1
|
Nguyen KT, Huynh TNT, Ratanathawornkiti K, Juthathan M, Thamyongkit P, Sukwattanasinitt M, Wacharasindhu S. NaI-Mediated Electrochemical Cyclization-Desulfurization for the Synthesis of N-Substituted 2-Aminobenzimidazoles. J Org Chem 2024; 89:1591-1608. [PMID: 38102091 DOI: 10.1021/acs.joc.3c02212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
An electrochemical method for the synthesis of N-substituted 2-aminobenzimidazoles through a NaI-mediated desulfurization-cyclization process is reported. This electrosynthesis method utilizes cost-effective NaI as both a mediator and an electrolyte in a catalytic amount (0.2 equiv), replacing traditional oxidizing reagents. N-Substituted o-phenylenediamines and isothiocyanates undergo a thiourea formation/cyclization/desulfurization process to provide N-substituted 2-aminobenzimidazoles (55 examples, up to 98% yield) in a single reaction vessel. Importantly, this electrochemical methodology is applicable to gram-scale synthesis, maintaining reaction efficiency.
Collapse
Affiliation(s)
- Khuyen Thu Nguyen
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Thao Nguyen Thanh Huynh
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | | | - Methasit Juthathan
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Patchanita Thamyongkit
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | | | - Sumrit Wacharasindhu
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
- Green Chemistry for Fine Chemical Productions and Environmental Remediation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| |
Collapse
|
2
|
Tian JN, Shi XD, Wang XK, Wang S, Xu JX, Yang CX. Astemizole protects against human umbilical vein endothelial cell injury induced by hydrogen peroxide via the p53 signaling pathway. Mol Med Rep 2017; 15:4286-4290. [DOI: 10.3892/mmr.2017.6497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 01/30/2017] [Indexed: 11/06/2022] Open
|
3
|
García-Quiroz J, García-Becerra R, Barrera D, Santos N, Avila E, Ordaz-Rosado D, Rivas-Suárez M, Halhali A, Rodríguez P, Gamboa-Domínguez A, Medina-Franco H, Camacho J, Larrea F, Díaz L. Astemizole synergizes calcitriol antiproliferative activity by inhibiting CYP24A1 and upregulating VDR: a novel approach for breast cancer therapy. PLoS One 2012; 7:e45063. [PMID: 22984610 PMCID: PMC3440370 DOI: 10.1371/journal.pone.0045063] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 08/14/2012] [Indexed: 11/23/2022] Open
Abstract
Background Calcitriol antiproliferative effects include inhibition of the oncogenic ether-à-go-go-1 potassium channel (Eag1) expression, which is necessary for cell cycle progression and tumorigenesis. Astemizole, a new promising antineoplastic drug, targets Eag1 by blocking ion currents. Herein, we characterized the interaction between calcitriol and astemizole as well as their conjoint antiproliferative action in SUM-229PE, T-47D and primary tumor-derived breast cancer cells. Methodology/Principal Findings Molecular markers were studied by immunocytochemistry, Western blot and real time PCR. Inhibitory concentrations were determined by dose-response curves and metabolic activity assays. At clinically achievable drug concentrations, synergistic antiproliferative interaction was observed between calcitriol and astemizole, as calculated by combination index analysis (CI <1). Astemizole significantly enhanced calcitriol’s growth-inhibitory effects (3–11 folds, P<0.01). Mean IC20 values were 1.82±2.41 nM and 1.62±0.75 µM; for calcitriol (in estrogen receptor negative cells) and astemizole, respectively. Real time PCR showed that both drugs alone downregulated, while simultaneous treatment further reduced Ki-67 and Eag1 gene expression (P<0.05). Astemizole inhibited basal and calcitriol-induced CYP24A1 and CYP3A4 mRNA expression (cytochromes involved in calcitriol and astemizole degradation) in breast and hepatoma cancer cells, respectively, while upregulated vitamin D receptor (VDR) expression. Conclusions/Significance Astemizole synergized calcitriol antiproliferative effects by downregulating CYP24A1, upregulating VDR and targeting Eag1. This study provides insight into the molecular mechanisms involved in astemizole-calcitriol combined antineoplastic effect, offering scientific support to test both compounds in combination in further preclinical and clinical studies of neoplasms expressing VDR and Eag1. VDR-negative tumors might also be sensitized to calcitriol antineoplastic effects by the use of astemizole. Herein we suggest a novel combined adjuvant therapy for the management of VDR/Eag1-expressing breast cancer tumors. Since astemizole improves calcitriol bioavailability and activity, decreased calcitriol dosing is advised for conjoint administration.
Collapse
Affiliation(s)
- Janice García-Quiroz
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del I.P.N., México, D.F., México
| | - Rocío García-Becerra
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - David Barrera
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Nancy Santos
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del I.P.N., México, D.F., México
| | - Euclides Avila
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - David Ordaz-Rosado
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Mariana Rivas-Suárez
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Ali Halhali
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Pamela Rodríguez
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Armando Gamboa-Domínguez
- Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Heriberto Medina-Franco
- Departamento de Cirugía, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Javier Camacho
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del I.P.N., México, D.F., México
| | - Fernando Larrea
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
| | - Lorenza Díaz
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D.F., México
- * E-mail:
| |
Collapse
|
4
|
Ailanthus altissima swingle has anti-anaphylactic effect and inhibits inflammatory cytokine expression via suppression of nuclear factor-kappaB activation. In Vitro Cell Dev Biol Anim 2009; 46:72-81. [DOI: 10.1007/s11626-009-9237-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 09/03/2009] [Indexed: 01/11/2023]
|
5
|
Shin HY, Kim SH, Jeong HJ, Kim SY, Shin TY, Um JY, Hong SH, Kim HM. Epigallocatechin-3-Gallate Inhibits Secretion of TNF-α, IL-6 and IL-8 through the Attenuation of ERK and NF-κB in HMC-1 Cells. Int Arch Allergy Immunol 2006; 142:335-44. [PMID: 17135765 DOI: 10.1159/000097503] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 10/05/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Epigallocatechin-3-gallate (EGCG) is a major form of tea catechin and has a variety of biological activities. In the present study, we investigated the effect of EGCG on the secretion of TNF-alpha, IL-6 and IL-8, as well as its possible mechanism of action by using the human mast cell line (HMC-1). METHODS EGCG was treated before the activation of HMC-1 cells with phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore (A23187). To investigate the effect of EGCG on PMA+A23187-stimulated HMC-1 cells, ELISA, Western blot analysis, electrophorectic mobility shift assay and luciferase assay were used in this study. RESULTS EGCG (100 microM) inhibited PMA+A23187-induced TNF-alpha, IL-6 and IL-8 expression and production. EGCG inhibited the intracellular Ca(2+) level. EGCG attenuated PMA+A23187-induced NF-kappaB and extracellular signal-regulated kinase (ERK1/2) activation, but not that of c-Jun N-terminal kinase or p38 mitogen-activated protein kinase. CONCLUSION EGCG inhibited the production of TNF-alpha, IL-6 and IL-8 through the inhibition of the intracellular Ca(2+) level, and of ERK1/2 and NF-kappaB activation. These results indicate that EGCG may be helpful in regulating mast-cell-mediated allergic inflammatory response.
Collapse
Affiliation(s)
- Hye-Young Shin
- Department of Pharmacology, College of Oriental Medicine, Institute of Oriental Medicine, Kyung Hee University, Dongdaemun-Gu, Seoul, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Xia Q, Zhou WM, Yang S, Zhang SQ, Chen B, Wang DB, Wang Y, Zhang XJ. Influence of mizolastine on antigen-induced activation of signalling pathways in murine mast cells. Clin Exp Dermatol 2006; 31:260-5. [PMID: 16487106 DOI: 10.1111/j.1365-2230.2006.02050.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND There is accumulating evidence that some antihistamines can interrupt intermediate signalling events that regulate cell function. The effect of mizolastine on both the generation and release process of many cytokines in mast cells further implies that the inhibition by mizolastine may target signalling pathways. AIM To observe the influence of mizolastine on antigen-induced activation of signalling pathways in murine mast cells. METHODS Western blot analysis and enzyme assay were performed. Immunoblots were prepared from whole cell lysates and probed with antibodies against Fyn, Akt, ERK, p38, phospho-Fyn, phospho-Akt, phospho-ERK and phospho-p38, respectively. RESULTS Our study showed that signalling molecules such as IP3, Fyn, p38 and ERK were enhanced when mast cells were stimulated by antigen, and that this was not inhibited by treatment with mizolastine. Mizolastine at concentrations from 10(-9) to 10(-5) mol/L could inhibit activation of the PI3K kinase downstream signalling molecule Akt to antigen stimulation. The study also demonstrated that mizolastine exerted inhibitory ability on protein kinase C (PKC) activation in a dose-dependent manner. CONCLUSION PKC-mediated phosphorylation of Akt can be blocked by mizolastine. There may be a PKC-independent pathway effectively activating MAPK pathways in mast cells in response to antigen induction, which cannot be affected by mizolastine.
Collapse
Affiliation(s)
- Q Xia
- Department of Biochemistry, Anhui Medical University, Hefei, China
| | | | | | | | | | | | | | | |
Collapse
|
7
|
García-Ferreiro RE, Kerschensteiner D, Major F, Monje F, Stühmer W, Pardo LA. Mechanism of block of hEag1 K+ channels by imipramine and astemizole. ACTA ACUST UNITED AC 2004; 124:301-17. [PMID: 15365094 PMCID: PMC2233905 DOI: 10.1085/jgp.200409041] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ether à go-go (Eag; KV10.1) voltage-gated K+ channels have been detected in cancer cell lines of diverse origin and shown to influence their rate of proliferation. The tricyclic antidepressant imipramine and the antihistamine astemizole inhibit the current through Eag1 channels and reduce the proliferation of cancer cells. Here we describe the mechanism by which both drugs block human Eag1 (hEag1) channels. Even if both drugs differ in their affinity for hEag1 channels (IC50s are approximately 2 microM for imipramine and approximately 200 nM for astemizole) and in their blocking kinetics, both drugs permeate the membrane and inhibit the hEag1 current by selectively binding to open channels. Furthermore, both drugs are weak bases and the IC50s depend on both internal an external pH, suggesting that both substances cross the membrane in their uncharged form and act from inside the cell in their charged forms. Accordingly, the block by imipramine is voltage dependent and antagonized by intracellular TEA, consistent with imipramine binding in its charged form to a site located close to the inner end of the selectivity filter. Using inside- and outside-out patch recordings, we found that a permanently charged, quaternary derivative of imipramine (N-methyl-imipramine) only blocks channels from the intracellular side of the membrane. In contrast, the block by astemizole is voltage independent. However, as astemizole competes with imipramine and intracellular TEA for binding to the channel, it is proposed to interact with an overlapping intracellular binding site. The significance of these findings, in the context of structure-function of channels of the eag family is discussed.
Collapse
Affiliation(s)
- Rafael E García-Ferreiro
- Abteilung Molekulare Biologie Neuronaler Signale, Max-Planck Institut für Experimentelle Medizin, 37075 Göttingen, Germany.
| | | | | | | | | | | |
Collapse
|
8
|
Leurs R, Church MK, Taglialatela M. H1-antihistamines: inverse agonism, anti-inflammatory actions and cardiac effects. Clin Exp Allergy 2002; 32:489-98. [PMID: 11972592 DOI: 10.1046/j.0954-7894.2002.01314.x] [Citation(s) in RCA: 259] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This review addresses novel concepts of histamine H1-receptor function and attempts to relate them to the anti-inflammatory effects of H1-antihistamines. Furthermore, the molecular mechanisms underlying the cardiotoxic effects of H1-antihistamines are discussed. H1-receptors are G-protein-coupled-receptors (GPCRs), the inactive and active conformations of which coexist in equilibrium. The degree receptor activation in the absence of histamine is its 'constitutive activity'. In this two-state model, histamine acts as an agonist by combining with and stabilizing the activated conformation of the H1-receptor to shift the equilibrium towards the activated state. Drugs classified previously as antagonists act as either inverse agonists or neutral antagonists. Inverse agonists combine with and stabilize the inactive conformation of the receptor to shift the equilibrium towards the inactive state. Thus, they may down-regulate constitutive receptor activity, even in the absence of histamine. Neutral antagonists combine equally with both conformations of the receptor, do not affect basal receptor activity but do interfere with agonist binding. All H1-antihistamines examined to date are inverse agonists. As the term 'H1-receptor antagonists' is obviously erroneous, we suggest that it be replaced by 'H1-antihistamines'. The observations that H1-receptors modulate NF-kappaB activation and that there are complex interactions between GPCRs, has allowed us to postulate receptor dependent-mechanisms for some anti-inflammatory effects of H1-antihistamines, e.g. inhibition of ICAM-1 expression and the effects of bradykinin. Finally, the finding that blockade of HERG1 K+ channels is the mechanism by which some H1-antihistamines may cause cardiac arrhythmias has allowed the development of preclinical tests to predict such activity.
Collapse
Affiliation(s)
- R Leurs
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, the Netherlands
| | | | | |
Collapse
|
9
|
Taglialatela M, Secondo A, Fresi A, Rosati B, Pannaccione A, Castaldo P, Giorgio G, Wanke E, Annunziato L. Inhibition of depolarization-induced [3H]noradrenaline release from SH-SY5Y human neuroblastoma cells by some second-generation H(1) receptor antagonists through blockade of store-operated Ca(2+) channels (SOCs). Biochem Pharmacol 2001; 62:1229-38. [PMID: 11705456 DOI: 10.1016/s0006-2952(01)00754-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the present study, the effect of the blockade of membrane calcium channels activated by intracellular Ca(2+) store depletion on basal and depolarization-induced [3H]norepinephrine ([3H]NE) release from SH-SY5Y human neuroblastoma cells was examined. The second-generation H(1) receptor blockers astemizole, terfenadine, and loratadine, as well as the first-generation compound hydroxyzine, inhibited [3H]NE release induced by high extracellular K(+) concentration ([K(+)](e)) depolarization in a concentration-dependent manner (the IC(50)s were 2.3, 1.7, 4.8, and 9.4 microM, respectively). In contrast, the more hydrophilic second-generation H(1) receptor blocker cetirizine was completely ineffective (0.1-30 microM). The inhibition of high [K(+)](e)-induced [3H]NE release by H(1) receptor blockers seems to be related to their ability to inhibit Ca(2+) channels activated by Ca(i)(2+) store depletion (SOCs). In fact, astemizole, terfenadine, loratadine, and hydroxyzine, but not cetirizine, displayed a dose-dependent inhibitory action on the increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)) obtained with extracellular Ca(2+) reintroduction after Ca(i)(2+) store depletion with thapsigargin (1 microM), an inhibitor of the sarcoplasmic-endoplasmic reticulum calcium ATPase (SERCA) pump. The rank order of potency for SOC inhibition by these compounds closely correlated with their inhibitory properties on depolarization-induced [3H]NE release from SH-SY5Y human neuroblastoma cells. Nimodipine (1 microM) plus omega-conotoxin (100 nM) did not interfere with the present model for SOC activation. In addition, the inhibition of depolarization-induced [3H]NE release does not seem to be attributable to the blockade of the K(+) currents carried by the K(+) channels encoded by the human Ether-a-Gogo Related Gene (I(HERG)) by these antihistamines. In fact, whole-cell voltage-clamp experiments revealed that the IC(50) for astemizole-induced hERG blockade is about 300-fold lower than that for the inhibition of high K(+)-induced [3H]NE release. Furthermore, current-clamp experiments in SH-SY5Y cells showed that concentrations of astemizole (3 microM) which were effective in preventing depolarization-induced [3H]NE release were unable to interfere with the cell membrane potential under depolarizing conditions (100 mM [K(+)](e)), suggesting that hERG K(+) channels do not contribute to membrane potential control during exposure to elevated [K(+)](e). Collectively, the results of the present study suggest that, in SH-SY5Y human neuroblastoma cells, the inhibition of SOCs by some second-generation antihistamines can prevent depolarization-induced neurotransmitter release.
Collapse
Affiliation(s)
- M Taglialatela
- Unit of Pharmacology, Department of Neuroscience, University of Naples Federico II, School of Medicine, Via S. Pansini 5, I-80131, Naples, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Secondo A, Taglialatela M, Cataldi M, Giorgio G, Valore M, Di Renzo G, Annunziato L. Pharmacological blockade of ERG K(+) channels and Ca(2+) influx through store-operated channels exerts opposite effects on intracellular Ca(2+) oscillations in pituitary GH(3) cells. Mol Pharmacol 2000; 58:1115-28. [PMID: 11040061 DOI: 10.1124/mol.58.5.1115] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the present study, the effects on intracellular calcium concentration ([Ca(2+)](i)) oscillations of the blockade of ether-a-go-go-related gene (ERG) K(+) channels and of Ca(2+) influx through store-operated channels (SOC) activated by [Ca(2+)](i) store depletion have been studied in GH(3) cells by means of a combination of single-cell fura-2 microfluorimetry and whole-cell mode of the patch-clamp technique. Nanomolar concentrations (1-30 nM) of the piperidinic second-generation antihistamines terfenadine and astemizole and of the class III antiarrhythmic methanesulfonanilide dofetilide, by blocking ERG K(+) channels, increased the frequency and the amplitude of [Ca(2+)](i) oscillations in resting oscillating GH(3) cells. These compounds also induced the appearance of an oscillatory pattern of [Ca(2+)](i) in a subpopulation of nonoscillating GH(3) cells. The effects of ERG K(+) channel blockade on [Ca(2+)](i) oscillations appeared to be due to the activation of L-type Ca(2+) channels, because they were prevented by 300 nM nimodipine. By contrast, the piperazinic second-generation antihistamine cetirizine (0.01-30 microM), which served as a negative control, failed to affect ERG K(+) channels and did not interfere with [Ca(2+)](i) oscillations in GH(3) cells. Interestingly, micromolar concentrations of terfenadine and astemizole (0.3-30 microM), but not of dofetilide (10-100 microM), produced an inhibition of the spontaneous oscillatory pattern of [Ca(2+)](i) changes. This effect was possibly related to an inhibition of SOC, because these compounds inhibited the increase of [Ca(2+)](i) achieved by extracellular calcium reintroduction after intracellular calcium store depletion with the sarcoplasmic or endoplasmic reticulum calcium ATPase pump inhibitor thapsigargin (10 microM) in an extracellular calcium-free medium. The same inhibitory effect on [Ca(2+)](i) oscillations and SOC was observed with the first-generation antihistamine hydroxyzine (1-30 microM), the more hydrophobic metabolic precursor of cetirizine. Collectively, the results of the present study obtained with compounds that interfere in a different concentration range with ERG K(+) channels or SOC suggest that 1) ERG K(+) channels play a relevant role in controlling the oscillatory pattern of [Ca(2+)](i) in resting GH(3) cells and 2) the inhibition of SOC might induce an opposite effect, i.e., an inhibition of [Ca(2+)](i) oscillations.
Collapse
Affiliation(s)
- A Secondo
- Unit of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Naples, Italy
| | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
Many antihistamines exhibit inhibition of mediator release from mast cells and basophils, in in vitro studies in addition to H1 antagonism. The underlying mechanism is unclear but is unrelated to H1-receptor antagonism. Clinical studies of antihistamins in antigen challenge and seasonal allergy demonstrate reduction of mast cell mediators in nasal lavage. It is not known what mechanism(s) underly these observations, although the concentrations required in in vitro studies suggests that a direct effect on mast cells is unlikely. Furthermore, the therapeutic contribution of this effect is difficult to assess because of concomitant clinically significant H1 antagonism. This and other potential anti-allergic effects may enhance the therapeutic benefit of antihistamines and long-term studies are underway to explore this possibility.
Collapse
Affiliation(s)
- F M Cuss
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
| |
Collapse
|
12
|
Paulussen JJ, Fischer MJ, Roozendaal RL, van der Heijden VC, van Dijken P, de Mol NJ, Janssen LH. Effects of oxatomide and derivatives on high affinity IgE receptor-activated signal transduction pathways in rat basophilic leukemia cells: role of protein tyrosine hyperphosphorylation and inhibition of extracellular calcium influx. Biochem Pharmacol 1998; 56:693-701. [PMID: 9751073 DOI: 10.1016/s0006-2952(98)00038-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The antiallergic drug oxatomide and analogs inhibit mediator release from a rat basophilic leukemia (RBL-2H3) cell line, which is frequently used as a mast cell model. By investigating a series of derivatives of oxatomide with different inhibiting activities on exocytosis, we aimed to evaluate the role of their effects on the early steps of the signal transduction cascade in the inhibition of exocytosis. The active compounds induced hyperphosphorylation of tyrosine residues both in stimulated as well as in resting cells. Furthermore, some elevation of the inositol 1,4,5-trisphosphate (IP3) formation upon antigen activation was observed for the active derivatives. Ca2+ fluxes were also studied. The inhibition of the antigen-induced 45Ca2+ influx correlated with the effects of the drugs on exocytosis. Furthermore, the inhibitory activity on antigen- and thapsigargin-mediated exocytosis correlated well. Adherence of the cells to fibronectin, stimulating cellular integrin receptors, was synergistic to antigen activation of the RBL cells. However, oxatomide did lack any effect on integrin-mediated processes, as the IC50 value for exocytosis was identical for fibronectin-adhered cells and standard cultured cells. We conclude that oxatomide and its analogs inhibit exocytosis, mainly by inhibiting Ca2+ influx over store-operated Ca2+ (SOC) channels. The drugs have a direct effect on the store-operated Ca2+ channels or affect the direct regulation of these channels.
Collapse
Affiliation(s)
- J J Paulussen
- Department of Medicinal Chemistry, Utrecht Institute for Pharmaceutical Sciences, Faculty of Pharmacy, Utrecht University, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
13
|
Fischer MJ, Paulussen JJ, Tollenaere JP, De Mol NJ, Janssen LH. Structure-activity relationships of astemizole derivatives for inhibition of store operated Ca2+ channels and exocytosis. Eur J Pharmacol 1998; 350:353-61. [PMID: 9696427 DOI: 10.1016/s0014-2999(98)00270-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of a series of analogues of the antiallergic drug astemizole on the exocytosis of the enzyme beta-hexosaminidase were studied in a mast cell model, the rat basophilic leukemia (RBL-2H3) cell. Besides differences in the effects on Fc epsilonRI receptor-stimulated exocytosis, changes were also observed in Ca2+ influx and in the perturbation of the cell membrane. A strong correlation was found between the effects on antigen- and thapsigargin-stimulated 45Ca2+ influx. Furthermore, the inhibition of 45Ca2+ influx was correlated with the inhibition of beta-hexosaminidase release and membrane stabilization. It is concluded that the astemizole analogues are capable of inhibiting mast cell beta-hexosaminidase release through inhibition of Ca2+-store-operated Ca2+ channels (SOC). Compounds with high lipophilicity also released Ca2+ from intracellular stores. Lowering of the hydrophobicity by introduction of nitrogens or truncation at different sites in the astemizole structure decreased inhibitory activity on SOC channels. The inhibition of SOC channels cannot completely be ascribed to non-specific membrane effects. The piperidinyl-benzimidazole moiety was found to be important for inhibition of SOC channels. The observed differences in activity possibly depend on the way the compounds penetrate the membrane bilayer. Astemizole is an interesting new tool to study SOC channels and can be a lead for the design of mast cell-stabilizing antiallergic drugs.
Collapse
Affiliation(s)
- M J Fischer
- Department of Pharmaceutical Chemistry, Utrecht Institute for Pharmaceutical Sciences, Faculty of Pharmacy, Utrecht University, The Netherlands
| | | | | | | | | |
Collapse
|
14
|
Fischer MJ, Paulussen JJ, de Mol NJ, Janssen LH. Dual effect of the anti-allergic astemizole on Ca2+ fluxes in rat basophilic leukemia (RBL-2H3) cells: release of Ca2+ from intracellular stores and inhibition of Ca2+ release-activated Ca2+ influx. Biochem Pharmacol 1998; 55:1255-62. [PMID: 9719481 DOI: 10.1016/s0006-2952(97)00600-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The antiallergic drugs astemizole and norastemizole inhibit exocytosis in mast cells, which might be relevant for their therapeutic action. From previous studies, it appeared that the drugs inhibited 45Ca2+ influx. Here, we present a more detailed study on the effects of astemizole and norastemizole on Ca2+ fluxes. Fura-2-loaded rat basophilic leukemia (RBL-2H3) cells were activated through the high-affinity receptor for IgE (FcepsilonRI) with antigen or by the endoplasmatic reticulum ATPase inhibitor thapsigargin, bypassing direct FcepsilonRI-related events. It appeared that astemizole (>15 microM), in contrast to norastemizole, showed a dual effect on intracellular calcium concentration ([Ca2+]i): a rise in intracellular calcium concentration was induced, which originated in the release of intracellular Ca2+ stores, whereas Ca2+ influx via store-operated Ca2+ (SOC) channels was inhibited. Ca2+ influx was further characterized using Ba2+ influx, whereas processes in the absence of Ca2+ influx were studied using Ni2+ or EGTA. It was concluded that the drugs most likely affect the store-operated Ca2+ channels in RBL cells directly. The two effects of astemizole on Ca2+ fluxes had opposing influences on exocytosis, thereby accounting for the biphasic effect of increasing astemizole concentration on mediator release in RBL cells.
Collapse
Affiliation(s)
- M J Fischer
- Department of Medicinal Chemistry, Utrecht Institute for Pharmaceutical Sciences, Faculty of Pharmacy, Utrecht University, The Netherlands.
| | | | | | | |
Collapse
|