In Vitro Antihepatoma Activity of Novel 3D-Copper Cyanide Supramolecular Coordination Polymers

2016 ◽  
Vol 99 (5) ◽  
pp. 1240-1246
Author(s):  
Noura M Darwish ◽  
Ahmed S Sultan ◽  
Ahmed M Malki ◽  
Hossam Khamis ◽  
Mohamed El-Ziady
Keyword(s):  
Protein Expression ◽  
Western Blot ◽  
Coordination Polymers ◽  
Hepg2 Cells ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Invasive Potential ◽  
Dna Ladder ◽  
Supramolecular Coordination

Abstract This study aimed to investigate the inhibitory effect of novel 3D-organocopper supramolecular coordination polymers (SCPs) on the invasive potential of HepG2 cells. Chemoprevention could represent an important means to inhibit the process of hepatocarcinogenesis. The inhibitory effect of an SCP compound on the proliferation of HepG2 hepatoma cells was evaluated by cell vibility assay. DNA ladder bands were observed by DNA agarose gel electrophoresis. The influence of the SCP compound on phosphorylated ERK1/2, Bcl-2, and β-catenin protein expression of HepG2 cells was analyzed by Western blot. The SCP compound exerted an inhibitory effect on HepG2 cell proliferation in a dose-dependent manner. This inhibitory effect was confirmed by examination of cell morphology and DNA fragmentation. Furthermore, Western blot analysis revealed that phosphorylated ERK1/2 and β-catenin protein expression was inhibited after 24 h of treatment with the SCP compound, and that this event was associated with decreased Bcl-2 expression. We concluded that SCP can effectively inhibit the invasive potential of the ERK signaling pathway in HepG2 cells by altering apoptosis and by inhibiting Bcl-2 and β-catenin, which may play a significant role in this process.

Effect of Auraptene on angiogenesis in Xenograft model of breast cancer

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Reza Shiran ◽  
Elham Mahmoudian ◽  
Abolghasem Ajami ◽  
Seyed Mostafa Hosseini ◽  
Ayjamal Khojasteh ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Animal Model ◽  
Protein Expression ◽  
Western Blot ◽  
Xenograft Model ◽  
Dependent Manner ◽  
Concentration Dependent Manner

Abstract Objectives Angiogenesis is the most important challenge in breast cancer treatment. Recently, scientists become interesting in rare natural products and intensive researches was performed to identify their pharmacological profile. Auraptene shows helpful effects such as cancer chemo-preventive, anti-inflammatory, anti-oxidant, immuno-modulatory. In this regard, we investigated the anti-angiogenesis effect of Auraptene in in-vitro and in-vivo model of breast cancer. Methods In this study, 4T, MDA-MB-231 and HUVEC cell lines were used. The proliferation study was done by MTT assay. For tube formation assay, 250 matrigel, 1 × 104 HUVEC treated with Auraptene, 20 ng/mL EGF, 20 ng/mL bFGF and 20 ng/mL VEGF were used. Gene expression of important gene related to angiogenesis in animal model of breast cancer was investigated by Real-time PCR. Protein expression of VCAM-1 and TNFR-1 gene related to angiogenesis in animal model of breast cancer was investigated by western-blot. Results Auraptene treatment led to reduction in cell viability of MDA-MB-231 in a concentration-dependent manner. Also, we observed change in the number of tubes or branches formed by cells incubated with 40 and 80 μM Auraptene. Auraptene effect the gene expression of important gene related to angiogenesis (VEGF, VEGFR2, COX2, IFNɣ). Moreover, the western blot data exhibited that Auraptene effect the protein expression of VCAM-1 and TNFR-1. Conclusions Overall, this study shows that Auraptene significantly suppressed angiogenesis via down-regulation of VEGF, VEGFR2, VCAM-1, TNFR-1, COX-2 and up-regulation of IFNγ.

scholarly journals Novel Roles of Chloroquine and Hydroxychloroquine in Graves’ Orbitopathy Therapy by Targeting Orbital Fibroblasts

2020 ◽  
Vol 105 (6) ◽  
pp. 1906-1917 ◽  
Author(s):  
Yan Guo ◽  
Hai Li ◽  
Xueying Chen ◽  
Huasheng Yang ◽  
Hongyu Guan ◽  
...  
Keyword(s):  
Western Blot ◽  
Real Time ◽  
Fluorescent Protein ◽  
Inhibitory Effect ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Graves Orbitopathy ◽  
Orbital Fibroblasts

Abstract Context Graves’ orbitopathy (GO) causes infiltrative exophthalmos by inducing excessive proliferation, adipogenesis, and glycosaminoglycan production in orbital fibroblasts (OFs). Interference with OF autophagy is a potential therapy for proptosis. Objectives Here, we aimed to evaluate the effects of chloroquine (CQ) and hydroxychloroquine (HCQ), the autophagy inhibitors commonly used in clinical practice, on OFs. Design/Setting/Participants OFs isolated from patients with GO (GO-OFs) or control individuals (non-GO-OFs) were cultured in proliferation medium (PM) or subjected to differentiation medium. OFs were treated with CQ or HCQ (0, 0.5, 2, and 10 μM), and subsequently examined in vitro. Main Outcome Measures CCK-8, EdU incorporation, and flow cytometry assays were used to assess cellular viability. Adipogenesis was assessed with Western blot analysis, real-time polymerase chain reaction (PCR) , and Oil Red O staining. Hyaluronan production was determined by real-time PCR and enzyme-linked immunosorbent assay. Autophagy flux was detected through red fluorescent protein (RFP)-green fluorescent protein (GFP)-LC3 fluorescence staining and Western blot analyses. Results CQ/HCQ halted proliferation and adipogenesis in GO-OFs in a concentration-dependent manner through blockage of autophagy, phenotypes that were not detected in non-GO-OFs. The inhibitory effect of CQ/HCQ on hyaluronan secretion of GO-OFs was also concentration dependent, mediated by downregulation of hyaluronan synthase 2 rather than hyaluronidases. Moreover, CQ (10 μM) induced GO-OF apoptosis without aggravating oxidative stress. Conclusions The antimalarials CQ/HCQ affect proliferation, adipogenesis, and hyaluronan generation in GO-OFs by inhibiting autophagy, providing evidence that they can be used to treat GO as autophagy inhibitors.

scholarly journals Naringin alleviates methotrexate-induced liver injury in male albino rats and enhances its antitumor efficacy in HepG2 cells

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Hany Elsawy ◽  
Abdulmohsen I. Algefare ◽  
Manal Alfwuaires ◽  
Mahmoud Khalil ◽  
Omar M. Elmenshawy ◽  
...  
Keyword(s):  
Protein Expression ◽  
Hepg2 Cells ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Albino Rats ◽  
Dependent Manner ◽  
Protective Effects ◽  
Expression Ratio ◽  
Hepatocyte Ultrastructure

Abstract Methotrexate (MTX) is an efficient chemotherapeutic and immunosuppressant drug, but the hepatotoxicity of MTX limits its clinical use. Naringin (Nar) is a flavonoid derived from Citrus paradise, and has been shown to possess several pharmacological activities, including free-radical scavenging and antioxidant properties. In the present study, we first tested the possible protective effects of multiple doses of Nar against MTX-induced acute hepatotoxicity in rats, and then we investigated the growth inhibition and apoptotic effects of MTX and/or Nar against the HepG2 hepatocarcinoma cell line. Our in vivo results showed that Nar significantly reduced MTX-induced increases in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin levels. Nar also reduced MTX-induced oxidative stress by significantly reducing liver malondialdehyde (MDA) and nitric oxide (NO) content and increasing superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH). In addition, Nar significantly counteracted MTX-induced increases in hepatic interleukin-6 and tumor necrosis factor-α (TNF-α). Further, Nar greatly protected hepatocyte ultrastructure against MTX-induced injury. In contrast, in vitro MTX and/or Nar treatment of HepG2 cells for 48 h exhibited a cytotoxic effect and induced apoptosis in a dose-dependent manner mediated by a significant increase in the Bax/Bcl-2 protein expression ratio. Noticeably, Nar potentiated the MTX effect on the Bax/Bcl-2 ratio. In conclusion, Nar decreased MTX-induced functional and ultrastructural liver damage in a tumor-free animal model. Also, our data introduce MTX and Nar as promising antiproliferative agents with a distinctive mode of action, inducing apoptosis in HepG2 tumor cells through activation of Bax and down-regulation of Bcl-2 protein expression.

Effects of Gossypol Acetate on Proliferation and Apoptosis in Lymphoblastoid Cell Line and Primary ALL and CLL Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4405-4405
Author(s):  
Yongqiang Zhao ◽  
Wei Cheng ◽  
Baolai Hua ◽  
Shujie Wang ◽  
Dajun Yang
Keyword(s):  
Protein Expression ◽  
Colorimetric Assay ◽  
B Cell Lymphoma ◽  
Time Dependent ◽  
G1 Arrest ◽  
Dependent Manner ◽  
Dna Ladder ◽  
Raji Cells ◽  
Anticancer Efficacy

Abstract Gossypol is a polyphenolic compound extracted from the cotton plant of Malvaceae family. It was originally demonstrated as a male antifertility agent. In the 1960’s, its anticancer efficacy was identified. In the last few years, gossypol has been approved to have antiproliferative and apoptosis-inducing effects on some kinds of cancer cell lines in vitro. Very recently, it has been showed that gossypol is a potent small-molecule inhibitor of Bcl-2 and Bcl-XL proteins. It can bind to Bcl-2/Bcl-XL and block the heterodimerization of Bcl-2/Bcl-XL with proapoptotic proteins, such as Bax, Bak and Bad. Such a blocking of antiapoptotic-proapoptotic protein heterodimerization in turn may inhibit the antiapoptotic function of Bcl-2/Bcl-XL, and induce apoptosis of cancer cells. Overexpression of Bcl-2 has been observed in B-cell lymphoma, B-ALL, B-CLL and correlates closely with the occurrence, progress, recurrence and multidrug-resistance of these malignancies. In this study, we found that gossypol acetate was able to inhibit the proliferation and survival of Raji cells in vitro at concentrations of more than 5 μmol/L. The effect was dose and time dependent. IC50 were 11.9±1.2 μmol/L at 24h and 6.8±0.4 μmol/L at 72h, which were 7.1 and 9.1 folds lower than that of normal MNCs, respectively. Gossypol acetate can remarkably increased pro-apoptosis activity of dexamethasone in Raji cells. Cell cycle analysis by flow cytometry (FCM) indicated that gossypol acetate could induce G0/G1 arrest. Apoptosis was demonstrated both morphologically by Wright-Giemsa staining, Hoechst 33342 staining and by DNA ladder formation in agarose-gel electrophoresis. By determination the percentage of subdiploid amount of DNA, apoptosis was quantified. The result showed that gossypol acetate could increase the percentage of cells with fragmented DNA in time and dose dependent manners at the concentrations of more than 1μmol/L. The fraction of annexin V+/PI− cells was also increased with dose. Colorimetric assay showed that an activation of caspase-3 was seen at 12h and peaked at 24h at the concentration of 25μmol/L. Protein expression of Bcl-2 decreased 13.6±3.8% at 12h and 69.5±6.2% at 24h. Gossypol acetate also had apoptosis-inducing effects in primary leukemia cells from patients with ALL (n=7) and CLL (n=3). The concentration inducing apoptosis in CLL cells was higher than that in ALL cells. It was concluded that gossypol acetate could inhibit the proliferation and induce the apoptosis of Raji cells and primary cultured ALL and CLL cells in a dose and time dependent manner. It seems that down-regulation of Bcl-2 protein expression may play a role in the apoptosis.

Improved Method for Obtaining of Arctigenin from Arctium Lappa L. and its Antiproliferative Effect on Human Hepatocarcinoma HepG2 Cells

2020 ◽  
Vol 16 (3) ◽  
pp. 358-362
Author(s):  
Renan S. Teixeira ◽  
Paulo H.D. Carvalho ◽  
Jair A.K. Aguiar ◽  
Valquíria P. Medeiros ◽  
Ademar A. Da Silva Filho ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Crude Extract ◽  
Hepg2 Cells ◽  
Liver Carcinoma ◽  
Adhesion Assay ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Arctium Lappa ◽  
Nih 3T3

Background: Arctigenin is a lignan found in Arctium lappa L. (Asteraceae) that displays anti-inflammatory activities. Previous studies showed that the crude extract of A. Lappa has antitumor activity in human liver carcinoma, lung and stomach cancer cells. The aim of this study was to obtain arctigenin from A. lappa L., as well as to evaluate its antiproliferative effects in cells of liver carcinoma (HepG2) and fibroblasts (NIH/3T3). Methods: Arctigenin was obtained from the hydrolysis of arctiin, which was isolated from the crude extract of A. lappa. The effects of arctigenin and arctiin on HepG2 cell viability and cell adhesion were analyzed by MTT method. Adhesion assay was also carried out to evaluate the antitumor activity. Results: Our results showed that the analytical process to obtain arctigenin was fast and easy. In vitro experiments showed that arctigenin (107-269 μM) decreased HepG2 cells viability and did not cause cytotoxicity on NIH/3T3 cells. Arctigenin (27-269 μM) demonstrated anti-adhesion in HepG2 cells in a concentration-dependent manner, when compared with control. Conclusion: These results suggest a promising pharmacological activity for arctigenin as an antiproliferative compound.

The Anti-tumor Activity and Mechanisms of rLj-RGD3 on Human Laryngeal Squamous Carcinoma Hep2 Cells

2020 ◽  
Vol 19 (17) ◽  
pp. 2108-2119
Author(s):  
Yang Jin ◽  
Li Lv ◽  
Shu-Xiang Ning ◽  
Ji-Hong Wang ◽  
Rong Xiao
Keyword(s):  
Wound Healing ◽  
Western Blot ◽  
Morphological Changes ◽  
In Vivo Studies ◽  
Migration And Invasion ◽  
Tunel Staining ◽  
Dna Ladder ◽  
Western Blot Assay

Background: Laryngeal Squamous Cell Carcinoma (LSCC) is a malignant epithelial tumor with poor prognosis and its incidence rate increased recently. rLj-RGD3, a recombinant protein cloned from the buccal gland of Lampetra japonica, contains three RGD motifs that could bind to integrins on the tumor cells. Methods: MTT assay was used to detect the inhibitory rate of viability. Giemsa’s staining assay was used to observe the morphological changes of cells. Hoechst 33258 and TUNEL staining assay, DNA ladder assay were used to examine the apoptotic. Western blot assay was applied to detect the change of the integrin signal pathway. Wound-healing assay, migration, and invasion assay were used to detect the mobility of Hep2 cells. H&E staining assay was used to show the arrangement of the Hep2 cells in the solid tumor tissues. Results: In the present study, rLj-RGD3 was shown to inhibit the viability of LSCC Hep2 cells in vitro by inducing apoptosis with an IC50 of 1.23µM. Western blot showed that the apoptosis of Hep2 cells induced by rLj- RGD3 was dependent on the integrin-FAK-Akt pathway. Wound healing, transwells, and western blot assays in vitro showed that rLj-RGD3 suppressed the migration and invasion of Hep2 cells by integrin-FAKpaxillin/ PLC pathway which could also affect the cytoskeleton arrangement in Hep2 cells. In in vivo studies, rLj-RGD3 inhibited the growth, tumor volume, and weight, as well as disturbed the tissue structure of the solid tumors in xenograft models of BALB/c nude mice without reducing their body weights. Conclusion: hese results suggested that rLj-RGD3 is an effective and safe suppressor on the growth and metastasis of LSCC Hep2 cells from both in vitro and in vivo experiments. rLj-RGD3 might be expected to become a novel anti-tumor drug to treat LSCC patients in the near future.

VDAC1 Mediated Anticancer Activity of Gallic Acid in Human Lung Adenocarcinoma A549 Cells

2018 ◽  
Vol 18 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Aikebaier Maimaiti ◽  
Amier Aili ◽  
Hureshitanmu Kuerban ◽  
Xuejun Li
Keyword(s):  
Western Blot ◽  
Cell Viability ◽  
Gallic Acid ◽  
Molecular Mechanisms ◽  
A549 Cells ◽  
Dependent Manner ◽  
Lung Carcinoma Cells ◽  
Induced Apoptosis ◽  
The Impact

Aims: Gallic acid (GA) is generally distributed in a variety of plants and foods, and possesses cell growth-inhibiting activities in cancer cell lines. In the present study, the impact of GA on cell viability, apoptosis induction and possible molecular mechanisms in cultured A549 lung carcinoma cells was investigated. Methods: In vitro experiments showed that treating A549 cells with various concentrations of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA inhibits cell viability, comparative proteomic analysis was applied. The changed proteins were identified by Western blot and siRNA methods. Results: Two-dimensional electrophoresis revealed changes that occurred to the cells when treated with or without GA. Four up-regulated protein spots were clearly identified as malate dehydrogenase (MDH), voltagedependent, anion-selective channel protein 1(VDAC1), calreticulin (CRT) and brain acid soluble protein 1(BASP1). VDAC1 in A549 cells was reconfirmed by western blot. Transfection with VDAC1 siRNA significantly increased cell viability after the treatment of GA. Further investigation showed that GA down regulated PI3K/Akt signaling pathways. These data strongly suggest that up-regulation of VDAC1 by GA may play an important role in GA-induced, inhibitory effects on A549 cell viability.

scholarly journals In vitro study on the effect of cornin on the activity of cytochrome P450 enzymes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qun Zhang ◽  
Zengqiang Qu ◽  
Yanqing Zhou ◽  
Jin Zhou ◽  
Junwei Yang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Interaction ◽  
Liver Microsomes ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Cytochrome P450 Enzymes ◽  
Drug Drug Interaction ◽  
Dose Dependent

Abstract Background Cornin is a commonly used herb in cardiology for its cardioprotective effect. The effect of herbs on the activity of cytochrome P450 enzymes (CYP450s) can induce adverse drug-drug interaction even treatment failure. Therefore, it is necessary to investigate the effect of cornin on the activity of CYP450s, which can provide more guidance for the clinical application of cornin. Methods Cornin (100 μM) was incubated with eight isoforms of CYP450s, including CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1, in pooled human liver microsomes. The inhibition model and corresponding parameters were also investigated. Results Cornin exerted significant inhibitory effect on the activity of CYP3A4, 2C9, and 2E1 in a dose-dependent manner with the IC50 values of 9.20, 22.91, and 14.28 μM, respectively (p < 0.05). Cornin inhibited the activity of CYP3A4 non-competitively with the Ki value of 4.69 μM, while the inhibition of CYP2C9 and 2E1 by cornin was competitive with the Ki value of 11.31 and 6.54 μM, respectively. Additionally, the inhibition of CYP3A4 by cornin was found to be time-dependent with the KI/Kinact value of 6.40/0.055 min− 1·μM− 1. Conclusions The inhibitory effect of cornin on the activity of CYP3A4, 2C9, and 2E1 indicated the potential drug-drug interaction between cornin and drugs metabolized by these CYP450s, which needs further investigation and validation.

scholarly journals SAT0363 DELPHINIDIN DOSE-DEPENDENTLY DIMINISHES PERIPHERAL IL-17 AND IFN-Γ PRODUCING LYMPHOCYTES IN PSORIATIC ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1128.1-1129
Author(s):  
A. Mavropoulos ◽  
S. Tsiogkas ◽  
D. Skyvalidas ◽  
C. Liaskos ◽  
A. Roussaki-Schulze ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Cell Viability ◽  
Annexin V ◽  
Nkt Cells ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Research Support ◽  
Research Activities ◽  
Ifn Γ

Background:Delphinidin, a dietary anthocyanidin and powerful anti-oxidant from pigmented fruits and vegetables, has broad anti-inflammatory properties. In a human skin model of psoriasis, delphinidin reduced expression of proliferative and inflammatory markers (1).Objectives:The rationale of our study was to assess whether delphinidin can in vitro suppress IL-17 and IFN-γ production in peripheral blood mononuclear cell (PBMC) subsets from patients with psoriatic arthritis (PsA).Methods:PBMCs were obtained from 24 patients with PsA attending the outpatient clinic of the Department of Rheumatology/clinical Immunology at the University General Hospital of Larissa, Greece. 16 age- and sex-matched healthy volunteers were also included in the study. Delphinidin was supplemented at a concentration ranging from 1 to 50μg/ml, one hour prior to cell stimulation. Cell viability (Annexin V staining) and innate/adaptive lymphocyte subpopulations were assessed by flow cytometry with a panel of fluorochrome-conjugated antibodies against CD56, CD3, CD4 and CD8. Intracellular expression of IL-17 and IFN-γ was measured following PMA/ionomycin stimulation for 5 hours using standard cell permeabilization protocols and monoclonal antibodies against IL-17 and IFN-γResults:Delphinidin at concentration ≥10 μg/ml sharply diminished IL-17-production by CD4(+) T cells (Th17) and CD56(+)CD3(+) (NKT) cells from patients with psoriatic arthritis and normal controls (p≤0.05). IFN-γ producing T (CD4 and CD8) cells, as well as NK and NKT cells were also dose-dependently suppressed following delphinidin pre-incubation in both patients and healthy controls. Inhibition of IFN-γ(+) cells ranged from 27 to 69% and peaked at delphinidin concentration 20-50μg/ml. The inhibitory effect of delphinidin on IL-17 and IFN-γ producing lymphocytes was not due to compromised cell viability, as assessed by annexin V binding.Conclusion:Delphinidin exerts, in a dose-dependent manner, a profound in vitro inhibitory effect on T cell and NKT cell IL-17 and IFN-γ production in PsA, and therefore, it may be used as a dietary immunosuppressant, complementary to standard treatment.References:[1]Chamcheu JC Skin Pharmacol Physiol. 2015;28(4):177-88. doi: 10.1159/000368445Disclosure of Interests:ATHANASIOS MAVROPOULOS: None declared, Sotirios Tsiogkas: None declared, Dimitrios Skyvalidas: None declared, Christos Liaskos: None declared, Aggeliki Roussaki-Schulze Grant/research support from: Received a grant to support the educational and research activities of the department from Genesis Pharma (2018), Speakers bureau: Received honoraria from Genesis Pharma and Janssen(2017) and from Roche and Pharmaserve Lilly(2018), Efterpi Zafiriou Speakers bureau: Received honoraria from Genesis Pharma, Abbvie, Novartis, Roche, Jansses(2017) and Novartis, Abbvie(2018), Dimitrios Bogdanos: None declared, Lazaros Sakkas Grant/research support from: Received a grant to support the educational and research activities of the department from Bristol-Meyers Squib, Speakers bureau: Received honoraria from Actellion(2018), Janssen(2017), Novartis(2017), Sanofi-Aventis(2018), Abbvie(2017) and Roche(2017)

Cerebrovascular characterization of clazosentan, the first nonpeptide endothelin receptor antagonist clinically effective for the treatment of cerebral vasospasm. Part I: Inhibitory effect on endothelinA receptor—mediated contraction

2005 ◽  
Vol 102 (6) ◽  
pp. 1101-1107 ◽  
Author(s):  
Hartmut Vatter ◽  
Michael Zimmermann ◽  
Veronika Tesanovic ◽  
Andreas Raabe ◽  
Lothar Schilling ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Cerebral Vasospasm ◽  
Isometric Force ◽  
Inhibitory Effect ◽  
Affinity Constant ◽  
Dependent Manner ◽  
Content Type ◽  
The Right ◽  
Fine Print

Object. The central role of endothelin (ET)—1 in the development of cerebral vasospasm after subarachnoid hemorrhage is indicated by the successful treatment of this vasospasm in several animal models by using selective ETA receptor antagonists. Clazosentan is a selective ETA receptor antagonist that provides for the first time clinical proof that ET-1 is involved in the pathogenesis of cerebral vasospasm. The aim of the present investigation was, therefore, to define the pharmacological properties of clazosentan that affect ETA receptor—mediated contraction in the cerebrovasculature. Methods. Isometric force measurements were performed in rat basilar artery (BA) ring segments with (E+) and without (E−) endothelial function. Concentration effect curves (CECs) were constructed by cumulative application of ET-1 or big ET-1 in the absence or presence of clazosentan (10−9, 10−8, and 10−7 M). The inhibitory potency of clazosentan was determined by the value of the affinity constant (pA2). The CECs for contraction induced by ET-1 and big ET-1 were shifted to the right in the presence of clazosentan in a parallel dose-dependent manner, which indicates competitive antagonism. The pA2 values for ET-1 were 7.8 (E+) and 8.6 (E−) and the corresponding values for big ET-1 were 8.6 (E+) and 8.3 (E−). Conclusions. The present data characterize clazosentan as a potent competitive antagonist of ETA receptor—mediated constriction of the cerebrovasculature by ET-1 and its precursor big ET-1. These functional data may also be used to define an in vitro profile of an ET receptor antagonist with a high probability of clinical efficacy.

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