Inhibition of Amyloidogenesis by Nonsteroidal Anti-inflammatory Drugs and Their Hybrid Nitrates

Poor blood-brain barrier penetration of nonsteroidal anti-inflammatory drugs (NSAIDs) has been blamed for the failure of the selective amyloid lowering agent (SALA) R-flurbiprofen in phase 3 clinical trials for Alzheimer's disease (AD). NO-donor NSAIDs (NO-NSAIDs) provide an alternative, gastric-sparing approach to NSAID SALAs, which may improve bioavailability. NSAID analogues were studied for anti-inflammatory activity and for SALA activity in N2a neuronal cells transfected with human amyloid precursor protein (APP). Flurbiprofen (I) analogues were obtained with enhanced anti-inflammatory and antiamyloidogenic properties compared to I, however, esterification led to elevated A beta(1-42) levels. Hybrid nitrate prodrugs possessed superior anti-inflammatory activity and reduced toxicity relative to the parent NSAIDs, including clinical candidate CHF5074. Although hybrid nitrates elevated A beta(1-42) at higher concentration, SALA activity was observed at low concentrations (<= 1 mu M): both A beta(1-42) and the ratio of A beta(1-42)/A beta(1-40) were lowered. This biphasic SALA activity was attributed to the intact nitrate drug. For several compounds, the selective modulation of amyloidogenesis was tested using an immunoprecipitation MALDI-TOF approach. These data support the development of NO-NSAIDs as an alternative approach toward a clinically useful SALA.