B1 but not B2 bradykinin receptor agonists promote DU145 prostate cancer cell proliferation and migration

Background

The kallikrein-kinin system (KKS) is an endogenous pathway involved in angiogenesis and tumourigenesis, both vital for cancer growth and progression.

Objectives

To investigate the effect of two bradykinin receptor (B1R and B2R) agonists on growth and motility of prostate tumour (DU145) and micro-vascular endothelial cells (dMVECs).

Methods

Increasing concentrations of selective B1R and B2R agonists were added to cultured cells. Cell proliferation and migration were assessed using the 3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and modified Boyden Chamber assays, respectively. Where significant stimulation was found, the influence of an antagonist was also investigated.

Results

Neither growth nor motility of endothelial cells was affected by either agonist. In DU145 cells, while the B2R agonist was without any significant effect, the B1R agonist stimulated proliferation and migration at concentrations of 10nM and 50nM respectively. Further, this effect was abrogated when cells were pre-incubated with a B1R antagonist.

Conclusions

Unlike the physiologically-active B2R, the pathologically-inducible B1R may be implicated in prostate tumourigenic events. The involvement of the KKS in malignant prostate pathology supports on-going exploration of bradykinin receptor antagonists as target candidates in the development of alternate approaches to cancer therapy.     

Role played by NK2 receptor and cyclooxygenase activation in bradykinin B2 receptor mediated-airway effects in guinea pigs

We have investigated the effects of SR-48968, an NK₂ receptor antagonist, and indomethacin, a cyclooxygenase inhibitor, against bronchoconstriction and airway microvascular leakage induced by bradykinin (BK) in anesthetized guinea pigs. In addition, we have determined whether these effects were mediated via bradykinin B₂ receptor activation, using a B₂ receptor antagonist HOE 140. Lung resistance (R _L) and extravasation of Evans blue dye into airway tissues were used as indexes of airway caliber and microvascular leakage, respectively. BK (15 nmol/kg i.v.) induced a significant increase inR _L and leakage of dye at all airway levels, responses which were completely abolished by HOE 140 (0.13 mg/kg i.v.). SR-48968 (1.5 mg/kg i.v.) had no effect against BK-induced airway effects. Indomethacin (5 mg/kg i.v.) completely blocked the increase inR _L and significantly inhibited the leakage of dye in peripheral intrapulmonary airway. In conclusion, bronchoconstriction induced by i.v. BK is mediated by release of cyclooxygenase products but not by stimulation of NK₂ receptors, while the airway microvascular leakage only partly involves cyclooxygenase activation. Cyclooxygenase activation may occur following bradykinin B₂ receptor stimulation.     

MiR-29b-3p affects growth and biological functions of human extravillous trophoblast cells by regulating bradykinin B2 receptor

IntroductionThis study investigated miR-29b-3p’s effects and mechanisms in preeclampsia development.Material and methodsIn this study, we analysed the pathology and expression of miR-29b-3p and B2R mRNA from normal and preeclampsia placenta tissues using hematoxylin and eosin staining and RT-qPCR assay. For cell experiments, we used transwell assay CCK-8, flow cytometry and wound healing assay to determine the effects and correlation of miR-29b-3p and B2R in HTR-8/SVneo cell proliferation, apoptosis, cell cycle, cell invasion and migration in a preeclampsia cell model. Moreover, the mechanisms were determined using Western blot or immunofluorescence in different groups.ResultsClinical analysis revealed that miR-29b-3p gene expression dramatically increased with increasing degree of preeclampsia (p < 0.001 or p < 0.05, respectively). The HTR-8/SVneo cell biological activities of the model group were significantly depressed (p < 0.001). However, with miR-29b-3p inhibitor or B2R transfection, the HTR-8/SVneo cell biological activities significantly recovered (p < 0.001). Western blot assay showed that B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 levels were suppressed in the model group, compared with those in the NC groups (p < 0.001, respectively). With miR-29b-3p inhibitor or B2R transfection, the protein expression levels of B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 dramatically increased (p < 0.001, respectively).ConclusionsThe down-regulation of miR-29b-3p could improve HTR-8/SVneo cell biological activities in a preeclampsia cell model by targeting B2R.     

Role of kinins in seasonal allergic rhinitis: icatibant, a bradykinin B2 receptor antagonist, abolishes the hyperresponsiveness and nasal eosinophilia induced by antigen

BACKGROUND: Icatibant, a bradykinin B(2) receptor antagonist, inhibits the reduction in nasal patency after challenge with house dust mite antigen in sensitive subjects and abolishes the nasal hyperresponsiveness induced by platelet-activating factor in nonatopic subjects. OBJECTIVE: We sought to investigate the effect of icatibant on the response to nasal antigen challenge in subjects with seasonal allergic rhinitis. METHODS: Patients allergic to grass pollen antigen (n = 9-13) were included in a double-blind, randomized-block, placebo-controlled, crossover study outside the pollen season. Subjects first received an intranasal spray of icatibant (200 microg per nostril) or a saline control. Subjects were then challenged with antigen or diluent (control), and their responses were monitored by using acoustic rhinometry. Six hours later, nasal lavage fluid was collected and quantified for inflammatory cells and various inflammatory mediators (kinin, eosinophil cationic protein, IL-5, and IL-8). At 24 hours, the response of the nasal airways to 200 microg of histamine was assessed, and a further nasal lavage was carried out. RESULTS: Antigen challenge caused a significant increase in nasal obstruction and albumin extravasation, which was not affected by icatibant. Nasal hyperresponsiveness to histamine was present 24 hours after antigen and was abolished by pretreatment with icatibant. Icatibant also reduced the antigen-induced increase in eosinophils, eosinophil cationic protein, kinin, and IL-8 in nasal lavage fluid. CONCLUSION: Pretreatment with icatibant does not affect the acute inflammatory response in seasonal allergic rhinitis. However, our results imply the involvement of kinins and the bradykinin B(2) receptor in the development of antigen-induced hyperresponsiveness and the associated eosinophilia in the human nasal airway.