor function for PKC-delta in colonic carcinogenesis.
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Affiliation(s)
- S R Cerda
- Department of Medicine, Division of Gastroenterology, University of Chicago, Chicago, IL 60637, USA.
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Maioli E, Vittoria F. Can the apparent conflicting roles of PKC delta on cell proliferation and survival be reconciled? Breast Cancer Res Treat 2005; 95:97-8. [PMID: 16319994 DOI: 10.1007/s10549-005-9029-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Accepted: 07/07/2005] [Indexed: 11/29/2022]
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38
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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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Devidze N, Pfaff DW, Kow LM. Potentiation of genomic actions of estrogen by membrane actions in mcf-7 cells and the involvement of protein kinase C activation. Endocrine 2005; 27:253-8. [PMID: 16230781 DOI: 10.1385/endo:27:3:253] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 06/02/2005] [Accepted: 06/10/2005] [Indexed: 02/05/2023]
Abstract
It is now well established that estrogens (E) have at least two kinds of actions: genomic and nongenomic. But the relationship between these actions has hardly been explored. In this study we investigated this relationship in MCF-7 cells, a human breast cancer cell line, and explored the possible involvement of protein kinase C (PKC) signaling pathways. For this purpose a two-pulse paradigm was used: cells were treated with 17beta-estradiol (E), E conjugated with bovine serum albumin (E-BSA or fE'), or other test agents in the first pulse and with E in the second pulse following a 4-h interval. An E-BSA+E paradigm was used to show that replacement of E with the membrane-impermeable E-BSA in the first pulse could potentiate genomic actions of E, in the second pulse. To investigate involvement of signaling pathways, two PKC activators, phorbol 12,13-diacetate (PDAc) or phorbol 12-myristate 13-acetate (PMA), and inhibitors (chelerythrine chloride and H7-dihydrochloride) were used to replace E or E-BSA in the first pulse. PDAc was as effective as E or E-BSA in potentiating the genomic action of E in the second pulse, while PMA was almost without an effect. Conversely, the potentiating effects of E-BSA and PDAc were blocked by chelerythrine chloride but, interestingly, not by H7. The exact reason underlying these differences is not known. In summary, in MCF-7 cells a membrane action of E can potentiate a later genomic action and involves PKC signaling.
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Affiliation(s)
- Nino Devidze
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, NY 10021, USA.
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40
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Nakagawa M, Oliva JL, Kothapalli D, Fournier A, Assoian RK, Kazanietz MG. Phorbol ester-induced G1 phase arrest selectively mediated by protein kinase Cdelta-dependent induction of p21. J Biol Chem 2005; 280:33926-34. [PMID: 16055435 DOI: 10.1074/jbc.m505748200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Although protein kinase C (PKC) has been widely implicated in the positive and negative control of proliferation, the underlying cell cycle mechanisms regulated by individual PKC isozymes are only partially understood. In this report, we show that PKCdelta mediates phorbol ester-induced G1 arrest in lung adenocarcinoma cells and establish an essential role for this novel PKC in controlling the expression of the cell cycle inhibitor p21. Activation of PKC with phorbol 12-myristate 13-acetate (PMA) in early G1 phase impaired progression of lung adenocarcinoma cells into S phase, an effect that was completely abolished by specific depletion of PKCdelta, but not PKCalpha. Although the PKC effect was unrelated to the inhibition of cyclin D1 expression, PKC activation significantly up-regulated p21 and down-regulated Rb hyperphosphorylation and cyclin A expression. Elevations in p21 mRNA and protein by PMA were mediated by PKCdelta but not PKCalpha. Studies using luciferase reporters also revealed an essential role for PKCdelta in the PMA-induced inhibition of Rb-dependent cyclin A promoter activity. Finally, we showed that the cell cycle inhibitory effect of PKCdelta is greatly attenuated by RNA interference-mediated knock-down of p21. Our results identify a novel link between PKCdelta and G1 arrest via p21 up-regulation and highlight the complexities in the downstream effectors of PKC isozymes in the context of cell cycle progression and proliferation.
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Affiliation(s)
- Motonori Nakagawa
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA
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Yokoyama G, Fujii T, Tayama K, Yamana H, Kuwano M, Shirouzu K. PKCdelta and MAPK mediate G(1) arrest induced by PMA in SKBR-3 breast cancer cells. Biochem Biophys Res Commun 2005; 327:720-6. [PMID: 15649406 DOI: 10.1016/j.bbrc.2004.12.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Indexed: 10/26/2022]
Abstract
The effects of activating endogenous protein kinase C (PKC) on cell proliferation and the cell cycle were investigated by treating the breast cancer cell line SKBR-3 with phorbol 12-myristate 13 acetate (PMA). This inhibited cell growth in a concentration-dependent manner, causing a marked arrest of cells in G(1). Pre-treatment with GF109203X completely blocked the antiproliferative effect of PMA, and pre-treatment with the PKCdelta inhibitor rottlerin partially blocked it. Infecting SKBR-3 cells with an adenovirus vector containing wild-type PKCdelta, WTPKCdeltaAdV, had similar effects on PMA. Infecting the cells with a dominant-negative PKCdeltaAdV construct blocked the growth inhibition induced by PMA. Downstream of PKC, PMA treatment inhibited extracellular signal-regulated kinase mitogen-activated protein kinase phosphorylation, up-regulated c-jun NH(2)-terminal kinase phosphorylation, and inhibited retinoblastoma (Rb) phosphorylation. These results strongly implicated PKC (mainly PKCdelta) in the G(1) arrest induced by PMA and suggested PKC as a target for breast cancer treatment.
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Affiliation(s)
- Goro Yokoyama
- Department of Surgery, Kurume University School of Medicine, 67 Asahimachi, Fukuoka 830-0011, Japan
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Aeder SE, Martin PM, Soh JW, Hussaini IM. PKC-eta mediates glioblastoma cell proliferation through the Akt and mTOR signaling pathways. Oncogene 2005; 23:9062-9. [PMID: 15489897 DOI: 10.1038/sj.onc.1208093] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We previously demonstrated that protein kinase C-eta (PKC-eta) mediates a phorbol 12-myristate-13-acetate (PMA)-induced proliferative response in human glioblastoma (GBM) cells. In this report, we show that PMA-stimulated activation of PKC-eta in U-251 GBM cells resulted in activation of both Akt and the mammalian target of rapamycin (mTOR) signaling pathways and an increase in cell proliferation. Expression of a kinase dead PKC-eta (PKC-etaKR) construct reduced the basal and PMA-evoked proliferation of PKC-eta-expressing U-251 GBM cells, as well as abrogated the PMA-induced activation of Akt, mTOR, and the mTOR targets 4E-BP1 and STAT-3. Treatment of cells with the PI-3 kinase inhibitor LY294002 (10 muM) or the mTOR inhibitor rapamycin (10 nM) also reduced PMA-induced proliferation and cell-cycle progression. Expression of a constitutively active PKC-eta (PKC-etaDeltaNPS) construct in a GBM cell line with no endogenous PKC-eta (U-1242) also provided evidence that PKC-eta targets the Akt and mTOR signaling pathways. Moreover, activation of 4E-BP1 and STAT-3 in both PMA-treated U-251 and PKC-etaDeltaNPS-expressing U-1242 GBM cells was inhibited by rapamycin. However, activation of Akt, but not mTOR was inhibited by the PI-3 kinase inhibitor LY294002. This study identifies Akt and mTOR as downstream targets of PKC-eta that are involved in GBM cell proliferation.
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Affiliation(s)
- Sean E Aeder
- Department of Pathology and Neurology, University of Virginia, Charlottesville, VA 22908, USA.
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Alisi A, Spagnuolo S, Napoletano S, Spaziani A, Leoni S. Thyroid hormones regulate DNA-synthesis and cell-cycle proteins by activation of PKC? and p42/44 MAPK in chick embryo hepatocytes. J Cell Physiol 2004; 201:259-65. [PMID: 15334660 DOI: 10.1002/jcp.20060] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The molecular mechanism by which thyroid hormones exert their effects on cell growth is still unknown. In this study, we used chick embryo hepatocytes at different stages of development as a model to investigate the effect of the two thyroid hormones, T3 and T4, and of their metabolite T2, on the control of cell proliferation. We observed that T2 provokes increase of DNA-synthesis as well as T3 and T4, independently of developmental stage. We found that this stimulatory effect on the S phase is reverted by specific inhibitors of protein kinase C (PKC) and p42/44 mitogen-activated protein kinase (p42/44 MAPK), Ro 31-8220 or PD 98059. Furthermore, the treatment with thyroid hormones induces the activation of PKCalpha and p42/44 MAPK, suggesting their role as possible downstream mediators of cell response mediated by thyroid hormones. The increase of DNA-synthesis is well correlated with the increased levels of cyclin D1 and cdk4 that control the G1 phase, and also with the activities of cell-cycle proteins involved in the G1 to S phase progression, such as cyclin E/A-cdk2 complexes. Interestingly, the activity of cyclin-cdk2 complexes is strongly repressed in the presence of PKC and p42/44 MAPK inhibitors. In conclusion, we demonstrated that the thyroid hormones could modulate different signaling pathways that are able to control cell-cycle progression, mainly during G1/S transition.
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Affiliation(s)
- A Alisi
- Department of Cellular and Developmental Biology, University La Sapienza, Roma, Italy
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Lachmann S, Rommeleare J, Nüesch JPF. Novel PKCeta is required to activate replicative functions of the major nonstructural protein NS1 of minute virus of mice. J Virol 2003; 77:8048-60. [PMID: 12829844 PMCID: PMC161934 DOI: 10.1128/jvi.77.14.8048-8060.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The multifunctional protein NS1 of minute virus of mice (MVMp) is posttranslationally modified and at least in part regulated by phosphorylation. The atypical lambda isoform of protein kinase C (PKClambda) phosphorylates residues T435 and S473 in vitro and in vivo, leading directly to an activation of NS1 helicase function, but it is insufficient to activate NS1 for rolling circle replication. The present study identifies an additional cellular protein kinase phosphorylating and regulating NS1 activities. We show in vitro that the recombinant novel PKCeta phosphorylates NS1 and in consequence is able to activate the viral polypeptide in concert with PKClambda for rolling circle replication. Moreover, this role of PKCeta was confirmed in vivo. We thereby created stably transfected A9 mouse fibroblasts, a typical MVMp-permissive host cell line with Flag-tagged constitutively active or inactive PKCeta mutants, in order to alter the activity of the NS1 regulating kinase. Indeed, tryptic phosphopeptide analyses of metabolically (32)P-labeled NS1 expressed in the presence of a dominant-negative mutant, PKCetaDN, showed a lack of distinct NS1 phosphorylation events. This correlates with impaired synthesis of viral DNA replication intermediates, as detected by Southern blotting at the level of the whole cell population and by BrdU incorporation at the single-cell level. Remarkably, MVM infection triggers an accumulation of endogenous PKCeta in the nuclear periphery, suggesting that besides being a target for PKCeta, parvovirus infections may also affect the regulation of this NS1 regulating kinase. Altogether, our results underline the tight interconnection between PKC-mediated signaling and the parvoviral life cycle.
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Affiliation(s)
- Sylvie Lachmann
- Applied Tumour Virology Program, Department F010 and Institut National de la Santé et de la Recherche Médicale U375, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
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Yamamoto D, Sonoda Y, Hasegawa M, Funakoshi-Tago M, Aizu-Yokota E, Kasahara T. FAK overexpression upregulates cyclin D3 and enhances cell proliferation via the PKC and PI3-kinase-Akt pathways. Cell Signal 2003; 15:575-83. [PMID: 12681445 DOI: 10.1016/s0898-6568(02)00142-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We previously demonstrated that FAK-transfected HL-60 (HL-60/FAK) cells exhibit anti-apoptotic capacity. Here, we report that HL-60/FAK cells proliferate much faster than vector-transfected control (HL-60/Vect) cells with a 1.5-fold faster doubling time. This observation prompted us to investigate the mechanism of how HL-60/FAK cells augment cell proliferation. Since a protein kinase C (PKC) inhibitor, chelerythrine, or a PI3-kinase inhibitor, LY294002, suppressed cell proliferation effectively, both PKC and PI-3-kinase pathways are presumed to be involved in the cell proliferation. Among cyclins and CDKs, cyclin D3 expression was particularly prominent in the HL-60/FAK cells. Among PKC family, particularly PKCalpha, beta and eta isoforms were activated and directly associated with FAK in HL-60/FAK cells. We assumed that FAK activates PKC and PI3-kinase-Akt pathway, which resulted in marked induction of cyclin D3 expression and CDK activity.
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Affiliation(s)
- Daisuke Yamamoto
- Department of Biochemistry, Kyoritsu College of Pharmacy, Shibakoen 1-5-30, Minato-ku, Tokyo 105-8512, Japan
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Shtutman M, Hershko T, Maissel A, Fima E, Livneh E. PKCeta associates with cyclin E/Cdk2 complex in serum-starved MCF-7 and NIH-3T3 cells. Exp Cell Res 2003; 286:22-9. [PMID: 12729791 DOI: 10.1016/s0014-4827(03)00087-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Protein kinase C (PKC) encodes a family of enzymes implicated in cellular differentiation, growth control, and tumor promotion. However, very little is known with respect to the molecular mechanisms that link protein kinase C to cell cycle control. Here we report that PKCeta associates with the cyclin E/Cdk2 complex. This is shown for the ectopically overexpressed PKCeta in NIH-3T3 cells, the inducibly expressed PKCeta in MCF-7 cells (under control of the tetracycline-responsive promoter), and the endogenously expressed PKCeta in mouse mammary epithelial HC11 cells. Subcellular cell fractionation experiments revealed that the complex with cyclin E is formed mostly in the nuclear fractions, although in these cells PKCeta is predominantly expressed in the cytosolic fractions. The complex of PKCeta and cyclin E was studied at various phases of the cell cycle, in serum-starved quiescent cells and in cells stimulated with serum to reenter the cell cycle. Interestingly, the interaction between PKCeta and cyclin E was most prominent in serum-starved cells and was disintegrated when cells entered the cells cycle. Immunofluorescence staining demonstrated that in serum-starved cells PKCeta is concentrated at the perinuclear zone, which is also the site of its colocalization with cyclin E. Colocalization of PKCeta and cyclin E in the perinuclear region was observed in serum-starved cells, and less in proliferating cells. These experiments suggest that the interaction between PKCeta and cyclin E is carefully regulated, and is correlated with the inactivated form of the cyclin E/Cdk2 complex. Thus, our studies support an important link between PKC and cell cycle control.
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Affiliation(s)
- Marat Shtutman
- 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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