Sulfonamide Inhibitors of Human Carbonic Anhydrases Designed through a Three-Tails Approach: Improving Ligand/Isoform Matching and Selectivity of Action.

The "tail approach" has become a milestone in human carbonic anhydrase inhibitor (hCAI) design for various therapeutics, including antiglaucoma agents. Besides the classical hydrophobic/hydrophilic division of hCAs active site, several subpockets have been identified at the middle/outer active sites rim, which could be targeted to increase the CAI isoform selectivity. This postulate is explored here by three-tailed benzenesulfonamide CAIs (TTI) to fully exploit such amino acid differences among hCAs. In this proof-of-concept study, an extensive structure-activity relationship (SAR) study was carried out with 32 such benzenesulfonamides differing in tails combination that were assayed for hCAs I, II, IV, and XII inhibition. A structural study was undertaken by X-ray crystallography and in silico tools to assess the ligand/target interaction mode. The most active and selective inhibitors against isoforms implicated in glaucoma were assessed in a rabbit model of the disease achieving an intraocular pressure-lowering action comparable to the clinically used dorzolamide.

Discovery of ß-Adrenergic Receptors Blocker-Carbonic Anhydrase Inhibitor Hybrids for Multitargeted Antiglaucoma Therapy.

The combination of a ß-adrenergic receptors (AR) blocker and a carbonic anhydrase (CA, EC 4.2.1.1) inhibitor in eye drops formulations is one of the most clinically used treatment for glaucoma. A novel approach consisting of single-molecule, multitargeted compounds for the treatment of glaucoma is proposed here by designing compounds which concomitantly interact with the ß-adrenergic and CA targets. Most derivatives of the two series of benzenesulfonamides incorporating 2-hydroxypropylamine moieties reported here exhibited striking efficacy against the target hCA II and XII, whereas a subset of compounds also showed significant modulation of ß1- and ß2-ARs. X-ray crystallography studies provided rationale for the observed hCA inhibition. The best dual-agents decreased IOP more effectively than clinically used dorzolamide, timolol, and the combination of them in an animal model of glaucoma. The reported evidence supports the proof-of-concept of ß-ARs blocker-CAI hybrids for antiglaucoma therapy with an innovative mechanism of action.

Advances in Anti-Cancer Drug Development Targeting Carbonic Anhydrase IX and XII.

The microenvironment within a solid tumor is heterogeneous with regions being both acidic and hypoxic. As a result of this, cancer cells upregulate genes that allow survival in such environments. Some of these genes are pH regulatory factors, including carbonic anhydrase IX (CA IX) and in some cases XII (CA XII). CA IX helps to maintain normal cytoplasmic pH (pHi) while simultaneously contributing to the extracellular pH (pHe). CA XII is also thought to be responsible for stabilizing pHe at physiological conditions. Extracellular acidification of the tumor microenvironment promotes local invasion and metastasis while decreasing the effectiveness of adjuvant therapies, thus contributing to poor cancer clinical outcomes. In this review, we describe the properties of CA IX and CA XII that substantiate their potential use as anticancer targets. We also discuss the current status of CA isoform-selective inhibitor development and patents of CA IX/XII targeted inhibitors that show potential for treating aggressive tumors. Some of the recently published patents discussed include sulfonamide-based small molecule inhibitors including derivatives of boron cluster compounds; metal complexes of poly(carboxyl)amine-containing ligands; nitroi-midazole-, ureidosulfonamide-, and coumarin-based compounds; as well as G250 and A610 monoclonal antibodies for cancer treatment.

PC-SPES down-regulates COX-2 via inhibition of NF-kappaB and C/EBPbeta in non-small cell lung cancer cells.

Aberrant expression of COX-2 occurs in many types of malignancies including colon and lung cancers, and is implicated in development and progression of cancer. The molecular mechanisms associated with aberrant expression of COX-2 in lung cancer cells remain to be fully elucidated. In this study, we found that non-small cell lung cancer (NSCLC) NCI-H520 and NCI-H460 cells constitutively expressed COX-2 and produced prostaglandin E2 (PGE2) as measured by Western blotting and enzyme-linked immunosorbent assay (ELISA), respectively. Reporter assays showed that transcriptional regulation of COX-2 was blunted when either the NF-IL6 (C/EBPbeta) or nuclear factor-kappaB (NF-kappaB) binding site in the COX-2 promoter was mutated, suggesting that C/EBPbeta and NF-kappaB transcription factors have an important role in aberrant expression of COX-2 in these lung cancer cells. In addition, the eight herbal mixture PC-SPES (Lot. 5431219) caused growth arrest and apoptosis of NCI-H520 and NCI-H460 cells in association with blockade of NF-kappaB and down-regulation of C/EBPbeta, resulting in down-regulation of COX-2 and PGE2 in these cells. On the other hand, PC-SPES up-regulated the level of C/EBPbeta in these cells. Taken together, C/EBPbeta and NF-kappaB may be promising molecular targets for COX-2 inhibition in lung cancer cells. PC-SPES might be useful in the adjuvant setting for the treatment of individuals with resected NSCLC as well as other types of cancer in which COX-2 is activated.

Zinc-induced copper deficiency: a report of three cases initially recognized on bone marrow examination.

Copper deficiency is a rare cause of sideroblastic anemia and neutropenia that often is not suspected clinically. The morphologic findings in bone marrow, while not pathognomonic, are sufficiently characteristic to suggest the diagnosis, leading to further testing to establish the correct diagnosis. Excess zinc ingestion is among the causes of copper deficiency. We present 3 cases of zinc-induced copper deficiency in which the diagnosis first was suggested on the basis of bone marrow examination. The first patient was a 47-year-old man with a debilitating peripheral neuropathy that had progressed during the previous 18 months, mild anemia, and severe neutropenia. The second was a 21-year-old man receiving zinc supplementation for acrodermatitis enteropathica in whom moderate normocytic anemia and neutropenia developed. The third patient was a 42-year-old man with anemia, severe neutropenia, and a peripheral neuropathy that had progressed during 8 months. The bone marrow findings in all cases suggested copper deficiency, which was confirmed by further laboratory testing and determined to be due to zinc excess. The morphologic features, clinical manifestations, differential diagnosis, and pathogenetic mechanisms are discussed.