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ABSTRACT: Multiple sclerosis (MS) is an autoimmune-mediated inflammatory disease characterized by multifocal areas of demyelination. Experimental evidence indicates that A2A adenosine receptors (ARs) play a pivotal role in the inhibition of inflammatory processes. The aim of this study was to investigate the contribution of A2A ARs in the inhibition of key pro-inflammatory mediators for the pathogenesis of MS. In lymphocytes from MS patients, A1 , A2A , A2B and A3 ARs were analyzed by using RT-PCR, western blotting, immunofluorescence and binding assays. Moreover the effect of A2A AR stimulation on pro-inflammatory cytokine release such as tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), interleukin (IL)-6, IL-1β, IL-17 and on lymphocyte proliferation was evaluated. The capability of an A2A AR agonist on the modulation of very late antigen-4 (VLA-4) expression and nuclear factor κB (NF-κB) was also explored. A2A AR upregulation was observed in lymphocytes from MS patients in comparison with healthy subjects. The stimulation of these receptors mediated a significant inhibition of TNF-α, IFN-γ, IL-6, IL-1β, IL-17 and cell proliferation as well as VLA-4 expression and NF-κB activation. This new evidence highlights that A2A AR agonists could represent a novel therapeutic tool for MS treatment as suggested by the anti-inflammatory role of A2A ARs in lymphocytes from MS patients. This article is protected by copyright. All rights reserved.
European Journal of Immunology 05/2013; · 5.10 Impact Factor
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Lucia Squarcialupi,
Vittoria Colotta,
Daniela Catarzi,
Flavia Varano,
Guido Filacchioni,
Katia Varani,
Carmen Corciulo, Fabrizio Vincenzi,
Pier Andrea Borea,
Carla Ghelardini,
Lorenzo Di Cesare Mannelli,
Antonella Ciancetta,
Stefano Moro
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ABSTRACT: On the basis of our previously reported 2-arylpyrazolo[4,3-d]pyrimidin-7-ones, a set of 2-arylpyrazolo[4,3-d]pyrimidin-7-amines were designed as new human (h) A3 adenosine receptor (AR) antagonists. Lipophilic groups with different steric bulk were introduced at the 5-position of the bicyclic scaffold (R5 = Me, Ph, CH2Ph), and different acyl and carbamoyl moieties (R7) were appended on the 7-amino group, as well as a para-methoxy group inserted on the 2-phenyl ring. The presence of acyl groups turned out to be of paramount importance for an efficient and selective binding at the hA3 AR. In fact, most of the 7-acylamino derivatives showed low nanomolar affinity (Ki = 2.5-45 nM) and high selectivity toward this receptor. A few selected pyrazolo[4,3-d]pyrimidin-7-amides were effective in counteracting oxaliplatin-induced apoptosis in rat astrocyte cell cultures, an in vitro model of neurotoxicity. Through an in silico receptor-driven approach the obtained binding data were rationalized and the molecular bases of the observed hA3 AR affinity and hA3 versus hA2A AR selectivity were explained.
Journal of Medicinal Chemistry 03/2013; · 4.80 Impact Factor
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ABSTRACT: Cannabinoid CB2 receptor activation by selective agonists has been shown to produce analgesic effects in preclinical models of inflammatory, neuropathic, and bone cancer pain. In this study the effect of a novel CB2 agonist (MT178) was evaluated in different animal models of pain. First of all, in vitro competition binding experiments performed on rat, mouse, or human CB receptors revealed a high affinity, selectivity, and potency of MT178. The analgesic properties of the novel CB2 agonist were evaluated in various in vivo experiments, such as writhing and formalin assays, showing a good efficacy comparable with that produced by the nonselective CB agonist WIN 55,212-2. A dose-dependent antiallodynic effect of the novel CB2 compound in the streptozotocin-induced diabetic neuropathy was found. In a bone cancer pain model and in the acid-induced muscle pain model, MT178 was able to significantly reduce mechanical hyperalgesia in a dose-related manner. Notably, MT178 failed to provoke locomotor disturbance and catalepsy, which were observed following the administration of WIN 55,212-2. CB2 receptor mechanism of action was investigated in dorsal root ganglia where MT178 mediated a reduction of [(3)H]-d-aspartate release. MT178 was also able to inhibit capsaicin-induced substance P release and NF-κB activation. These results demonstrate that systemic administration of MT178 produced a robust analgesia in different pain models via CB2 receptors, providing an interesting approach to analgesic therapy in inflammatory and chronic pain without CB1-mediated central side effects.
Pain 02/2013; · 5.78 Impact Factor
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Mojgan Aghazadeh Tabrizi,
Pier Giovanni Baraldi,
Giulia Saponaro,
Allan R Moorman,
Romeo Romagnoli,
Delia Preti,
Stefania Baraldi,
Carmen Corciulo, Fabrizio Vincenzi,
Pier Andrea Borea,
Katia Varani
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ABSTRACT: Recent developments indicate that CB2 receptor ligands have the potential to become therapeutically important. To explore this potential, it is necessary to develop compounds with high affinity for the CB2 receptor. Very recently, we have identified the oxazinoquinoline carboxamides as a novel class of CB2 receptor full agonists. In this paper we describe the medicinal chemistry of a new series of heteroaryl-4-oxopyridine/7-oxo-pyrimidine derivatives. Some of the reported compounds showed high affinity and potency at the CB2 receptor while showing only modest affinity for the centrally expressed CB1 cannabinoid receptor. Moreover, we found that the functionality of these ligands is controlled by the nature of the heteroaryl function condensed with the pyridine ring. In 3,5-cyclic adenosine monophosphate (cAMP) assays, the novel series show dose-dependent effects on the modulation of forskolin-induced cAMP production, revealing different behaviors as full agonists, partial agonists and inverse agonists.
Journal of Medicinal Chemistry 01/2013; · 4.80 Impact Factor
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ABSTRACT: Hyaline cartilage lesions represent an important global health problem. Several approaches have been developed in the last decades to resolve this disability cause, including tissue engineering, but to date there is not a definitive procedure able to promote a repair tissue with the same mechanical and functional characteristics of native cartilage, and to obtain its integration in the subchondral bone. The need of resolutive technologies to obtain a "more effective" tissue substitutes has led Butler to propose the "Functional Tissue Engineering" (FTE) paradigm, whose principles are outlined in a so-called FTE road map. It consists in two-phases strategy: in vitro tissue engineering and clinically surgery evaluation. The first phase, based on construct development, should take into account the chondrocytes biology, as their sensitivity to biochemical and physical stimuli, the risk of dedifferentiation in culture, and the ability to produce extracellular matrix, but also the features of suitable scaffolds. The in vivo phase analyzes the inflammatory microenvironment where the construct will be placed, because the cytokines released by synoviocytes and chondrocytes could affect the construct integrity, and in particular cause matrix degradation. The use of pulsed electromagnetic fields (PEMFs) represents an innovative therapeutic approach because it is demonstrated that this physical stimulus increases the anabolic activity of chondrocytes and cartilage explants with consequent increase of matrix synthesis, but at the same time PEMFs limit the catabolic effects of inflammatory cytokines, reducing the construct degradation inside the surgical microenvironment. PEMFs mediate an upregulation of A2A adenosine receptors and a potentiation of their anti-inflammatory effects.
Tissue Engineering Part B Reviews 01/2013; · 4.64 Impact Factor
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ABSTRACT: A(2A) adenosine receptors (ARs) play a key role in the inhibition of the inflammatory process. The purpose of this study was to evaluate the modulation of A(2A)ARs in rheumatoid arthritis (RA) patients after different pharmacological treatments and to investigate the effect of A(2A)AR stimulation in a rat model of arthritis. We investigated A(2A)AR density and functionality in RA progression by using a longitudinal study in RA patients before and after methotrexate (MTX), anti-TNFα agents or rituximab treatments. A(2A)ARs were analyzed by saturation binding assays in lymphocytes from RA patients throughout the 24-month study timeframe. In an adjuvant-induced arthritis model in rats we showed the efficacy of the A(2A)AR agonist, CGS 21680 in comparison with standard therapies by means of paw volume assessment, radiographic and ultrasonographic imaging. Arthritic-associated pain was investigated in mechanical allodynia and thermal hyperalgesia tests. IL-10 release following A(2A)AR stimulation in lymphocytes from RA patients and in serum from arthritic rats was measured. In lymphocytes obtained from RA patients, the A(2A)AR up-regulation was gradually reduced in function of the treatment time and the stimulation of these receptors mediated a significant increase of IL-10 production. In the same cells, CGS 21680 did not affected cell viability and did not produced cytotoxic effects. The A(2A)AR agonist CGS 21680 was highly effective, as suggested by the marked reduction of clinical signs, in rat adjuvant-induced arthritis and associated pain. This study highlighted that A(2A)AR agonists represent a physiological-like therapeutic alternative for RA treatment as suggested by the anti-inflammatory role of A(2A)ARs in lymphocytes from RA patients. The effectiveness of A(2A)AR stimulation in a rat model of arthritis supported the role of A(2A)AR agonists as potential pharmacological treatment for RA.
PLoS ONE 01/2013; 8(1):e54195. · 4.09 Impact Factor
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Daniela Catarzi,
Vittoria Colotta,
Flavia Varano,
Daniela Poli,
Lucia Squarcialupi,
Guido Filacchioni,
Katia Varani, Fabrizio Vincenzi,
Pier Andrea Borea,
Diego Dal Ben,
Catia Lambertucci,
Gloria Cristalli
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ABSTRACT: A number of 5-oxo-pyrazolo[1,5-c]quinazolines (series B-1), bearing at position-2 the claimed (hetero)aryl moiety (compounds 1-8) but also a carboxylate group (9-14), were designed as hA(3) AR antagonists. This study produced some interesting compounds endowed with good hA(3) receptor affinity and high selectivity, being totally inactive at all the other AR subtypes. In contrast, the corresponding 5-ammino derivatives (series B-2) do not bind or bind with very low affinity at the hA(3) AR, the only exception being the 5-N-benzoyl compound 19 that shows a hA(3)K(i) value in the high μ-molar range. Evaluation of the synthetic intermediates led to the identification of some 5(3)-(2-aminophenyl)-3(5)-(hetero)arylpyrazoles 20-24 with modest affinity but high selectivity toward the hA(3) AR subtype. Molecular docking of the herein reported tricyclic and simplified derivatives was carried out to depict their hypothetical binding mode to our model of hA(3) receptor.
Bioorganic & medicinal chemistry 10/2012; · 2.82 Impact Factor
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Romeo Romagnoli,
Pier Giovanni Baraldi,
Maria Dora Carrion,
Carlota Lopez Cara,
Olga Cruz-Lopez,
Maria Kimatrai Salvador,
Delia Preti,
Mojgan Aghazadeh Tabrizi,
Allan R Moorman, Fabrizio Vincenzi,
Pier Andrea Borea,
Katia Varani
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ABSTRACT: We have recently reported a detailed structure-activity relationship study around a wide series of 2-amino-3-(4-chlorobenzoyl)-4-[(4-arylpiperazin-1-yl)methyl]thiophene derivatives as potent allosteric enhancers of the A(1) adenosine receptor. In the current study, we have continued to explore the potential of these molecules by synthesizing of a novel series of analogues that share a common 2-amino-3-(4-chlorobenzoyl)thiophene nucleus. Modifications were focused on varying the nature and the position of electron-withdrawing or electron-releasing groups on the phenyl of an arylpiperazine moiety attached at the 4-position of the thiophene ring by a methylene chain, combined with the presence of small alkyl groups (methyl or ethyl), bromine, or aryl moieties at the thiophene C-5 position. In this series of compounds, substitution at the 5-position had a fundamental effect on activity, with the 5-aryl group contributing additively to the allosteric enhancer activity. The thiophene C-5 aryl derivatives 4ad, 4ak, and 4al were the most active compounds in binding and functional experiments.
Journal of Medicinal Chemistry 08/2012; 55(17):7719-35. · 4.80 Impact Factor
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ABSTRACT: Amongst cancers with poor prognosis those originating from breast commonly metastasise to the skeleton for the high affinity of breast cancer cells to bone. A(3) adenosine receptor (A(3)AR) agonists were found to be potent anti-tumour agents even if their effect on bone-residing breast cancer has not yet been investigated. An animal model of surgery-induced metastasis was used to mimic the human condition in an attempt to develop a novel effective treatment strategy. Sprague-Dawley rats receiving intra-tibial injections of syngeneic MRMT-1 rat mammary gland carcinoma cells developed cancer-associated osteolytic lesions and structural damage that were monitored by microcomputed tomography imaging and histological analysis. To address the involvement of A(3)ARs in tumour-related signalling pathway, A(3)AR expression and functional role were analysed in MRMT-1 cells. The effect of chronic treatment with an A(3)AR agonist, 2-chloro-N(6)-(3-iodobenzyl)-adenosine-5'-N-methyl-uronamide (Cl-IB-MECA) in comparison with cisplatin, was evaluated on rat tumour growth and bone cancer pain. A(3)ARs were expressed in MRMT-1 cells and their activation reduced NF-kB, increased p53 expression and apoptosis, inhibited tumour cell proliferation and migration. In vivo Cl-IB-MECA administration, started on day 1 after tumour cell injection, produced a significant reduction in tumour growth and cancer pain. Cl-IB-MECA treatment, performed on days 5 and 10 after the tumour cell inoculation, revealed the capability of A(3)AR stimulation to partially reduce tumour progression. Our findings highlighted the effectiveness of A(3)AR stimulation in the inhibition of breast tumour-derived bone metastasis growth strongly suggesting that targeting A(3)ARs may have promising therapeutic value in the treatment of bone-residing breast cancer.
European journal of cancer (Oxford, England: 1990) 07/2012; · 4.12 Impact Factor
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Pier Giovanni Baraldi,
Giulia Saponaro,
Allan R Moorman,
Romeo Romagnoli,
Delia Preti,
Stefania Baraldi,
Emanuela Ruggiero,
Katia Varani,
Martina Targa, Fabrizio Vincenzi,
Pier Andrea Borea,
Mojgan Aghazadeh Tabrizi
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ABSTRACT: Cannabinoid receptor agonists have gained attention as potential therapeutic targets of inflammatory and neuropathic pain. Here, we report the identification and optimization of a series of 7-oxo-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxamide derivatives as a novel chemotype of selective cannabinoid CB(2) receptor agonists. Structural modifications led to the identification of several compounds as potent and selective cannabinoid receptor agonists (20, hCB(2)K(i) = 2.5 nM, SI = 166; 21, hCB(2)K(i) = 0.81 nM, SI = 383; 38, hCB(2)K(i) = 15.8 nM, SI > 633; 56, hCB(2)K(i) = 8.12 nM, SI > 1231; (R)-58, hCB(2)K(i) = 9.24 nM, SI > 1082). The effect of a chiral center on the biological activity was also investigated, and it was found that the (R)-enantiomers exhibited greater affinity at the CB(2) receptor than the (S)-enantiomers. In 3,5-cyclic adenosine monophosphate assays, the novel series behaved as agonists, exhibiting functional activity at the human CB(2) receptor.
Journal of Medicinal Chemistry 06/2012; 55(14):6608-23. · 4.80 Impact Factor
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ABSTRACT: A(3) adenosine receptors (ARs) play a pivotal role in the development of cancer and their activation is involved in the inhibition of tumor growth. The effects of pulsed electromagnetic fields (PEMFs) on cancer have been controversially discussed and the detailed mechanisms are not yet fully understood. In the past we have demonstrated that PEMFs increased A(2A) and A(3)AR density and functionality in human neutrophils, human and bovine synoviocytes, and bovine chondrocytes. In the same cells, PEMF exposure increased the anti-inflammatory effect mediated by A(2A) and/or A(3)ARs. The primary aim of the present study was to evaluate if PEMF exposure potentiated the anti-tumor effect of A(3)ARs in PC12 rat adrenal pheochromocytoma and U87MG human glioblastoma cell lines in comparison with rat cortical neurons. Saturation binding assays and mRNA analysis revealed that PEMF exposure up-regulated A(2A) and A(3)ARs that are well coupled to adenylate cyclase activity and cAMP production. The activation of A(2A) and A(3)ARs resulted in the decrease of nuclear factor-kappa B (NF-kB) levels in tumor cells, whilst only A(3)ARs are involved in the increase of p53 expression. A(3)AR stimulation mediated an inhibition of tumor cell proliferation evaluated by thymidine incorporation. An increase of cytotoxicity by lactate dehydrogenase (LDH) release and apoptosis by caspase-3 activation in PC12 and U87MG cells, but not in cortical neurons, was observed following A(3)AR activation. The effect of the A(3)AR agonist in tumor cells was enhanced in the presence of PEMFs and blocked by using a well-known selective antagonist. Together these results demonstrated that PEMF exposure significantly increases the anti-tumor effect modulated by A(3)ARs.
PLoS ONE 01/2012; 7(6):e39317. · 4.09 Impact Factor
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ABSTRACT: The reduction of the inflammatory status represents one of the most important targets in rheumatoid arthritis (RA). A central role of A2A and A3 adenosine receptors (ARs) in mechanisms of inflammation has been reported in different pathologies. The primary aim of this study was to investigate the A2A and A3ARs and their involvement in RA progression measured by Disease Activity Score in 28 or 44 joints (DAS28 or DAS).
ARs were analyzed by saturation binding assays, mRNA and Western blotting analysis in lymphocytes from early and established RA patients. The effect of A2A and A3AR agonists in nuclear factor kB (NF-kB) pathway was evaluated. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) release was carried out by A2A and A3AR activation. AR pharmacological regulation in matrix metalloproteinase-1 (MMP-1) and metalloproteinase-3 (MMP-3) release was also studied.
In lymphocytes obtained from RA patients, A2A and A3ARs were up-regulated if compared with healthy controls. A2A and A3AR activation inhibited the NF-kB pathway and diminished inflammatory cytokines such as TNF-α, IL-1β and IL-6. A2A and A3AR agonists mediated a reduction of MMP-1 and MMP-3 release. A2A and A3AR density inversely correlated with DAS28 and DAS suggesting a direct role of the endogenous activation of these receptors in the control of RA joint inflammation.
Taken together these data demonstrate that the inflammatory and clinical responses in RA are regulated by A2A and A3ARs and support the use of A2A and/or A3AR agonists as novel and effective pharmacological treatment in RA patients.
Arthritis research & therapy 12/2011; 13(6):R197. · 4.27 Impact Factor
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Romeo Romagnoli,
Pier Giovanni Baraldi,
Maria Dora Carrion,
Carlota Lopez Cara,
Olga Cruz-Lopez,
Maria Kimatrai Salvador,
Delia Preti,
Mojgan Aghazadeh Tabrizi,
John C Shryock,
Allan R Moorman, Fabrizio Vincenzi,
Katia Varani,
Pier Andrea Borea
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ABSTRACT: In a preliminary article, we reported the potent allosteric enhancer activity at the A(1) adenosine receptor of a small series of 2-amino-3-(4-chlorobenzoyl)-4-[4-(aryl)piperazin-1-yl)methyl]thiophene derivatives bearing electron-withdrawing or electron-releasing groups at the para-position of the phenylpiperazine moiety. In the present study, we report the development of the compounds previously studied by modifying both the number and position of substituents on the phenylpiperazine moiety, aimed at establishing a structure-activity relationship identifying additional compounds with improved activity. The nature and the position of substituents on the phenyl ring tethered to the piperazine seemed to exert a fundamental influence on the allosteric enhancer activity, with the 3,4-difluoro 4i, 3-chloro-4-fluoro 4o, and 4-trifluoromethoxy 4ak derivatives being the most active compounds in binding (saturation and competition experiments) and functional cAMP studies. This study shows that it is also possible to obtain a good separation between allosteric enhancement and antagonistic activity at the A(1) adenosine receptor.
Bioorganic & medicinal chemistry 12/2011; 20(2):996-1007. · 2.82 Impact Factor
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ABSTRACT: Different effects of pulsed electromagnetic field (PEMF) exposure on brain tissue have been described in pre-clinical models and in clinical settings. Nevertheless, the mechanism of action and the possible interaction with membrane receptors such as adenosine receptors (ARs) has not been investigated. The present study focused on the effect of PEMFs on A(1) and A(2A) ARs in the rat cerebral cortex and cortical neurons. Affinity and density of ARs were evaluated by means of saturation binding experiments while mRNA expression was investigated through retro-transcription polymerase chain reaction (RT-PCR). PEMF treatment of the intact rat cerebral cortex or cortical neurons at 1.5 mT mediated a transient and significant increase in A(2A) ARs after 4 h (2.0-fold increase) and 6 h (1.4- and 1.8-fold increase, respectively) of exposure. In addition, PEMF treatment of the rat cerebral cortex and rat cortical neurons at 3 mT upregulated A(2A) ARs after 2 h (2.0- and 2.2-fold increase, respectively) and 4 h (1.6- and 1.9-fold increase, respectively). The treatment of rat cortex membranes with PEMFs at 1.5 and 3 mT induced an increase in A(2A) AR density after 2 h (1.9- and 2.2-fold increase, respectively) and was constant at all incubation times investigated. In rat cortical neurons, mRNA levels of A(1) and A(2A) ARs were not affected by PEMF exposure for the times and intensities used. These results suggest that PEMF treatment has different biological effects in whole organs or cells in comparison with isolated membranes. Bioelectromagnetics. © 2011 Wiley Periodicals, Inc.
Bioelectromagnetics 10/2011; · 1.84 Impact Factor
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Ombretta Lenzi,
Vittoria Colotta,
Daniela Catarzi,
Flavia Varano,
Lucia Squarcialupi,
Guido Filacchioni,
Katia Varani, Fabrizio Vincenzi,
Pier Andrea Borea,
Diego Dal Ben,
Catia Lambertucci,
Gloria Cristalli
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ABSTRACT: This paper reports the study of new 2-phenyl- and 2-methylpyrazolo[3,4-c]quinolin-4-ones (series A) and 4-amines (series B), designed as adenosine receptor (AR) antagonists. The synthesized compounds bear at the 6-position various groups, with different lipophilicity and steric hindrance, that were thought to increase human A(1) and A(2A) AR affinities and selectivities, with respect to those of the parent 6-unsubstituted compounds. In series A, this modification was not tolerated since it reduced AR affinity, while in series B it shifted the binding towards the hA(1) subtype. To rationalize the observed structure-affinity relationships, molecular docking studies at A(2A)AR-based homology models of the A(1) and A(3) ARs and at the A(2A)AR crystal structure were carried out.
Bioorganic & medicinal chemistry 06/2011; 19(12):3757-68. · 2.82 Impact Factor
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ABSTRACT: A strong link has been established between exposure to asbestos and increased risk for pleural malignant mesothelioma (MM). Adenosine plays a key role in inflammatory processes and cancer, where it is involved in the regulation of cell death and proliferation.
The primary aim of this study was to investigate the presence of adenosine receptors (ARs) in human MM pleura (MMP) and healthy mesothelial pleura (HMP). To shed some light on the interaction between adenosine and MM, the presence and functionality of ARs were explored in human healthy mesothelial cells (HMC) and in malignant mesothelioma cells (MMC).
ARs were analyzed by using reverse transcriptase-polymerase chain reaction, Western blotting, and saturation binding assays. HMC were treated with crocidolite asbestos, which is the principal risk factor for MM. The role of A₃ ARs on these cellular models, evaluating cAMP production, Akt phosphorylation, and nuclear factor (NF)-κB activation, was investigated. The dual effect of A₃AR stimulation on healthy and cancer cell growth was studied by means of proliferation, apoptosis, and cytotoxicity assays.
A₃AR was up-regulated by 2.5-fold (P < 0.01) in MMP when compared with HMP. Stimulation of A₃ARs decreased proliferation and exerted a cytotoxic and proapoptotic effect on MMC and on HMC exposed to asbestos and tumor necrosis factor-α, but not on HMC with an involvement of the deregulation of Akt/NF-κB cell survival pathway.
These new findings suggest that A₃AR could represent a pharmacological target to prevent tumor development after asbestos exposure and to treat full-blown MM.
American Journal of Respiratory and Critical Care Medicine 02/2011; 183(4):522-30. · 11.08 Impact Factor
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ABSTRACT: Rheumatoid arthritis (RA), is the most common inflammatory musculoskeletal disease inducing diminished quality-of-life in the affected individuals and having major impact on society due to decrease work ability. Early diagnosis and immediate, effective therapy are crucial in order to prevent unfavorable outcome. Treatment of RA has progressed during the past two decades thanks to the advent of a large number of new agents targeting different specific molecules and pathways involved in the modulation of the inflammation. In this scenario an important role is covered by adenosine, a purine nucleoside released from a variety of cells in response to metabolic and inflammatory stress, which is considered to be a potent endogenous regulator acting through its interaction with 4 cell surface receptors named as A(1), A(2A), A(2B) and A(3). Adenosine receptor stimulation has complex effects on the release of pro-inflammatory cytokines depending on selective receptor engagement. Recent data show the involvement of adenosine pathways in RA and its potential therapeutic implications.
Autoimmunity reviews 12/2010; 10(2):61-4. · 6.37 Impact Factor
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ABSTRACT: P2X receptors are membrane ion channels activated by extracellular adenosine 5'-triphosphate (ATP) which contribute to various physiological processes. The present study describes in synovial fibroblasts (SFs) obtained from osteoarthritis (OA) patients and in SW 982 cells derived from human synovial sarcoma a pharmacological characterization of P2X(1) and P2X(3) receptors implicated in the modulation of inflammatory processes in joint diseases.
mRNA, western blotting, saturation and competition binding experiments were used to characterize purinergic receptors. From a functional point of view nuclear factor kappaB (NF-kappaB) activation, tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and prostaglandin E(2) (PGE(2)) production were evaluated by means of enzyme-linked immunosorbent assays.
P2X(1) and P2X(3) receptors were present with high affinity and density. Selected purinergic agonists and antagonists exhibited a different thermodynamic behavior. P2X(1) receptors showed an anti-inflammatory effect reducing NF-kappaB activation and TNF-alpha release whilst P2X(3) receptors mediated opposite response. No effect was mediated by P2X(1) and P2X(3) receptors on IL-6 and PGE(2) production.
SFs from OA patients and SW 982 cells similarly express P2X(1) and P2X(3) receptors which are able to modulate in opposite way some functional responses closely associated with inflammation suggesting that purinergic receptors may represent a potential target in therapeutic anti-inflammatory joint interventions.
Cellular Physiology and Biochemistry 01/2010; 25(2-3):325-36. · 2.86 Impact Factor
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Katia Varani,
Gaetano Caramori, Fabrizio Vincenzi,
Alice Tosi,
Adam Barczyk,
Marco Contoli,
Paolo Casolari,
Massimo Triggiani,
Trevor Hansel,
Edward Leung,
Stephen Maclennan,
Peter J Barnes,
Kian Fan Chung,
Ian Adcock,
Alberto Papi,
Pier Andrea Borea
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ABSTRACT: The primary aim of this study was to investigate adenosine receptors (ARs) in bronchoalveolar lavage (BAL) macrophages from patients with chronic obstructive pulmonary disease (COPD) and age-matched healthy smokers. A(2B)ARs were significantly decreased in BAL macrophages from patients with COPD when compared with healthy smokers. The effect of proinflammatory cytokines and oxidative/nitrosative stress on AR expression and function in U937 cells before and after PMA treatment was evaluated. IL-1beta and TNF-alpha treatment up-regulated A(2A)- and A(3)ARs but not A(1)- or A(2B)ARs, whereas IL-6 did not modify AR expression. In contrast, oxidative/nitrosative stress selectively decreased A(2B)AR expression, which was associated with a reduction in the potency of the adenosine agonist 5'-N-ethylcarboxamideadenosine (NECA) to induce cAMP. Further, the ability of NECA to enhance cell proliferation was increased after oxidative/nitrosative stress. The specific involvement of A(2B)ARs was investigated by using potent and selective A(2B)AR antagonist and by A(2B)AR knockdown using siRNA and demonstrated responses similar to those obtained with oxidative/nitrosative stress. N-acetylcysteine (NAC), an antioxidant agent, counteracted the decrease in A(2B)AR expression, as well as the altered NECA effects on cAMP and cell proliferation. These findings highlight the central role of A(2B)ARs in alveolar macrophages, suggesting that their modulation could represent an innovative pharmacological strategy to manage COPD.-Varani, K., Caramori, G., Vincenzi, F., Tosi, A., Barczyk, A., Contoli, M., Casolari, P., Triggiani, M., Hansel, T., Leung, E., MacLennan, S., Barnes, P. J., Fan Chung, K., Adcock, I., Papi, A., Borea, P. A. Oxidative/nitrosative stress selectively altered A(2B) adenosine receptors in chronic obstructive pulmonary disease.
The FASEB Journal 12/2009; 24(4):1192-204. · 5.71 Impact Factor
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Ombretta Lenzi,
Vittoria Colotta,
Daniela Catarzi,
Flavia Varano,
Daniela Poli,
Guido Filacchioni,
Katia Varani, Fabrizio Vincenzi,
Pier Andrea Borea,
Silvia Paoletta,
Erika Morizzo,
Stefano Moro
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ABSTRACT: A molecular simplification approach of previously reported 2-arylpyrazolo[3,4-c]quinolin-4-ones was applied to design 2-arylpyrazolo[4,3-d]pyrimidin-7-one derivatives as new human A(3) adenosine receptor antagonists. Substituents with different lipophilicity and steric hindrance were introduced at the 5-position of the bicyclic scaffold (R(5) = H, Me, Et, Ph, CH(2)Ph) and on the 2-phenyl ring (OMe, Me). Most of the synthesized derivatives were highly potent hA(3) adenosine receptor antagonists, the best being the 2-(4-methoxyphenyl)pyrazolo[4,3-d]pyrimidin-7-one (K(i) = 1.2 nM). The new compounds were also highly selective, being completely devoid of affinity toward hA(1), hA(2A), and hA(2B) adenosine receptors. On the basis of the recently published human A(2A) receptor crystallographic information, we propose a novel receptor-driven hypothesis to explain both A(3) AR affinity and A(3) versus A(2A) selectivity profiles of these new antagonists.
Journal of Medicinal Chemistry 10/2009; 52(23):7640-52. · 4.80 Impact Factor
