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Black AR, Black JD. The complexities of PKCα signaling in cancer. Adv Biol Regul 2021; 80:100769. [PMID: 33307285 PMCID: PMC8141086 DOI: 10.1016/j.jbior.2020.100769] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/15/2020] [Indexed: 01/06/2023]
Abstract
Protein kinase C α (PKCα) is a ubiquitously expressed member of the PKC family of serine/threonine kinases with diverse functions in normal and neoplastic cells. Early studies identified anti-proliferative and differentiation-inducing functions for PKCα in some normal tissues (e.g., regenerating epithelia) and pro-proliferative effects in others (e.g., cells of the hematopoietic system, smooth muscle cells). Additional well documented roles of PKCα signaling in normal cells include regulation of the cytoskeleton, cell adhesion, and cell migration, and PKCα can function as a survival factor in many contexts. While a majority of tumors lose expression of PKCα, others display aberrant overexpression of the enzyme. Cancer-related mutations in PKCα are uncommon, but rare examples of driver mutations have been detected in certain cancer types (e. g., choroid gliomas). Here we review the role of PKCα in various cancers, describe mechanisms by which PKCα affects cancer-related cell functions, and discuss how the diverse functions of PKCα contribute to tumor suppressive and tumor promoting activities of the enzyme. We end the discussion by addressing mutations and expression of PKCα in tumors and the clinical relevance of these findings.
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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, 68198, USA
| | - Jennifer D Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Massenavette L, Paul W, Corriveau S, Pasquier JC, Rousseau É. Phorbol 12,13-dibutyrate-induced protein kinase C activation triggers sustained contracture in human myometrium in vitro. Am J Obstet Gynecol 2017; 217:358.e1-358.e9. [PMID: 28479286 DOI: 10.1016/j.ajog.2017.04.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/28/2017] [Accepted: 04/25/2017] [Indexed: 10/24/2022]
Abstract
BACKGROUND Although physiologic transition from rhythmic contractions to uterine retraction postpartum remains a poorly understood process, it has been shown that the latter is essential in the prevention of hemorrhage and its negative consequences. OBJECTIVE To investigate the transition from oscillatory contractions to tonic contracture in human myometrium after delivery, a mechanism purported to facilitate postpartum hemostasis. Protein kinase C (PKC) plays a key regulatory role in human uterine contractions because it can prevent dephosphorylation of regulatory proteins and sensitize the contractile machinery to low Ca2+. Thus, activation of PKC by phorbol 12,13-dibutyrate (PDBu) may act as a strong uterotonic agent. STUDY DESIGN Uterine biopsies were obtained from consenting women undergoing elective caesarian delivery at term without labor (N = 19). Isometric tension measurements were performed on uterine strips (n = 114). The amplitudes and area under the curve of phasic contractions and tonic responses were measured and compared. A total of 1 μM PDBu was added to the isolated organ baths, and maximal tension of the uterine contracture was determined in the absence and presence of either 1 μM of staurosporine, 100 nM nifedipine, or 10 μM cyclopiazonic acid to assess the role of PKC and calcium sensitivity on uterine contractility. RESULTS On the addition of PDBu on either basal or oxytocin-induced activity, consistent contractures were obtained concomitant with complete inhibition of phasic contractions. After a 30-minute incubation period, the mean amplitude of the PDBu-induced tone represented 65.3% of the amplitude of spontaneous contraction. Staurosporine, a protein kinase inhibitor, induced a 91.9% inhibition of PDBu contractures, a process not affected by nifedipine or cyclopiazonic acid, thus indicating that this mechanism is largely Ca2+ independent. CONCLUSION Pharmacologic activation of PKC leads to a significant contracture of the myometrium. Together, these data suggest that the up-regulation of PKC plays a physiologic role in the modulation of uterine contracture after delivery. A switch from phasic to strong tonic contractions potentially may facilitate postpartum hemostasis.
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Effects of mitochondrial ATP-sensitive K(+) channel on protein kinase C pathway and airway smooth muscle cell proliferation in asthma. ACTA ACUST UNITED AC 2012; 32:480-484. [PMID: 22886957 DOI: 10.1007/s11596-012-0083-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Indexed: 10/28/2022]
Abstract
The effects of ATP-sensitive mitochondrial K(+) channel (mitoK(ATP)) on mitochondrial membrane potential (Δψm), cell proliferation and protein kinase C alpha (PKCα) expression in airway smooth muscle cells (ASMCs) were investigated. Thirty-six Sprague-Dawley (SD) rats were immunized with saline (controls) or ovalbumin (OVA) with alum (asthma models). ASMCs were cultured from the lung of control and asthma rats. ASMCs were treated with diazoxide (the potent activator of mitoK(ATP)) or 5-hydroxydencanote (5-HD, the inhibitor of mitoK(ATP)). Rhodamine-123 (R-123) was used to detect Δψm. The expression of PKCα protein was examined by using Western blotting, while PKCα mRNA expression was detected by using real-time PCR. The proliferation of ASMCs was measured by MTT assay and cell cycle analysis. In diazoxide-treated normal ASMCs, the R-123 fluorescence intensity, protein and mRNA levels of PKCα, MTT A values and percentage of cells in S phase were markedly increased as compared with untreated controls. The ratio of G(0)/G(1) cells was decreased (P<0.05) in diazoxide-treated ASMCs from normal rats. However, there were no significant differences between the ASMCs from healthy rats treated with 5-HD and the normal control group. In untreated and diazoxide-treated ASMCs of asthmatic rats, the R-123 fluorescence intensity, protein and mRNA levels of PKCα, MTT A values and the percentage of cells in S phase were increased in comparison to the normal control group. Furthermore, in comparison to ASMCs from asthmatic rats, these values were considerably increased in asthmatic group treated with diazoxide (P<0.05). After exposure to 5-HD for 24 h, these values were decreased as compared with asthma control group (P<0.05). In ASMCs of asthma, the signal transduction pathway of PKCα may be involved in cell proliferation, which is induced by the opening of mitoK(ATP) and the depolarization of Δψm.
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Tanfin Z, Breuiller-Fouché M. The endothelin axis in uterine leiomyomas: new insights. Biol Reprod 2012; 87:5, 1-10. [PMID: 22553222 DOI: 10.1095/biolreprod.111.097725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The endothelin axis, comprising endothelin-1 (ET-1) and its receptors (ETA and ETB), is involved in the pathophysiology of different human tumors. Here we review conventional approaches and gene expression profiling indicating the association of ET-1 and its cognate receptors with human and rat leiomyomas, the most common benign tumors of myometrium. Specifically, ET-1/ETA interactions affect human and rat leiomyoma cell proliferation through protein kinase C and mitogen-activated protein kinase-dependent signaling pathways. Recent experiments demonstrate that the ET-1 axis exerts a potent antiapoptotic effect involving sphingolipid metabolism and prostaglandin-endoperoxide synthase 2/prostaglandin system in the rat Eker leiomyoma tumor-derived ELT3 cell line. Evidence supports that steroid hormones, growth factors, and extracellular matrix are key regulators of the leiomyoma growth. Interestingly, the ET-1 axis is under steroid hormones and can cooperate with these growth factors. Therefore, ET-1 alone or in association with these factors could contribute to the complex regulation of uterine tumor growth, such as proliferation, survival, and extracellular matrix production. This review summarizes current knowledge and emerging data on ET-1 in uterine leiomyoma pathology.
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Affiliation(s)
- Zahra Tanfin
- Université Paris-Sud-11, Centre National de la Recherche Scientifique (CNRS), Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Equipe Signalisation Moléculaire et Cellulaire utérine, Orsay, France
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Breuiller-Fouché M, Dubois O, Sediki M, Garcia-Verdugo I, Palaniyar N, Tanfin Z, Chissey A, Cabrol D, Charpigny G, Mehats C. Secreted surfactant protein A from fetal membranes induces stress fibers in cultured human myometrial cells. Am J Physiol Endocrinol Metab 2010; 298:E1188-97. [PMID: 20233942 DOI: 10.1152/ajpendo.00746.2009] [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] [Indexed: 11/22/2022]
Abstract
In the present study, we investigated the ability of human fetal membranes (amnion and choriodecidua) to regulate human maternal uterine cell functions through the secretion of surfactant protein (SP)-A and SP-D at the end of pregnancy. We detected the expression of both SP-A (SP-A1 and SP-A2) and SP-D by quantitative reverse transcription polymerase chain reaction. Immunohistochemistry revealed that human fetal membranes expressed both SP-A and SP-D. By Western blot analysis, we demonstrated that SP-A protein expression was predominant in choriodecidua, whereas the amnion predominantly expressed SP-D. Only the secretion of SP-A was evidenced in the culture supernatants of amnion and choriodecidua explants by immunodot blot and confirmed by Western blot. Exogenous human purified SP-A induced stress fiber formation in cultured human myometrial cells via a pathway involving Rho-kinase. Conditioned medium from choriodecidua and amnion explants mimicked the SP-A effect. Treatment of myometrial cells with SP-A-depleted conditioned medium from choriodecidua or amnion explants failed to change the actin dynamic. These data indicate that SP-A released by human fetal membranes is able to exert a paracrine regulation of F-actin filament organization in myometrial cells.
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Affiliation(s)
- Michelle Breuiller-Fouché
- Institut National de la Santé et de la Recherche Médicale (INSERM), U767, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, Paris V, Paris, France.
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Nierth-Simpson EN, Martin MM, Chiang TC, Melnik LI, Rhodes LV, Muir SE, Burow ME, McLachlan JA. Human uterine smooth muscle and leiomyoma cells differ in their rapid 17beta-estradiol signaling: implications for proliferation. Endocrinology 2009; 150:2436-45. [PMID: 19179429 PMCID: PMC2671893 DOI: 10.1210/en.2008-0224] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Uterine leiomyomas, benign uterine smooth muscle tumors that affect 30% of reproductive-aged women, are a significant health concern. The initiation event for these tumors is unclear, but 17beta-estradiol (E2) is an established promoter of leiomyoma growth. E2 not only alters transcription of E2-regulated genes but also can rapidly activate signaling pathways. The aim of our study is to investigate the role of rapid E2-activated cytoplasmic signaling events in the promotion of leiomyomas. Western blot analysis revealed that E2 rapidly increases levels of phosphorylated protein kinase C alpha (PKC alpha) in both immortalized uterine smooth muscle (UtSM) and leiomyoma (UtLM) cell lines, but increases levels of phosphorylated ERK1/2 only in UtLM cells. Our studies demonstrate a paradoxical effect of molecular and pharmacological inhibition of PKC alpha on ERK1/2 activation and cellular proliferation in UtLM and UtSM cells. PKC alpha inhibition decreases levels of phosphorylated ERK1/2 and proliferation in UtLM cells but raises these levels in UtSM cells. cAMP-PKA signaling is rapidly activated only in UtSM cells with E2 and inhibits ERK1/2 activation and proliferation. We therefore propose a model whereby E2's rapid activation of PKC alpha and cAMP-PKA signaling plays a central role in the maintenance of a low proliferative index in normal uterine smooth muscle via its inhibition of the MAPK cascade and these pathways are altered in leiomyomas to promote MAPK activation and proliferation. These studies demonstrate that rapid E2-signaling pathways contribute to the promotion of leiomyomas.
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Fomin VP, Kronbergs A, Gunst S, Tang D, Simirskii V, Hoffman M, Duncan RL. Role of Protein Kinase Cα in Regulation of [Ca2+]I and Force in Human Myometrium. Reprod Sci 2008; 16:71-9. [DOI: 10.1177/1933719108324892] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Victor P. Fomin
- Department of Biological Sciences, University of Delaware, Newark, Delaware,
| | - Andris Kronbergs
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - Susan Gunst
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Dale Tang
- Center for Cardiovascular Sciences, Albany Medical College, Albany, New York
| | - Vladimir Simirskii
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - Matthew Hoffman
- Department of Obstetrics and Gynecology, Christiana Hospital, Newark, Delaware
| | - Randall L. Duncan
- Department of Biological Sciences, University of Delaware, Newark, Delaware
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Wang WL, Yeh SF, Huang EYK, Lu YL, Wang CF, Huang CYF, Lin WJ. Mitochondrial anchoring of PKCalpha by PICK1 confers resistance to etoposide-induced apoptosis. Apoptosis 2008; 12:1857-71. [PMID: 17610064 DOI: 10.1007/s10495-007-0098-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Various pathways, including regulation of functions of the Bcl-2 family, are implicated in the survival promotion by PKCalpha, however the molecular mechanisms are still obscure. We have previously demonstrated that PKCalpha is selectively anchored to mitochondria by PICK1 in fibroblasts NIH 3T3. In this study, we show that over-expression of PICK1 in leukemia REH confers resistance to etoposide-induced apoptosis, which requires an interaction with PKCalpha as the non-interacting mutant PICK1 loses the pro-survival activity. The PKCalpha selective inhibitor Gö6976 also abolishes the anti-apoptotic effect indicating a requirement for PKC activity. Disruption of PICK1/PKCalpha interactions by inhibitory peptides significantly increases cellular susceptibility to etoposide. Similar effects are also observed in HL60 cells, which exhibit an intrinsic resistance to etoposide. Molecular analysis shows that the wild type PICK1, but not the non-interacting mutant, prevents the loss of mitochondrial membrane potential with a coincident increase in phosphorylation of the anti-apoptotic Bcl-2(Ser70) and a decrease in dimerization of the pro-apoptotic Bax. PICK1 may provide the spatial proximity for phosphorylation of Bcl-2(Ser70) by PKCalpha which then leads to a higher survival. Taken together, our results suggest that PICK1 may mediate the pro-survival activity of PKCalpha by serving as a molecular link between PKCalpha and mitochondria.
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Affiliation(s)
- Wei-Li Wang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, and Department of Education and Research, Taipei City Hospital, 112, Taiwan, ROC
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Ivey ME, Osman N, Little PJ. Endothelin-1 signalling in vascular smooth muscle: pathways controlling cellular functions associated with atherosclerosis. Atherosclerosis 2008; 199:237-47. [PMID: 18436225 DOI: 10.1016/j.atherosclerosis.2008.03.006] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 03/04/2008] [Accepted: 03/10/2008] [Indexed: 12/16/2022]
Abstract
Atherosclerosis is the primary ischaemic vascular condition underlying a majority of cardiovascular disease related deaths. Endothelin-1 is a vasoactive peptide agent upregulated in atherosclerosis and in conjunction with its G protein-coupled receptors exerts diverse actions on all cells of the vasculature in particular vascular smooth muscle cells (VSMC). The effects of endothelin-1 include cell proliferation, migration and contraction, and the induction of extracellular matrix components and growth factors. VSMC as the major component of the neointima in atherosclerotic plaques accordingly play a key role in atherogenesis. In this review we examine classic and novel signalling pathways activated by endothelin-1 in VSMC (including phospholipase C, adenylate cyclase, Rho kinase, transactivation of receptor tyrosine kinases, mitogen activated protein kinase cascades and beta-arrestin) and their likely impact on the development and progression of atherosclerosis.
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Affiliation(s)
- Melanie E Ivey
- Cell Biology of Diabetes Laboratory, Baker Heart Research Institute, Melbourne, Victoria, Australia
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Effect of cigarette smoke extract on proliferation of rat pulmonary artery smooth muscle cells and the relevant roles of protein kinase C. Chin Med J (Engl) 2007. [DOI: 10.1097/00029330-200709010-00011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Ivanov V, Roomi MW, Kalinovsky T, Niedzwiecki A, Rath M. Natural nutrient mixture effectively reduces collagen matrix contraction driven by human uterine smooth muscle cells. J Obstet Gynaecol Res 2006; 32:23-31. [PMID: 16445522 DOI: 10.1111/j.1447-0756.2006.00367.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Abnormal uterine myometrial contractility causes preterm delivery, contributing to perinatal morbidity and mortality. Disturbances in hormonal regulation and inflammation-related processes have been attributed a role in the pathophysiological mechanisms of uterine contractility. We investigated the effects of natural nutrients on uterine tissue contractility in vitro. METHODS We used an in vitro model of collagen I gel contraction driven by embedded cultured human uterine smooth muscle cells (SMC). The effects of tested compounds were evaluated using their capacity to affect gel contraction (measured by reduction in gel area during 24-h incubation in serum free medium). Cellular expression of matrix metalloproteinases (MMP) was followed by gel zymography. RESULTS Collagen gel contraction driven by uterine SMC was significantly stimulated by potassium chloride, pituitary hormone oxytocin and by inflammatory cytokine alpha-tumor necrosis factor (TNF-alpha). Accelerated gel contraction was accompanied by elevated secretion of MMP-2 and MMP-9 into cell culture media. Among a variety of purified bioflavonoids and polyphenol-enriched plant extracts tested for their ability to counteract uterine SMC-dependent collagen gel contraction, the strongest effects were demonstrated by epigallocatechin gallate and green tea leaf extract, respectively. The addition of ascorbic acid and the amino acids lysine, arginine, cysteine and proline to green tea extract further increased its effectiveness. A reduction in gel contraction correlated with decreased MMP expression. CONCLUSION Based on these findings, we found that nutrients can effectively counteract uterine myometrial contraction and MMP activity in vitro, suggesting that pathophysiological mechanisms of abnormal uterine myometrial contractility can be counteracted by a combination of naturally occurring nutrients. These mechanisms might involve extracellular matrix remodeling.
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Affiliation(s)
- Vadim Ivanov
- Matthias Rath Research Institute, Santa Clara, California, USA
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Breuiller-Fouche M, Germain G. Gene and protein expression in the myometrium in pregnancy and labor. Reproduction 2006; 131:837-50. [PMID: 16672349 DOI: 10.1530/rep.1.00725] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Microarray technologies widen our comprehension of the major structural and metabolic transformations which affect the myometrium from the very beginning of pregnancy until parturition. The results are coherent with the mass of information which was accumulated previously, primarily on the basis of studies of selected critical factors. They highlight the activation of precise signaling pathways, some of which may have been previously under evaluated. The remodelling and maturation processes that the myometrium undergoes in pregnancy appear clearly as phenomena which last during the full course of gestation. Comparatively, the onset of labor is perhaps the phenomenon which remains the least well described by these methods of analysis. Nevertheless, genomic studies constitute a necessary first step of orientation and help establishing new links between the generic signaling pathways that are activated during the normal or pathological gestation. These studies also represent an indicative step that will have to be paralleled, in the future, with the results of the systematic proteomic analysis of the myometrium.
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Ren YP, Huang RW, Lü ZR. Ouabain at pathological concentrations might induce damage in human vascular endothelial cells. Acta Pharmacol Sin 2006; 27:165-72. [PMID: 16412265 DOI: 10.1111/j.1745-7254.2006.00244.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AIM To examine the time- and dose-dependent effects of ouabain on human umbilical vein endothelial cells (HUVEC) in vivo, and the changes in aortic endothelium and the different expression levels of Kv4.2 in vitro. METHODS The proliferation of HUVEC and cell death were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, the incorporation of [3H]TdR, trypan blue staining, and lactate dehydrogenase (LDH) release. The response of endothelial cells to ouabain was explored with a complementary DNA microarray and a candidate gene was found. Ouabain-sensitive hypertensive rats were established by chronic administration of ouabain. Changes in the aortic endothelium were observed by electron microscopy, and the expression level of Kv4.2 in different animals was studied by using real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS Ouabain stimulated the proliferation of HUVEC at physiological concentrations (0.3-0.9 nmol/L). Ouabain at pathological concentrations (0.9-1.8 nmol/L) inhibited proliferation and induced cell death. mRNA profile analysis indicated that 340 genes were differentially expressed after ouabain treatment: 145 were upregulated, of which 6 were upregulated significantly, including KCND2 (encoding the potassium voltage-gated channel shal-related subfamily member 2). The upregulated genes were mainly related to cell metabolism and transcription. In ouabain-sensitive hypertensive rats, the aortic endothelium was damaged and Kv4.2 (coded by KCND2) was over-expressed. CONCLUSION The physiological role of ouabain in HUVEC might involve the control of growth and metabolism. Ouabain at pathological concentrations might affect the structure and function of the vascular endothelium by modification of expression of the KCND2 gene, and participate vascular remodeling in hypertension.
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Affiliation(s)
- Yan-ping Ren
- Geriatric-Cardiovascular Department, First Hospital of Xi-an Jiaotong University, Xi-an 710061, China.
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Zhu XY, Liu YJ, Lu J, Xu RB. Knockdown of glucocorticoid receptor expression by RNA interference promotes cell proliferation in murine macrophage RAW264.7 cells. J Steroid Biochem Mol Biol 2004; 92:375-82. [PMID: 15698542 DOI: 10.1016/j.jsbmb.2004.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/30/2004] [Indexed: 11/15/2022]
Abstract
It is well documented that glucocorticoids (GC) promote arrest in the G1-S transition of the cell cycle in many cell types, resulting in a decrease in proliferation. However, the relationship between glucocorticoid receptor (GR) and the cell-cycle regulation remains unclear. Suppression of GR is important for exploring GR dependent processes. This study applied RNA interference targeting GR to the murine macrophage RAW264.7 cells. Transient transfection of the GR-siRNA expression vector reduced GR synthesis as measured on mRNA and protein level by RT-PCR and Western blot. GR-siRNA also depressesed GR transcriptional activity. A cell line [RAW-(GR-)] stably transfected with GR-siRNA expression vector was then established, the decreased GR level in this cell line was confirmed by Western blot. MTT assay showed RAW-(GR-) cells grew faster than control cells, which indicated that knockdown of GR promoted cell proliferation in macrophages. Further studies showed decreased p27 expression, increased PKC-alpha expression and enhanced basal and LPS-induced NF-kappaB activity in RAW-(GR-) cells as compared to the RAW-control cells. In contrast, virtually no change in p21, ERK1/2 and p38 expression was detected. In conclusion, these results indicate that GR itself is an inhibitor of cell proliferation in RAW264.7 cell line. This effect may be associated with the decreased expression of p27, the increased expression of PKC-alpha, and the activation of NF-kappaB. As all the experiments are carried out in GC free or serum-free medium, this study also shows the possibility for GR to have some constitutive functions, which are independent on GC activation.
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Affiliation(s)
- Xiao-Yan Zhu
- Department of Pathophysiology, Second Military Medical University, Shanghai 200433, PR China.
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Robin P, Chouayekh S, Bole-Feysot C, Leiber D, Tanfin Z. Contribution of phospholipase D in endothelin-1-mediated extracellular signal-regulated kinase activation and proliferation in rat uterine leiomyoma cells. Biol Reprod 2004; 72:69-77. [PMID: 15355882 DOI: 10.1095/biolreprod.104.033852] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Endothelin (ET)-1 is a mitogenic factor in numerous cell types, including rat myometrial cells. In the present study, we investigated the potential role of ET-1 in the proliferation of tumoral uterine smooth muscle cells (ELT-3 cells). We found that ET-1 exerted a more potent mitogenic effect in ELT-3 cells than in normal myometrial cells, as indicated by the increase in [3H]thymidine incorporation, cell number, and bromodeoxyuridine incorporation. The ET-1 was more efficient than platelet-derived growth factor and epidermal growth factor to stimulate proliferation. The ET-1-mediated cell proliferation was inhibited in the presence of U0126, a specific inhibitor of (mitogen-activated protein kinase ERK kinase), indicating that extracellular signal-regulated kinase (ERK) activation is involved. Additionally, ET-1 induced the activation of phospholipase (PL) D, leading to the synthesis of phosphatidic acid (PA). The ET-1-induced activation of PLD was twofold higher in ELT-3 cells compared to that in normal cells. The two cell types expressed mRNA for PLD1a and PLD2, whereas PLD1b was expressed only in ELT-3 cells. The exposure of cells to butan-1-ol reduced ET-1-mediated production of PA by PLD and partially inhibited ERK activation and DNA synthesis. Addition of exogenous PLD or PA in the medium reproduced the effect of ET-1 on ERK activation and cell proliferation. Collectively, these data indicate that ET-1 is a potent mitogenic factor in ELT-3 cells via a signaling pathway involving a PLD-dependent activation of ERK. This highlights the potential role of ET-1 in the development of uterine leiomyoma, and it reinforces the role of PLD in tumor growth.
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Affiliation(s)
- Philippe Robin
- Laboratoire de signalisation et régulations cellulaires, IBBMC, CNRS UMR 8619, Bat 430 Université Paris Sud, 91 405 Orsay Cedex, France
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Robin P, Boulven I, Bôle-Feysot C, Tanfin Z, Leiber D. Contribution of PKC-dependent and -independent processes in temporal ERK regulation by ET-1, PDGF, and EGF in rat myometrial cells. Am J Physiol Cell Physiol 2004; 286:C798-806. [PMID: 14644778 DOI: 10.1152/ajpcell.00465.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelin-1 (ET-1), platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) stimulated thymidine incorporation with different efficiency (PDGF ≫ EGF = ET-1) in rat myometrial cells. They also stimulated ERK activation, which culminated at 5 min and then declined to reach a plateau (at 45 min: EGF > 90%, PDGF = 50%, and ET-1 < 10% of maximum). Inhibition and downregulation of PKC demonstrated that ERK activation at 5 min involved PKCδ and -ζ for ET-1 and PKCα plus another PKC isoform for PDGF. By contrast, the EGF response did not involve PKC. Stimulation of Ras was more important with EGF than with PDGF, with ET-1 being the weakest activator. The simultaneous incubation of the cells with EGF and ET-1 potentiated the ERK activation at 5 min and mimicked the plateau phase obtained with PDGF. Under these conditions thymidine incorporation was comparable to that induced by PDGF. Taken together, our results indicated that the kinetic profile of ERK activation and its impact on cell proliferation can be modulated by the differential involvement of PKC isoforms and the amplitude of Ras activation.
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Affiliation(s)
- Philippe Robin
- Laboratoire de Signalisation et Régulations Cellulaires, CNRS UMR 8619, Bâtiment 430, Université de Paris-Sud, 91405 Orsay Cedex, France.
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Di Liberto G, Dallot E, Eude-Le Parco I, Cabrol D, Ferré F, Breuiller-Fouché M. A critical role for PKC zeta in endothelin-1-induced uterine contractions at the end of pregnancy. Am J Physiol Cell Physiol 2003; 285:C599-607. [PMID: 12748064 DOI: 10.1152/ajpcell.00040.2003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously shown that protein kinase C (PKC) zeta and/or PKC delta are necessary for endothelin-1 (ET-1)-induced human myometrial contraction at the end of pregnancy (Eude I, Paris P, Cabrol D, Ferré F, and Breuiller-Fouché M. Biol Reprod 63: 1567-1573, 2000). Here, we report that the selective inhibitor of PKC delta isoform, Rottlerin, does not prevent ET-1-induced contractions, whereas LY-294002, a phosphatidylinositol (PI) 3-kinase inhibitor, affects the contractile response. This study characterized the in vitro contractile response of cultured human pregnant myometrial cells to ET-1 known to induce in vitro contractions of intact uterine smooth muscle strips. Cultured myometrial cells incorporated into collagen lattices have the capacity to reduce the size of these lattices, referred to as lattice contraction. Neither the selective conventional PKC isoform inhibitor, Gö-6976, or rottlerin affected myometrial cell-mediated gel contraction by ET-1, whereas this effect was blocked by LY-294002. We found that treatment of myometrial cell lattices with an inhibitory peptide specific for PKC zeta or with an antisense against PKC zeta resulted in a significant loss of ET-1-induced contraction. Evidence is also presented by using confocal microscopy that ET-1 induced translocation of PKC zeta to a structure coincident with the actin-rich microfilaments of the cytoskeleton. We have shown that PKC zeta has a role in the actin organization in ET-1-stimulated cells. Accordingly, our results suggest that PKC zeta plays a role in myometrial contraction in pregnant women.
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Affiliation(s)
- G Di Liberto
- Institut National de la Santé et de la Recherche Médicale U361, Pavillon Baudelocque, 75014 Paris, France
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Charpigny G, Leroy MJ, Breuiller-Fouché M, Tanfin Z, Mhaouty-Kodja S, Robin P, Leiber D, Cohen-Tannoudji J, Cabrol D, Barberis C, Germain G. A functional genomic study to identify differential gene expression in the preterm and term human myometrium. Biol Reprod 2003; 68:2289-96. [PMID: 12606369 DOI: 10.1095/biolreprod.102.013763] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The mechanisms that lead to the onset of human parturition are still unknown, although selected critical factors have been identified. To investigate the changes in myometrial gene expression associated with parturition, we used two macroarrays each containing 1176 different complementary human cDNA clones. Methods involving hierarchical clustering and conventional statistical analysis allowed us to generate a profile of genes expression at three stages of late pregnancy: preterm (29 wk amenorrhea); full term, not in labor (38 wk amenorrhea); and full term in labor (39 wk amenorrhea). Only 4% of the genes investigated were differentially expressed between the preterm and term groups (P < 0.05). These genes could be clustered as groups of either down-regulated or up-regulated transcripts. The changes in transcript abundance were particularly marked between the preterm and term stages of gestation, whereas the differences between term not in labor and term in labor were less pronounced. The parturition was characterized by a massive down-regulation of a large panel of developmental, cell adhesion molecule and proliferation-related genes, along with the up-regulation of inflammatory, contraction and apoptosis associated genes. We propose that the mechanisms of parturition consist primarily in the arrest of the processes of myometrial development, a step that might be essential to allow the uterus to recover appropriate contractile function before delivery.
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Affiliation(s)
- G Charpigny
- Physiologie Animale, INRA, Centre de Recherches de Jouy, 78352 Jouy en Josas cedex, France
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Kim B, Kim YS, Ahn J, Kim J, Cho S, Won KJ, Ozaki H, Karaki H, Lee SM. Conventional-type protein kinase C contributes to phorbol ester-induced inhibition of rat myometrial tension. Br J Pharmacol 2003; 139:408-14. [PMID: 12770946 PMCID: PMC1573838 DOI: 10.1038/sj.bjp.0705237] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1 Phorbol ester decreases muscle tension in the rat myometrium, and the effect is more potent in late-pregnant myometrium than in nonpregnant myometrium. In the present study, we have examined the contribution of protein kinase C (PKC) isoforms to the phorbol ester-induced inhibition of tension in rat uterine smooth muscle. 2 Thymeleatoxin (THX), a selective activator of conventional-type PKC (cPKC), and 12-deoxyphorbol 13-isobutyrate (DPB), an activator of pan PKC, inhibited the tension induced by high K(+), and inhibitions were significantly increased in pregnant myometrium compared to nonpregnant myometrium. The inhibition by DPB and THX of high K(+)-induced tension was significantly attenuated when PKC was downregulated by long-term pretreatment with THX and inhibited by Go6976, a cPKC inhibitor. 3 Of the cPKCs, PKC alpha is predominantly expressed in the rat myometrium, as detected by Western blot analysis. The expression of PKC alpha gradually increases from the beginning of gestation, reaching a maximum at day 21 of pregnancy. Treatment with DPB induced PKC alpha to translocate from the cytosol to the membrane in the pregnant myometrium. PKC epsilon and PKC zeta, other dominant PKC isoforms in the rat myometrium, decrease during gestation, reaching a minimum in late pregnancy. 4 These results suggest that cPKC may be at least partly involved in the PKC-mediated inhibition of muscle tension in the rat myometrium.
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Affiliation(s)
- Bokyung Kim
- Department of Physiology, College of Medicine, Konkuk University, Danwol-dong 322, Choongju 380-701, Korea.
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Dallot E, Pouchelet M, Gouhier N, Cabrol D, Ferré F, Breuiller-Fouché M. Contraction of cultured human uterine smooth muscle cells after stimulation with endothelin-1. Biol Reprod 2003; 68:937-42. [PMID: 12604645 DOI: 10.1095/biolreprod.102.008367] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
To our knowledge, the problem of how to maintain isolated smooth cells in a "contractile" phenotypic state without deviation after subculturing has yet to be resolved. The present study characterized the in vitro contractile response of human uterine smooth muscle cell to endothelin-1, which induces contractions in isolated uterine strips. Contractile effects were qualitatively investigated using silicone rubber substrata. Endothelin-1 was able to distort and reduce the wrinkles in the silicone surface. Contractions were also quantified by measuring the resulting change in the collagen lattice area. Endothelin-1 significantly increased the contractile response in a dose-dependent manner by selectively activating endothelin A receptors. When myometrial cells were cultured within collagen lattices, a microfilament-disrupting agent, cytochalasin B, abolished contractions, and no change was observed in smooth muscle alpha-actin immunostaining. Taken together, these observations show that the uterine smooth muscle cells are contractile and respond appropriately to a potent uterotonic agent. Based on these findings, a cultured uterine smooth muscle cell model, which could be used to elucidate the mechanisms controlling uterine activity, is proposed.
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Affiliation(s)
- Emmanuelle Dallot
- INSERM U 361, Université René Descartes, Pavillon Baudelocque, 75014 Paris, France
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