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Richartz N, Pietka W, Yadav A, Bostad M, Bhagwat S, Naderi S, Naderi EH, Stokke T, Ruud E, Blomhoff HK. N-acetyl cysteine turns EPAC activators into potent killers of acute lymphoblastic leukemia cells. J Biol Chem 2024; 300:105509. [PMID: 38042493 PMCID: PMC10772734 DOI: 10.1016/j.jbc.2023.105509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 12/04/2023] Open
Abstract
Today, the majority of patients with pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL, hereafter ALL) survive their disease, but many of the survivors suffer from life-limiting late effects of the treatment. ALL develops in the bone marrow, where the cells are exposed to cAMP-generating prostaglandin E2. We have previously identified the cAMP signaling pathway as a putative target for improved efficacy of ALL treatment, based on the ability of cAMP signaling to reduce apoptosis induced by DNA damaging agents. In the present study, we have identified the antioxidant N-acetyl cysteine (NAC) as a powerful modifier of critical events downstream of the cell-permeable cAMP analog 8-(4-chlorophenylthio) adenosine-3', 5'- cyclic monophosphate (8-CPT). Accordingly, we found NAC to turn 8-CPT into a potent killer of ALL cells in vitro both in the presence and absence of DNA damaging treatment. Furthermore, we revealed that NAC in combination with 8-CPT is able to delay the progression of ALL in a xenograft model in NOD-scid IL2Rγnull mice. NAC was shown to rely on the ability of 8-CPT to activate the guanine-nucleotide exchange factor EPAC, and we demonstrated that the ALL cells are killed by apoptosis involving sustained elevated levels of calcium imposed by the combination of the two drugs. Taken together, we propose that 8-CPT in the presence of NAC might be utilized as a novel strategy for treating pediatric ALL patients, and that this powerful combination might be exploited to enhance the therapeutic index of current ALL targeting therapies.
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Affiliation(s)
- Nina Richartz
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Wojciech Pietka
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Ajay Yadav
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Monica Bostad
- Department of Core Facilities, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sampada Bhagwat
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Soheil Naderi
- Division of Laboratory Medicine, Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Elin Hallan Naderi
- Section of Head and Neck Oncology, Department of Oncology, Oslo University Hospital, Oslo, Norway
| | - Trond Stokke
- Department of Core Facilities, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Ellen Ruud
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Heidi Kiil Blomhoff
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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Miao Y, Peng L, Chen Z, Hu Y, Tao L, Yao Y, Wu Y, Yang D, Xu T. Recent advances of Phosphodiesterase 4B in cancer. Expert Opin Ther Targets 2023; 27:121-132. [PMID: 36803246 DOI: 10.1080/14728222.2023.2183496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
INTRODUCTION Phosphodiesterase 4B (PDE4B) is a crucial enzyme in the phosphodiesterases (PDEs), acting as a regulator of cyclic adenosine monophosphate (cAMP). It is involved in cancer process through PDE4B/cAMP signaling pathway. Cancer occurs and develops with the regulation of PDE4B in the body, suggesting that PDE4B is a promising therapeutic target. AREAS COVERED This review covereed the function and mechanism of PDE4B in cancer. We summarized the possible clinical applications of PDE4B, and highlighted the possible ways to develop clinical applications of PDE4B inhibitors. We also discussed some common PDEs inhibitors, and expected the development of combined targeting PDE4B and other PDEs drugs in the future. EXPERT OPINION The existing research and clinical data can strongly prove the role of PDE4B in cancer. PDE4B inhibition can effectively increase cell apoptosis, inhibit cell proliferation, transformation, migration, etc., indicating that PDE4B inhibition can effectively inhibit the development of cancer. Other PDEs may antagonize or coordinate this effect. As for the further study on the relationship between PDE4B and other PDEs in cancer, it is still a challenge to develop multi-targeted PDEs inhibitors.
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Affiliation(s)
- Yu Miao
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Li Peng
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Zhaolin Chen
- Department of Pharmacy, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui Provincial Hospital, Hefei, Anhui Province, China
| | - Ying Hu
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Liangsong Tao
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Yan Yao
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Yincui Wu
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Dashuai Yang
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
| | - Tao Xu
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, China.,Anhui Key Laboratory of Bioactivity of Natural Products, Institute for Liver Diseases of Anhui Medical University, Anhui Medical University, Hefei, Anhui Province, China
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Ahmed MB, Alghamdi AAA, Islam SU, Lee JS, Lee YS. cAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach. Cells 2022; 11:cells11132020. [PMID: 35805104 PMCID: PMC9266045 DOI: 10.3390/cells11132020] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/17/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
Cancer is one of the most common causes of death globally. Despite extensive research and considerable advances in cancer therapy, the fundamentals of the disease remain unclear. Understanding the key signaling mechanisms that cause cancer cell malignancy may help to uncover new pharmaco-targets. Cyclic adenosine monophosphate (cAMP) regulates various biological functions, including those in malignant cells. Understanding intracellular second messenger pathways is crucial for identifying downstream proteins involved in cancer growth and development. cAMP regulates cell signaling and a variety of physiological and pathological activities. There may be an impact on gene transcription from protein kinase A (PKA) as well as its downstream effectors, such as cAMP response element-binding protein (CREB). The position of CREB downstream of numerous growth signaling pathways implies its oncogenic potential in tumor cells. Tumor growth is associated with increased CREB expression and activation. PKA can be used as both an onco-drug target and a biomarker to find, identify, and stage tumors. Exploring cAMP effectors and their downstream pathways in cancer has become easier using exchange protein directly activated by cAMP (EPAC) modulators. This signaling system may inhibit or accelerate tumor growth depending on the tumor and its environment. As cAMP and its effectors are critical for cancer development, targeting them may be a useful cancer treatment strategy. Moreover, by reviewing the material from a distinct viewpoint, this review aims to give a knowledge of the impact of the cAMP signaling pathway and the related effectors on cancer incidence and development. These innovative insights seek to encourage the development of novel treatment techniques and new approaches.
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Affiliation(s)
- Muhammad Bilal Ahmed
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Korea; (M.B.A.); (J.-S.L.)
| | | | - Salman Ul Islam
- Department of Pharmacy, Cecos University, Peshawar, Street 1, Sector F 5 Phase 6 Hayatabad, Peshawar 25000, Pakistan;
| | - Joon-Seok Lee
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Korea; (M.B.A.); (J.-S.L.)
| | - Young-Sup Lee
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Korea; (M.B.A.); (J.-S.L.)
- Correspondence: ; Tel.: +82-53-950-6353; Fax: +82-53-943-2762
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The Role of Neuropeptide-Stimulated cAMP-EPACs Signalling in Cancer Cells. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27010311. [PMID: 35011543 PMCID: PMC8746471 DOI: 10.3390/molecules27010311] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 02/06/2023]
Abstract
Neuropeptides are autocrine and paracrine signalling factors and mainly bind to G protein-coupled receptors (GPCRs) to trigger intracellular secondary messenger release including adenosine 3′, 5′-cyclic monophosphate (cAMP), thus modulating cancer progress in different kind of tumours. As one of the downstream effectors of cAMP, exchange proteins directly activated by cAMP (EPACs) play dual roles in cancer proliferation and metastasis. More evidence about the relationship between neuropeptides and EPAC pathways have been proposed for their potential role in cancer development; hence, this review focuses on the role of neuropeptide/GPCR system modulation of cAMP/EPACs pathways in cancers. The correlated downstream pathways between neuropeptides and EPACs in cancer cell proliferation, migration, and metastasis is discussed to glimmer the direction of future research.
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Abstract
The well-known second messenger cyclic adenosine monophosphate (cAMP) regulates the morphology and physiology of neurons and thus higher cognitive brain functions. The discovery of exchange protein activated by cAMP (Epac) as a guanine nucleotide exchange factor for Rap GTPases has shed light on protein kinase A (PKA)-independent functions of cAMP signaling in neural tissues. Studies of cAMP-Epac-mediated signaling in neurons under normal and disease conditions also revealed its diverse contributions to neurodevelopment, synaptic remodeling, and neurotransmitter release, as well as learning, memory, and emotion. In this mini-review, the various roles of Epac isoforms, including Epac1 and Epac2, highly expressed in neural tissues are summarized, and controversies or issues are highlighted that need to be resolved to uncover the critical functions of Epac in neural tissues and the potential for a new therapeutic target of mental disorders.
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Affiliation(s)
- Kyungmin Lee
- Laboratory for Behavioral Neural Circuitry and Physiology, Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu 41944, Korea
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6
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Liu Y, Garron TM, Chang Q, Su Z, Zhou C, Gong EC, Zheng J, Yin Y, Ksiazek T, Brasel T, Jin Y, Boor P, Comer JE, Gong B. Cell-type apoptosis in lung during SARS-CoV-2 infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 33398280 DOI: 10.1101/2020.12.23.424254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The SARS-CoV-2 pandemic has inspired renewed interest in understanding the fundamental pathology of acute respiratory distress syndrome (ARDS) following infection because fatal COVID-19 cases are commonly linked to respiratory failure due to ARDS. The pathologic alteration known as diffuse alveolar damage in endothelial and epithelial cells is a critical feature of acute lung injury in ARDS. However, the pathogenesis of ARDS following SRAS-CoV-2 infection remains largely unknown. In the present study, we examined apoptosis in post-mortem lung sections from COVID-19 patients and lung tissues from a non-human primate model of SARS-CoV-2 infection, in a cell-type manner, including type 1 and 2 alveolar cells and vascular endothelial cells (ECs), macrophages, and T cells. Multiple-target immunofluorescence (IF) assays and western blotting suggest both intrinsic and extrinsic apoptotic pathways are activated during SARS-CoV-2 infection. Furthermore, we observed that SARS-CoV-2 fails to induce apoptosis in human bronchial epithelial cells (i.e., BEAS2B cells) and primary human umbilical vein endothelial cells (HUVECs), which are refractory to SARS-CoV-2 infection. However, infection of co-cultured Vero cells and HUVECs or Vero cells and BEAS2B cells with SARS-CoV-2 induced apoptosis in both Vero cells and HUVECs/BEAS2B cells, but did not alter the permissiveness of HUVECs or BEAS2B cells to the virus. Post-exposure treatment of the co-culture of Vero cells and HUVECs with an EPAC1-specific activator ameliorated apoptosis in HUVECs. These findings may help to delineate a novel insight into the pathogenesis of ARDS following SARS-CoV-2 infection.
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Wehbe N, Slika H, Mesmar J, Nasser SA, Pintus G, Baydoun S, Badran A, Kobeissy F, Eid AH, Baydoun E. The Role of Epac in Cancer Progression. Int J Mol Sci 2020; 21:ijms21186489. [PMID: 32899451 PMCID: PMC7555121 DOI: 10.3390/ijms21186489] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022] Open
Abstract
Cancer continues to be a prime contributor to global mortality. Despite tremendous research efforts and major advances in cancer therapy, much remains to be learned about the underlying molecular mechanisms of this debilitating disease. A better understanding of the key signaling events driving the malignant phenotype of cancer cells may help identify new pharmaco-targets. Cyclic adenosine 3',5'-monophosphate (cAMP) modulates a plethora of biological processes, including those that are characteristic of malignant cells. Over the years, most cAMP-mediated actions were attributed to the activity of its effector protein kinase A (PKA). However, studies have revealed an important role for the exchange protein activated by cAMP (Epac) as another effector mediating the actions of cAMP. In cancer, Epac appears to have a dual role in regulating cellular processes that are essential for carcinogenesis. In addition, the development of Epac modulators offered new routes to further explore the role of this cAMP effector and its downstream pathways in cancer. In this review, the potentials of Epac as an attractive target in the fight against cancer are depicted. Additionally, the role of Epac in cancer progression, namely its effect on cancer cell proliferation, migration/metastasis, and apoptosis, with the possible interaction of reactive oxygen species (ROS) in these phenomena, is discussed with emphasis on the underlying mechanisms and pathways.
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Affiliation(s)
- Nadine Wehbe
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
| | - Hasan Slika
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
| | - Joelle Mesmar
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
| | - Suzanne A. Nasser
- Department of Pharmacology, Beirut Arab University, P.O. Box 11-5020 Beirut, Lebanon;
| | - Gianfranco Pintus
- Department of Biomedical Sciences, University of Sharjah, P.O. Box 27272 Sharjah, UAE;
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43, 07100 Sassari, Italy
| | - Serine Baydoun
- Department of Radiology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
| | - Adnan Badran
- Department of Basic Sciences, University of Petra, P.O. Box 961343, Amman 11196, Jordan;
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236, Beirut, Lebanon;
| | - Ali H. Eid
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon;
- Department of Pharmacology and Therapeutics, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236, Beirut, Lebanon
- Correspondence: (A.H.E.); (E.B.); Tel.: +961-1-350-000 (ext. 4891) (A.H.E. & E.B.)
| | - Elias Baydoun
- Department of Biology, American University of Beirut, P.O. Box 11-0236 Beirut, Lebanon; (N.W.); (J.M.)
- Correspondence: (A.H.E.); (E.B.); Tel.: +961-1-350-000 (ext. 4891) (A.H.E. & E.B.)
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Richard SA. EPAC2: A new and promising protein for glioma pathogenesis and therapy. Oncol Rev 2020; 14:446. [PMID: 32395202 PMCID: PMC7204831 DOI: 10.4081/oncol.2020.446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 04/16/2020] [Indexed: 01/02/2023] Open
Abstract
Gliomas are prime brain cancers which are initiated by malignant modification of neural stem cells, progenitor cells and differentiated glial cells such as astrocyte, oligodendrocyte as well as ependymal cells. Exchange proteins directly activated by cAMP (EPACs) are crucial cyclic adenosine 3’,5’-monophosphate (cAMP)-determined signaling pathways. Cyclic AMP-intermediated signaling events were utilized to transduce protein kinase A (PKA) leading to the detection of EPACs or cAMP-guanine exchange factors (cAMP-GEFs). EPACs have been detected as crucial proteins associated with the pathogenesis of neurological disorders as well as numerous human diseases. EPAC proteins have two isoforms. These isoforms are EPAC1 and EPAC2. EPAC2 also known as Rap guanine nucleotide exchange factor 4 (RAPGEF4) is generally expression in all neurites. Higher EAPC2 levels was detected in the cortex, hippocampus as well as striatum of adult mouse brain. Activation as well as over-secretion of EPAC2 triggers apoptosis in neurons and EPAC-triggered apoptosis was intermediated via the modulation of Bcl-2 interacting member protein (BIM). EPAC2 secretory levels has proven to be more in low-grade clinical glioma than high-grade clinical glioma. This review therefore explores the effects of EPAC2/RAPGEF4 on the pathogenesis of glioma instead of EPAC1 because EPAC2 and not EPAC1 is predominately expressed in the brain. Therefore, EPAC2 is most likely to modulate glioma pathogenesis rather than EPAC1.
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Affiliation(s)
- Seidu A Richard
- Department of Medicine, Princefield University, Ho, Ghana, West Africa
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Qi X, Chen H, Fu B, Huang Z, Mou Y, Liu J, Xu Y, Xiong W, Cao Y. LncRNAs NR-026690 and ENST00000447867 are upregulated in CD4 + T cells in patients with acute exacerbation of COPD. Int J Chron Obstruct Pulmon Dis 2019; 14:699-711. [PMID: 30988604 PMCID: PMC6440447 DOI: 10.2147/copd.s191815] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Objective The aim of the study was to determine the expression profile of long noncoding RNAs (lncRNAs) in CD4+ T cells from COPD patients and explore the clinical value of the lncRNAs. Methods First, microarray analysis was performed. Differentially expressed lncRNAs were validated by quantitative real-time reverse transcription-PCR (qRT-PCR) in samples from 56 patients with acute exacerbations of COPD (AECOPD), 56 patients with stable COPD, and 35 healthy controls. Meanwhile, the clinical value was tested by receiver operating characteristic curve analysis. The functions of lncRNAs were analyzed by the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database. The potential target genes that might be regulated by NR-026690 and ENST00000447867 were identified by the lncRNA-mRNA network and competing endogenous RNA network. The transcriptional expression level of rap guanine nucleotide exchange factor 3 (RAPGEF3) was tested by qRT-PCR. The correlation of the expression between NR-026690, ENST00000447867, and RAPGEF3 was analyzed by Spearman's correlation test. Results We found that the relative expression levels of ENST00000447867 and NR-026690 in the CD4+ T cells of AECOPD patients were significantly higher than in the stable COPD patients and control subjects by microarray and qRT-PCR validation. The transcriptional expression level of RAPGEF3 in the CD4+ T cells was significantly higher in the AECOPD group compared to the control group (P<0.01) and the stable COPD group (P<0.05). RAPGEF3 expression was positively associated with NR-026690 (r=0.4925, P<0.01) and ENST00000447867 (r=0.4065, P<0.01). Conclusion NR-026690 and ENST00000447867 might be potential biomarkers for COPD. They might affect RAPGEF3 as miRNA sponges to regulate COPD development.
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Affiliation(s)
- Xuefei Qi
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Huilong Chen
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Bohua Fu
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Zhenli Huang
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Yong Mou
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Juan Liu
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Yongjian Xu
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Weining Xiong
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
| | - Yong Cao
- Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Key Cite of National Clinical Research Center for Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences & Technology, Wuhan, China,
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Mele S, Devereux S, Pepper AG, Infante E, Ridley AJ. Calcium-RasGRP2-Rap1 signaling mediates CD38-induced migration of chronic lymphocytic leukemia cells. Blood Adv 2018; 2:1551-1561. [PMID: 29970392 PMCID: PMC6039665 DOI: 10.1182/bloodadvances.2017014506] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 05/24/2018] [Indexed: 01/08/2023] Open
Abstract
CD38 is a transmembrane exoenzyme that is associated with poor prognosis in chronic lymphocytic leukemia (CLL). High CD38 levels in CLL cells are linked to increased cell migration, but the molecular basis is unknown. CD38 produces nicotinic acid adenine dinucleotide phosphate and adenosine 5'-diphosphate-ribose, both of which can act to increase intracellular Ca2+ levels. Here we show that CD38 expression increases basal intracellular Ca2+ levels and stimulates CLL cell migration both with and without chemokine stimulation. We find that CD38 acts via intracellular Ca2+ to increase the activity of the Ras family GTPase Rap1, which is in turn regulated by the Ca2+-sensitive Rap1 guanine-nucleotide exchange factor RasGRP2. Both Rap1 and RasGRP2 are required for CLL cell migration, and RasGRP2 is polarized in primary CLL cells with high CD38 levels. These results indicate that CD38 promotes RasGRP2/Rap1-mediated CLL cell adhesion and migration by increasing intracellular Ca2+ levels.
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Affiliation(s)
- Silvia Mele
- Randall Centre for Cell and Molecular Biophysics, and
- School of Cancer Sciences, King's College London, London, United Kingdom
| | - Stephen Devereux
- School of Cancer Sciences, King's College London, London, United Kingdom
| | - Andrea G Pepper
- School of Cancer Sciences, King's College London, London, United Kingdom
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom; and
| | | | - Anne J Ridley
- Randall Centre for Cell and Molecular Biophysics, and
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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11
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Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
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12
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Lima KM, Vago JP, Caux TR, Negreiros-Lima GL, Sugimoto MA, Tavares LP, Arribada RG, Carmo AAF, Galvão I, Costa BRC, Soriani FM, Pinho V, Solito E, Perretti M, Teixeira MM, Sousa LP. The resolution of acute inflammation induced by cyclic AMP is dependent on annexin A1. J Biol Chem 2017; 292:13758-13773. [PMID: 28655761 DOI: 10.1074/jbc.m117.800391] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Indexed: 12/17/2022] Open
Abstract
Annexin A1 (AnxA1) is a glucocorticoid-regulated protein known for its anti-inflammatory and pro-resolving effects. We have shown previously that the cAMP-enhancing compounds rolipram (ROL; a PDE4 inhibitor) and Bt2cAMP (a cAMP mimetic) drive caspase-dependent resolution of neutrophilic inflammation. In this follow-up study, we investigated whether AnxA1 could be involved in the pro-resolving properties of these compounds using a model of LPS-induced inflammation in BALB/c mice. The treatment with ROL or Bt2cAMP at the peak of inflammation shortened resolution intervals, improved resolution indices, and increased AnxA1 expression. In vitro studies showed that ROL and Bt2cAMP induced AnxA1 expression and phosphorylation, and this effect was prevented by PKA inhibitors, suggesting the involvement of PKA in ROL-induced AnxA1 expression. Akin to these in vitro findings, H89 prevented ROL- and Bt2cAMP-induced resolution of inflammation, and it was associated with decreased levels of intact AnxA1. Moreover, two different strategies to block the AnxA1 pathway (by using N-t-Boc-Met-Leu-Phe, a nonselective AnxA1 receptor antagonist, or by using an anti-AnxA1 neutralizing antiserum) prevented ROL- and Bt2cAMP-induced resolution and neutrophil apoptosis. Likewise, the ability of ROL or Bt2cAMP to induce neutrophil apoptosis was impaired in AnxA-knock-out mice. Finally, in in vitro settings, ROL and Bt2cAMP overrode the survival-inducing effect of LPS in human neutrophils in an AnxA1-dependent manner. Our results show that AnxA1 is at least one of the endogenous determinants mediating the pro-resolving properties of cAMP-elevating agents and cAMP-mimetic drugs.
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Affiliation(s)
- Kátia M Lima
- From the Programa de Pós-Graduação em Biologia Celular, Departamento de Morfologia, Instituto de Ciências Biológicas.,the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Juliana P Vago
- From the Programa de Pós-Graduação em Biologia Celular, Departamento de Morfologia, Instituto de Ciências Biológicas.,the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Thaís R Caux
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Graziele Letícia Negreiros-Lima
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Michelle A Sugimoto
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Luciana P Tavares
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Raquel G Arribada
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Aline Alves F Carmo
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Izabela Galvão
- the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Bruno Rocha C Costa
- the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Frederico M Soriani
- the Departamento de Biologia Geral, Genética, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Pampulha 31270-901, Belo Horizonte, Brazil and
| | - Vanessa Pinho
- From the Programa de Pós-Graduação em Biologia Celular, Departamento de Morfologia, Instituto de Ciências Biológicas.,the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Egle Solito
- the William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Mauro Perretti
- the William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Mauro M Teixeira
- the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
| | - Lirlândia P Sousa
- From the Programa de Pós-Graduação em Biologia Celular, Departamento de Morfologia, Instituto de Ciências Biológicas, .,the Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia.,the Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, and
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13
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Xiao LY, Kan WM. Cyclic AMP (cAMP) confers drug resistance against DNA damaging agents via PKAIA in CML cells. Eur J Pharmacol 2016; 794:201-208. [PMID: 27894809 DOI: 10.1016/j.ejphar.2016.11.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 12/15/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) regulates many vital functions such as metabolism, proliferation, differentiation and death. Depending on cell types and stimulators, cAMP could either promote or attenuate cell death. cAMP signal can be transduced by protein kinase A (PKA) and/or exchange protein directly activated by cAMP (EPAC). In CML cells, cAMP may suppress their proliferation and enhance their differentiation. However, the role of cAMP on DNA damaging agent toxicity and the mechanism involved has not been studied. In this study, we studied the effect of cAMP on the sensitivity of CML cells to DNA damaging agents. We observed that forskolin (FSK) and dibutyryl-cAMP (DBcAMP) decreased cisplatin and etoposide-induced cell death in K562 cells. Moreover, PKA activator prevented K562 cells from DNA damaging agent-induced cell death while EPAC activator had no effect. Furthermore, we found that the PKA subtype, PKAIA, was involved in cAMP-attenuated resistance in K562 cells. Taken together, our results suggest that increased cAMP level confers CML cells to acquire a novel mechanism against DNA damaging agent toxicity via PKAIA. Thus, PKAIA inhibitor may be helpful in overcoming the resistance to DNA damaging agents in CML cells.
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Affiliation(s)
- Ling-Yi Xiao
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Wai-Ming Kan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan; Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
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14
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Gao M, Ma Y, Bast RC, Li Y, Wan L, Liu Y, Sun Y, Fang Z, Zhang L, Wang X, Wei Z. Epac1 knockdown inhibits the proliferation of ovarian cancer cells by inactivating AKT/Cyclin D1/CDK4 pathway in vitro and in vivo. Med Oncol 2016; 33:73. [PMID: 27277757 DOI: 10.1007/s12032-016-0786-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/27/2016] [Indexed: 12/14/2022]
Abstract
Ovarian cancer is the leading cause of death among gynecological malignancies, and high grade serous ovarian carcinoma is the most common and most aggressive subtype. Recently, it was demonstrated that cAMP mediates protein kinase A-independent effects through Epac (exchange protein directly activated by cAMP) proteins. Epac proteins, including Epac1 and Epac2, are implicated in several diverse cellular responses, such as insulin secretion, exocytosis, cellular calcium handling and formation of cell-cell junctions. Several reports document that Epac1 could play vital roles in promoting proliferation, invasion and migration of some cancer cells. However, the expression levels and roles of Epac1 in ovarian cancer have not been investigated. In the present study, we detected the expression levels of Epac1 mRNA and protein in three kinds of ovarian cancer cells SKOV3, OVCAR3 and CAOV3. Furthermore, the effect of Epac1 knockdown on the proliferation and apoptosis of SKOV3 and OVCAR3 cells was evaluated in vitro and in vivo. The results showed that there was higher expression of Epac1 mRNA and protein in SKOV3 and OVCAR3 cells. Epac1 knockdown inhibited the proliferation of SKOV3 and OVCAR3 cells in vitro and in vivo. Decreased proliferation may be due to downregulation of Epac1-induced G1 phase arrest by inactivating the AKT/Cyclin D1/CDK4 pathway, but not to alterations in the MAPK pathway or to apoptosis. Taken together, our data provide new insight into the essential role of Epac1 in regulating growth of ovarian cancer cells and suggest that Epac1 might represent an attractive therapeutic target for treatment of ovarian cancer.
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Affiliation(s)
- Meng Gao
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yanyan Ma
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Robert C Bast
- Department of Experimental Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yue Li
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Lu Wan
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yanping Liu
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China.,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Yingshuo Sun
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China.,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Zhenghui Fang
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China
| | - Lining Zhang
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China
| | - Xiaoyan Wang
- Department of Immunology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China.
| | - Zengtao Wei
- Department of Gynecology and Obstetrics, Jinan Central Hospital Affiliated to Shandong University, 105# Jiefang Road, Jinan, 250013, Shandong, People's Republic of China. .,Department of Gynecology and Obstetrics, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012, Shandong, People's Republic of China.
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15
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Tan Y, Watkins AA, Freeman BB, Meyers JA, Rifkin IR, Lerner A. Inhibition of type 4 cyclic nucleotide phosphodiesterase blocks intracellular TLR signaling in chronic lymphocytic leukemia and normal hematopoietic cells. THE JOURNAL OF IMMUNOLOGY 2016; 194:101-12. [PMID: 25416804 DOI: 10.4049/jimmunol.1401854] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A subset of chronic lymphocytic leukemia (CLL) BCRs interacts with Ags expressed on apoptotic cells, suggesting that CLL BCRs have the potential to internalize apoptotic cell RNA- or DNA-containing fragments with resultant activation of TLR7 or TLR9, respectively. By blocking cAMP degradation, type 4 cAMP phosphodiesterase (PDE4) inhibitors activate cAMP-mediated signaling and induce apoptosis in CLL cells. In this study, we show that autologous irradiated leukemic cells induce proliferation in CLL cells and that such proliferation is blocked by a TLR7/8/9 inhibitor, by DNase, and by the PDE4 inhibitor rolipram. Rolipram also inhibited CLL cell proliferation induced by synthetic TLR7 and TLR9 agonists, as well as TLR agonist-induced costimulatory molecule expression and TNF-a (but not IL-6 or IL-10) production. Whereas treatment with a TLR9 agonist protected IgH V region unmutated, but not mutated, CLL cells from apoptosis, PDE4 inhibitors augmented apoptosis in both subtypes, suggesting that cAMP-mediated signaling may abrogate a TLR9-mediated survival signal in prognostically unfavorable IGHV unmutated CLL cells. Rolipram inhibited both TLR7/8- and TLR9-induced IFN regulatory factor 5 and NF-kB p65 nuclear translocation. PDE4 inhibitors also blocked TLR signaling in normal human immune cells. In PBMC and CD14-positive monocytes, PDE4 inhibitors blocked IFN-a or TNF-a (but not IL-6) production, respectively, following stimulation with synthetic TLR agonists or RNA-containing immune complexes. These results suggest that PDE4 inhibitors may be of clinical utility in CLL or autoimmune diseases that are driven by TLR-mediated signaling.
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Affiliation(s)
- Ying Tan
- Section of Hematology/Oncology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - Amanda A Watkins
- Section of Nephrology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - Benjamin B Freeman
- Section of Hematology/Oncology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - John A Meyers
- Section of Hematology/Oncology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - Ian R Rifkin
- Section of Nephrology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - Adam Lerner
- Section of Hematology/Oncology, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118 and Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118
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16
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Lewis AE, Aesoy R, Bakke M. Role of EPAC in cAMP-Mediated Actions in Adrenocortical Cells. Front Endocrinol (Lausanne) 2016; 7:63. [PMID: 27379015 PMCID: PMC4904129 DOI: 10.3389/fendo.2016.00063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/30/2016] [Indexed: 12/31/2022] Open
Abstract
Adrenocorticotropic hormone regulates adrenal steroidogenesis mainly via the intracellular signaling molecule cAMP. The effects of cAMP are principally relayed by activating protein kinase A (PKA) and the more recently discovered exchange proteins directly activated by cAMP 1 and 2 (EPAC1 and EPAC2). While the intracellular roles of PKA have been extensively studied in steroidogenic tissues, those of EPACs are only emerging. EPAC1 and EPAC2 are encoded by the genes RAPGEF3 and RAPGEF4, respectively. Whereas EPAC1 is ubiquitously expressed, the expression of EPAC2 is more restricted, and typically found in endocrine tissues. Alternative promoter usage of RAPGEF4 gives rise to three different isoforms of EPAC2 that vary in their N-termini (EPAC2A, EPAC2B, and EPAC2C) and that exhibit distinct expression patterns. EPAC2A is expressed in the brain and pancreas, EPAC2B in steroidogenic cells of the adrenal gland and testis, and EPAC2C has until now only been found in the liver. In this review, we discuss current knowledge on EPAC expression and function with focus on the known roles of EPAC in adrenal gland physiology.
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Affiliation(s)
- Aurélia E. Lewis
- Department of Molecular Biology, University of Bergen, Bergen, Norway
- *Correspondence: Aurélia E. Lewis,
| | - Reidun Aesoy
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Marit Bakke
- Department of Biomedicine, University of Bergen, Bergen, Norway
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17
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Almahariq M, Mei FC, Cheng X. The pleiotropic role of exchange protein directly activated by cAMP 1 (EPAC1) in cancer: implications for therapeutic intervention. Acta Biochim Biophys Sin (Shanghai) 2016; 48:75-81. [PMID: 26525949 DOI: 10.1093/abbs/gmv115] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/30/2015] [Indexed: 01/03/2023] Open
Abstract
The pleiotropic second messenger adenosine 3',5'-cyclic monophosphate (cAMP) regulates a myriad of biological processes under both physiological and pathophysiological conditions. Exchange protein directly activated by cAMP 1 (EPAC1) mediates the intracellular functions of cAMP by acting as a guanine nucleotide exchange factor for the Ras-like Rap small GTPases. Recent studies suggest that EPAC1 plays important roles in immunomodulation, cancer cell migration/metastasis, and metabolism. These results, coupled with the successful development of EPAC-specific small molecule inhibitors, identify EPAC1 as a promising therapeutic target for cancer treatments.
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Affiliation(s)
- Muayad Almahariq
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Fang C Mei
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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18
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cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP). Biochem Soc Trans 2014; 42:89-97. [PMID: 24450633 DOI: 10.1042/bst20130253] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The second messenger cAMP plays a central role in mediating vascular smooth muscle relaxation in response to vasoactive transmitters and in strengthening endothelial cell-cell junctions that regulate the movement of solutes, cells and macromolecules between the blood and the surrounding tissue. The vasculature expresses three cAMP effector proteins: PKA (protein kinase A), CNG (cyclic-nucleotide-gated) ion channels, and the most recently discovered Epacs (exchange proteins directly activated by cAMP). Epacs are a family of GEFs (guanine-nucleotide-exchange factors) for the small Ras-related GTPases Rap1 and Rap2, and are being increasingly implicated as important mediators of cAMP signalling, both in their own right and in parallel with the prototypical cAMP target PKA. In the present paper, we review what is currently known about the role of Epac within blood vessels, particularly with regard to the regulation of vascular tone, endothelial barrier function and inflammation.
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19
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Park KH, Park HJ, Shin KS, Lee MK. Multiple treatments with L-3,4-dihydroxyphenylalanine modulate dopamine biosynthesis and neurotoxicity through the protein kinase A-transient extracellular signal-regulated kinase and exchange protein activation by cyclic AMP-sustained extracellular signal-regulated kinase signaling pathways. J Neurosci Res 2014; 92:1746-56. [PMID: 25044243 DOI: 10.1002/jnr.23450] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 06/02/2014] [Indexed: 02/06/2023]
Abstract
Multiple treatments with L-3,4-dihydroxyphenylalanine (L-DOPA; 20 µM) induce neurite-like outgrowth and reduce dopamine biosynthesis in rat adrenal pheochromocytoma (PC) 12 cells. We therefore investigated the effects of multiple treatments with L-DOPA (MT-LD) on cell survival and death over a duration of 6 days by using PC12 cells and embryonic rat midbrain primary cell cultures. MT-LD (10 and 20 µM) decreased cell viability, and both types of cells advanced to the differentiation process at 4-6 days. MT-LD induced cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) phosphorylation and exchange protein activation by cAMP (Epac) expression at 1-3 days, which led to transient extracellular signal-regulated kinase (ERK1/2) phosphorylation in both cells. In these states, MT-LD activated cAMP-response element binding protein (CREB; Ser133) and tyrosine hydroxylase (Ser40) phosphorylation in PC12 cells, which led to an increase in intracellular dopamine levels. In contrast, MT-LD induced prolonged Epac expression at 4-5 days in both cells, which led to sustained ERK1/2 phosphorylation. In these states, the dopamine levels were decreased in PC12 cells. In addition, MT-LD induced c-Jun N-terminal kinase1/2 phosphorylation and cleaved caspase-3 expression at 4-6 days in both cells. These results suggest that MT-LD maintains cell survival via PKA-transient ERK1/2 activation, which stimulates dopamine biosynthesis. In contrast, at the later time period, MT-LD induces differentiation via both prolonged Epac and sustained ERK1/2 activation, which subsequently leads to the cell death process. Our data demonstrate that L-DOPA can cause neurotoxicity by modulating the Epac-ERK pathways in neuronal and PC12 cells.
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Affiliation(s)
- Keun Hong Park
- College of Pharmacy and Research Center for Bioresource and Health, Chungbuk National University, Cheongju, Republic of Korea
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20
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Role of soluble adenylyl cyclase in cell death and growth. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2646-55. [PMID: 25010002 DOI: 10.1016/j.bbadis.2014.06.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
cAMP signaling is an evolutionarily conserved intracellular communication system controlling numerous cellular functions. Until recently, transmembrane adenylyl cyclase (tmAC) was considered the major source for cAMP in the cell, and the role of cAMP signaling was therefore attributed exclusively to the activity of this family of enzymes. However, increasing evidence demonstrates the role of an alternative, intracellular source of cAMP produced by type 10 soluble adenylyl cyclase (sAC). In contrast to tmAC, sAC produces cAMP in various intracellular microdomains close to specific cAMP targets, e.g., in nucleus and mitochondria. Ongoing research demonstrates involvement of sAC in diverse physiological and pathological processes. The present review is focused on the role of cAMP signaling, particularly that of sAC, in cell death and growth. Although the contributions of sAC to the regulation of these cellular functions have only recently been discovered, current data suggest that sAC plays key roles in mitochondrial bioenergetics and the mitochondrial apoptosis pathway, as well as cell proliferation and development. Furthermore, recent reports suggest the importance of sAC in several pathologies associated with apoptosis as well as in oncogenesis. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Baljinnyam E, Umemura M, Chuang C, De Lorenzo MS, Iwatsubo M, Chen S, Goydos JS, Ishikawa Y, Whitelock JM, Iwatsubo K. Epac1 increases migration of endothelial cells and melanoma cells via FGF2-mediated paracrine signaling. Pigment Cell Melanoma Res 2014; 27:611-20. [PMID: 24725364 PMCID: PMC4283731 DOI: 10.1111/pcmr.12250] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 04/09/2014] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factor (FGF2) regulates endothelial and melanoma cell migration. The binding of FGF2 to its receptor requires N-sulfated heparan sulfate (HS) glycosamine. We have previously reported that Epac1, an exchange protein activated by cAMP, increases N-sulfation of HS in melanoma. Therefore, we examined whether Epac1 regulates FGF2-mediated cell–cell communication. Conditioned medium (CM) of melanoma cells with abundant expression of Epac1 increased migration of human umbilical endothelial cells (HUVEC) and melanoma cells with poor expression of Epac1. CM-induced increase in migration was inhibited by antagonizing FGF2, by the removal of HS and by the knockdown of Epac1. In addition, knockdown of Epac1 suppressed the binding of FGF2 to FGF receptor in HUVEC, and in vivo angiogenesis in melanoma. Furthermore, knockdown of Epac1 reduced N-sulfation of HS chains attached to perlecan, a major secreted type of HS proteoglycan that mediates the binding of FGF2 to FGF receptor. These data suggested that Epac1 in melanoma cells regulates melanoma progression via the HS–FGF2-mediated cell–cell communication.
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Affiliation(s)
- Erdene Baljinnyam
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, NJ, USA
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22
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Souza NHC, Marcondes PT, Albertini R, Mesquita-Ferrari RA, Fernandes KPS, Aimbire F. Low-level laser therapy suppresses the oxidative stress-induced glucocorticoids resistance in U937 cells: relevance to cytokine secretion and histone deacetylase in alveolar macrophages. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 130:327-36. [PMID: 24419178 DOI: 10.1016/j.jphotobiol.2013.12.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 12/10/2013] [Accepted: 12/12/2013] [Indexed: 02/07/2023]
Abstract
Oxidative stress is present in severe asthma and contributes to the low response to corticoids through the downregulation of histone deacetylase (HDAC) and the increase of cytokines. Low-level laser therapy (LLLT) has been proven to be an anti-inflammatory. Thus, we investigated the laser effect on lipopolysaccharide (LPS)-induced cytokine secretion and HDAC activity in U937 cells under oxidative stress. U937 cells activated with oxidative stress were treated with dexamethasone (dexa) or laser. Cytokines and phosphoinositide 3-kinase (PI3K) were measured by ELISA whilst the HDAC was detected through colorimetric assay. LPS activated- U937 cells cytokines secretion increased with H2O2 (hydrogen peroxide) as well as with TSA (trichostatin). The HDAC activity in activated U937 cells was decreased. LLLT and dexa inhibited the LPS-stimulated U937 cells cytokines, but dexa effect disappeared with H2O2. With TSA, the LLLT was less effective on H2O2/LPS stimulated- U937 cells cytokines. Dexa failed on H2O2/LPS- induced HDAC, while LLLT restored the HDAC and the dexa effect. LLLT plus prostaglandin E2 (PGE2) increased cyclic adenosine monophosphate (cAMP) and potentiated the laser action on oxidative stress-induced cytokine. LLLT reduced the PI3K and its effects on cytokine and HDAC was suppressed with LY294002. In situations of corticoid resistance, LLLT acts decreasing the cytokines and HDAC through the activation of the protein kinase A via the inhibition of PI3K.
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Affiliation(s)
- N H C Souza
- Rehabilitation Sciences Department, University Nove de Julho - Rua Vergueiro, 235 São Paulo, SP, Brazil
| | - P T Marcondes
- Department of Science and Technology, Federal University of São Paulo - Unifesp, São José dos Campos, SP, Brazil
| | - R Albertini
- Rehabilitation Sciences Department, University Nove de Julho - Rua Vergueiro, 235 São Paulo, SP, Brazil
| | - R A Mesquita-Ferrari
- Rehabilitation Sciences Department, University Nove de Julho - Rua Vergueiro, 235 São Paulo, SP, Brazil
| | - K P S Fernandes
- Rehabilitation Sciences Department, University Nove de Julho - Rua Vergueiro, 235 São Paulo, SP, Brazil
| | - F Aimbire
- Department of Science and Technology, Federal University of São Paulo - Unifesp, São José dos Campos, SP, Brazil.
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Phosphorylation of the guanine-nucleotide-exchange factor CalDAG-GEFI by protein kinase A regulates Ca(2+)-dependent activation of platelet Rap1b GTPase. Biochem J 2013; 453:115-23. [PMID: 23600630 DOI: 10.1042/bj20130131] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In blood platelets the small GTPase Rap1b is activated by cytosolic Ca2+ and promotes integrin αIIbβ3 inside-out activation and platelet aggregation. cAMP is the major inhibitor of platelet function and antagonizes Rap1b stimulation through a mechanism that remains unclear. In the present study we demonstrate that the Ca2+-dependent exchange factor for Rap1b, CalDAG-GEFI (calcium and diacylglycerol-regulated guanine-nucleotide-exchange factor I), is a novel substrate for the cAMP-activated PKA (protein kinase A). CalDAG-GEFI phosphorylation occurred in intact platelets treated with the cAMP-increasing agent forskolin and was inhibited by the PKA inhibitor H89. Purified recombinant CalDAG-GEFI was also phosphorylated in vitro by the PKA catalytic subunit. By screening a panel of specific serine to alanine residue mutants, we identified Ser116 and Ser586 as PKA phosphorylation sites in CalDAG-GEFI. In transfected HEK (human embryonic kidney)-293 cells, as well as in platelets, forskolin-induced phosphorylation of CalDAG-GEFI prevented the activation of Rap1b induced by the Ca2+ ionophore A23187. In platelets this effect was associated with the inhibition of aggregation. Moreover, cAMP-mediated inhibition of Rap1b was lost in HEK-293 cells transfected with a double mutant of CalDAG-GEFI unable to be phosphorylated by PKA. The results of the present study demonstrate that phosphorylation of CalDAG-GEFI by PKA affects its activity and represents a novel mechanism for cAMP-mediated inhibition of Rap1b in platelets.
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Off-target effect of the Epac agonist 8-pCPT-2'-O-Me-cAMP on P2Y12 receptors in blood platelets. Biochem Biophys Res Commun 2013; 437:603-8. [PMID: 23850619 DOI: 10.1016/j.bbrc.2013.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 07/02/2013] [Indexed: 11/21/2022]
Abstract
The primary target of the cAMP analogue 8-pCPT-2'-O-Me-cAMP is exchange protein directly activated by cAMP (Epac). Here we tested potential off-target effects of the Epac activator on blood platelet activation signalling. We found that the Epac analogue 8-pCPT-2'-O-Me-cAMP inhibits agonist-induced-GPCR-stimulated, but not collagen-stimulated, P-selectin surface expression on Epac1 deficient platelets. In human platelets, 8-pCPT-2'-O-Me-cAMP inhibited P-selectin expression elicited by the PKC activator PMA. This effect was abolished in the presence of the extracellular ADP scavenger system CP/CPK. In silico modelling of 8-pCPT-2'O-Me-cAMP binding into the purinergic platelet receptor P2Y12 revealed that the analogue docks similar to the P2Y12 antagonist 2MeSAMP. The 8-pCPT-2'-O-Me-cAMP analogue per se, did not provoke Rap 1 (Rap 1-GTP) activation or phosphorylation on the vasodilator-stimulated phosphoprotein (VASP) at Ser-157. In addition, the protein kinase A (PKA) antagonists Rp-cAMPS and Rp-8-Br-cAMPS failed to block the inhibitory effect of 8-pCPT-2'-O-Me-cAMP on thrombin- and TRAP-induced Rap 1 activation, thus suggesting that PKA is not involved. We conclude that the 8-pCPT-2'-O-Me-cAMP analogue is able to inhibit agonist-induced-GPCR-stimulated P-selectin independent from Epac1; the off-target effect of the analogue appears to be mediated by antagonistic P2Y12 receptor binding. This has implications when using cAMP analogues on specialised system involving such receptors. We found, however that the Epac agonist 8-Br-2'-O-Me-cAMP did not affect platelet activation at similar concentrations.
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Key Words
- (Rp)-adenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer
- (β-phenyl-1), N(2)-etheno-8-bromoguanosine-3′,5′-cyclic monophosphate
- 2-methylthio-adenosine diphosphate
- 2-methylthio-adenosine monophosphate
- 2MeSADP
- 2MeSAMP
- 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole-3′,5′-cyclic monophosphorothioate, Sp-isomer
- 8-(4-chlorophenylthio)-2′-O-methyladenosine-3′,5′-cyclic monophosphate
- 8-(4-chlorophenylthio)-2′-O-methyladenosine-3′,5′-cyclic monophosphorothioate, Sp-isomer
- 8-Br-PET-cGMP
- 8-bromoadenosineadenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer
- 8-pCPT-2′-O-Me-cAMP
- ADP
- Blood platelets
- CP/CPK
- Epac
- P2Y(12) receptor
- PI3K
- PKA
- PKG
- PMA
- Rp-8-Br-cAMPS
- Rp-cAMPS
- Sp-5, 6-DCL-cBIMPS
- Sp-8-pCPT-2′-O-Me-cAMPS
- Thromboxane
- TxA(2)
- adenosine diphosphate
- cAMP
- cAMP-activated protein kinase
- cGMP-activated protein kinase
- creatine phosphate/creatine phosphokinase
- cyclic adenosine monophosphate
- exchange factor directly activated by cAMP
- phorbol 12-myristate 13-acetate
- phosphatidyl-inositol-3 kinase
- thromboxane receptor A(2)
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Murray F, Insel PA. Targeting cAMP in chronic lymphocytic leukemia: a pathway-dependent approach for the treatment of leukemia and lymphoma. Expert Opin Ther Targets 2013; 17:937-49. [PMID: 23647244 DOI: 10.1517/14728222.2013.798304] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Cyclic AMP (cAMP) promotes growth arrest and/or apoptosis of various types of lymphoma, in particular chronic lymphocytic leukemia (CLL). These responses have spurred the interest in developing agents that increase cAMP to treat such malignancies and to identify mechanisms of the responses. AREAS COVERED The murine T-lymphoma cell line S49, has provided an important, pioneering model to define mechanisms of cAMP-mediated lymphoid cell death. Studies with S49 cells demonstrated that cAMP, acting via protein kinase A (PKA), is pro-apoptotic through a mitochondria-dependent pathway and identified cAMP/PKA-regulated targets involved in apoptosis. Akin to such findings, cAMP promotes apoptosis via PKA of cells from patients with CLL. Analysis of mediators of cAMP accumulation and cAMP-promoted apoptosis in CLL cells has revealed approaches to increase cAMP and engage its pro-apoptotic action. EXPERT OPINION This 'pathway approach' targeted to cAMP has identified GPCR agonists/antagonists, AC activators (e.g., AC7), PDE inhibitors (e.g., PDE7B) and/or activators or inhibitors of downstream mediators (PKA and Epac, respectively), which might be utilized therapeutically in CLL. Therapy directed at such targets may prove to be clinically useful and may also provide a proof-of-principle of the utility of targeting cAMP signaling in other types of cancer.
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Affiliation(s)
- Fiona Murray
- University of California San Diego, Department of Pharmacology, La Jolla, CA 92093, USA
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Safavi M, Baeeri M, Abdollahi M. New methods for the discovery and synthesis of PDE7 inhibitors as new drugs for neurological and inflammatory disorders. Expert Opin Drug Discov 2013; 8:733-51. [DOI: 10.1517/17460441.2013.787986] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Schmidt M, Dekker FJ, Maarsingh H. Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions. Pharmacol Rev 2013; 65:670-709. [PMID: 23447132 DOI: 10.1124/pr.110.003707] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.
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Affiliation(s)
- Martina Schmidt
- Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands.
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Shirshev SV. Role of Epac proteins in mechanisms of cAMP-dependent immunoregulation. BIOCHEMISTRY (MOSCOW) 2012; 76:981-98. [PMID: 22082266 DOI: 10.1134/s000629791109001x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review presents observations on the role of Epac proteins (exchange protein directly activated by cAMP) in immunoregulation mechanisms. Signaling pathways that involve Epac proteins and their domain organization and functions are considered. The role of Epac1 protein expressed in the immune system cells is especially emphasized. Molecular mechanisms of the cAMP-dependent signal via Epac1 are analyzed in monocytes/macrophages, T-cells, and B-lymphocytes. The role of Epac1 is shown in the regulation of adhesion, leukocyte chemotaxis, as well as in phagocytosis and bacterial killing. The molecular cascade initiated by Epac1 is examined under conditions of antigen activation of T-cells and immature B-lymphocytes.
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Affiliation(s)
- S V Shirshev
- Institute of Ecology and Genetics of Microorganisms, Ural Branch of the Russian Academy of Sciences, Perm, Russia.
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Insel PA, Zhang L, Murray F, Yokouchi H, Zambon AC. Cyclic AMP is both a pro-apoptotic and anti-apoptotic second messenger. Acta Physiol (Oxf) 2012; 204:277-87. [PMID: 21385327 DOI: 10.1111/j.1748-1716.2011.02273.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The second messenger cyclic AMP (cAMP) can either stimulate or inhibit programmed cell death (apoptosis). Here, we review examples of cell types that show pro-apoptotic or anti-apoptotic responses to increases in cAMP. We also show that cells can have both such responses, although predominantly having one or the other. Protein kinase A (PKA)-promoted changes in phosphorylation and gene expression can mediate pro-apoptotic responses, such as in murine S49 lymphoma cells, based on evidence that mutants lacking PKA fail to undergo cAMP-promoted, mitochondria-dependent apoptosis. Mechanisms for the anti-apoptotic response to cAMP likely involve Epac (Exchange protein activated by cAMP), a cAMP-regulated effector that is a guanine nucleotide exchange factor (GEF) for the low molecular weight G-protein, Rap1. Therapeutic approaches that activate PKA-mediated pro-apoptosis or block Epac-mediated anti-apoptotisis may provide a means to enhance cell killing, such as in certain cancers. In contrast, efforts to block PKA or stimulate Epac have the potential to be useful in diseases settings (such as heart failure) associated with cAMP-promoted apoptosis.
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Affiliation(s)
- P A Insel
- Department of Pharmacology, University of California, San Diego, La Jolla, 92093-0636, USA.
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Phosphodiesterase inhibitors control A172 human glioblastoma cell death through cAMP-mediated activation of protein kinase A and Epac1/Rap1 pathways. Life Sci 2011; 90:373-80. [PMID: 22227470 DOI: 10.1016/j.lfs.2011.12.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/22/2011] [Accepted: 12/13/2011] [Indexed: 11/22/2022]
Abstract
AIMS We investigated whether cAMP-mediated protein kinase A(PKA) and Epac1/Rap1 pathways differentially affect brain tumor cell death using 4-(3-cyclopentyloxy-4-methoxyphenyl)-2-pyrrolidone(rolipram), specific phosphodiesterase type IV(PDE IV) inhibitor. MAIN METHODS A172 and U87MG human glioblastoma cells were used. Percentage of cell survival was determined by MTT assay. PKA and Epac1/Rap1 activation was determined by western blotting and pull-down assay, respectively. Cell cycle and hypodiploid cell formation were assessed by flow cytometry analysis. KEY FINDINGS Non-specific PDE inhibitors, isobutylmethylxanthine(IBMX) and theophylline reduce survival percentage of A172 and U87MG cells. The expression of PDE4A and PDE4B was detected in A172 and U87MG cells. Rolipram-treated A172 or U87MG cell survival was lower in the presence of forskolin, adenylate cyclase activator, than that in its absence. Co-treatment with rolipram and forskolin also enhanced CREB phosphorylation on serine 133 that was inhibited by H-89, PKA inhibitor and cAMP-responsive guanine nucleotide exchange factor 1(Epac1), a Rap GDP exchange factor-mediated Rap1 activity in A172 cells. When A172 cells were treated with cell-permeable dibutyryl-cAMP(dbcAMP), PKA activator or 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate(CPT), Epac1 activator, basal level of cell death was increased and cell cycle was arrested at the phase of G2/M. Rolipram-induced A172 cell death was also increased by the co-treatment with dbcAMP or CPT, but it was inhibited by the pre-treatment with H-89. SIGNIFICANCE These findings demonstrate that PKA and Epac1/Rap1 pathways could cooperatively play a role in rolipram-induced brain tumor cell death. It suggests that rolipram might regulate glioblastoma cell density through dual pathways of PKA- and Epac1/Rap1-mediated cell death and cell cycle arrest.
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Safa M, Kazemi A, Zaker F, Razmkhah F. Cyclic AMP-induced p53 destabilization is independent of EPAC in pre-B acute lymphoblastic leukemia cells in vitro. J Recept Signal Transduct Res 2011; 31:256-63. [PMID: 21619452 DOI: 10.3109/10799893.2011.578140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Activation of the tumor suppressor protein p53 facilitates the cellular response to genotoxic stress. Thus, releasing the wild-type p53 from indirect suppression would be crucial to successful killing of cancer cells by DNA-damaging therapeutic agents. OBJECTIVE The aim of this study was to investigate the inhibitory role of cyclic adenosine monophosphate (cAMP) levels on p53 protein in acute lymphoblastic leukemia (ALL) cells. More importantly, we were interested to show through which receptor cAMP acts to promote p53 degradation. MATERIALS AND METHODS In cell cultures, we investigated the effects of forskolin/3-isobutyl-1-methylxanthine (IBMX) on stimulated p53 of ALL cell lines. Western blotting analysis was performed to detect the expression of p53, phospho-p53, acetylated-p53, phospho-cAMP response element-binding protein (CREB), and Mdm2 proteins. Flow cytometry was applied to analyze apoptosis. The gene expression of p53 and its target genes was examined by real-time polymerase chain reaction. RESULTS We show that elevation of cAMP levels in ALL cells exposed to DNA damage attenuates p53 accumulation. Inhibition of proteosome function with MG-132 reversed the inhibitory effect of cAMP on p53. However, targeting the p53-Mdm2 interaction did not rescue accumulated p53 from the destabilizing signal of cAMP. The specific agonist of the cAMP receptor exchange protein activated by cAMP had no effect on p53 expression in doxorubicin-treated NALM-6 cells, whereas PKA activators decreased p53 accumulation. DISCUSSION AND CONCLUSION Our studies demonstrate that cAMP-PKA pathway regulates the sensitivity toward DNA-damaging agents via inhibition of a p53-dependent pathway in B-cell precursor ALL (BCP-ALL) cells.
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Affiliation(s)
- Majid Safa
- Department of Hematology, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran.
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Activation of cAMP signaling interferes with stress-induced p53 accumulation in ALL-derived cells by promoting the interaction between p53 and HDM2. Neoplasia 2011; 13:653-63. [PMID: 21750659 DOI: 10.1593/neo.11542] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 12/11/2022] Open
Abstract
The tumor suppressor p53 provides an important barrier to the initiation and maintenance of cancers. As a consequence, p53 function must be inactivated for a tumor to develop. This is achieved by mutation in approximately 50% of cases and probably by functional inactivation in the remaining cases. We have previously shown that the second messenger cAMP can inhibit DNA damage-induced wild-type p53 accumulation in acute lymphoblastic leukemia cells, leading to a profound reduction of their apoptotic response. In the present article, we provide a mechanistic insight into the regulation of p53 levels by cAMP. We show that increased levels of cAMP augment the binding of p53 to its negative regulator HDM2, overriding the DNA damage-induced dissociation of p53 from HDM2. This results in maintained levels of p53 ubiquitination and proteasomal degradation, which in turn counteracts the DNA damage-induced stabilization of the p53 protein. The apoptosis inhibitory effect of cAMP is further shown to depend on this effect on p53 levels. These findings potentially implicate deregulation of cAMP signaling as a candidate mechanism used by transformed cells to quench the p53 response while retaining wild-type p53.
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Toll-like receptor 4-mediated cAMP production up-regulates B-cell activating factor expression in Raw264.7 macrophages. Exp Cell Res 2011; 317:2447-55. [PMID: 21782812 DOI: 10.1016/j.yexcr.2011.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/18/2011] [Accepted: 07/05/2011] [Indexed: 11/22/2022]
Abstract
B-cell activating factor (BAFF) plays a role in the generation and the maintenance of mature B cells. Lipopolysaccharide (LPS) increased BAFF expression through the activation of toll-like receptor 4 (TLR4)-dependent signal transduction. Here, we investigated the mechanism of action on mouse BAFF (mBAFF) expression by cAMP production in Raw264.7 mouse macrophages. mBAFF expression was increased by the treatment with a cAMP analogue, dibutyryl-cAMP which is the activator of protein kinase A (PKA), cAMP effector protein. PKA activation was measured by the phosphorylation of cAMP-response element binding protein (CREB) on serine 133 (S133). cAMP production and CREB (S133) phosphorylation were augmented by LPS-stimulation. While mBAFF promoter activity was enhanced by the co-transfection with pS6-RSV-CREB, it was reduced by siRNA-CREB. PKA inhibitor, H-89, reduced CREB (S133) phosphorylation and mBAFF expression in control and LPS-stimulated macrophages. Another principal cAMP effector protein is cAMP-responsive guanine nucleotide exchange factor (Epac), a Rap GDP exchange factor. Epac was activated by the treatment with 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (CPT), Epac activator, as judged by the measurement of Rap1 activation. Basal level of mBAFF expression was increased by CPT treatment. LPS-stimulated mBAFF expression was also slightly enhanced by co-treatment with CPT. In addition, dibutyryl-cAMP and CPT enhanced mBAFF expression in bone marrow-derived macrophages (BMDM). With these data, it suggests that the activation of PKA and cAMP/Epac1/Rap1 pathways could be required for basal mBAFF expression, as well as being up-regulated in the TLR4-induced mBAFF expression.
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Dash-Koney M, Deevi RK, McFarlane C, Dib K. Exchange protein directly activated by cAMP 1 (Epac1) is expressed in human neutrophils and mediates cAMP-dependent activation of the monomeric GTPase Rap1. J Leukoc Biol 2011; 90:741-9. [PMID: 21750123 DOI: 10.1189/jlb.0211108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Epac1 and Epac2 bind cAMP and mediate cAMP-dependent activation of Rap1. cAMP is produced in neutrophils in response to many chemoattractants. This second messenger plays a key role in the regulation of the functions of neutrophils. However, it is still not known whether Epacs are expressed in human neutrophils. We found that stimulation of PLB-985 cells differentiated into neutrophil-like cells, human neutrophils with 8CPT-2Me-cAMP (a selective activator of Epacs), or FK (a diterpene that augments the intracellular level of cAMP) led to GTP-loading of Rap1. Epac1 mRNA was expressed in UND and DF PLB-985 cells, but Epac1 protein was only detected in DF PLB-985 cells. In human neutrophils, the Epac1 transcript was present, and Epac1 protein could be detected by Western blot analysis if the cells had been treated with the serine protease inhibitor PMSF. FK induced adhesion of PLB-985 cells and human neutrophils on fibrinogen, a ligand for β2 integrins. Interestingly, in DF PLB-985 cells, but not in human neutrophils, 8CPT-2Me-cAMP induced β2 integrin-dependent adhesion. The failure of 8CPT-2Me-cAMP to induce β2 integrin-dependent human neutrophil adhesion could be explained by the fact that this compound did not induce a switch of the β2 integrins from a low-affinity to a high-affinity ligand-binding conformation. We concluded that Epac1 is expressed in human neutrophils and is involved in cAMP-dependent regulation of Rap1. However, the loading of GTP on Rap1 per se is not sufficient to promote activation of β2 integrins.
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Affiliation(s)
- Madhuri Dash-Koney
- Centre for Infection and Immunity, Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom
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Gβγ subunits inhibit Epac-induced melanoma cell migration. BMC Cancer 2011; 11:256. [PMID: 21679469 PMCID: PMC3141774 DOI: 10.1186/1471-2407-11-256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/17/2011] [Indexed: 12/11/2022] Open
Abstract
Background Recently we reported that activation of Epac1, an exchange protein activated by cAMP, increases melanoma cell migration via Ca 2+ release from the endoplasmic reticulum (ER). G-protein βγ subunits (Gβγ) are known to act as an independent signaling molecule upon activation of G-protein coupled receptor. However, the role of Gβγ in cell migration and Ca 2+ signaling in melanoma has not been well studied. Here we report that there is crosstalk of Ca 2+ signaling between Gβγ and Epac in melanoma, which plays a role in regulation of cell migration. Methods SK-Mel-2 cells, a human metastatic melanoma cell line, were mainly used in this study. Intracellular Ca 2+ was measured with Fluo-4AM fluorescent dyes. Cell migration was examined using the Boyden chambers. Results The effect of Gβγ on Epac-induced cell migration was first examined. Epac-induced cell migration was inhibited by mSIRK, a Gβγ -activating peptide, but not its inactive analog, L9A, in SK-Mel-2 cells. Guanosine 5', α-β-methylene triphosphate (Gp(CH2)pp), a constitutively active GTP analogue that activates Gβγ, also inhibited Epac-induced cell migration. In addition, co-overexpression of β1 and γ2, which is the major combination of Gβγ, inhibited Epac1-induced cell migration. By contrast, when the C-terminus of β adrenergic receptor kinase (βARK-CT), an endogenous inhibitor for Gβγ, was overexpressed, mSIRK's inhibitory effect on Epac-induced cell migration was negated, suggesting the specificity of mSIRK for Gβγ. We next examined the effect of mSIRK on Epac-induced Ca 2+ response. When cells were pretreated with mSIRK, but not with L9A, 8-(4-Methoxyphenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8-pMeOPT), an Epac-specific agonist, failed to increase Ca 2+ signal. Co-overexpression of β1 and γ2 subunits inhibited 8-pMeOPT-induced Ca 2+ elevation. Inhibition of Gβγ with βARK-CT or guanosine 5'-O-(2-thiodiphosphate) (GDPβS), a GDP analogue that inactivates Gβγ, restored 8-pMeOPT-induced Ca 2+ elevation even in the presence of mSIRK. These data suggested that Gβγ inhibits Epac-induced Ca 2+ elevation. Subsequently, the mechanism by which Gβγ inhibits Epac-induced Ca 2+ elevation was explored. mSIRK activates Ca 2+ influx from the extracellular space. In addition, W-5, an inhibitor of calmodulin, abolished mSIRK's inhibitory effects on Epac-induced Ca 2+ elevation, and cell migration. These data suggest that, the mSIRK-induced Ca 2+ from the extracellular space inhibits the Epac-induced Ca 2+ release from the ER, resulting suppression of cell migration. Conclusion We found the cross talk of Ca 2+ signaling between Gβγ and Epac, which plays a major role in melanoma cell migration.
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Baljinnyam E, Umemura M, De Lorenzo MS, Iwatsubo M, Chen S, Goydos JS, Iwatsubo K. Epac1 promotes melanoma metastasis via modification of heparan sulfate. Pigment Cell Melanoma Res 2011; 24:680-7. [DOI: 10.1111/j.1755-148x.2011.00863.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Safa M, Zand H, Mousavizadeh K, Kazemi A, Bakhshayesh M, Hayat P. Elevation of cyclic AMP causes an imbalance between NF-kappaB and p53 in NALM-6 cells treated by doxorubicin. FEBS Lett 2010; 584:3492-8. [PMID: 20624391 DOI: 10.1016/j.febslet.2010.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/30/2010] [Accepted: 07/04/2010] [Indexed: 01/26/2023]
Abstract
We previously showed that cAMP can inhibit DNA damage-induced wild type p53 accumulation in human pre-B NALM-6 cells, leading to a profound reduction of their apoptotic response. Here, we provide evidence for the potentiation of DNA damage-induced NF-kappaB activation by cAMP. We found that inhibition of NF-kappaB activation prevents the inhibitory effect of cAMP on doxorubicin-induced apoptosis. Moreover, cAMP exerts its inhibitory effect on doxorubicin-induced apoptosis in a PKA-independent manner. The present study also shows that elevation of cAMP prolongs the phosphorylation of IkappaB and subsequent activation of NF-kappaB in doxorubicin treated NALM-6 cells in a proteasome-dependent manner. Taken together, our results demonstrate that cAMP abrogates the balance between apoptotic and antiapoptotic transcription factors that are hallmarks of DNA damage signaling.
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Affiliation(s)
- Majid Safa
- Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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Gerlo S, Verdood P, Kooijman R. Modulation of cytokine production by cyclic adenosine monophosphate analogs in human leukocytes. J Interferon Cytokine Res 2010; 30:883-91. [PMID: 20586615 DOI: 10.1089/jir.2009.0021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP) is a well-known second messenger that operates through different signaling molecules, including protein kinase A (PKA) and guanine exchange proteins directly activated by cAMP (EPAC). Cell-permeable cAMP analogs such as 8-(4-chloro-phenyl-thio)-cAMP (8-pCPT-cAMP) modulate cytokine secretion by different leukocyte subsets, including T cells and monocytes. Since cAMP-modulating drugs such as phosphodiesterase inhibitors are being tested in inflammatory disorders such as asthma and chronic obstructive lung disease, it is important to obtain more insight into the regulation of cytokine production by cAMP. To address the signaling molecules involved in cAMP-mediated modulation of cytokine production, we used cAMP derivatives such as N(6)-benzoyladenosine-cAMP (6-Bnz-cAMP) and 8-pCPT-2-O-methyl cAMP (8-pCPT-2'-O-Me-cAMP), which selectively activate either PKA or EPAC, respectively. We show that in T cells, 6-Bnz-cAMP exerts similar globally inhibiting effects on cytokine secretion as 8-pCPT-cAMP, indicating that these effects are mediated by PKA. On the contrary, 8-pCPT-2'-O-Me-cAMP specifically inhibits the production of interleukin-10 (IL-10) in lipopolysaccharide-activated T-cell-depleted peripheral blood mononuclear cells, whereas the production of IL-1β, tumor necrosis factor α, and IL-12 is not or hardly affected. Inhibition by 8-pCPT-2'-O-Me-cAMP of IL-10 production was confirmed using purified monocytes. Further, in B cells 6-Bnz-cAMP, but not 8-pCPT-2'-O-Me-cAMP, stimulated IL-10 production. In conclusion, cAMP stimulates IL-10 production via PKA in activated B cells, but inhibits IL-10 production in activated monocytes through EPAC. We speculate that selective effects of PKA and EPAC on cytokine production in leukocyte subsets open up therapeutic possibilities using selective activators or inhibitors of EPAC or PKA.
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Affiliation(s)
- Sarah Gerlo
- Lab of Eukaryotic Gene Expression and Signal Transduction, Department of Physiology, University Gent, Brussels, Belgium
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Baljinnyam E, De Lorenzo MS, Xie LH, Iwatsubo M, Chen S, Goydos JS, Nowycky MC, Iwatsubo K. Exchange protein directly activated by cyclic AMP increases melanoma cell migration by a Ca2+-dependent mechanism. Cancer Res 2010; 70:5607-17. [PMID: 20551063 DOI: 10.1158/0008-5472.can-10-0056] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Melanoma has a poor prognosis due to its strong metastatic ability. Although Ca(2+) plays a major role in cell migration, little is known about the role of Ca(2+) in melanoma cell migration. We recently found that the exchange protein directly activated by cyclic AMP (Epac) increases melanoma cell migration via a heparan sulfate-related mechanism. In addition to this mechanism, we also found that Epac regulates melanoma cell migration by a Ca(2+)-dependent mechanism. An Epac agonist increased Ca(2+) in several different melanoma cell lines but not in melanocytes. Ablation of Epac1 with short hairpin RNA inhibited the Epac agonist-induced Ca(2+) elevation, suggesting the critical role of Epac1 in Ca(2+) homeostasis in melanoma cells. Epac-induced Ca(2+) elevation was negated by the inhibition of phospholipase C (PLC) and inositol triphosphate (IP(3)) receptor. Furthermore, Epac-induced cell migration was reduced by the inhibition of PLC or IP(3) receptor. These data suggest that Epac activates Ca(2+) release from the endoplasmic reticulum via the PLC/IP(3) receptor pathway, and this Ca(2+) elevation is involved in Epac-induced cell migration. Actin assembly was increased by Epac-induced Ca(2+), suggesting the involvement of actin in Epac-induced cell migration. In human melanoma specimens, mRNA expression of Epac1 was higher in metastatic melanoma than in primary melanoma, suggesting a role for Epac1 in melanoma metastasis. In conclusion, our findings reveal that Epac is a potential target for the suppression of melanoma cell migration, and, thus, the development of metastasis.
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Affiliation(s)
- Erdene Baljinnyam
- Department of Cell Biology and Molecular Medicine, UMDNJ-New Jersey Medical School, Newark, New Jersey, USA
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Suzuki S, Yokoyama U, Abe T, Kiyonari H, Yamashita N, Kato Y, Kurotani R, Sato M, Okumura S, Ishikawa Y. Differential roles of Epac in regulating cell death in neuronal and myocardial cells. J Biol Chem 2010; 285:24248-59. [PMID: 20516079 DOI: 10.1074/jbc.m109.094581] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cell survival and death play critical roles in tissues composed of post-mitotic cells. Cyclic AMP (cAMP) has been known to exert a distinct effect on cell susceptibility to apoptosis, protecting neuronal cells and deteriorating myocardial cells. These effects are primarily studied using protein kinase A activation. In this study we show the differential roles of Epac, an exchange protein activated by cAMP and a new effector molecule of cAMP signaling, in regulating apoptosis in these cell types. Both stimulation of Epac by 8-p-methoxyphenylthon-2'-O-methyl-cAMP and overexpression of Epac significantly increased DNA fragmentation and TUNEL (terminal deoxynucleotidyltransferase-mediated biotin nick end-labeling)-positive cell counts in mouse cortical neurons but not in cardiac myocytes. In contrast, stimulation of protein kinase A increased apoptosis in cardiac myocytes but not in neuronal cells. In cortical neurons the expression of the Bcl-2 interacting member protein (Bim) was increased by stimulation of Epac at the transcriptional level and was decreased in mice with genetic disruption of Epac1. Epac-induced neuronal apoptosis was attenuated by the silencing of Bim. Furthermore, Epac1 disruption in vivo abolished the 3-nitropropionic acid-induced neuronal apoptosis that occurs in wild-type mice. These results suggest that Epac induces neuron-specific apoptosis through increasing Bim expression. Because the disruption of Epac exerted a protective effect on neuronal apoptosis in vivo, the inhibition of Epac may be a consideration in designing a therapeutic strategy for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Sayaka Suzuki
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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Savai R, Pullamsetti SS, Banat GA, Weissmann N, Ghofrani HA, Grimminger F, Schermuly RT. Targeting cancer with phosphodiesterase inhibitors. Expert Opin Investig Drugs 2010; 19:117-31. [PMID: 20001559 DOI: 10.1517/13543780903485642] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
IMPORTANCE OF THE FIELD For many cancers, there has been a shift from management with traditional, nonspecific cytotoxic chemotherapies to treatment with molecule-specific targeted therapies that are used either alone or in combination with traditional chemotherapy and radiation therapy. Accumulating data suggest that multi-targeted agents may produce greater benefits than those observed with single-targeted therapies, may have acceptable tolerability profiles, and may be active against a broader range of tumour types. Thus, regulation of cyclic nucleotide signalling is properly regarded as a composite of multiple component pathways involved in diverse aspects of tumour cell function. The impairment of cAMP and/or cGMP generation by overexpression of PDE isoforms that has been described in various cancer pathologies, and the effects of PDE inhibitors in tumour models in vitro and in vivo, may offer promising insight into future cancer treatments because of the numerous advantages of PDE inhibitors. AREAS COVERED IN THIS REVIEW In this review, we focus on the expression and regulation of cyclic nucleotide phosphodiesterases (PDEs) in tumour progression and provide evidence that PDE inhibitors may be effective agents for treating cancer; the review covers literature from the past several years. WHAT THE READER WILL GAIN PDEs have been studied in a variety of tumours; data have suggested that the levels of PDE activity are elevated and, therefore, the ratio of cGMP to cAMP is affected. In addition, PDE inhibitors may be potential targets for tumour cell growth inhibition and induction of apoptosis. This review explores the prospects of targeting PDEs with therapeutic agents for cancer, as well as the shortcomings of this approach such as dose-limiting side effects, toxicity/efficacy ratio and selectivity towards tumour tissue. In addition, it includes opinions and suggestion for developing PDE inhibition for cancer treatment from initial concept to potential therapeutic application and final relevance in clinical use. TAKE HOME MESSAGE Impaired cAMP and/or cGMP generation upon overexpression of PDE isoforms has been described in various cancer pathologies. Inhibition of selective PDE isoforms, which raises the levels of intracellular cAMP and/or cGMP, induces apoptosis and cell cycle arrest in a broad spectrum of tumour cells and regulates the tumour microenvironment. Therefore, the development and clinical application of inhibitors specific for individual PDE isoenzymes may selectively restore normal intracellular signalling, providing antitumour therapy with reduced adverse effects.
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Affiliation(s)
- Rajkumar Savai
- Max-Planck-Institute for Heart and Lung Research, Department of Lung Development and Remodelling, Bad Nauheim, Germany
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Sousa LP, Lopes F, Silva DM, Tavares LP, Vieira AT, Rezende BM, Carmo AF, Russo RC, Garcia CC, Bonjardim CA, Alessandri AL, Rossi AG, Pinho V, Teixeira MM. PDE4 inhibition drives resolution of neutrophilic inflammation by inducing apoptosis in a PKA-PI3K/Akt-dependent and NF-κB-independent manner. J Leukoc Biol 2010; 87:895-904. [DOI: 10.1189/jlb.0809540] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Grandoch M, Roscioni SS, Schmidt M. The role of Epac proteins, novel cAMP mediators, in the regulation of immune, lung and neuronal function. Br J Pharmacol 2009; 159:265-84. [PMID: 19912228 DOI: 10.1111/j.1476-5381.2009.00458.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chronic degenerative inflammatory diseases, such as chronic obstructive pulmonary disease and Alzheimer's dementia, afflict millions of people around the world, causing death and debilitation. Despite the global impact of these diseases, there have been few innovative breakthroughs into their cause, treatment or cure. As with many debilitating disorders, chronic degenerative inflammatory diseases may be associated with defective or dysfunctional responses to second messengers, such as cyclic adenosinemonophosphate (cAMP). The identification of the cAMP-activated guanine nucleotide exchange factors for Ras-like GTPases, Epac1 (also known as cAMP-GEF-I) and Epac2 (also known as cAMP-GEF-II), profoundly altered the prevailing assumptions concerning cAMP signalling, which until then had been solely associated with protein kinase A (PKA). Studies of the molecular mechanisms of Epac-related signalling have demonstrated that these novel cAMP sensors regulate many physiological processes either alone and/or in concert with PKA. These include calcium handling, cardiac and smooth muscle contraction, learning and memory, cell proliferation and differentiation, apoptosis, and inflammation. The diverse signalling properties of cAMP might be explained by spatio-temporal compartmentalization, as well as A-kinase anchoring proteins, which seem to coordinate Epac signalling networks. Future research should focus on the Epac-regulated dynamics of cAMP, and, hopefully, the development of compounds that specifically interfere with the Epac signalling system in order to determine the precise significance of Epac proteins in chronic degenerative inflammatory disorders.
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Affiliation(s)
- Maria Grandoch
- Institut für Pharmakologie, Universitätsklinikum Essen, Essen, Germany
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Meyers JA, Su DW, Lerner A. Chronic lymphocytic leukemia and B and T cells differ in their response to cyclic nucleotide phosphodiesterase inhibitors. THE JOURNAL OF IMMUNOLOGY 2009; 182:5400-11. [PMID: 19380787 DOI: 10.4049/jimmunol.0804255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphodiesterase (PDE)4 inhibitors, which activate cAMP signaling by reducing cAMP catabolism, are known to induce apoptosis in B lineage chronic lymphocytic leukemia (CLL) cells but not normal human T cells. The explanation for such differential sensitivity remains unknown. In this study, we report studies contrasting the response to PDE4 inhibitor treatment in CLL cells and normal human T and B cells. Affymetrix gene chip analysis in the three cell populations following treatment with the PDE4 inhibitor rolipram identified a set of up-regulated transcripts with unusually high fold changes in the CLL samples, several of which are likely part of compensatory negative feedback loops. The high fold changes were due to low basal transcript levels in CLL cells, suggesting that cAMP-mediated signaling may be unusually tightly regulated in this cell type. Rolipram treatment augmented cAMP levels and induced ATF-1/CREB serine 63/133 phosphorylation in both B lineage cell types but not T cells. As treatment with the broad-spectrum PDE inhibitor 3-isobutyl-1-methylxanthine induced T cell CREB phosphorylation, we tested a series of family-specific PDE inhibitors for their ability to mimic 3-isobutyl-1-methylxanthine-induced ATF-1/CREB phosphorylation. Whereas PDE3 inhibitors alone had no effect, the combination of PDE3 and PDE4 inhibitors induced ATF-1/CREB serine 63/133 phosphorylation in T cells. Consistent with this observation, PDE3B transcript and protein levels were low in CLL cells but easily detectable in T cells. Combined PDE3/4 inhibition did not induce T cell apoptosis, suggesting that cAMP-mediated signal transduction that leads to robust ATF-1/CREB serine 63/133 phosphorylation is not sufficient to induce apoptosis in this lymphoid lineage.
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Affiliation(s)
- John A Meyers
- Evans Department of Medicine, Section of Hematology and Oncology, Boston Medical Center, Boston, MA 02118, USA
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Gates A, Hohenester S, Anwer MS, Webster CRL. cAMP-GEF cytoprotection by Src tyrosine kinase activation of phosphoinositide-3-kinase p110 beta/alpha in rat hepatocytes. Am J Physiol Gastrointest Liver Physiol 2009; 296:G764-74. [PMID: 19196950 PMCID: PMC2670669 DOI: 10.1152/ajpgi.90622.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cyclic AMP protects against hepatocyte apoptosis by a protein kinase A-independent cAMP-GEF/phosphoinositide-3-kinase (PI3K)/Akt signaling pathway. However, the signaling pathway coupling cAMP-GEF with PI3K is unknown. The aim of this study was to investigate the role of Src tyrosine kinases (Src-TYK) and PI3K-p110 isoforms in this pathway. Studies were done in rat hepatocytes using the hydrophobic bile acid glycochenodeoxycholic acid (GCDC) to induce apoptosis. cAMP-binding guanine nucleotide exchange factors (cAMP-GEFs) were selectively activated by using 4-(4-chloro-phenylthio)-2'-O-methyladenosine-3'-5'-cyclic monophosphate (CPT-2-Me-cAMP), which sequentially phosphorylated Src-TYK (within 1 min) followed by Akt (within 5 min). The Src inhibitors PP2 and SU6656 inhibited basal and CPT-2-Me-cAMP-mediated Src and Akt phosphorylation. These inhibitors had no effect on CPT-2-Me-cAMP-mediated activation of Rap GTPases. CPT-2-Me-cAMP induced transient Src dependent autophosphorylation of the epidermal growth factor receptor (EGFR). Inhibition of the EGFR with AG 1478 partially inhibited the ability of CPT-2-Me to phosphorylate Akt. Whereas PP2 completely abolished the protective effect of CPT-2-Me-cAMP in GCDC induced apoptosis, AG 1478 partially inhibited the cytoprotective effect. CPT-2-Me-cAMP treatment resulted in Src-dependent activation of the p110 beta and alpha subunits of PI3K, but only the latter was sensitive to inhibition with AG 1478. In conclusion, activation of cAMP-GEFs results in phosphorylation of Src-TYK and Akt and activation of the p110 beta/alpha subunits of PI3K. Maximal cAMP-GEF-mediated Akt phosphorylation as well as protection from bile acid-induced apoptosis requires activation of Src-TYK and the EGFR. These studies support the existence of two pathways: cAMP-GEF/Rap/Src/PI3Kbeta/Akt and cAMP-GEF/Rap/Src/EGFR/PI3Kalpha/Akt, both of which are necessary for maximal cytoprotective effect of cAMP-GEFs in hepatocytes.
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Affiliation(s)
- Anna Gates
- Departments of Clinical Sciences and Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts
| | - Simon Hohenester
- Departments of Clinical Sciences and Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts
| | - M. Sawkat Anwer
- Departments of Clinical Sciences and Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts
| | - Cynthia R. L. Webster
- Departments of Clinical Sciences and Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts
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Borland G, Smith BO, Yarwood SJ. EPAC proteins transduce diverse cellular actions of cAMP. Br J Pharmacol 2009; 158:70-86. [PMID: 19210747 DOI: 10.1111/j.1476-5381.2008.00087.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
It has now been over 10 years since efforts to completely understand the signalling actions of cAMP (3'-5'-cyclic adenosine monophosphate) led to the discovery of exchange protein directly activated by cAMP (EPAC) proteins. In the current review we will highlight important advances in the understanding of EPAC structure and function and demonstrate that EPAC proteins mediate multiple actions of cAMP in cells, revealing future targets for pharmaceutical intervention. It has been known for some time that drugs that elevate intracellular cAMP levels have proven therapeutic benefit for diseases ranging from depression to inflammation. The challenge now is to determine which of these positive actions of cAMP involve activation of EPAC-regulated signal transduction pathways. EPACs are specific guanine nucleotide exchange factors for the Ras GTPase homologues, Rap1 and Rap2, which they activate independently of the classical routes for cAMP signalling, cyclic nucleotide-gated ion channels and protein kinase A. Rather, EPAC activation is triggered by internal conformational changes induced by direct interaction with cAMP. Leading from this has been the development of EPAC-specific agonists, which has helped to delineate numerous cellular actions of cAMP that rely on subsequent activation of EPAC. These include regulation of exocytosis and the control of cell adhesion, growth, division and differentiation. Recent work also implicates EPAC in the regulation of anti-inflammatory signalling in the vascular endothelium, namely negative regulation of pro-inflammatory cytokine signalling and positive support of barrier function. Further elucidation of these important signalling mechanisms will no doubt support the development of the next generation of anti-inflammatory drugs.
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Affiliation(s)
- Gillian Borland
- Division of Molecular and Cellular Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
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Grandoch M, López de Jesús M, Oude Weernink PA, Weber AA, Jakobs KH, Schmidt M. B cell receptor-induced growth arrest and apoptosis in WEHI-231 immature B lymphoma cells involve cyclic AMP and Epac proteins. Cell Signal 2009; 21:609-21. [PMID: 19167486 DOI: 10.1016/j.cellsig.2009.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 12/23/2008] [Accepted: 01/01/2009] [Indexed: 12/13/2022]
Abstract
Signaling by the B cell antigen receptor (BCR) is essential for B lymphocyte homeostasis and immune function. In immature B cells, ligation of the BCR promotes growth arrest and apoptosis, and BCR-driven balancing between pro-apoptotic extracellular signal-regulated kinase 1 and 2 (ERK1/2) and anti-apoptotic phosphoinositide 3-kinase-dependent Akt seems to define the final cellular apoptotic response. Dysfunction of these late BCR signaling events can lead to the development of immunological diseases. Here we report on novel cyclic AMP-dependent mechanisms of BCR-induced growth arrest and apoptosis in the immature B lymphoma cell line WEHI-231. BCR signaling to ERK1/2 and Akt requires cyclic AMP-regulated Epac, the latter acting as a guanine nucleotide exchange factor for Rap1 and H-Ras independent of protein kinase A. Importantly, activation of endogenously expressed Epac by a specific cyclic AMP analog enhanced the induction of growth arrest (reduced DNA synthesis) and apoptosis (nuclear condensation, annexin V binding, caspase-3 cleavage and poly-ADP-ribose polymerase processing) by the BCR. Our data indicate that cyclic AMP-dependent Epac signals to ERK1/2 and Akt upon activation of Rap1 and H-Ras, and is involved in BCR-induced growth arrest and apoptosis in WEHI-231 cells.
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Affiliation(s)
- Maria Grandoch
- Institut für Pharmakologie, Universitätsklinikum Essen, Essen, Germany.
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Cyclic nucleotide phosphodiesterase profiling reveals increased expression of phosphodiesterase 7B in chronic lymphocytic leukemia. Proc Natl Acad Sci U S A 2008; 105:19532-7. [PMID: 19033455 DOI: 10.1073/pnas.0806152105] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cyclic nucleotide phosphodiesterase (PDE) isoforms can influence disease pathogenesis and be novel therapeutic targets. Because lower cAMP levels may contribute to the decreased apoptosis that occurs in chronic lymphocytic leukemia (CLL), we assessed the expression levels of PDE isoforms in peripheral blood mononuclear cells (PBMC) of healthy adults and patients with CLL. We found a unique PDE mRNA signature in CLL: higher levels than in normal PBMC of PDE7B (increased approximately 23-fold) and lower levels of PDE3B, 4D, 5A, and 9A mRNA (each decreased approximately 30-fold). Increased PDE7B mRNA in CLL correlates with a 10-fold-higher expression of PDE7B protein and results in an increased contribution of PDE7 to total PDE activity. Consistent with the higher level of PDE7B expression, inhibitors of PDE7 (BRL-50481, IR-202) and a dual PDE4/PDE7 inhibitor (IR-284) selectively increase apoptosis in CLL cells compared with normal PBMC or B cells. Apoptosis of CLL cells promoted by inhibitors of PDE7 and PDE4/7 is attenuated by PKA inhibition, occurs via a mitochondrial-dependent process, and is associated with increased cAMP accumulation and down-regulation of the antiapoptotic protein survivin and of PDE7B. The increase in PDE7B expression and PDE7 inhibitor-promoted apoptosis implicates PDE7B as a drug target in CLL. Our findings identify a unique PDE signature in CLL and illustrate the utility of broad analyses of PDE isoform expression in human disease.
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Till KJ, Harris RJ, Linford A, Spiller DG, Zuzel M, Cawley JC. Cell motility in chronic lymphocytic leukemia: defective Rap1 and alphaLbeta2 activation by chemokine. Cancer Res 2008; 68:8429-36. [PMID: 18922916 DOI: 10.1158/0008-5472.can-08-1758] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chemokine-induced activation of alpha4beta1 and alphaLbeta2 integrins (by conformational change and clustering) is required for lymphocyte transendothelial migration (TEM) and entry into lymph nodes. We have previously reported that chemokine-induced TEM is defective in chronic lymphocytic leukemia (CLL) and that this defect is a result of failure of the chemokine to induce polar clustering of alphaLbeta2; engagement of alpha4beta1 and autocrine vascular endothelial growth factor (VEGF) restore clustering and TEM. The aim of the present study was to characterize the nature of this defect in alphaLbeta2 activation and determine how it is corrected. We show here that the alphaLbeta2 of CLL cells is already in variably activated conformations, which are not further altered by chemokine treatment. Importantly, such treatment usually does not cause an increase in the GTP-loading of Rap1, a GTPase central to chemokine-induced activation of integrins. Furthermore, we show that this defect in Rap1 GTP-loading is at the level of the GTPase and is corrected in CLL cells cultured in the absence of exogenous stimuli, suggesting that the defect is the result of in vivo stimulation. Finally, we show that, because Rap1-induced activation of both alpha4beta1 and alphaLbeta2 is defective, autocrine VEGF and chemokine are necessary to activate alpha4beta1 for ligand binding. Subsequently, this binding and both VEGF and chemokine stimulation are all needed for alphaLbeta2 activation for motility and TEM. The present study not only clarifies the nature of the alphaLbeta2 defect of CLL cells but is the first to implicate activation of Rap1 in the pathophysiology of CLL.
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Affiliation(s)
- Kathleen J Till
- Division of Hematology, School of Cancer Studies, School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom.
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Implication of protein kinase A for a hepato-protective mechanism of milrinone pretreatment. J Surg Res 2008; 155:32-9. [PMID: 19111324 DOI: 10.1016/j.jss.2008.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Revised: 05/22/2008] [Accepted: 07/02/2008] [Indexed: 11/24/2022]
Abstract
BACKGROUND We have previously reported that an increase of adenosine 3',5'-cyclic monophosphate (cAMP) in liver tissue after an administration of milrinone, a phosphodiesterase-3 inhibitor attenuates hepatic warm ischemia-reperfusion injury. The aim of this study was to determine whether cAMP-dependent protein kinase (protein kinase A) activation was involved in the milrinone-induced hepatoprotective effect on an ischemia-reperfusion injury in an in vivo model. MATERIALS AND METHODS Male Lewis rats were allocated into 3 groups. In Group M, milrinone was administrated before ischemia; in Group I, a protein kinase A inhibitor, adenosine 3',5'-cyclic monophosphorothioate, 8-bromo-, Rp-isomer, sodium salt (Rp-8-Br-cAMPS), was injected prior to the administration of milrinone; and in Group C, the control group, there was no pretreatment. After pretreatment, all rats were exposed to a 45-min total hepatic inflow occlusion. RESULTS After milrinone administration, liver cAMP concentrations and protein kinase A activity ratios were elevated. They protected the liver from ischemia-reperfusion injury. Rp-8-Br-cAMPS suppressed protein kinase A activation without affecting cAMP elevating responses to milrinone. Compared with Group C, hepatocellular necrosis, neutrophil infiltration, and congestion were ameliorated, and serum tumor necrosis factor-alpha, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels were significantly suppressed in Group M. Rp-8-Br-cAMPS canceled this effect, showing histological damages in Group I as severe as in Group C. The levels of tumor necrosis factor-alpha, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase were the same in Groups C and I. CONCLUSIONS Activation of protein kinase A might play an important role in the mechanism of milrinone-induced ischemic tolerance in the liver.
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