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We investigated the effect of siRNA targeting enhancer of EZH2 on cell proliferation, invasion, migration, and apoptosis of human bladder cancer T24 cells. An siRNA-expressing plasmid targeting the EZH2 gene was transfected into T24 cells. Quantitative polymerase chain reaction and Western blot analysis were used to detect EZH2 expression at the mRNA and protein levels, respectively. Proliferation, invasion, and migration of T24 cells were examined in vivo using MTT, wound healing, and transwell chamber migration assays, respectively. Annexin V-fluorescein isothiocyanate/propidium iodide flow cytometric analysis was performed to determine cell apoptosis levels. Expression of EZH2 in T24 cells was suppressed at the mRNA and protein levels. Following transfection for 48 h, growth was inhibited by 37.9%, which was markedly lower than that in the negative control group (P < 0.05). Following a wound-healing assay for 24 h, transfected cell migration distance was 1.37 ± 0.12, which was markedly less than the horizontal migration distance of negative control group cells (P < 0.01). In addition, the cell invasion ability of EZH2- siRNA group cells decreased by 67% compared with negative control group cells (P < 0.01). Following transfection for 48 h, early- and late-stage apoptosis rates for T24 cells were 22.8 and 3.60%, respectively, which were higher than in the negative control group (P < 0.01). EZH2 gene silencing effectively suppressed the proliferation, invasion, and migration abilities of human bladder cancer cells, promoting apoptosis.

1. Cigarette smoke induces plasma exudation in the airways of rodents by activation of capsaicin-sensitive 'sensory-efferent' nerves. The response is mediated predominantly by substance P (SP) and the magnitude of exudation is regulated by neutral endopeptidase (NEP). The component(s) of the smoke responsible for the activation of the nerves may be reactive oxygen radicals. We investigated the effect of the hydroxyl radical scavenger dimethylthiourea (DMTU), a regulator of superoxide anion, superoxide dismutase (SOD), and a regulator of hydrogen peroxide, catalase, on plasma exudation (measured using Evans blue dye) induced by cigarette smoke in guinea-pig main bronchi in vivo. The effect of DMTU on plasma exudation and non-cholinergic bronchoconstriction (measured as pulmonary insufflation pressure, PIP) induced by electrical stimulation of the vagus nerves was also assessed. Interaction between hydroxyl radicals and NEP was assessed with the NEP inhibitor phosphoramidon. 2. In each of the experiments, cigarette smoke increased plasma exudation by approximately 200% above air-exposed controls. Acute administration of DMTU (1.5 g kg-1, i.v. for 20 min) significantly reduced cigarette smoke-induced plasma exudation by 69%. In contrast, neither SOD (240,000 u kg-1, i.v.) nor catalase (400,000 u kg-1, i.v.) significantly affected the exudative response. 3. Chronic pretreatment with DMTU (1.25 g kg-1 over 4 days) significantly reduced bronchial plasma exudation induced by cigarette smoke by 72%. Phosphoramidon (1.5 mg kg-1, i.v.) completely reversed the inhibition by DMTU of cigarette smoke-induced plasma exudation. 4. Vagal stimulation increased plasma exudation by approximately 200% and PIP by approximately 250%. Acute treatment with DMTU had no significant inhibitory effect on these responses, whereas chronic pretreatment inhibited them by approximately 80%. Phosphoramidon reversed the inhibition by chronic DMTU. 5. SP (1 nmol kg-1) increased plasma exudation by approximately 250%, a response which was not inhibited by either acute or chronic DMTU. 6. We conclude that hydroxyl radicals, rather than superoxide anion or hydrogen peroxide, are involved in the induction of neurogenic plasma exudation and bronchoconstriction induced by cigarette smoke or by electrical stimulation of the vagus nerves. These radicals also affect the activity of NEP. Acute DMTU may affect directly the neural actions of hydroxyl radicals contained in the cigarette smoke. Chronic pretreatment with DMTU may inhibit the neurogenic airway responses by effects on tachykinin biosynthesis and/or axonal transport.

1. We compared the effects of two novel tachykinin receptor antagonists, FK888 (selective at the tachykinin NK1 receptor) and FK224 (dual antagonist at NK1 and NK2 tachykinin receptors) on stimulus-evoked airway plasma exudation, bronchoconstriction and systemic hypotension in guinea-pigs in vivo. Plasma exudation was induced by substance P (SP), synthetic tachykinin receptor agonists, platelet activating factor (PAF), electrical stimulation of the cervical vagus nerves or by inhalation of cigarette smoke. Changes in airway tone and in carotid artery blood pressure (BP) were induced by synthetic tachykinin agonists, PAF and vagal stimulation. 2. Both FK224 and FK888 dose-dependently inhibited SP-induced plasma exudation in the lower trachea and main bronchi (ID50 values respectively of 1.1 and 0.1 mumol kg-1 in lower trachea, and of 0.5 and 0.1 mumol kg-1 in main bronchi) with complete inhibition at both airway levels at 10 mumol kg-1 for FK224 and at 2 mumol kg-1 for FK888. 3. The NK1-selective tachykinin receptor agonist, [Sar9,Met(O2)11]substance P ([Sar]SP), induced plasma exudation, a response which was blocked by both FK888 and FK224. The NK2-selective agonist, [beta-Ala8]neurokinin A-(4-10) ([beta-Ala]NKA), did not induce plasma exudation: neither FK888 nor FK224 affected this lack of response to [beta-Ala]NKA. 4. [beta-Ala]NKA induced bronchoconstriction, a response which was blocked by FK224 but which was completely unaffected by FK888. [Sar]SP induced a small but significant bronchoconstriction which was completely inhibited by both tachykinin antagonists. 5. In animals pretreated with capsaicin to deplete sensory neuropeptides, PAF induced both plasma exudation and bronchoconstriction. Neither response to PAF was inhibited by either FK888 or FK224.6. Both FK888 and FK224 inhibited plasma exudation induced by vagus nerve stimulation or by cigarette smoke, with FK888 more potent than FK224.7. FK224 inhibited non-cholinergic bronchoconstriction induced by vagal stimulation, whereas FK888,at doses inhibiting vagally-induced plasma exudation, did not.8. Decreases in BP induced by SP or [Sar]SP were blocked by both FK888 and FK224. In contrast,neither antagonist had any significant inhibitory effect on the decrease in BP induced by vagal stimulation (in the presence of atropine) or PAF. [beta-Ala]NKA did not decrease BP and neither tachykinin antagonist had any significant effect on this lack of response.9. We conclude that in guinea-pig airways, plasma leakage induced by endogenous tachykinins is mediated predominantly via NK1-receptors, whereas bronchoconstriction is mediated predominantly via NK2-receptors. In addition, SP-evoked decreases in BP are also mediated via NK1 receptors, whereas the contribution of endogenous tachykinins to vagally-induced decreases in BP appears to be minimal.Development of selective tachykinin receptor antagonists will be important in understanding the involvement of tachykinins in airway physiology and pathophysiology, whereas potent dual tachykinin receptor antagonists such as FK224 may have greater therapeutic potential in certain airway diseases in which tachykinins have been implicated in pathogenesis, including asthma and chronic bronchitis associated with cigarette smoking.

1. We investigated the effect of the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) and the peptidase alpha-chymotrypsin on non-adrenergic, non-cholinergic (NANC neural) bronchoconstriction induced by electrical stimulation of the vagus nerves and by capsaicin in anaesthetized guinea-pigs in vivo using pulmonary insufflation pressure (PIP) as an index of bronchial tone. We also investigated the contribution of soluble guanylyl cyclase (SGC) to NANC neural relaxant mechanisms. 2. In the presence of atropine and propranolol, electrical stimulation of the vagus nerves induced a frequency-dependent increase in PIP above baseline of 67% at 2.5 Hz, of 128% at 5 Hz and of 230% at 10 Hz. L-NAME (1-50 mg kg-1, i.v.), at doses inducing increases in systemic blood pressure, dose-relatedly potentiated NANC bronchoconstriction. At 10 mg kg-1 i.v., L-NAME significantly (P < 0.05) potentiated NANC bronchoconstriction by a further 106% at 2.5 Hz and a further 147% at 5 Hz but did not potentiate the increase in PIP at 10 Hz. L-NAME did not induce bronchoconstriction in sham-stimulated control animals. D-NAME did not potentiate NANC bronchoconstriction. Raising systemic blood pressure with phenylephrine did not potentiate vagally-induced bronchoconstriction (2.5 Hz). 3. The NO precursor L-arginine, but not D-arginine, (100 mg kg-1, i.v.) significantly reversed the potentiation by L-NAME of NANC bronchoconstriction. L-Arginine alone significantly inhibited neurogenic bronchoconstriction at 10 Hz (by 74%); the inhibition of 25% at 2.5 Hz was not significant. 4. L-NAME did not significantly affect the increases in PIP induced by intravenous substance P. neurokinin A (NKA) or capsaicin. 5. The inhibitor of SGC, methylene blue (10 mg kg', i.v.) potentiated (by 110-140%) NANC neural bronchoconstriction induced by lower frequencies of nerve stimulation and reversed the reduction in PIP induced by the SGC activator, sodium nitroprusside (SNP, 1.05 mg kg- 1, i.v.). SNP significantly (P <0.05) reduced by 65% the bronchoconstriction induced by nerve stimulation at 10 Hz. Methylene blue did not effect baseline PIP in sham-stimulated controls. The airway effects of methylene blue and SNP were not associated with their cardiovascular effects. 6. a-Chymotrypsin (2 units kg-', i.v.) significantly potentiated vagally-induced bronchoconstriction by a further 63% at 2.5 Hz, by a further 95.6% at 5 Hz but did not potentiate the increase in PIP at 10 Hz. alpha-Chymotrypsin also potentiated (by 116%) capsaicin-induced bronchoconstriction. Vasoactive intestinal peptide (VIP, 10 ig kg-' i.v. infused over min) significantly reduced by 70% the increase in PIP induced by NKA (0.1 .Lmol kg-' i.v., infused over 30 s). 7. The combination of a-chymotrypsin (2 units kg-', i.v.) and L-NAME (5 mg kg-', i.v.) significantly potentiated NANC bronchoconstriction by a further 304% at 2.5 Hz, an increase in PIP which was greater than that induced by either a-chymotrypsin or L-NAME alone (P <0.05). 8. We conclude that endogenous NO and a bronchodilator peptide, possibly VIP, released in association with nerve stimulation, as well as activation of soluble guanylyl cyclase, regulate the magnitude of NANC neurogenic bronchoconstriction in guinea-pigs in vivo.

A new non-peptide tachykinin antagonist, CP-96,345, inhibited airway plasma exudation induced in guinea-pigs by i.v. substance P in a dose-dependent manner with dose-ratios in the main bronchi of 5 at 1 nmol kg-1 and 19 at 100 nmol kg-1. At 100 nmol kg-1, CP-96,345 completely inhibited plasma exudation induced by either electrical stimulation of the cervical vagus nerves or i.v. capsaicin, indicating inhibition of the effects of endogenous tachykinins, but did not inhibit the bronchoconstrictor response to neurokinin A, suggesting selectivity for NK1 receptors. CP-96,345 may be useful in examining the role of endogenous tachykinins in vivo.