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Zhao X, Zhou D, Liu Y, Li C, Zhao X, Li Y, Li W. Ganoderma lucidum polysaccharide inhibits prostate cancer cell migration via the protein arginine methyltransferase 6 signaling pathway. Mol Med Rep 2017; 17:147-157. [PMID: 29115463 PMCID: PMC5780085 DOI: 10.3892/mmr.2017.7904] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 06/12/2017] [Indexed: 02/07/2023] Open
Abstract
Prostate cancer is one of the most common types of malignant tumor of men worldwide and the incidence and mortality rate is gradually increasing. At present, the molecular mechanisms of growth and migration in human prostate cancer have not been completely elucidated. Studies have demonstrated that Ganoderma lucidum polysaccharides (GLP) can inhibit cancer. Therefore the present study investigated the effect and molecular mechanism of GLP on cell growth and migration of LNCaP human prostate cancer cells. LNCaP cells were transfected with either a protein arginine methyltransferase 6 (PRMT6) overexpression plasmid or PRMT6 small interfering (si)RNA. The cell growth and migration, and the expression of PRMT6 signaling-associated proteins, were investigated following treatment with 5 and 20 µg/ml GLP. The results demonstrated that GLP inhibited cell growth, induced cell cycle arrest, decreased PRMT6, cyclin-dependent kinase 2 (CDK2), focal adhesion kinase (FAK) and steroid receptor coactivator, (SRC) expression, and increased p21 expression in LNCaP cells, as determined by using a Coulter counter, flow cytometry, and reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. Furthermore, GLP significantly inhibited cell migration, as determined by Transwell migration and scratch assays, and altered CDK2, FAK, SRC and p21 expression in LNCaP cells transfected with the PRMT6 overexpression plasmid. By contrast, PRMT6 knockdown by siRNA reduced the effect of GLP on cell migration. These results indicate that GLP was effective in inhibiting cell growth, the cell cycle and cell migration, and the suppressive effect of GLP on cell migration may occur via the PRMT6 signaling pathway. Therefore, it is suggested that GLP may act as a tumor suppressor with applications in the treatment of prostate cancer. The results of the present study provide both the preliminary theoretical and experimental basis for the investigation of GLP as a therapeutic agent.
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Affiliation(s)
- Xiaohui Zhao
- Oncology Department, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Dayu Zhou
- Virology Laboratory, Microbiology Department, The Center of Jinzhou Disease Control and Prevention, Jinzhou, Liaoning 121000, P.R. China
| | - Yunen Liu
- Laboratory of Rescue Center of Severe Wound and Trauma PLA, Emergency Medicine Department, General Hospital of Shenyang Military Command, Shenyang, Liaoning 110016, P.R. China
| | - Chun Li
- College of Mathematics and Physics, Bohai University, Jinzhou, Liaoning 121000, P.R. China
| | - Xiaoguang Zhao
- Oncology Department, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Ying Li
- Oncology Department, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Wei Li
- Oncology Department, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
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Feng C, Luo T, Zhang S, Liu K, Zhang Y, Luo Y, Ge P. Lycopene protects human SH‑SY5Y neuroblastoma cells against hydrogen peroxide‑induced death via inhibition of oxidative stress and mitochondria‑associated apoptotic pathways. Mol Med Rep 2016; 13:4205-14. [PMID: 27035331 PMCID: PMC4838073 DOI: 10.3892/mmr.2016.5056] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 03/14/2016] [Indexed: 11/30/2022] Open
Abstract
Oxidative stress, which is characterized by excessive production of reactive oxygen species (ROS), is a common pathway that results in neuronal injury or death due to various types of pathological stress. Although lycopene has been identified as a potent antioxidant, its effect on hydrogen peroxide (H2O2)-induced neuronal damage remains unclear. In the present study, pretreatment with lycopene was observed to protect SH-SY5Y neuroblastoma cells against H2O2-induced death via inhibition of apoptosis resulting from activation of caspase-3 and translocation of apoptosis inducing factor (AIF) to the nucleus. Furthermore, the over-produced ROS, as well as the reduced activities of anti-oxidative enzymes, superoxide dismutase and catalase, were demonstrated to be alleviated by lycopene. Additionally, lycopene counteracted H2O2-induced mitochondrial dysfunction, which was evidenced by suppression of mitochondrial permeability transition pore opening, attenuation of the decline of the mitochondrial membrane potential, and inhibition of the increase of Bax and decrease of Bcl-2 levels within the mitochondria. The release of cytochrome c and AIF from the mitochondria was also reduced. These results indicate that lycopene is a potent neuroprotectant against apoptosis, oxidative stress and mitochondrial dysfunction, and could be administered to prevent neuronal injury or death.
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Affiliation(s)
- Chunsheng Feng
- Department of Anesthesiology, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Tianfei Luo
- Department of Neurology, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Shuyan Zhang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Kai Liu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yanhong Zhang
- Department of Emergent Medicine, People's Hospital of Jilin Province, Changchun, Jilin 130021, P.R. China
| | - Yinan Luo
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Pengfei Ge
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
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Lim JA, Juhnn YS. Isoproterenol increases histone deacetylase 6 expression and cell migration by inhibiting ERK signaling via PKA and Epac pathways in human lung cancer cells. Exp Mol Med 2016; 48:e204. [PMID: 27534532 PMCID: PMC4892858 DOI: 10.1038/emm.2015.98] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 02/07/2023] Open
Abstract
Stress conditions are correlated with tumor growth, progression and metastasis. We
hypothesized that stress signals might affect tumor progression via epigenetic
control of gene expression and investigated the effects of stress signals on the
expression levels of histone deacetylases (HDACs) and the underlying mechanisms of
these effects in lung cancer cells. Treatment with isoproterenol (ISO), an analog of
the stress signal epinephrine, increased the expression of HDAC6 protein and mRNA in
H1299 lung cancer cells. ISO caused the deacetylation of α-tubulin and
stimulated cell migration in an HDAC6-dependent manner. HDAC6 expression was
increased by treatment with selective activators of cAMP-dependent protein kinase
(PKA) or exchange protein activated by cAMP (Epac). ISO activated Rap1 via Epac, and
constitutively active Rap1A increased the HDAC6 level; however, the knockdown of
Rap1A decreased the 8-(4-cholorophenylthio)-2′-O-methyl-cAMP-induced
increase in HDAC6 expression. Both PKA and Rap1A decreased c-Raf activation to
inhibit extracellular signal-regulated kinase (ERK) signaling. Inhibition of ERK
caused an increase in HDAC6 expression, and constitutively active MEK1 decreased the
ISO-induced HDAC6 expression. We concluded that ISO increases HDAC6 expression via a
PKA/Epac/ERK-dependent pathway that stimulates the migration of lung cancer
cells. This study suggests that stress signals can stimulate the migration of cancer
cells by inducing HDAC6 expression in lung cancer cells.
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Affiliation(s)
- Jeong Ah Lim
- Department of Biochemistry and Molecular Biology and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Yong-Sung Juhnn
- Department of Biochemistry and Molecular Biology and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Park JY, Juhnn YS. cAMP signaling increases histone deacetylase 8 expression by inhibiting JNK-dependent degradation via autophagy and the proteasome system in H1299 lung cancer cells. Biochem Biophys Res Commun 2016; 470:336-342. [PMID: 26792731 DOI: 10.1016/j.bbrc.2016.01.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 01/08/2016] [Indexed: 12/31/2022]
Abstract
This study aimed to investigate the roles of autophagy and the ubiquitin-proteasome system in the degradation of histone deacetylase 8 (HDAC8) and to clarify the mechanism by which cAMP signaling regulates this degradation. cAMP signaling was activated by treating H1299 non-small cell lung cancer cells with isoproterenol or forskolin/3-isobutyl-1-methylxanthine, and HDAC8 expression was assessed by western blot analysis. The inhibition of autophagy and ubiquitin-proteasome-dependent degradation increased HDAC8 expression. cAMP signaling inhibited JNK activation, which decreased the phosphorylation of Bcl-2, thereby reducing autophagy, and the phosphorylation of Itch, thereby reducing ubiquitination. These results suggest that the HDAC8 protein is degraded via autophagy and the ubiquitin-proteasome system and that cAMP signaling increases HDAC8 protein levels by reducing JNK-mediated autophagy and ubiquitin-proteasome-dependent degradation of the HDAC8 protein in H1299 lung cancer cells.
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Affiliation(s)
- Ji-Yeon Park
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Yong-Sung Juhnn
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea.
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Liu Y, Tan D, Tong C, Zhang Y, Xu Y, Liu X, Gao Y, Hou M. Blueberry anthocyanins ameliorate radiation-induced lung injury through the protein kinase RNA-activated pathway. Chem Biol Interact 2015; 242:363-71. [DOI: 10.1016/j.cbi.2015.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/26/2015] [Accepted: 11/03/2015] [Indexed: 01/25/2023]
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Kim EJ, Juhnn YS. Cyclic AMP signaling reduces sirtuin 6 expression in non-small cell lung cancer cells by promoting ubiquitin-proteasomal degradation via inhibition of the Raf-MEK-ERK (Raf/mitogen-activated extracellular signal-regulated kinase/extracellular signal-regulated kinase) pathway. J Biol Chem 2015; 290:9604-13. [PMID: 25713071 DOI: 10.1074/jbc.m114.633198] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 12/18/2022] Open
Abstract
The cAMP signaling system regulates various cellular functions, including metabolism, gene expression, and death. Sirtuin 6 (SIRT6) removes acetyl groups from histones and regulates genomic stability and cell viability. We hypothesized that cAMP modulates SIRT6 activity to regulate apoptosis. Therefore, we examined the effects of cAMP signaling on SIRT6 expression and radiation-induced apoptosis in lung cancer cells. cAMP signaling in H1299 and A549 human non-small cell lung cancer cells was activated via the expression of constitutively active Gαs plus treatment with prostaglandin E2 (PGE2), isoproterenol, or forskolin. The expression of sirtuins and signaling molecules were analyzed by Western blotting. Activation of cAMP signaling reduced SIRT6 protein expression in lung cancer cells. cAMP signaling increased the ubiquitination of SIRT6 protein and promoted its degradation. Treatment with MG132 and inhibiting PKA with H89 or with a dominant-negative PKA abolished the cAMP-mediated reduction in SIRT6 levels. Treatment with PGE2 inhibited c-Raf activation by increasing inhibitory phosphorylation at Ser-259 in a PKA-dependent manner, thereby inhibiting downstream MEK-ERK signaling. Inhibiting ERK with inhibitors or with dominant-negative ERKs reduced SIRT6 expression, whereas activation of ERK by constitutively active MEK abolished the SIRT6-depleting effects of PGE2. cAMP signaling also augmented radiation-induced apoptosis in lung cancer cells. This effect was abolished by exogenous expression of SIRT6. It is concluded that cAMP signaling reduces SIRT6 expression by promoting its ubiquitin-proteasome-dependent degradation, a process mediated by the PKA-dependent inhibition of the Raf-MEK-ERK pathway. Reduced SIRT6 expression mediates the augmentation of radiation-induced apoptosis by cAMP signaling in lung cancer cells.
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Affiliation(s)
- Eui-Jun Kim
- From the Department of Biochemistry and Molecular Biology and Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Yong-Sung Juhnn
- From the Department of Biochemistry and Molecular Biology and Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea
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7
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Ramiro-Diaz JM, Giermakowska W, Weaver JM, Jernigan NL, Gonzalez Bosc LV. Mechanisms of NFATc3 activation by increased superoxide and reduced hydrogen peroxide in pulmonary arterial smooth muscle. Am J Physiol Cell Physiol 2014; 307:C928-38. [PMID: 25163518 DOI: 10.1152/ajpcell.00244.2014] [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] [Indexed: 01/30/2023]
Abstract
We recently demonstrated increased superoxide (O2(·-)) and decreased H2O2 levels in pulmonary arteries of chronic hypoxia-exposed wild-type and normoxic superoxide dismutase 1 (SOD1) knockout mice. We also showed that this reciprocal change in O2(·-) and H2O2 is associated with elevated activity of nuclear factor of activated T cells isoform c3 (NFATc3) in pulmonary arterial smooth muscle cells (PASMC). This suggests that an imbalance in reactive oxygen species levels is required for NFATc3 activation. However, how such imbalance activates NFATc3 is unknown. This study evaluated the importance of O2(·-) and H2O2 in the regulation of NFATc3 activity. We tested the hypothesis that an increase in O2(·-) enhances actin cytoskeleton dynamics and a decrease in H2O2 enhances intracellular Ca(2+) concentration, contributing to NFATc3 nuclear import and activation in PASMC. We demonstrate that, in PASMC, endothelin-1 increases O2(·-) while decreasing H2O2 production through the decrease in SOD1 activity without affecting SOD protein levels. We further demonstrate that O2(·-) promotes, while H2O2 inhibits, NFATc3 activation in PASMC. Additionally, increased O2(·-)-to-H2O2 ratio activates NFATc3, even in the absence of a Gq protein-coupled receptor agonist. Furthermore, O2(·-)-dependent actin polymerization and low intracellular H2O2 concentration-dependent increases in intracellular Ca(2+) concentration contribute to NFATc3 activation. Together, these studies define important and novel regulatory mechanisms of NFATc3 activation in PASMC by reactive oxygen species.
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Affiliation(s)
- Juan Manuel Ramiro-Diaz
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Wieslawa Giermakowska
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - John M Weaver
- Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, New Mexico; and Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Laura V Gonzalez Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico;
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8
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Cho EA, Kim EJ, Kwak SJ, Juhnn YS. cAMP signaling inhibits radiation-induced ATM phosphorylation leading to the augmentation of apoptosis in human lung cancer cells. Mol Cancer 2014; 13:36. [PMID: 24568192 PMCID: PMC4234305 DOI: 10.1186/1476-4598-13-36] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 01/21/2014] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The ataxia-telangiectasia mutated (ATM) protein kinase plays a central role in coordinating the cellular response to radiation-induced DNA damage. cAMP signaling regulates various cellular responses including metabolism and gene expression. This study aimed to investigate the mechanism through which cAMP signaling regulates ATM activation and cellular responses to ionizing radiation in lung cancer cells. METHODS Lung cancer cells were transfected with constitutively active stimulatory G protein (GαsQL), and irradiated with γ-rays. The phosphorylation of ATM and protein phosphatase 2A was analyzed by western blotting, and apoptosis was assessed by western blotting, flow cytometry, and TUNNEL staining. The promoter activity of NF-κB was determined by dual luciferase reporter assay. BALB/c mice were treated with forskolin to assess the effect in the lung tissue. RESULTS Transient expression of GαsQL significantly inhibited radiation-induced ATM phosphorylation in H1299 human lung cancer cells. Treatment with okadaic acid or knock down of PP2A B56δ subunit abolished the inhibitory effect of Gαs on radiation-induced ATM phosphorylation. Expression of GαsQL increased phosphorylation of the B56δ and PP2A activity, and inhibition of PKA blocked Gαs-induced PP2A activation. GαsQL enhanced radiation-induced cleavage of caspase-3 and PARP and increased the number of early apoptotic cells. The radiation-induced apoptosis was increased by inhibition of NF-κB using PDTC or inhibition of ATM using KU55933 or siRNA against ATM. Pretreatment of BALB/c mice with forskolin stimulated phosphorylation of PP2A B56δ, inhibited the activation of ATM and NF-κB, and augmented radiation-induced apoptosis in the lung tissue. GαsQL expression decreased the nuclear levels of the p50 and p65 subunits and NF-κB-dependent activity after γ-ray irradiation in H1299 cells. Pretreatment with prostaglandin E2 or isoproterenol increased B56δ phosphorylation, decreased radiation-induced ATM phosphorylation and increased apoptosis. CONCLUSIONS cAMP signaling inhibits radiation-induced ATM activation by PKA-dependent activation of PP2A, and this signaling mechanism augments radiation-induced apoptosis by reducing ATM-dependent activation of NF-κB in lung cancer cells.
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Affiliation(s)
| | | | | | - Yong-Sung Juhnn
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea.
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Jia XY, Chang Y, Sun XJ, Wu HX, Wang C, Xu HM, Zhang L, Zhang LL, Zheng YQ, Song LH, Wei W. Total glucosides of paeony inhibit the proliferation of fibroblast-like synoviocytes through the regulation of G proteins in rats with collagen-induced arthritis. Int Immunopharmacol 2013; 18:1-6. [PMID: 24161745 DOI: 10.1016/j.intimp.2013.09.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 01/29/2023]
Abstract
The aim of this study was to investigate the expression of G proteins in fibroblast-like synoviocytes (FLSs) from rats with collagen-induced arthritis (CIA) and to determine the effect of total glucosides of paeony (TGP). CIA rats were induced with chicken type II collagen (CCII) in Freund's complete adjuvant. The rats with experimental arthritis were randomly separated into five groups and then treated with TGP (25, 50, and 100mg/kg) from days 14 to 35 after immunization. The secondary inflammatory reactions were evaluated through the polyarthritis index and histopathological changes. The level of cyclic adenosine monophosphate (cAMP) was measured by radioimmunoassay. The FLS proliferation response was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The toxin-catalyzed ADP-ribosylation of G proteins was performed through autoradiography. The results show that TGP (25, 50, and 100mg/kg) significantly decreased the arthritis scores of CIA rats and improved the histopathological changes. TGP inhibited the proliferation of FLSs and increased the level of cAMP. Moreover, the FLS proliferation and the level of Gαi expression were significantly increased, but the level of Gαs expression was decreased after stimulation with IL-1β (10ng/ml) in vitro. TGP (12.5 and 62.5μg/ml) significantly inhibited the FLS proliferation and regulated the balance between Gαi and Gαs. These results demonstrate that TGP may exert its anti-inflammatory effects through the suppression of FLS proliferation, which may be associated with its ability to regulate the balance of G proteins. Thus, TGP may have potential as a therapeutic agent for the treatment of rheumatoid arthritis.
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Affiliation(s)
- Xiao-Yi Jia
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China; School of Pharmacy, Anhui Xinhua University, Hefei 230088, China.
| | - Yan Chang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China.
| | - Xiao-Jing Sun
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Hua-Xun Wu
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China.
| | - Chun Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Hong-Mei Xu
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Lei Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Ling-Ling Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Yong-Qiu Zheng
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China
| | - Li-Hua Song
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China.
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine of the Education Ministry of China, Hefei 230032, China.
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cAMP signalling decreases p300 protein levels by promoting its ubiquitin/proteasome dependent degradation via Epac and p38 MAPK in lung cancer cells. FEBS Lett 2013; 587:1373-8. [PMID: 23523631 DOI: 10.1016/j.febslet.2013.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/05/2013] [Accepted: 03/13/2013] [Indexed: 01/21/2023]
Abstract
The transcriptional coactivator p300 functions as a histone acetyltransferase and a scaffold for transcription factors. We investigated the effect of cAMP signalling on p300 expression. The activation of cAMP signalling by the expression of constitutively active Gαs or by treatment with isoproterenol decreased the p300 protein expression in lung cancer cells. Isoproterenol promoted the ubiquitination and subsequent proteasomal degradation of p300 in an Epac-dependent manner. Epac promoted p300 degradation by inhibiting the activity of p38 MAPK. It is concluded that cAMP signalling decreases the level of the p300 protein by promoting its ubiquitin-proteasome dependent degradation, which is mediated by Epac and p38 MAPK, in lung cancer cells.
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Ramiro-Diaz JM, Nitta CH, Maston LD, Codianni S, Giermakowska W, Resta TC, Gonzalez Bosc LV. NFAT is required for spontaneous pulmonary hypertension in superoxide dismutase 1 knockout mice. Am J Physiol Lung Cell Mol Physiol 2013; 304:L613-25. [PMID: 23475768 DOI: 10.1152/ajplung.00408.2012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Elevated reactive oxygen species are implicated in pulmonary hypertension (PH). Superoxide dismutase (SOD) limits superoxide bioavailability, and decreased SOD activity is associated with PH. A decrease in SOD activity is expected to increase superoxide and reduce hydrogen peroxide levels. Such an imbalance of superoxide/hydrogen peroxide has been implicated as a mediator of nuclear factor of activated T cells (NFAT) activation in epidermal cells. We have shown that NFATc3 is required for chronic hypoxia-induced PH. However, it is unknown whether NFATc3 is activated in the pulmonary circulation in a mouse model of decreased SOD1 activity and whether this leads to PH. Therefore, we hypothesized that an elevated pulmonary arterial superoxide/hydrogen peroxide ratio activates NFATc3, leading to PH. We found that SOD1 knockout (KO) mice have elevated pulmonary arterial wall superoxide and decreased hydrogen peroxide levels compared with wild-type (WT) littermates. Right ventricular systolic pressure (RVSP) was elevated in SOD1 KO and was associated with pulmonary arterial remodeling. Vasoreactivity to endothelin-1 was also greater in SOD1 KO vs. WT mice. NFAT activity and NFATc3 nuclear localization were increased in pulmonary arteries from SOD1 KO vs. WT mice. Administration of A-285222 (selective NFAT inhibitor) decreased RVSP, arterial wall thickness, vasoreactivity, and NFAT activity in SOD1 KO mice to WT levels. The SOD mimetic, tempol, also reduced NFAT activity, NFATc3 nuclear localization, and RVSP to WT levels. These findings suggest that an elevated superoxide/hydrogen peroxide ratio activates NFAT in pulmonary arteries, which induces vascular remodeling and increases vascular reactivity leading to PH.
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Affiliation(s)
- Juan Manuel Ramiro-Diaz
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, NM 87131, USA
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12
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Li Y. Aggregatibacter Actinomycetemcomitans reduced GNAS Gene Expression in Human Trophoblasts. J HARD TISSUE BIOL 2013. [DOI: 10.2485/jhtb.22.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Watanabe S, Takahashi N, Uchida H, Wakasugi K. Human neuroglobin functions as an oxidative stress-responsive sensor for neuroprotection. J Biol Chem 2012; 287:30128-38. [PMID: 22787149 DOI: 10.1074/jbc.m112.373381] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian neuroglobin (Ngb) protects neuronal cells under conditions of oxidative stress. The mechanism underlying this function is only partly understood. Here, we report that human Ngb exists in lipid rafts only during oxidative stress and that lipid rafts are crucial for neuroprotection by Ngb. The ferrous oxygen-bound form of Ngb, which exists under normoxia, is converted to the ferric bis-His conformation during oxidative stress, inducing large tertiary structural changes. We clarified that ferric bis-His Ngb, but not ferrous ligand-bound Ngb, specifically binds to flotillin-1, a lipid raft microdomain-associated protein, as well as to α-subunits of heterotrimeric G proteins (Gα(i/o)). Moreover, we found that human ferric bis-His Ngb acts as a guanine nucleotide dissociation inhibitor for Gα(i/o) that has been modified by oxidative stress. In addition, our data shows that Ngb inhibits the decrease in cAMP concentration that occurs under oxidative stress, leading to protection against cell death. Furthermore, by using a mutated Ngb protein that cannot form the bis-His conformation, we demonstrate that the oxidative stress-induced structural changes of human Ngb are essential for its neuroprotective activity.
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Affiliation(s)
- Seiji Watanabe
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902, Japan
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14
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Cho EA, Juhnn YS. The cAMP signaling system inhibits the repair of γ-ray-induced DNA damage by promoting Epac1-mediated proteasomal degradation of XRCC1 protein in human lung cancer cells. Biochem Biophys Res Commun 2012; 422:256-62. [PMID: 22575451 DOI: 10.1016/j.bbrc.2012.04.139] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 04/25/2012] [Indexed: 02/01/2023]
Abstract
Cyclic AMP is involved in the regulation of metabolism, gene expression, cellular growth and proliferation. Recently, the cAMP signaling system was found to modulate DNA-damaging agent-induced apoptosis by regulating the expression of Bcl-2 family proteins and inhibitors of apoptosis. Thus, we hypothesized that the cAMP signaling may modulate DNA repair activity, and we investigated the effects of the cAMP signaling system on γ-ray-induced DNA damage repair in lung cancer cells. Transient expression of a constitutively active mutant of stimulatory G protein (GαsQL) or treatment with forskolin, an adenylyl cyclase activator, augmented radiation-induced DNA damage and inhibited repair of the damage in H1299 lung cancer cells. Expression of GαsQL or treatment with forskolin or isoproterenol inhibited the radiation-induced expression of the XRCC1 protein, and exogenous expression of XRCC1 abolished the DNA repair-inhibiting effect of forskolin. Forskolin treatment promoted the ubiquitin and proteasome-dependent degradation of the XRCC1 protein, resulting in a significant decrease in the half-life of the protein after γ-ray irradiation. The effect of forskolin on XRCC1 expression was not inhibited by PKA inhibitor, but 8-pCPT-2'-O-Me-cAMP, an Epac-selective cAMP analog, increased ubiquitination of XRCC1 protein and decreased XRCC1 expression. Knockdown of Epac1 abolished the effect of 8-pCPT-2'-O-Me-cAMP and restored XRCC1 protein level following γ-ray irradiation. From these results, we conclude that the cAMP signaling system inhibits the repair of γ-ray-induced DNA damage by promoting the ubiquitin-proteasome dependent degradation of XRCC1 in an Epac-dependent pathway in lung cancer cells.
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Affiliation(s)
- Eun-Ah Cho
- Department of Biochemistry and Molecular Biology, Cancer Research Center, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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Gerlo S, Kooijman R, Beck IM, Kolmus K, Spooren A, Haegeman G. Cyclic AMP: a selective modulator of NF-κB action. Cell Mol Life Sci 2011; 68:3823-41. [PMID: 21744067 PMCID: PMC11114830 DOI: 10.1007/s00018-011-0757-8] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/10/2011] [Accepted: 06/16/2011] [Indexed: 10/18/2022]
Abstract
It has been known for several decades that cyclic AMP (cAMP), a prototypical second messenger, transducing the action of a variety of G-protein-coupled receptor ligands, has potent immunosuppressive and anti-inflammatory actions. These actions have been attributed in part to the ability of cAMP-induced signals to interfere with the function of the proinflammatory transcription factor Nuclear Factor-kappaB (NF-κB). NF-κB plays a crucial role in switching on the gene expression of a plethora of inflammatory and immune mediators, and as such is one of the master regulators of the immune response and a key target for anti-inflammatory drug design. A number of fundamental molecular mechanisms, contributing to the overall inhibitory actions of cAMP on NF-κB function, are well established. Paradoxically, recent reports indicate that cAMP, via its main effector, the protein kinase A (PKA), also promotes NF-κB activity. Indeed, cAMP actions appear to be highly cell type- and context-dependent. Importantly, several novel players in the cAMP/NF-κB connection, which selectively direct cAMP action, have been recently identified. These findings not only open up exciting new research avenues but also reveal novel opportunities for the design of more selective, NF-κB-targeting, anti-inflammatory drugs.
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Affiliation(s)
- Sarah Gerlo
- VIB Department of Medical Protein Research, Ghent University (UGent), Albert Baertsoenkaai, Belgium.
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16
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Cho EA, Oh JM, Kim SY, Kim Y, Juhnn YS. Heterotrimeric stimulatory GTP-binding proteins inhibit cisplatin-induced apoptosis by increasing X-linked inhibitor of apoptosis protein expression in cervical cancer cells. Cancer Sci 2011; 102:837-44. [PMID: 21255191 DOI: 10.1111/j.1349-7006.2011.01883.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Treatment with cisplatin (cis-dichlorodiammineplatinum (II)) induces DNA double-stranded breaks and apoptosis in many human cancer cells. We have reported that heterotrimeric stimulatory GTP-binding proteins (Gαs) can modulate the apoptotic response of several cancer cells. This study investigated the effect of Gαs on apoptosis triggered by cisplatin and its underlying molecular mechanism in cervical cancer cells. Stable expression of constitutively active Gαs (GαsQL) decreased the release of cytochrome c from the mitochondria to the cytosol and cleavage of caspase-3 and poly(ADP-ribose) polymerases in HeLa cells treated with 30 μM cisplatin, indicating that Gαs inhibited cisplatin-induced apoptosis. Treatment with forskolin also inhibited apoptosis of C33A and CaSKi cervical cancer cells. Expression of GαsQL increased the expression of the X-linked inhibitor of apoptosis protein (XIAP) and partially maintained increased XIAP after cisplatin treatment. Knockdown of XIAP by siRNA augmented apoptosis. Expression of GαsQL increased XIAP mRNA; this increase was inhibited by a protein kinase A inhibitor and cAMP response element (CRE) decoy. A cAMP response element (CRE)-like element at -1396 bp in the XIAP promoter was found to mediate the induction of XIAP by Gαs. In addition, expression of GαsQL protected against the ubiquitin/proteasome-dependent degradation of the XIAP protein. This study shows that Gαs inhibits cisplatin-induced apoptosis by increasing transcription of XIAP and by decreasing degradation of XIAP protein in HeLa cervical cancer cells.
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Affiliation(s)
- Eun-Ah Cho
- Department of Biochemistry and Molecular Biology, Cancer Research Center, Seoul National University College of Medicine, Seoul, Korea
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17
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Seo M, Juhnn YS. Gq protein mediates UVB-induced cyclooxygenase-2 expression by stimulating HB-EGF secretion from HaCaT human keratinocytes. Biochem Biophys Res Commun 2010; 393:190-5. [PMID: 20117092 DOI: 10.1016/j.bbrc.2010.01.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 01/20/2010] [Indexed: 12/19/2022]
Abstract
Ultraviolet (UV) radiation induces cyclooxygenase-2 expression to produce cellular responses including aging and carcinogenesis in skin. We hypothesised that heterotrimeric G proteins mediate UV-induced COX-2 expression by stimulating secretion of soluble HB-EGF (sHB-EGF). In this study, we aimed to elucidate the role and underlying mechanism of the alpha subunit of Gq protein (Galphaq) in UVB-induced HB-EGF secretion and COX-2 induction. We found that expression of constitutively active Galphaq (GalphaqQL) augmented UVB-induced HB-EGF secretion, which was abolished by knockdown of Galphaq with shRNA in HaCaT human keratinocytes. Galphaq was found to mediate the UVB-induced HB-EGF secretion by sequential activation of phospholipase C (PLC), protein kinase Cdelta (PKCdelta), and matrix metaloprotease-2 (MMP-2). Moreover, GalphaqQL mediated UVB-induced COX-2 expression in an HB-EGF-, EGFR-, and p38-dependent manner. From these results, we concluded that Galphaq mediates UV-induced COX-2 expression through activation of EGFR by HB-EGF, of which ectodomain shedding was stimulated through sequential activation of PLC, PKCdelta and MMP-2 in HaCaT cells.
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Affiliation(s)
- MiRan Seo
- Department of Biochemistry and Molecular Biology and Cancer Research Institute, Seoul National University College of Medicine, Republic of Korea
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Choi YJ, Kim SY, Oh JM, Juhnn YS. Stimulatory heterotrimeric G protein augments gamma ray-induced apoptosis by up-regulation of Bak expression via CREB and AP-1 in H1299 human lung cancer cells. Exp Mol Med 2009; 41:592-600. [PMID: 19381065 DOI: 10.3858/emm.2009.41.8.065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Stimulatory heterotrimeric GTP-binding proteins (Gs protein) stimulate cAMP generation in response to various signals, and modulate various cellular phenomena such as proliferation and apoptosis. This study aimed to investigate the effect of Gs proteins on gamma ray-induced apoptosis of lung cancer cells and its molecular mechanism, as an attempt to develop a new strategy to improve the therapeutic efficacy of gamma radiation. Expression of constitutively active mutant of the alpha subunit of Gs (GalphasQL) augmented gamma ray-induced apoptosis via mitochondrial dependent pathway when assessed by clonogenic assay, FACS analysis of PI stained cells, and western blot analysis of the cytoplasmic translocation of cytochrome C and the cleavage of caspase-3 and ploy(ADP-ribose) polymerase (PARP) in H1299 human lung cancer cells. GalphasQL up-regulated the Bak expression at the levels of protein and mRNA. Treatment with inhibitors of PKA (H89), SP600125 (JNK inhibitor), and a CRE-decoy blocked GalphasQL-stimulated Bak reporter luciferase activity. Expression of GalphasQL increased basal and gamma ray-induced luciferase activity of cAMP response element binding protein (CREB) and AP-1, and the binding of CREB and AP-1 to Bak promoter. Furthermore, prostaglandin E2, a Galphas activating signal, was found to augment gamma ray-induced apoptosis, which was abolished by treatment with a prostanoid receptor antagonist. These results indicate that Galphas augments gamma ray-induced apoptosis by up-regulation of Bak expression via CREB and AP-1 in H1299 lung cancer cells, suggesting that the efficacy of radiotherapy of lung cancer may be improved by modulating Gs signaling pathway.
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Affiliation(s)
- Yoon Jung Choi
- Department of Biochemistry and Molecular Biology, Laboratory of Cellular Signaling, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea
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Chen KC, Liu WH, Kao PH, Chang LS. Calcium-stimulated mitogen-activated protein kinase activation elicits Bcl-xL downregulation and Bak upregulation in notexin-treated human neuroblastoma SK-N-SH cells. J Cell Physiol 2009; 222:177-86. [PMID: 19780038 DOI: 10.1002/jcp.21934] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Notechis scutatus scutatus notexin induced apoptotic death of SK-N-SH cells accompanied with downregulation of Bcl-xL, upregulation of Bak, mitochondrial depolarization, and ROS generation. Upon exposure to notexin, Ca(2+)-mediated JNK and p38 MAPK activation were observed in SK-N-SH cells. Production of ROS was a downstream event followed by Ca(2+)-mediated mitochondrial alteration. Notexin-induced cell death, mitochondrial depolarization, and ROS generation were suppressed by SB202190 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor). Moreover, phospho-p38 MAPK and phospho-JNK were proved to be involved in Bcl-xL degradation, and overexpression of Bcl-xL attenuated the cytotoxic effect of notexin. Bak upregulation was elicited by p38 MAPK-mediated ATF-2 activation and JNK-mediated c-Jun activation. Suppression of Bak upregulation by ATF-2 siRNA or c-Jun siRNA attenuated notexin-evoked mitochondrial depolarization and rescued viability of notexin-treated cells. Taken together, our data indicate that notexin-induced apoptotic death of SK-N-SH cells is mediated through mitochondrial alteration triggering by Ca(2+)-evoked p38 MAPK/ATF-2 and JNK/c-Jun signaling pathways.
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Affiliation(s)
- Ku-Chung Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung, Taiwan
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Abstract
Exposing rodents to brief episodes of hypoxia mimics the hypoxemia and the cardiovascular and metabolic effects observed in patients with obstructive sleep apnoea (OSA), a condition that affects between 5% and 20% of the population. Apart from daytime sleepiness, OSA is associated with a high incidence of systemic and pulmonary hypertension, peripheral vascular disease, stroke and sudden cardiac death. The development of animal models to study sleep apnoea has provided convincing evidence that recurrent exposure to intermittent hypoxia (IH) has significant vascular and haemodynamic impact that explain much of the cardiovascular morbidity and mortality observed in patients with sleep apnoea. However, the molecular and cellular mechanisms of how IH causes these changes is unclear and under investigation. This review focuses on the most recent findings addressing these mechanisms. It includes a discussion of the contribution of the nervous system, circulating and vascular factors, inflammatory mediators and transcription factors to IH-induced cardiovascular disease. It also highlights the importance of reactive oxygen species as a primary mediator of the systemic and pulmonary hypertension that develops in response to exposure to IH.
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Affiliation(s)
- Laura V González Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, NM, USA.
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Choi YJ, Oh JM, Kim SY, Seo M, Juhnn YS. Stimulatory heterotrimeric GTP-binding protein augments cisplatin-induced apoptosis by upregulating Bak expression in human lung cancer cells. Cancer Sci 2009; 100:1069-74. [PMID: 19320642 DOI: 10.1111/j.1349-7006.2009.01136.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The present study aimed to investigate the effect of the stimulatory heterotrimeric GTP-binding (Gs) protein signaling system on cisplatin-induced apoptosis of lung cancer cells and its underlying mechanism as an attempt to develop a novel strategy to improve the therapeutic efficacy of cisplatin. Overexpression of the constitutively active alpha subunit of Gs (GalphasQL) in A549 human lung cancer cells increased cisplatin-induced apoptosis, and knockdown of Galphas with small hairpin RNA decreased the percentage of apoptotic cells. GalphasQL increased the expression of the proapoptotic proteins B-cell leukemia/lymphoma-2 genes (Bcl-2) homologous antagonist killer protein (Bak) and Bcl-2 associated X protein (Bax), and decreased the expression of the antiapoptotic proteins Bcl-2 and Bcl-Xlong protein. Knockdown of Bak blocked the augmentative effects of GalphasQL. GalphasQL decreased the degradation rate of the Bak protein, and increased Bak mRNA transcript levels. GalphasQL increased Bak-luciferase activity in a protein kinase A and cyclic AMP response element-dependent manner. GalphasQL also augmented cisplatin-induced apoptosis of H1299 human lung cancer cells that lack functional p53. From this study, it is concluded that Galphas augments cisplatin-induced apoptosis of lung cancer cells partially through upregulating Bak expression by increasing transcription and by decreasing the rate of protein degradation.
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Affiliation(s)
- Yoon Jung Choi
- Department of Biochemistry and Molecular Biology, Laboratory of Cellular Signaling, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Seo M, Nam HJ, Kim SY, Juhnn YS. Inhibitory heterotrimeric GTP-binding proteins inhibit hydrogen peroxide-induced apoptosis by up-regulation of Bcl-2 via NF-kappaB in H1299 human lung cancer cells. Biochem Biophys Res Commun 2009; 381:153-8. [PMID: 19233129 DOI: 10.1016/j.bbrc.2009.01.188] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 01/31/2009] [Indexed: 10/21/2022]
Abstract
Inhibitory heterotrimeric GTP-binding proteins (Gi proteins) mediate a variety of signaling pathways by coupling receptors and effectors to regulate cellular proliferation, differentiation, and apoptosis. However, the role of Gi proteins in the modulation of hydrogen peroxide-induced apoptosis is not clearly understood. Thus, we investigated the effect of Gi proteins on hydrogen peroxide-induced apoptosis and the underlying mechanisms in H1299 human lung cancer cells. The stable expression of constitutively active alpha subunits of Gi1 (Galphai1QL), Gi2, or Gi3 inhibited hydrogen peroxide-induced apoptosis. The expression of Galphai1QL up-regulated Bcl-2 expression, and the knockdown of Bcl-2 with siRNA abolished the anti-apoptotic effect of Galphai1QL. Galphai1 induced the transcription of Bcl-2 by activation of NF-kappaB, which resulted from an increase in NF-kappaB p50 protein. We conclude that Galphai1 inhibits hydrogen peroxide-induced apoptosis of H1299 lung cancer cells by up-regulating the transcription of Bcl-2 through a p50-mediated NF-kappaB activation.
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Affiliation(s)
- Miran Seo
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, 28 Yongon-dong, Jongno-gu, Seoul 110-799, Republic of Korea
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Cardone RA, Busco G, Greco MR, Bellizzi A, Accardi R, Cafarelli A, Monterisi S, Carratù P, Casavola V, Paradiso A, Tommasino M, Reshkin SJ. HPV16 E7-dependent transformation activates NHE1 through a PKA-RhoA-induced inhibition of p38alpha. PLoS One 2008; 3:e3529. [PMID: 18953413 PMCID: PMC2568952 DOI: 10.1371/journal.pone.0003529] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Accepted: 10/03/2008] [Indexed: 11/30/2022] Open
Abstract
Background Neoplastic transformation originates from a large number of different genetic alterations. Despite this genetic variability, a common phenotype to transformed cells is cellular alkalinization. We have previously shown in human keratinocytes and a cell line in which transformation can be turned on and followed by the inducible expression of the E7 oncogene of human papillomavirus type 16 (HPV16), that intracellular alkalinization is an early and essential physiological event driven by the up-regulation of the Na/+H+ exchanger isoform 1 (NHE1) and is necessary for the development of other transformed phenotypes and the in vivo tumor formation in nude mice. Methodology Here, we utilize these model systems to elucidate the dynamic sequence of alterations of the upstream signal transduction systems leading to the transformation-dependent activation of NHE1. Principal Findings We observe that a down-regulation of p38 MAPK activity is a fundamental step in the ability of the oncogene to transform the cell. Further, using pharmacological agents and transient transfections with dominant interfering, constitutively active, phosphorylation negative mutants and siRNA strategy to modify specific upstream signal transduction components that link HPV16 E7 oncogenic signals to up-regulation of the NHE1, we demonstrate that the stimulation of NHE1 activity is driven by an early rise in cellular cAMP resulting in the down-stream inhibition of p38 MAPK via the PKA-dependent phosphorylation of the small G-protein, RhoA, and its subsequent inhibition. Conclusions All together these data significantly improve our knowledge concerning the basic cellular alterations involved in oncogene-driven neoplastic transformation.
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Affiliation(s)
- Rosa A. Cardone
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Giovanni Busco
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Maria R. Greco
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Antonia Bellizzi
- Clinical Experimental Oncology Laboratory, National Cancer Institute Giovanni Paolo II, Bari, Italy
| | - Rosita Accardi
- Infections and Cancer Biology Group, IARC-WHO, Lyon, France
| | - Antonella Cafarelli
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Stefania Monterisi
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | | | - Valeria Casavola
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
| | - Angelo Paradiso
- Clinical Experimental Oncology Laboratory, National Cancer Institute Giovanni Paolo II, Bari, Italy
| | | | - Stephan J. Reshkin
- Department of General and Environmental Physiology, University of Bari, Bari, Italy
- * E-mail:
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Oh JM, Kim SH, Lee YI, Seo M, Kim SY, Song YS, Kim WH, Juhnn YS. Human papillomavirus E5 protein induces expression of the EP4 subtype of prostaglandin E2 receptor in cyclic AMP response element-dependent pathways in cervical cancer cells. Carcinogenesis 2008; 30:141-9. [PMID: 18849297 DOI: 10.1093/carcin/bgn236] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Human papillomavirus (HPV) is the major cause of uterine cervical cancer, but the role of the HPV E5 in carcinogenesis is not clearly understood. Prostaglandins are known to contribute to carcinogenesis of cervical cancer, and we therefore investigated the effect of HPV16 E5 on the expression of prostaglandin E2 (PGE2) receptors and underlying mechanisms. Stable expression of the E5 induced expression of the EP4 subtype of PGE2 receptors in C33A cervical cancer cells, and transfection of E5 small interfering RNA (siRNA) decreased it. EP4 protein expression was increased in human cervical cancer tissues, and EP4 mediated E5-induced increase in anchorage-independent colony formation and vascular endothelial growth factor expression. E5 induced cyclooxygenase-2 (COX-2) expression, and COX-2 increased PGE2 secretion and EP4 expression. The induction of EP4 by PGE2 and E5 was inhibited by an EP4 antagonist, inhibitors of cyclic adenosine monophosphate-dependent protein kinase or phosphatidylinositol 3-kinase, and a cyclic adenosine monophosphate response element (CRE) decoy. E5 increased the luciferase expression controlled by a variant CRE of the EP4 promoter, and it also increased the binding of cyclic adenosine monophosphate response element binding protein (CREB) to oligonucleotides containing this CRE. We conclude that the HPV16 E5 protein induces EP4 receptor protein in cervical cancer cells and that this induction involves epidermal growth factor receptor, COX-2, PGE2, EP2 and EP4, protein kinase A, CREB and CRE.
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Affiliation(s)
- Jung-Min Oh
- Interdisciplinary Graduate Program in Tumor Biology, Cancer Research Institute, Seoul National University College of Medicine, Jongno-Gu, Seoul, Republic of Korea
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