Phenyl(thio)phosphon(amid)ate Benzenesulfonamides as Potent and Selective Inhibitors of Human Carbonic Anhydrases II and VII Counteract Allodynia in a Mouse Model of Oxaliplatin-Induced Neuropathy.

Alessio Nocentini,Giuseppina De Simone,Claudiu T Supuran,Roberto Cirilli,Marco Pierini,Carla Ghelardini,Vincenzo Alterio,Simona Maria Monti,Zeid A Alothman,Gianluca Bartolucci,Paola Gratteri,Davide Esposito,Martina Buonanno,Laura Micheli,Lorenzo Di Cesare Mannelli,Sameh M Osman,Silvia Bua

doi:10.1021/acs.jmedchem.9b02135

Abstract

Human carbonic anhydrase (CA; EC 4.2.1.1) isoforms II and VII are implicated in neuronal excitation, seizures, and neuropathic pain (NP). Their selective inhibition over off-target CAs is expected to produce an anti-NP action devoid of side effects due to promiscuous CA modulation. Here, a drug design strategy based on the observation of (dis)similarities between the target CA active sites was planned with benzenesulfonamide derivatives and, for the first time, a phosphorus-based linker. Potent and selective CA II/VII inhibitors were identified among the synthesized phenyl(thio)phosphon(amid)ates 3–22. X-ray crystallography depicted the binding mode of phosphonic acid 3 to both CAs II and VII. The most promising derivatives, after evaluation of their stability in acidic media, were tested in a mouse model of oxaliplatin-induced neuropathy. The most potent compound racemic mixture was subjected to HPLC enantioseparation, and the identification of the eutomer, the (S)-enantiomer, allowed to halve the dose totally relieving allodynia in mice.

Highlights

Neuropathic pain (NP) is pain initiated by a damage or ailment of the peripheral or central somatosensory system.1The prevalence of NP in the population is estimated to be 6.9−10% and amounts to 20−25% of all chronic pain cases.2,3Numbness, needle sensation and tingling, paresthesia, and neurological sensory deficits are NP main symptoms, which can occur both at the central and peripheral nervous systems.Peripheral neuropathies can derive from viral infections and traumatic, post-surgical, or diabetic neuropathies, while central pain syndromes are usual in patients who suffered from multiple sclerosis, spinal cord injury, or stroke.4 The syndromes can manifest in the form of spontaneous, continuous, or evoked pain
All clinically used carbonic anhydrase inhibitors (CAIs), among which primary sulfonamides and sulfamates investigated in the therapy of neuropathic pain such as acetazolamide, methazolamide, topiramate, zonisamide, celecoxib, and furosemide, are predominantly nonselective with respect to all human isoforms
By observing the significant similarity in amino acid composition and active site architecture existing between hCA II and hCA VII (Figure 1), a new series of CAIs were designed, which can concomitantly target both isozymes with the aim of achieving a neuropathic pain-relieving action

Summary

■ INTRODUCTION

Neuropathic pain (NP) is pain initiated by a damage or ailment of the peripheral or central somatosensory system.. The adopted structure-based drug design strategy produced a satisfactory result in terms of inhibition potency against the target CAs II and VII as well as selectivity over the other ubiquitous and off-target isoform CA I The latter isozyme was feebly inhibited by (thio)phosphon(amid)ates 3−22 with KI values (inhibition constants) spanning in the high nanomolar up to low micromolar range To understand the molecular basis responsible for the inhibition efficiency of phosphonate/ phosphonamidate benzenesulfonamides against CA II and CA VII, the crystal structure of these two isoforms was solved in adduct with phenylphosphonic acid 3 This compound based on the ChemAxon software has a pKa value of 1.62 and, is assumed to bind the enzyme at physiological pH and in crystallization conditions in a deprotonated, nonchiral form. This might indicate that a CA II and/or VII inhibition of a certain intensity (KI values of (R)-7 against CAs II and VII dropped by 15 and 6 times, respectively, with respect to 7) is necessary to produce an action, which relieves neuropathic pain

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES