Nitric Oxide-releasing Nonsteroidal Anti-inflammatory Drugs Research Articles

Effects of Non-steroidal Anti-inflammatory Drugs (NSAIDs) and Gastroprotective NSAIDs on the Gastrointestinal Tract: A Narrative Review.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for their anti-inflammatory, antipyretic, and analgesic properties. However, their use is often associated with gastrointestinal tract (GIT) side effects due to the inhibition of both cyclooxygenase (COX)-1 and COX-2 enzymes, leading to a decrease in gastroprotective prostaglandins (PG). To minimize these adverse effects, various approaches have been explored, including selective COX-2 inhibitors, NO-NSAIDs (nitric oxide-releasing NSAIDs), and dual COX/LOX (lipoxygenase) NSAIDs. However, the effects of these gastroprotective NSAIDs on the GIT and their efficacy remains uncertain. This review aims to provide an overview of the current understanding of the effects of traditional NSAIDs and gastroprotective NSAIDs on GIT. We discuss the underlying mechanisms of GIT damage caused by NSAIDs, including mucosal injury, ulceration, and bleeding, and the potential of gastroprotective NSAIDs to mitigate these effects. We also summarize recent studies on the efficacy and safety of various gastroprotective NSAIDs and highlight the limitations and challenges of these approaches. The review concludes with recommendations for future research in this field.

Vascular Inflammation in Hypertension: Targeting Lipid Mediators Unbalance and Nitrosative Stress.

Arterial hypertension is a worldwide public health threat. High Blood Pressure (BP) is commonly associated with endothelial dysfunction, nitric oxide synthases (NOS) unbalance and high peripheral vascular resistance. In addition to those, inflammation has also been designated as one of the major components of BP increase and organ damage in hypertension. This minireview discusses vascular inflammatory triggers of high BP and aims to fill the existing gaps of antiinflammatory therapy of hypertension. Among the reasons discussed, enhanced prostaglandins rather than resolvins lipid mediators, immune cell infiltration and oxidative/nitrosative stress are pivotal players of BP increase within the inflammatory hypothesis. To address these inflammatory targets, this review also proposes new concepts in hypertension treatment with non-steroidal antiinflammatory drugs (NSAIDs), nitric oxide-releasing NSAIDs (NO-NSAIDs) and specialized proresolving mediators (SPM). In this context, the failure of NSAIDs in hypertension treatment seems to be associated with the reduction of endogenous NO bioavailability, which is not necessarily an effect of all drug members of this pharmacological class. For this reason, NO-releasing NSAIDs seem to be safer and more specific therapy to treat vascular inflammation in hypertension than regular NSAIDs.

Gastric-sparing nitric oxide-releasable ‘true’ prodrugs of aspirin and naproxen

Nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) are gaining attention as potentially gastric-sparing NSAIDs. Herein, we report a novel class of ‘1-(nitrooxy)ethyl ester’ group-containing NSAIDS as efficient NO releasing ‘true’ prodrugs of aspirin and naproxen. While an aspirin prodrug exhibited comparable oral bioavailability and antiplatelet activity (i.e., TXB2 inhibition) to those of aspirin, a naproxen prodrug exhibited better bioavailability than naproxen. These promising NO-NSAIDs protected experimental rats from gastric damage. We therefore believe that these promising NO-NSAIDs could represent a new class of potentially ‘Safe NSAIDs’ for the treatment of arthritic pain, inflammation and cardiovascular disorders in the case of NO-aspirin.

Flurbiprofen benzyl nitrate (NBS-242) inhibits the growth of A-431 human epidermoid carcinoma cells and targets ß-catenin

BackgroundThe Wnt/β-catenin/T cell factor (TCF) signaling pathway is important in the development of nonmelanoma skin cancers (NMSCs). Nitric-oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) are chemopreventive agents consisting of a traditional NSAID attached to an NO-releasing moiety through a chemical spacer. Previously we showed that an aromatic spacer enhanced the potency of a particular NO-NSAID compared to an aliphatic spacer.MethodsWe synthesized an NO-releasing NSAID with an aromatic spacer (flurbiprofen benzyl nitrate, NBS-242), and using the human skin cancer cell line A-431, we evaluated its effects on cell kinetics, Wnt/β-catenin, cyclin D1, and caspase-3.ResultsNBS-242 inhibited the growth of A-431 cancer cells, being ~15-fold more potent than flurbiprofen and up to 5-fold more potent than NO-flurbiprofen with an aliphatic spacer, the half maximal inhibitory concentrations (IC50) for growth inhibition being 60 ± 4 μM, 320 ± 20 μM, and 880 ± 65 μM for NBS-242, NO-flurbiprofen, and flurbiprofen, respectively. This effect was associated with inhibition of proliferation, accumulation of cells in the G0/G1 phase of the cell cycle, and an increase in apoptotic cell population. NBS-242 cleaved β-catenin both in the cytoplasm and the nucleus of A-431 cells. NBS-242 activated caspase-3 whose activation was reflected in the cleavage of procaspase-3. To test the functional consequence of β-catenin cleavage, we determined the expression of cyclin D1, a Wnt-response gene. NBS-242 reduced cyclin D1 levels in a concentration dependent manner.ConclusionThese findings establish a strong inhibitory effect of NBS-242 in A-431 human epidermoid carcinoma cells. NBS-242 modulates parameters that are important in determining cellular mass.

The Proapoptotic Effect of Traditional and Novel Nonsteroidal Anti-Inflammatory Drugs in Mammalian and Yeast Cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat pain, fever, and inflammation. However, mounting evidence shows that NSAIDs, such as aspirin, have very promising antineoplastic properties. The chemopreventive, antiproliferative behaviour of NSAIDs has been associated with both their inactivation of cyclooxygenases (COX) and their ability to induce apoptosis via pathways that are largely COX-independent. In this review, the various proapoptotic pathways induced by traditional and novel NSAIDs such as phospho-NSAIDs, hydrogen sulfide-releasing NSAIDs and nitric oxide-releasing NSAIDs in mammalian cell lines are discussed, as well as the proapoptotic effects of NSAIDs on budding yeast which retains the hallmarks of mammalian apoptosis. The significance of these mechanisms in terms of the role of NSAIDs in effective cancer prevention is considered.

Nitric oxide-releasing sulindac is a novel skin cancer chemopreventive agent for UVB-induced photocarcinogenesis

Nitric oxide (NO)-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) which have been synthesized to reduce gastro-intestinal and cardiovascular toxicities of NSAIDs, possess anti-proliferative, pro-apoptotic and anti-cancer activities. Here, we show that NO-sulindac inhibited UVB-induced skin tumorigenesis in SKH-1 hairless mice. Topical application of NO-sulindac reduced tumor incidence, number (p<0.05) and volume (p<0.005) as compared to UVB (alone)-irradiated vehicle-treated mice. An increase in TUNEL-positive cells in skin lesions was accompanied by the enhanced Bax:Bcl-2 ratio. The expression of pro-apoptotic Bax was increased whereas anti-apoptotic Bcl-2 reduced. However, proliferation was identified as the major target of NO-sulindac in this study. A reduced expression of PCNA and cyclin D1 associated with the dampening of cell cycle progression was observed. The mechanism of this inhibition was related to the reduction in UVB-induced Notch signaling pathway. UVB-induced inflammatory responses were diminished by NO-sulindac as observed by a remarkable reduction in the levels of phosphorylated MAP Kinases Erk1/2, p38 and JNK1/2. In this regard, NO-sulindac also inhibited NFκB by enhancing IκBα as evidenced by the reduced expression of iNOS and COX-2, the direct NFκB transcription target proteins. NO-sulindac significantly diminished the progression of benign lesions to invasive carcinomas by suppressing the tumor aggressiveness and retarding epithelial–mesenchymal transition. A marked decrease in the expression of mesenchymal markers such as Fibronectin, N-cadherin, SNAI, Slug and Twist and an increase in epithelial cell polarity marker E-cadherin were noted in NO-sulindac-treated tumors. Our data suggest that NO-sulindac is a potent inhibitor of UVB-induced skin carcinogenesis and acts by targeting proliferation-regulatory pathways.

Effects of nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NONO-NSAIDs) on melanoma cell adhesion

A new class of nitric oxide (NO•)-releasing nonsteroidal anti-inflammatory drugs (NONO-NSAIDs) were developed in recent years and have shown promising potential as NSAID substitutes due to their gentle nature on cardiovascular and gastrointestinal systems. Since nitric oxide plays a role in regulation of cell adhesion, we assessed the potential use of NONO-NSAIDs as anti-metastasis drugs. In this regard, we compared the effects of NONO-aspirin and a novel NONO-naproxen to those exerted by their respective parent NSAIDs on avidities of human melanoma M624 cells. Both NONO-NSAIDs, but not the corresponding parent NSAIDs, reduced M624 adhesion on vascular cellular adhesion molecule-1 (VCAM-1) by 20–30% and fibronectin by 25–44% under fluid flow conditions and static conditions, respectively. Only NONO-naproxen reduced (~56%) the activity of β1 integrin, which binds to α4 integrin to form very late antigen-4 (VLA-4), the ligand of VCAM-1. These results indicate that the diazeniumdiolate (NO•)-donor moiety is critical for reducing the adhesion between VLA-4 and its ligands, while the NSAID moiety can impact the regulation mechanism of melanoma cell adhesion.

Abstract 3891: NOSH-aspirin, a novel nitric oxide- and hydrogen sulfide-releasing hybrid, is a potent inhibitor of colon cancer cell growth

Abstract Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) are recognized as the prototypical chemopreventive agents. However, their wide use is precluded due to significant toxicity. The search for better NSAIDs has led to generation of nitric oxide-releasing NSAIDs (NO-NSAIDs) and more recently, to a new class of hydrogen sulfide-releasing agents (HS-NSAIDs). Both of these have shown to be more potent and less toxic than their parent NSAID. However, the draw back to these compounds is their IC50 for cell growth inhibition. It is too high to make them attractive for development as pharmaceuticals. Therefore, we postulated that a new hybrid that incorporated the active parts of each compound may be more potent and effective than either one. Our hypothesis has proved to be correct. Here we describe the effects of a nitric oxide- and hydrogen sulfide-releasing aspirin (NOSH-aspirin) on the growth properties of several human colon cancer cell lines, on induction of reactive oxygen species (ROS), and on NF-κB whose induction is strongly implicated in some cancers. Methods: NOSH-aspirin was synthesized and purified at our lab with 1H-NMR verification. Colon cancer cell lines: HT-29, HCT 15, and SW480; Cell growth: MTT; Cell cycle phase distribution: Flow cytometry; Apoptosis: subdiploid (sub-G0/G1) peak in DNA content histograms; Proliferation: PCNA; NF-kB: enzyme-linked immunosorbent assay (ELISA); Reactive oxygen species (ROS): 2′,7′-dichlorodihydrofluorescein (H2DCFDA, probe for peroxides) or dihydroethidium (DHE, probe for superoxide anion) measured fluorescence by flow cytometry. Results: NOSH-aspirin inhibited the growth of HT-29, HCT 15, and SW480 cells with IC50 values of 48 ± 3, 50 ± 5, and 60 ± 4 nM at 24 hr, respectively. The corresponding IC50 for aspirin in all 3 cell lines was &amp;gt;5000 µM. This represents and enhanced potency of &amp;gt;80,000-fold in the 3 cell lines at 24 h. NOSH-aspirin treatment of HT-29 cells at 0.5xIC50, 1xIC50, and 2xIC50 for 24 hrs induced apoptosis (20 ± 1%, 52 ± 3%, 75 ± 3%), inhibited proliferation (PCNA, 70 ± 3%, 45 ± 4%, 22 ± 3%), and caused a G0/G1 cell cycle block. Activation of NF-κB was inhibited as demonstrated by ELISA, at 0.5xIC50, 1xIC50, and 2xIC50 the reduction was 11 ± 1%, 33 ± 2%, and 46 ± 3% respectively. NOSH-aspirin caused induction of oxidative stress as evidenced by increases in both H2DCFDA and DHE-derived fluorescence representing increases in intracellular levels of H2O2 and superoxide anion respectively Conclusions: NOSH-aspirin by inducing ROS is a potent inhibitor of colon cancer cell growth and it inhibits NF-κB activation. These data suggest that NOSH-aspirin may be useful as a chemopreventive agent against colon cancer and merits further evaluation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3891. doi:1538-7445.AM2012-3891

Nitric Oxide Release Is Not Required to Decrease the Ulcerogenic Profile of Nonsteroidal Anti-inflammatory Drugs

The objective of this work was to evaluate the biological properties of a new series of nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) possessing a tyrosol linker between the NSAID and the NO-releasing moiety (PROLI/NO); however, initial screening of ester intermediates without the PROLI/NO group showed the required (desirable) efficacy/safety ratio, which questioned the need for NO in the design. In this regard, NSAID ester intermediates were potent and selective COX-2 inhibitors in vitro, showed equipotent anti-inflammatory activity compared to the corresponding parent NSAID, but showed a markedly reduced gastric toxicity when administered orally. These results provide complementary evidence to challenge the currently accepted notion that hybrid NO-NSAIDs exert their cytoprotective effects by releasing NO. Results obtained in this work constitute a good body of evidence to initiate a debate about the future replacement of NSAID prodrugs for unprotected NSAIDs (possessing a free carboxylic acid group) currently in clinical use.

NO-NSAIDs. Part 3: Nitric Oxide-Releasing Prodrugs of Non-steroidal Anti-inflammatory Drugs

In continuation of our efforts to discover novel nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) as potentially "Safe NSAIDs," we report herein the design, synthesis and evaluation of 21 new NO-NSAIDs of commonly used NSAIDs such as aspirin, diclofenac, naproxen, flurbiprofen, ketoprofen, sulindac, ibuprofen and indomethacin. These prodrugs have NO-releasing disulfide linker attached to a parent NSAID via linkages such as an ester (compounds 9-16), a double ester (compounds 17-24), an imide (compounds 25-30) or an amide (compounds 31-33). Among these NO-NSAIDs, the ester-containing NO-aspirin (9), NO-diclofenac (10), NO-naproxen (11), and the imide-containing NO-aspirin (25), NO-flurbiprofen (27) and NO-ketoprofen (28) have shown promising oral absorption, anti-inflammatory activity and NO-releasing property, and also protected rats from NSAID-induced gastric damage. NO-aspirin compound 25, on further co-evaluation with aspirin at equimolar doses, exhibited comparable dose-dependent pharmacokinetics, inhibition of gastric mucosal prostaglandin E(2) (PGE(2)) synthesis and analgesic properties to those of aspirin, but retained its gastric-sparing properties even after doubling its oral dose. These promising NO-NSAIDs could therefore represent a new class of potentially "Safe NSAIDs" for the treatment of arthritic pain and inflammation.

Abstract 1487: Nitric oxide-releasing NSAIDs suppress NF-κB signaling and increase caspase-3 enzyme activity in vitro and in vivo through S-nitrosylation

Abstract Introduction: Nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) consisting of a conventional NSAID to which an NO releasing moiety -ONO2 is covalently attached through a spacer have emerged as a new class of pharmaceutical agents. The released NO has proapoptotic effects which may cause DNA damage, leading to p53 activation, proteasome inhibition, and/or cytochrome c release from mitochondria, resulting from activation of the mitochondrial permeability transition pore or damage to mitochondrial membrane phospholipids. NO can directly modify sulfhydryl residues of proteins through S-nitrosylation, which has emerged as an important posttranslational protein modification based on prototypic redox mechanisms in signal transduction. The transcription factor, NF-κB is constitutively expressed in many tumors and characterizes all inflammatory responses. As apoptosis is a dominant anti-tumor pathway for chemotherapy-induced cell death, NF-κB may also be involved in resistance to cancer chemotherapy. Caspase-3 activation is intimately involved in apoptosis. In this study we evaluated the actions of meta-NO-aspirin (m-NO-ASA) and NO-naproxen which inhibit cell growth and induce apoptosis on NF-κB expression and caspase-3 activity and determined whether these agents S-nitrosylate these proteins. Methods: m-NO-ASA and NO-naproxen synthesized by us. Cell line: HT-29 human colon cancer cells. Growth inhibition: MTT. Animal studies: Rats (5 per group) were gavaged with ASA (180 mg/kg) or naproxen (40 mg/kg) or equimolar amounts of NO-ASA or NO-naproxen and killed 6h later after which their stomachs were rapidly removed, gently washed, and frozen in liquid nitrogen. Caspase-3 activity: commercial kit. Protein S-nitrosylation: Biotin switch assay (Jaffrey et al, Nature Cell Biology, 2001, 3:193-197); NF-κB, caspase-3, TNF-α, and biotinylated protein levels: immunoblotting. We also used the NO-donor SNAP as a positive control. Results: In vitro: m-NO-ASA and NO-naproxen inhibited the growth of HT29 colon cancer cells with IC50s of 187 ± 10 µM and 97 ± 5 µM at 24 hr respectively. NF-κB expression was reduced, however, caspase-3 enzyme activity and protein levels were increased by these agents in a dose- and time-dependent manner. NO-NSAID treatment for 24 hr at 0.5 x IC50, IC50 and 2 x IC50 caused an increase in both the total S-nitrosylated proteins and S-nitrosylated NF-κB (p-65 protein) and caspase-3 expression. These effects were reversed by carboxy-PTIO (an NO scavenger). In vivo: NO-NSAIDs caused an increase in total S-nitrosylated proteins and an increase in S-nitrosylated NF-κB, and TNF-α protein levels. Conclusions: These data strongly suggest S-nitrosylation as a potential molecular mechanism for the observed effects of NO-NSAIDs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1487.

NO-NSAIDs: Gastric-sparing nitric oxide-releasable prodrugs of non-steroidal anti-inflammatory drugs

Recently, a new class of nitric-oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) is being studied as ‘Safe NSAIDs’ because of their gastric-sparing properties. As an extension of our novel disulfide linker technology, we have designed, synthesized and evaluated novel NO-releasing NSAID prodrugs such as NO-Aspirin ( 1b– d) and NO-Diclofenac ( 2b– c). Although the amide-containing derivative 1d did not show any bioavailability, the remaining compounds have shown fair to excellent pharmacokinetic, anti-inflammatory and gastric-sparing properties. Among them, however, the NO-Diclofenac ( 2b) has shown the most promising pharmacokinetic, anti-inflammatory and NO-releasing properties and protected rats from NSAID-induced gastric damage which could be attributable to the beneficial effects of NO released from these prodrugs.

Recent advances in gastric ulcer therapeutics

In developed countries at least, ulcers related to Helicobacter pylori infection are becoming rarer. However, ulcers associated with the use of non-steroidal anti-inflammatory drugs (NSAIDs) remain a major clinical problem, which has not been solved through the introduction of selective inhibitors of cyclooxygenase (COX)-2. Recent studies suggest that NSAID-induced ulcers can be prevented largely through co-administration of a proton pump inhibitor to block acid secretion in the stomach. In patients requiring aspirin therapy to prevent cardiovascular diseases, co-administration of aspirin plus a proton pump inhibitor was found to be safer than using another anti-platelet therapy that does not block gastric prostaglandin production (e.g. clopidogrel). Several recent papers have clarified further the contribution of COX-2 to gastric mucosal defence and to the healing of ulcers. In some circumstances, COX-2 produces a highly potent gastroprotective substance (15-R-lipoxin A(4)), and analogues of this substance could have therapeutic value for preventing gastric ulceration. Nitric oxide-releasing NSAIDs continue to show promise in terms of limiting damage to the gastrointestinal tract, even when given in combination with aspirin. Recent studies support the notion that platelets make a major contribution to ulcer healing, and the release of several key growth factors from platelets appears to be regulated by proteinase-activated receptors.

Novel Nonsteroidal Antiinflammatory Drugs Possessing a Nitric Oxide Donor Diazen-1-ium-1,2-diolate Moiety: Design, Synthesis, Biological Evaluation, and Nitric Oxide Release Studies

A novel group of hybrid nitric oxide-releasing nonsteroidal antiinflammatory drugs ((*)NO-NSAIDs) possessing a 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (11, 13, 15) or 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate (12, 14, 16) moiety attached via a one-carbon methylene spacer to the carboxylic acid group of the traditional NSAIDs aspirin, ibuprofen, and indomethacin were synthesized. Although none of these ester prodrugs (11-16) exhibited in vitro cyclooxygenase (COX) inhibitory activity against the COX-1 and COX-2 isozymes (IC(50) > 100 microM), all of the compounds (11-16) significantly decreased carrageenan-induced rat paw edema. In this regard, the ester prodrugs 11-16 showed equipotent antiinflammatory activities in vivo to that of the parent drugs aspirin, ibuprofen, and indomethacin. All of the compounds released nitric oxide upon incubation with either phosphate buffer solution at pH 7.4 (14-16% range) or porcine liver esterase (16-19% range), but the percentage of (*)NO released was up to sixfold higher (93%) when these ester prodrugs were incubated with guinea pig serum. These incubation studies suggest that both (*)NO and the parent NSAID would be released upon in vivo cleavage by nonspecific serum esterases. The simultaneous release of aspirin and nitric oxide from the (*)NO-aspirin prodrugs constitutes a potentially beneficial property for the prophylactic prevention of thrombus formation and adverse cardiovascular events such as stroke and myocardial infarction. The data acquired in an in vivo ulcer index (UI) assay showed that for this group of ester prodrugs, particularly the (*)NO-aspirins (11, 12) and (*)NO-ibuprofens (13, 14), no lesions were observed (UI = 0) when compared to the parent drugs aspirin (UI = 57, 250 mg/kg po dose), ibuprofen (UI = 45, 250 mg/kg po dose), or indomethacin (UI = 34, 30 mg/kg po dose) at equivalent doses. Accordingly, these hybrid (*)NO-NSAID prodrugs possessing a diazen-1-ium-1,2-diolate moiety, represent a new approach for the rational design of antiinflammatory drugs with reduced gastric ulcerogenicity.

In vitro and in vivo evaluation of NCX 4040 cytotoxic activity in human colon cancer cell lines

BackgroundNitric oxide-releasing nonsteroidal antiinflammatory drugs (NO-NSAIDs) are reported to be safer than NSAIDs because of their lower gastric toxicity. We compared the effect of a novel NO-releasing derivate, NCX 4040, with that of aspirin and its denitrated analog, NCX 4042, in in vitro and in vivo human colon cancer models and investigated the mechanisms of action underlying its antitumor activity.MethodsIn vitro cytotoxicity was evaluated on a panel of colon cancer lines (LoVo, LoVo Dx, WiDr and LRWZ) by sulforhodamine B assay. Cell cycle perturbations and apoptosis were evaluated by flow cytometry. Protein expression was detected by Western blot. In the in vivo experiments, tumor-bearing mice were treated with NCX 4040, five times a week, for six consecutive weeks.ResultsIn the in vitro studies, aspirin and NCX 4042 did not induce an effect on any of the cell lines, whereas NCX 4040 produced a marked cytostatic dose-related effect, indicating a pivotal role of the -NO2 group. Furthermore, in LoVo and LRWZ cell lines, we observed caspase-9 and -3-mediated apoptosis, whereas no apoptotic effect was observed after drug exposure in WiDr or LoVo Dx cell lines. In in vivo studies, both NCX 4040 and its parental compound were administered per os. NCX 4040 induced a 40% reduction in tumor weight. Conversely, aspirin did not influence tumor growth at all.ConclusionsNCX 4040, but not its parental compound, aspirin, showed an in vitro and in vivo antiproliferative activity, indicating its potential usefulness to treat colon cancer.

NSAIDs and chemoprevention.

Several epidemiological, clinical and experimental studies established nonsteroidal anti-inflammatory drugs (NSAIDs) as promising cancer chemopreventive agents. Long-term use of aspirin and other NSAIDs has been shown to reduce the risk of cancer of the colon and other gastrointestinal organs as well as of cancer of the breast, prostate, lung, and skin. Understanding the action of NSAIDs provides substantial insights into the mechanisms by which these unique agents regulate tumor cell growth and enable better strategies for prevention and treatment. NSAIDs restore normal apoptosis and reduce cell proliferation in human adenomatous colorectal polyps, experimental colonic tumors, and in various cancer cell lines that have lost critical genes required for normal function. NSAIDs, particularly selective cyclooxygenase-2 (COX-2) inhibitors such as celecoxib, have been shown to inhibit angiogenesis in cell culture and in rodent models of angiogenesis. Exploration of the multistep process of carcinogenesis has provided substantial insights into the mechanisms by which NSAIDs modulate these events. However, unresolved questions with regard to safety, efficacy, optimal treatment regimen, and mechanism of action currently limit the clinical application of NSAIDs to the prevention of polyposis in FAP patients. Moreover, the development of safe and effective NSAIDs for chemoprevention is complicated by the potential that rare, serious toxicity may offset the benefit of treatment with these drugs given to healthy individuals who have a low risk of developing the disease. Growing knowledge in this area has brought about innovative approaches using combine actions of NSAIDs with other agents that have different modes of action. It has also led to the development of nitric oxide-releasing NSAIDs, that induce tumor cell apoptosis and compensate for COX function, as a means of increasing efficacy and minimizing toxicity. There is growing optimism for the view that full exploration of the role of NSAIDs in the prevention and treatment of epithelial cancers will serve towards reducing of mortality and morbidity from various cancers.

Nitric oxide-releasing non steroidal anti-inflammatory drugs: a new generation of anti-tumoral molecules.

Colorectal cancer is the second most common cause of cancer-related mortality in the west. The high incidence and mortality make effective prevention an important public-health and economic issue. The regular intake of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with decreased incidence of certain types of cancer particularly those with an inflammatory component, and then are among the few agents known to be chemopreventive. Nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) are new chemical entities obtained by adding a nitric oxide-releasing moiety to classical molecules. This new class of molecules has been demonstrated to be much more safe than NSAIDs due to their ability to reduce gastric toxicity. They could therefore represent an alternative to classical NSAIDs treatment. In this review, we sumarise the recent findings in the mechanisms and pathways involved in the antitumoral effects of both NSAIDs and NO-NSAIDs as well as the clinical trials performed with these compounds.

NCX 4016, a nitric oxide-releasing aspirin derivative, exhibits a significant antiproliferative effect and alters cell cycle progression in human colon adenocarcinoma cell lines

Nitric oxide-releasing non-steroidal antiinflammatory drugs (NO-NSAIDs) are safer than NSAIDs due to their ability to reduce gastric toxicity. We assessed the cytotoxic activity of a new aspirin derivative, NCX 4016, after different exposure schedules, in three human colon adenocarcinoma cell lines. All the lines were positive for COX-1 protein and mRNA, as evaluated by Western blot and RT-PCR, respectively, while only one was positive for COX-2. The cytostatic and cytocidal activity was determined by sulforhodamine B assay and evaluated according to Monks' model. Cytostatic activity was observed after a 24-h drug exposure and 50% growth inhibition was reached at concentrations ranging from 165 to 250 micro M in all cell lines, whereas with aspirin the IC50 was never reached, even at the maximum concentration tested (500 micro M), and was independent of COX-1 or COX-2 status. Cytocidal activity was observed only at the highest concentrations and persisted for a long time after drug removal. Flow cytometric analysis showed that the NO-aspirin compound induced a persistent accumulation of cells in G2-M phase in all the cell lines after at least 48 h exposure. Specifically, the block pertained mainly to G2 phase, whereas mitotic index was not affected at all. Our results indicate that NCX 4016 has an in vitro cytostatic activity superior to that of its parental aspirin compound, which makes it a potentially important tumor preventive agent. Furthermore, the cytocidal effect observed at the highest concentrations and the induction of a specific block in G2 phase renders it a promising candidate for drug combination treatments.

Inhibition of nuclear factor-kappaB by a nitro-derivative of flurbiprofen: a possible mechanism for antiinflammatory and antiproliferative effect.

Nonsteroidal antiinflammatory drugs (NSAIDs) are widely used in the treatment of chronic inflammatory states. In addition, they show promise for the prevention and therapy of colon cancers and of Alzheimer's disease, although their gastrointestinal toxicity is of concern for these indications. Nitric oxide-releasing NSAIDs are reported to be safer than their parent compounds. We report here that flurbiprofen nitroxybutyl ester inhibits nuclear factor-kappaB (NF-kappaB) activity and cell growth in L929 cells at a concentration of 100 microM, whereas flurbiprofen is inactive. Inhibition of cell growth is not due to the induction of apoptosis, but to a retardation of all phases of the cell cycle. NF-kappaB is implicated both in the control of immune and inflammatory response and in the control of cell proliferation and apoptosis. Therefore, its inhibition at low concentrations by an NSAID with low gastrointestinal toxicity could be important for all the above-mentioned therapeutic indications.

Pharmacology and potential therapeutic applications of nitric oxide-releasing non-steroidal anti-inflammatory and related nitric oxide-donating drugs.

This review examines the biological significance, therapeutic potential and mechanism(s) of action of a range of nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAID) and related nitric oxide-releasing donating drugs (NODD). The slow release of nitric oxide (NO) from these compounds leads to subtle changes in the profile of pharmacological activity of the parent, non-steroidal anti-inflammatory drugs (NSAID). For example, compared with NSAID, NO-NSAID cause markedly diminished gastrointestinal toxicity and improved anti-inflammatory and anti-nociceptive efficacy. In addition, nitroparacetamol exhibits hepatoprotection as opposed to the hepatotoxic activity of paracetamol. The possibility that NO-NSAID or NODD may be of therapeutic benefit in a wide variety of disease states including pain and inflammation, thrombosis and restenosis, neurodegenerative diseases of the central nervous system, colitis, cancer, urinary incontinence, liver disease, impotence, bronchial asthma and osteoporosis is discussed.