We report the synthesis of novel 1:1 Schiff base copper complexes of quinoline-2-carboxaldehyde showing dose-dependent, antiproliferative, and proapoptotic activity in PC-3 and LNCaP prostate cancer cells. We found that quinoline thiosemicarbazone 2 (FPA-137) was the most potent and inhibited proteosome activity in intact human prostate cancer PC-3 and LNCaP cells (IC50 of 4 and 3.2 microM, respectively) compared to clioquinol and pyrrolidine dithiocarbamate (IC50 of 10 and 20 microM), supporting the novelty of 2.

A novel homologous series of bis(carbonyl)amidothiadiazole sulfonamides has been synthesized for structure-activity relationship studies, and initial characterization has been performed. The goal was synthesis of thiadiazole derivatives with appropriate lipid and water solubilities for utility as topically (corneal application) active carbonic anhydrase (CA) inhibitors. This series has solubility properties and pKa which bracket those of acetazolamide--the prototypical CA inhibitor. All of these compounds are active as in vitro CA inhibitors, and are 10-25% as potent as acetazolamide as in vitro enzyme inhibitors. Two of these compounds act as ocular hypotensive agents after topical application of a single dose to the corneas of normotensive New Zealand albino rabbits. The efficacy of the lead compound of this series (in this one model) is approximately equivalent to that of topical CA inhibitors that are presently in clinical trial. None of these novel compounds reacts to an appreciable extent with free sulfhydryl groups (a predictor of toxicity). This family of compounds will be useful for future studies of ocular pharmacokinetics, as well as ocular and systemic effects of topical administration of CA inhibitors. These and future studies may lead to development of thiadiazole sulfonamides useful in the management of glaucoma.

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