Abstract A42: Comparison between NO-ASA and NONO-ASA as safe anti-inflammatory, analgesic, antipyretic, antioxidant chemopreventive prodrugs

Abstract

Abstract Introduction: Chronic inflammation is widely recognized as an underlying etiological factor in carcinogenesis; there is enough evidence to support the use of non-steroidal anti-inflammatory drugs (NSAIDs), and more importantly, their chemically-modified NO-releasing prodrugs (NO-NSAIDs) as promising chemopreventive agents. Metabolic activation of organic nitrate-containing NO-aspirins may lead to a cytotoxic “activated” linker (a quinone methide), raising safety concerns. Replacement of organic nitrates with N-diazeniumdiolates as a second-generation NONO-NSAIDs allowed us to conduct a head-to-head comparison between NCX-4016 (NO-aspirin), CVM-01 (NONO-aspirin), and aspirin as analgesic, anti-inflammatory, and anti-pyretic agents with no significant gastrointestinal toxicity. Methods: a) Anti-inflammatory: paw edema induced by intraplantar injection of 100 µL of 1% carrageenan, paw volumes measured up to the tibiotarsal joint immediately prior to carrageenan injection and thereafter at 1hr intervals up to 6hrs. Drugs were administered orally 1 hr before carrageenan; b) Anti-pyretic: body core temperature was measured twice at 15 min intervals before administration of lipopolysaccaride (LPS, 50µg/kg, ip) to induce fever. Drugs administered 1hr before LPS; c) analgesic: the time-dependent analgesic effect of prodrugs was evaluated by carrageenan-induced hyperalgesia. Drugs were administered orally 2.5 hours after carrageenan; d) Anti-ulcerogenic: Rats fasted for 48h before drug administration. After 6 hrs animals were euthanized, stomachs removed, cut along the greater curvature, lightly rinsed with water, and observed (with magnifying lenses) to count the numbers and measure the lengths (in mm) of all hemorrhagic lesions (“gastric damage score”) for each stomach. Tissue samples immediately frozen in liquid nitrogen for PGE2, SOD, and MDA determination. Results: NCX-4016 and CVM-01 decreased the carrageenan-induced edema 1h after administration and maintained this anti-inflammatory effect throughout the experiment (up to 7h). Both compounds showed improved anti-inflammatory effect compared to aspirin 3–7h post administration. All test drugs (aspirin, NCX-4016, and CVM-01) were effective anti-pyretics, decreasing the body core temperature starting at 1h post-administration. At the end of the assay (5h) aspirin prodrugs showed slightly improved anti-pyretic effect compared to aspirin. Despite a drastic reduction of PGE2 levels induced by NCX-4016 and CVM-01 in stomach tissue, both prodrugs were devoid of gastric side effects (gastric index < 5) aspirin (GI=48). Lipid peroxidation induced by aspirin (MDA=57 nmol/mg protein) was higher than that observed by the prodrugs NCX-4016 (MDA= 9nmol/mg) and CVM-01 (13 nmol/mg), which resembled control tissue (MDA=12 nmol/mg). Superoxide dismutase (SOD): aspirin (SOD=12 U/mL), NCX-4016 (SOD=21 U/mL), CVM-01 (20 U/mL), control tissue (23 U/mL). Conclusions: The N-diazeniumdiolate containing aspirin prodrug CVM-01 is as effective as NCX-4016 (an organic nitrate-containing aspirin prodrug) in anti-inflammatory, analgesic, and anti-pyretic assays in vivo, and it showed an equivalent safety profile in stomach. These results underscore the use of diazeniumdiolate-containing NSAIDs (NONO-NSAIDs) in future chemopreventive assays. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A42.