Combination Of Nitric Oxide Donors Research Articles

Effects of In Vitro Combination of Nitric Oxide Donors and Hypochlorite on Acanthamoeba castellanii Viability.

To investigate the combined anti-Acanthamoeba effects of nitric oxide (NO) donors and hypochlorite to maximize amoebicidal outcomes while minimizing damage to human corneal epithelial cells (HCECs). Acanthamoeba castellanii and primary cultured HCECs and keratocytes were treated with sodium hypochlorite (NaOCl), NO donors (sodium nitroprusside [SNP] and sodium nitrite [NaNO2]), or a combination of hypochlorite and NO donors. The viability of A. castellanii, HCECs, and keratocytes was assessed. Minimal inhibitory concentration (MIC) and fractional inhibitory concentration of NaOCl and NO donors were determined. The activation of mammalian targets of rapamycin (mTOR) and ERK and the expression of nitrite reductase and Nrf2 were assessed in HCECs using Western blot analysis. The cysticidal effects of combined NaOCl and NO donors were also evaluated. A dose-dependent toxicity was observed in A. castellanii, HCECs, and keratocytes when treated with NaOCl and SNP. The range of tested NaNO2 concentrations showed no significant toxicity to HCECs; however, dose-dependent toxicity to A. castellanii was observed. The MIC of NaOCl against HCECs and A. castellanii was 8.0mg/mL. The MIC of NaNO2 and SNP was 500mM and 10mM in both HCECs and A. castellanii, respectively. Weak attenuation of the mTOR and ERK phosphorylation was observed and Nrf2 expression decreased slightly after exposure of HCECs to 2.0mg/mL NaOCl. For the combination treatment, NaOCl (0.125mg/mL) was selected based on the safety of HCECs and the toxicity of A. castellanii. A more potent anti-Acanthamoeba effect and HCEC toxicity were observed when NaOCl was combined with SNP rather than NaNO2. Combined NaOCl and NO donors had a stronger anti-Acanthamoeba effect compared to either drug alone. This study demonstrates that the combined use of various drugs for the treatment of Acanthamoeba infection can enhance the anti-Acanthamoeba effect while minimizing the toxicity of the individual drug.

Study of endothelin-1 dynamics in the pathogenesis of experimental peritonitis and under the influence of different methods of correction

Background. Currently, one of the most serious complications of acute inflammatory diseases of the abdominal cavity is peritonitis. Objective: to study the development of endothelial dysfunction in experimental peritonitis and compare its correction with a solution of decamethoxine, aminoguadine and L-arginine.
 Materials and methods of research. The study was conducted on 260 white rats of reproductive age (3 months), animal weight — 180–220 g. Animals were divided into 4 groups. Fecal peritonitis was simulated by introducing a 10 % fecal suspension at a dose of 0.5 ml per 100 g of animal weight to the abdominal cavity of laboratory animals by puncture method.
 Research results. Pathological increase in vasoconstriction caused by experimental peritonitis was revealed. It was found that the use of solution, consisting of decamethoxine (10 mg/50 ml of solution) and sodium hyaluronate, is an effective method of rehabilitation and the basis for further correction of complications of experimental fecal peritonitis.The use of aminoguadine in combination with the rehabilitation of the abdominal cavity with a solution of decamethoxine had a positive effect on reducing the level of endothelin-1 in the simulated peritonitis. Combination of nitric oxide donor with decamethoxine solution and sodium hyaluronate nitric oxide donor effect on reducing the level of endothelin-1 in the simulated peritonitis.
 Conclusions: Given the influence of endogenous intoxication on the increase of the marker of vasoconstriction, rehabilitation of the abdominal cavity, the choice of decamethoxine solution (10 mg/50 ml of solution) in the conditions of our study is justified.

Sigma Receptor Ligands Carrying a Nitric Oxide Donor Nitrate Moiety: Synthesis, In Silico, and Biological Evaluation.

We report the development of molecular hybrids in which a nitrate group serving as nitric oxide (NO) donor is covalently joined to σ receptor ligands to give candidates for double-targeted cancer therapy. The compounds have been evaluated in radioligand binding assay at both σ receptors and selected compounds tested for NO release. Compounds 9, 15, 18, 19, and 21 were subjected to MTT test. Compound 15 produced a significant reduction of MCF-7 and Caco-2 cellular viability with comparable IC50 as doxorubicin, being also not toxic for fibroblast HFF-1 cells. Compound 15 has shown a σ1 receptor antagonist/σ2 receptor agonist profile. Two derivatives of compound 15 lacking the nitrate group did not induce a reduction of MCF-7 cellular viability, suggesting a potential synergistic effect between the σ receptors and the NO-mediated events. Overall, the combination of NO donor and σ receptors ligands provided compounds with beneficial effects for the treatment of cancer.

Nitric Oxide-Mediated Enhancement and Reversal of Resistance of Anticancer Therapies.

In the last decade, immune therapies against human cancers have emerged as a very effective therapeutic strategy in the treatment of various cancers, some of which are resistant to current therapies. Although the clinical responses achieved with many therapeutic strategies were significant in a subset of patients, another subset remained unresponsive initially, or became resistant to further therapies. Hence, there is a need to develop novel approaches to treat those unresponsive patients. Several investigations have been reported to explain the underlying mechanisms of immune resistance, including the anti-proliferative and anti-apoptotic pathways and, in addition, the increased expression of the transcription factor Yin-Yang 1 (YY1) and the programmed death ligand 1 (PD-L1). We have reported that YY1 leads to immune resistance through increasing HIF-1α accumulation and PD-L1 expression. These mechanisms inhibit the ability of the cytotoxic T-lymphocytes to mediate their cytotoxic functions via the inhibitory signal delivered by the PD-L1 on tumor cells to the PD-1 receptor on cytotoxic T-cells. Thus, means to override these resistance mechanisms are needed to sensitize the tumor cells to both cell killing and inhibition of tumor progression. Treatment with nitric oxide (NO) donors has been shown to sensitize many types of tumors to chemotherapy, immunotherapy, and radiotherapy. Treatment of cancer cell lines with NO donors has resulted in the inhibition of cancer cell activities via, in part, the inhibition of YY1 and PD-L1. The NO-mediated inhibition of YY1 was the result of both the inhibition of the upstream NF-κB pathway as well as the S-nitrosylation of YY1, leading to both the downregulation of YY1 expression as well as the inhibition of YY1-DNA binding activity, respectively. Also, treatment with NO donors induced the inhibition of YY1 and resulted in the inhibition of PD-L1 expression. Based on the above findings, we propose that treatment of tumor cells with the combination of NO donors, at optimal noncytotoxic doses, and anti-tumor cytotoxic effector cells or other conventional therapies will result in a synergistic anticancer activity and tumor regression.

Nitric Oxide Donor-Based Cancer Therapy: Advances and Prospects.

The increasing understanding of the role of nitric oxide (NO) in cancer biology has generated significant progress in the use of NO donor-based therapy to fight cancer. These advances strongly suggest the potential adoption of NO donor-based therapy in clinical practice, and this has been supported by several clinical studies in the past decade. In this review, we first highlight several types of important NO donors, including recently developed NO donors bearing a dinitroazetidine skeleton, represented by RRx-001, with potential utility in cancer therapy. Special emphasis is then given to the combination of NO donor(s) with other therapies to achieve synergy and to the hybridization of NO donor(s) with an anticancer drug/agent/fragment to enhance the activity or specificity or to reduce toxicity. In addition, we briefly describe inducible NO synthase gene therapy and nanotechnology, which have recently entered the field of NO donor therapy.

Abstract 3633: Combination of PARP inhibitor ABT-888 with NO-donor SNAP sensitizes BRCA1 positive cancer cell lines to ionizing radiation

Abstract Loss or inhibition of Poly(ADP-ribose) polymerase 1 (PARP1) activity results in accumulation of DNA single-strand breaks, which are subsequently converted to DNA double-strand breaks (DSBs) by the cellular replication and/or transcription machinery. Breast cancer type 1 susceptibility protein (BRCA1) is essential for homologous recombination repair (HRR) of DNA DSB. In BRCA-positive cells, DSBs are repaired by HRR, but they cannot be properly repaired in BRCA-deficient cells, leading to genomic instability, chromosomal rearrangements, and cell death. The role of PARP1 in the DNA damage response promoted the development of PARP inhibitors (PARPi) as chemo- and radio-sensitizers for the treatment of cancers harboring mutations in the BRCA genes. However, inherited BRCA1 or BRCA2 mutations account for 5-10% of breast cancers and 10-15% of ovarian cancers. Hence, a low frequency of BRCA1 loss in non-hereditary tumors can limit the clinical use of this approach. Our recent work revealed significant down-regulation of BRCA1 gene expression by nitric oxide donors (NO-d) (Yakovlev, 2013). Hence, we assumed that combination of NO-d with PARP inhibitors could be effective in sensitization of the BRCA1-positive tumors to DNA-damaging therapy. We identified the optimal concentrations of PARPi ABT-888 at 20μM and NO-d SNAP at 200μM, which don't affect cell survival, but effectively block PARP1 activity or BRCA1 expression accordingly. Next, cancer cell lines were pretreated with ABT-888 or SNAP, or with they combination and irradiated. Survival curves were determined by clonogenic assay. Our preliminary data demonstrates significant radiosensitization when combining an NO-d with a PARPi in BRCA1 positive tumor cell lines (Table 1). We plan to test this drug combination on the additional cancer cell lines and on animal models for sensitization to ionizing radiation and to the different chemotherapeutic agents. Table 1.Clonogenic assay for A-549 and MDA-MB-231 cell lines: survival fraction.IR (Gy)02468A-549Control1.00±0.0380.55±0.0450.23±0.0360.09±0.0070.0242±0.004ABT-8881.00±0.0650.49±0.0310.18±0.0350.05±0.0040.0076±0.001SNAP0.97±0.0850.43±0.0450.16±0.0330.04±0.0080.0091±0.002ABT-888 + SNAP0.71±0.0750.24±0.0420.05±0.0070.01±0.0020.0014±0.0003MDA-MB-231Control1.00±0.0630.44±0.0380.15±0.0270.039±0.0070.0078±0.0007ABT-8880.85±0.0520.28±0.0170.07±0.0090.012±0.0020.0015±0.0005SNAP1.03±0.0380.3±0.0430.10±0.0080.020±0.0040.0034±0.0007ABT-888 + SNAP0.49±0.0660.12±0.0170.02±0.0070.002±0.00040.00013±0.0001 Citation Format: Aaron Wilson, Vasily A. Yakovlev. Combination of PARP inhibitor ABT-888 with NO-donor SNAP sensitizes BRCA1 positive cancer cell lines to ionizing radiation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3633. doi:10.1158/1538-7445.AM2015-3633

Nano carriers for nitric oxide delivery and its potential applications in plant physiological process: A mini review

Nitric oxide (NO) plays a key role in plant growth and defense. Since NO is a small molecule, devoid of charge and relatively lipophilic, it easily crosses cell membranes, acting as an important signaling messenger. Recently, several papers described the beneficial effects due to application of small molecular weight NO donors in plants. Exogenous NO donors break seed dormancy, stimulate plant germination and greening, control iron homeostasis in plants, and improve plant tolerance to salinity, metal toxicity, temperature and drought stress. However, these NO donors are thermally and photochemically unstable. A promising strategy that has been successfully used in biomedical applications is the combination of NO donors with nanomaterials. The encapsulation of NO donors in nanoparticles/nanotubes is able to control the release of therapeutic amounts of NO, thus improving its beneficial effects. Although nanomaterials have been used successfully to carry agrochemicals in plants, the delivery of NO is still to be studied. In this context, the present review highlights the advantages of applications of NO donors in plants, the uses of nanotechnology in agriculture, and the necessity to develop new strategies based on the combination of NO and nanomaterials in agriculture. Therefore, this review hopes to open up new perspectives in the area of nanobiotechnology, NO and agriculture.

Contribution of either YY1 or BclXL-induced inhibition by the NO-donor DETANONOate in the reversal of drug resistance, both in vitro and in vivo. YY1 and BclXL are overexpressed in prostate cancer

Nitric oxide (NO) donors have been shown to activate or inhibit constitutively-activated survival/anti-apoptotic pathways, such as NF-κB, in cancer cells. We report here that treatment of drug-resistant human prostate carcinoma cell lines with high levels (500–1000μM) of the NO-donor DETANONOate sensitized the resistant tumor cells to apoptosis by CDDP and the combination was synergistic. We hypothesized that DETANONOate inhibits previously identified NF-κB-regulated resistant factors such as Yin Yang 1 (YY1) and Bcl-2/BclXL. Lysates from tumor cells treated with DETANONOate showed inhibition of YY1 and BclXL expressions. Transfection with either YY1 or BclXL siRNA resulted in the inhibition of both YY1 and BclXL expressions and sensitized the cells to CDDP apoptosis. Mice bearing PC-3 tumor xenografts and treated with the combination of DETANONOate and CDDP resulted in significant inhibition of tumor growth; treatment with single agent alone did not have any effect on tumor growth. Analysis of patients TMA tissues with prostatic cancer revealed higher expression of both YY1 and BclXL as a function of tumor grades and their levels were directly correlated. Thus, both YY1 and BclXL are potential prognostic biomarkers. Overall, the above findings suggest that one mechanism of DETANONOate-induced sensitization of resistant tumor cells to CDDP correlated with the inhibition of NF-κB and its targets YY1 and BclXL. The examination of the combination of NO donors and cytotoxic therapy in the treatment of resistant prostate cancer may be warranted.

Role of nitric oxide signaling components in differentiation of embryonic stem cells into myocardial cells

Nitric oxide (NO) is involved in number of physiological and pathological events. Our previous studies demonstrated a differential expression of NO signaling components in mouse and human ES cells. Here, we demonstrate the effect of NO donors and soluble guanylyl cyclase (sGC) activators in differentiation of ES cells into myocardial cells. Our results with mouse and human ES cells demonstrate an increase in Nkx2.5 and myosin light chain (MLC2) mRNA expression on exposure of cells to NO donors and a decrease in mRNA expression of both cardiac-specific genes with nonspecific NOS inhibitor and a concomitant increase and decrease in the mRNA levels of sGC alpha(1) subunit. Although sGC activators alone exhibited an increase in mRNA expression of cardiac genes (MLC2 and Nkx2.5), robust inductions of mRNA and protein expression of marker genes were observed when NO donors and sGC activators were combined. Measurement of NO metabolites revealed an increase in the nitrite levels in the conditioned media and cell lysates on exposure of cells to the different concentrations of NO donors. cGMP analysis in undifferentiated stem cells revealed a lack of stimulation with NO donors. Differentiated cells however, acquired the ability to be stimulated by NO donors. Although, 3-(4-amino-5-cyclopropylpyrimidin-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo [3,4-b]pyridine (BAY 41-2272) alone was able to stimulate cGMP accumulation, the combination of NO donors and BAY 41-2272 stimulated cGMP levels more than either of the agents separately. These studies demonstrate that cGMP-mediated NO signaling plays an important role in the differentiation of ES cells into myocardial cells.

Dendrimers as a Scaffold for Nitric Oxide Release

The preparation and characterization of nitric oxide (NO)-releasing dendrimer conjugates are reported. Generation 3 and 5 polypropylenimine dendrimers (DAB-Am-16 and DAB-Am-64) were modified at the exterior to impart different amine functionalities. The ability to store NO on a dendritic scaffold using N-diazeniumdiolate NO donors was examined via the reaction of primary amine, secondary amine, and amide functionalities with high pressures of NO (5 atm). The secondary amine dendrimer conjugates exhibited a high storage capacity for NO (up to 5.6 micromol NO/mg), greatly increasing the "payload" of released NO over existing macromolecular NO donors. The mechanism of diazeniumdiolate decomposition was proton initiated, generating NO spontaneously under physiological conditions (pH 7.4, 37 degrees C). The NO release durations (>16 h) observed for the secondary amine dendrimers were significantly longer compared to small molecule alkyl secondary amine diazeniumdiolates, thus illustrating a dendritic effect on NO release kinetics. The multivalent exterior of dendrimers allows for the future combination of NO donors and other functionalities on a single molecular scaffold, enabling diverse utility as NO storage/delivery systems.

Attenuation of canine warm ischemic small bowel injury by novel combination of nitric oxide donor, FK409, and cytokine suppressive anti-inflammatory agent FR167653

Organ ischemia-reperfusion injury is caused by two consecutive steps, microcirculatory disturbance and neutrophil-endothelial cell interactions, which are caused by inflammatory cytokines. We examined the hypothesis that combination therapy with a donor (FK409) of nitric oxide, one of the potent mediators with diverse roles as a vosodilator and a platelet inhibitor, together with the cytokine suppressor agent (FR167653) attenuates warm ischemic injury in canine small bowel. Small bowel ischemia was initiated by clamping the superior mesenteric artery and vein. Animals were divided into two groups: a control group ( n = 5) subjected to 2-hour small bowel ischemia only, and a combination therapy group (FK/FR group, n = 5) that received FK409 (300 mcg/kg/h) plus FR167653 (1 mg/kg/h) intravenously before and after the ischemic event. We evaluated animal survival, small bowel tissue blood flow, and enzyme release from the small bowel. All controls died from severe acidosis within 2 days and all the FK/FR animals survived 7 days ( P < .05). The FK/FR group recovered more than 70% of blood flow immediately after the revascularization, while the flow was less than 40% among the controls. Serum creatine phosphokinase values in the control group after reperfusion were significantly higher than those in the FK/FR group. In conclusion improvement of the microcirculation by FK409 and inhibition of cytokine release by FR167653 together attenuated warm ischemic small bowel injury.

Activation of a NO-cyclic GMP system by NO donors potentiates β-endorphin-induced antinociception in the mouse

Nitric oxide (NO) donors such as sodium nitroprusside (SNP, 0.01-1 μg) or 3-morpholino-sydnonimine (SIN-1, 0.1–10 μg) administered intracerebroventricularly (i.c.v.) produced a dose-dependent potentiation of β-endorphin-induced antinociception assessed by the tail-flick test in ICR mice. The same i.c.v. treatment with SNP or SIN-1 did not affect the antinociception induced by μ-, δ-, or κ-opioid receptor agonists. The goal of the present study was to determine if the potentiation of the β-endorphin-induced antinociception by NO donors is mediated by the activation of a NO-cGMP system. Co-administration of hemoglobin (30–120 μg) or methylene blue (1.25-5 μg), but not N ω-nitro- l-arginine (1–5 μg) with β-endorphin (0.1 μg) given i.c.v. dose-dependently attenuated the potentiating effects of SNP or SIN-1 on β-endorphin-induced antinociception. However, the same i.c.v. treatments of mice with hemoglobin, methylene blue or N ω-nitro-L-arginine did not directly affect the i.c.v. administered β-endorphin-induced antinociception. On the other hand, the treatment of mice with a combination of NO donor (SNP, 0.1 μg or SIN-1, 1 μg) and zaprinast (a cGMP phosphodiesterase inhibitor, 1 μg) further potentiated β-endorphin-induced antinociception. These results indicate that the potentiating effect of SNP or SIN-1 on β-endorphin-induced antinociception is mediated by the increased production of NO-cyclic GMP in the brain. However, the NO-cGMP system is not directly involved in the β-endorphin-induced antinociception.