Characterization of the anti-inflammatory properties of NCX 429, a dual-acting compound releasing nitric oxide and naproxen.

AIMS: Cyclooxygenase (COX)-inhibiting nitric oxide donors (CINODs) are a new class of drugs that structurally combine a COX inhibitor with a nitric oxide (NO) donating moiety. This combination reduces potential toxicity of the non-steroidal anti-inflammatory drugs (NSAIDs) whilst maintaining the analgesic and anti-inflammatory effects. The present study was undertaken to investigate the anti-inflammatory effects of NCX 429, a naproxen-based CINOD, and to assess the additional properties of NO donation beyond those related to naproxen. MAIN METHODS: We evaluated the in vitro effects of NCX 429 on oxy-radical production, phagocytosis, cytokine release, MMP-9, PPARγ expression and NF-κB activation in human monocytes/MDM and compared to naproxen. Moreover, we compared the in vivo efficacy of NCX 429 and naproxen in a murine model of peritonitis. KEY FINDINGS: In all the experiments performed in vitro, NCX 429 reduced the inflammatory responses with equal or higher efficacy compared to naproxen. Moreover, in in vivo experiments, NCX 429, at the lowest dose tested, was able to significantly inhibit cell influx in response to IL-1ß administration although naproxen was found to be more potent than NCX 429 at reducing PGE2 in inflammatory exudates. SIGNIFICANCE: These results demonstrate that both in vitro and in vivo--in a murine model of peritonitis--NCX 429 elicits significant anti-inflammatory activity, beyond the simple COX inhibition or pure NO release. Therefore, NO donation along with COX inhibition may represent a strategy for investigating inflammatory diseases in which pain and function are not fully resolved by analgesics/anti-inflammatory drugs.

Nitric oxide inhibits the expression of AT1 receptors in neurons.

We have previously observed an increased of angiotensin II (ANG II) type 1 receptor (AT(1)R) with enhanced AT(1)R-mediated sympathetic outflow and concomitant downregulation of neuronal nitric oxide (NO) synthase (nNOS) with reduced NO-mediated inhibition from the paraventricular nucleus (PVN) in rats with heart failure. To test the hypothesis that NO exerts an inhibitory effect on AT(1)R expression in the PVN, we used primary cultured hypothalamic cells of neonatal rats and neuronal cell line NG108-15 as in vitro models. In hypothalamic primary culture, NO donor sodium nitroprusside (SNP) induced dose-dependent decreases in mRNA and protein of AT(1)R (10(-5) M SNP, AT(1)R protein was 10 ± 2% of control level) while NOS inhibitor N(G)-monomethyl-l-arginine (l-NMMA) induced dose-dependent increases in mRNA and protein levels of AT(1)R (10(-5) M l-NMMA, AT(1)R protein was 148 ± 8% of control level). Similar effects of SNP and l-NMMA on AT(1)R expression were also observed in NG108-15 cell line (10(-6) M SNP, AT(1)R protein was 30 ± 4% of control level while at the dose of 10(-6) M l-NMMA, AT(1)R protein was 171 ± 15% of the control level). Specific inhibition of nNOS, using antisense, caused an increase in AT(1)R expression while overexpression of nNOS, using adenoviral gene transfer (Ad.nNOS), caused an inhibition of AT(1)R expression in NG108 cells. Antisense nNOS transfection augmented the increase while Ad.nNOS infection blunted the increase in intracellular calcium concentration in response to ANG II treatment in NG108 cells. In addition, downregulation of AT(1)R mRNA as well as protein level in neuronal cell line in response to S-nitroso-N-acetyl pencillamine (SNAP) treatment was blocked by protein kinase G (PKG) inhibitor, while the peroxynitrite scavenger deforxamine had no effect. These results suggest that NO acts as an inhibitory regulator of AT(1)R expression and the activation of PKG is the required step in the regulation of AT(1)R gene expression via cGMP-dependent signaling pathway.

Ocular hypotensive activity of BOL-303259-X, a nitric oxide donating prostaglandin F2α agonist, in preclinical models.

The aim of the study was to investigate the ocular hypotensive activity of a nitric oxide (NO)-donating latanoprost, BOL-303259-X, following topical administration. The effect of BOL-303259-X (also known as NCX 116 and PF-3187207) on intraocular pressure (IOP) was investigated in monkeys with laser-induced ocular hypertension, dogs with naturally-occurring glaucoma and rabbits with saline-induced ocular hypertension. Latanoprost was used as reference drug. NO, downstream effector cGMP, and latanoprost acid were determined in ocular tissues following BOL-303259-X administration as an index of prostaglandin and NO-mediated activities. In primates, a maximum decrease in IOP of 31% and 35% relative to baseline was achieved with BOL-303259-X at doses of 0.036% (9 µg) and 0.12% (36 µg), respectively. In comparison, latanoprost elicited a greater response than vehicle only at 0.1% (30 µg) with a peak effect of 26%. In glaucomatous dogs, IOP decreased from baseline by 44% and 10% following BOL-303259-X (0.036%) and vehicle, respectively. Latanoprost (0.030%) lowered IOP by 27% and vehicle by 9%. Intravitreal injection of hypertonic saline in rabbits increased IOP transiently. Latanoprost did not modulate this response, whereas BOL-303259-X (0.036%) significantly blunted the hypertensive phase. Following BOL-303259-X treatment, latanoprost acid was significantly elevated in rabbit and primate cornea, iris/ciliary body and aqueous humor as was cGMP in aqueous humor. BOL-303259-X lowered IOP more effectively than latanoprost presumably as a consequence of a contribution by NO in addition to its prostaglandin activity. The compound is now in clinical development for the treatment of glaucoma and ocular hypertension.

Dual role of NO donors in the reversal of tumor cell resistance and EMT: Downregulation of the NF-κB/Snail/YY1/RKIP circuitry.

Several studies have implicated the role of Nitric Oxide (NO) in the regulation of tumor cell behavior and have shown that NO either promotes or inhibits tumorigenesis. These conflicting findings have been resolved, in part, by the levels of NO used such that low levels promote tumor growth and high levels inhibit tumor growth. Our studies have focused on the use of high levels of NO provided primarily by the NO donor, DETANONOate. We have shown that treatment of resistant tumor cells with DETANONOate sensitizes them to apoptosis by both chemotherapeutic drugs and cytotoxic immunotherapeutic ligands. The underlying mechanisms by which NO sensitizes tumor cells to apoptosis were shown to be regulated, in part, by NO-mediated inhibition of the NF-κB survival/anti-apoptotic pathways and downstream of NF-κB by inhibition of the transcription factor Yin Yang 1 (YY1). In addition to NO-induced sensitization to apoptosis, we have also shown that NO induced the expression of the metastasis-suppressor/immunosurveillance cancer gene product, Raf-1 kinase inhibitor protein (RKIP). Overexpression of RKIP mimics NO in tumor cells-induced sensitization to apoptosis. The induction of RKIP by NO was the result of the inhibition of the RKIP repressor, Snail, downstream of NF-κB. These findings established the presence of a dysregulated NF-κB/Snail/YY1/ RKIP circuitry in resistance and that treatment with NO modifies this loop in tumor cells in favor of the inhibition of tumor cell survival and the response to cytotoxic drugs. Noteworthy, the NF-κB/Snail/YY1/RKIP loop consists of gene products that regulate the epithelial to mesenchymal transition (EMT) and, thus, tumor metastasis. Hence, we have found that treatment of metastatic cancer cell lines with DETANONOate inhibited the EMT phenotype, through both the inhibition of the metastasis-inducers, NF-κB and Snail and the induction of the metastasis-suppressor, RKIP. Altogether, the above findings establish, for the first time, the dual role of high levels of NO in the sensitization of tumor cells to apoptotic stimuli as well as inhibition of EMT. Hence, NO donors may be considered as novel potential therapeutic agents with dual roles in the treatment of patients with refractory cancer and in the prevention of the initiation of the metastatic cascade via EMT.

Oral bioavailability, efficacy and gastric tolerability of P2026, a novel nitric oxide-releasing diclofenac in rat.

The present study was designed to evaluate, P2026 [(2-((2-(nitrooxy)ethyl)disulfanyl)ethyl 2-(2-(2,6-dichlorophenylamino)phenyl)acetate)], a novel NO (nitric oxide) donor prodrug of diclofenac for its ability to release NO and diclofenac, and whether P2026 provides advantage of improved activity/gastric tolerability over diclofenac. Oral bioavailability of P2026 was estimated from plasma concentration of diclofenac and nitrate/nitrite (NOx). Anti-inflammatory activity was evaluated in three different models of inflammation: acute (carrageenan-induced paw oedema), chronic (adjuvant-induced arthritis), and systemic (lipopolysaccharide-induced endotoxic shock). Gastric tolerability was evaluated from compound's propensity to cause gastric ulcers. P2026 exhibited dose-dependent diclofenac and NOx release. Similar to diclofenac, P2026 showed potent anti-inflammatory activity in acute and chronic model, whereas it improved activity in systemic model. Both diclofenac and P2026 inhibited gastric prostaglandin, but only diclofenac produced dose-dependent haemorrhagic ulcers. Thus, the results suggest that coupling of NO and diclofenac contribute to improved gastric tolerability while retaining the anti-inflammatory properties of diclofenac.

Physicochemical profile and in vitro permeation behavior of a new class of non-steroidal anti-inflammatory drug candidates.

Recently a new series of nitrooxy-acyl derivatives of salicylic acid (SA) was described presenting similar anti-inflammatory activities but reduced or no gastrotoxicity compared to aspirin. In this work, lipophilicity and permeability profiles of SA derivatives were performed to evaluate their ADME properties related to oral or transdermic delivery. All tested compounds showed potential good passive permeation through gastrointestinal track and also through percutaneous barrier which could be a way to avoid the first hepatic pass.

Pre-clinical pharmacokinetics of the cyclooxygenase-inhibiting nitric oxide donor (CINOD) AZD3582.

The pre-clinical pharmacokinetics of AZD3582 (4-(nitrooxy)butyl-(2S)-2-(6-methoxy-2-naphthyl) propanoate) and its primary metabolites (naproxen and nitrate) were evaluated. AZD3582 had intermediate and passive intestinal permeability (40 times lower than for naproxen), high systemic plasma clearance (CL), substantial gastrointestinal hydrolysis, intermediate volume of distribution (Vss; >or=3.4 L kg-1) and half-life (t1/2; 7 h), negligible plasma protein binding (approximately 0.1%), low/intermediate oral uptake (>or=13% as intact substance) and low and varying oral bioavailability (mean 1.4% in minipigs and 3.9% in dogs). Following administration of therapeutically relevant oral doses, plasma concentrations of AZD3582 were very low (40 h in rats, minipigs and dogs, respectively. The Vss and CL for naproxen were small. Plasma protein binding was extensive, and saturation was observed within the therapeutic dose and concentration range. Intake of food prolonged the systemic absorption of naproxen in the minipig. The pharmacokinetics of naproxen did not show apparent time- or gender-related dependency. Following oral dosing of [3H]-, [14C]- and [15N]-AZD3582, most [14C]- and [3H]-activity was excreted in urine and expired air, respectively. Seventeen per cent of [15N] was recovered in minipig urine as [15N]-nitrate. About 30% of [3H]-activity (naproxen and/or naproxen-related metabolites) was excreted in bile and re-absorbed. Concentrations of [14C]-activity (nitrooxy-butyl group and/or its metabolites) in milk were higher than in plasma and [3H]-activity in milk. [3H]- and [14C]-excretion data indicated that intact AZD3582 was not excreted in urine, bile or milk to a significant extent. There was no apparent consistency between tissue distribution of [14C]- and [3H]-activity in the rat, which suggests rapid and extensive metabolism of extravascularly distributed AZD3582. A substantial increase of plasma nitrate levels was found after single and repeated oral doses of AZD3582 in the minipig. No inhibition or induction of CYP450 was found.