dorzolamide and Stomach-Neoplasms

DNA clones for the beta-class carbonic anhydrase (CA, EC 4.2.1.1) of Helicobactor pylori (hpbetaCA) were obtained. A recombinant hpbetaCA protein lacking the N-terminal 15-amino acid residues was produced and purified, representing a catalytically efficient CA. hpbetaCA was strongly inhibited (K(I)s in the range of 24-45 nM) by many sulfonamides/sulfamates, among which acetazolamide, ethoxzolamide, topiramate, and sulpiride, all clinically used drugs. The dual inhibition of alpha- and/or beta-class CAs of H. pylori might represent a useful alternative for the management of gastritis/gastric ulcers, as well as gastric cancer. This is also the first study showing that a bacterial beta-CA can be a drug target.

Topics: Amino Acid Sequence; Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Chemistry, Pharmaceutical; Cloning, Molecular; Drug Design; Enzyme Inhibitors; Helicobacter pylori; Humans; Molecular Sequence Data; Recombinant Proteins; Sequence Homology, Amino Acid; Stomach Neoplasms; Stomach Ulcer; Sulfonamides

We have cloned and sequenced Helicobacter pylori alpha-class carbonic anhydrase (hpCA) from patients with different gastric mucosal lesions, including gastritis (n=15), ulcer (n=6), and cancer (n=16). Although several polymorphisms were newly identified such as 12Ala, 13Thr, 16Ile, and 168Phe, there was no significant relevance of any polymorphism with gastric mucosal lesion types. A library of sulfonamides/sulfamates has been investigated for the inhibition of hpCA, whereas new derivatives have been obtained by attaching 4-tert-butyl-phenylcarboxamido/sulfonamido tails to benzenesulfonamide/1,3,4-thiadiazole-2-sulfonamide scaffolds. All types of activity for inhibition of hpCA have been detected. Dorzolamide and simple 4-substituted benzenesulfonamides were weak inhibitors (KI 873-4360 nM). Sulfanilamide, orthanilamide, some of their derivatives, and indisulam showed better activity (KI 413-640 nM), whereas most of the clinically used inhibitors, such as methazolamide, ethoxzolamide, dichlorophenamide, brinzolamide, topiramate, zonisamide, etc., acted as medium-potency inhibitors (KI 105-378 nM). Some potent hpCA inhibitors were detected too (KI 12-84 nM) among acetazolamide, 4-amino-6-chloro-1,3-benzenedisulfonamide and some newly designed compounds incorporating lipophilic tails. Some of the newly prepared derivatives had selectivity ratios for inhibiting hpCA over hCA II in the range of 1.25-3.48, showing thus some selectivity for inhibiting the bacterial enzyme. Since hpCA is essential for the survival of the pathogen in acid, it might be used as a new pharmacologic tool in the management of drug-resistant H. pylori.

Topics: Amino Acid Sequence; Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Cloning, Molecular; DNA, Bacterial; Gastric Mucosa; Gastritis; Helicobacter pylori; Humans; Molecular Sequence Data; Polymorphism, Genetic; Stomach Neoplasms; Stomach Ulcer; Sulfonamides; Sulfonic Acids