cgs-27023a and marimastat

The matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases involved in the degradation of the extracellular matrix. The MMPs have been implicated in the processes of tumor growth, invasion, and metastasis; are frequently overexpressed in malignant tumors; and have been associated with an aggressive malignant phenotype and adverse prognosis in patients with cancer. A number of MMP inhibitors are being developed for the treatment of cancer. The most extensively studied class of MMP inhibitors includes collagen peptidomimetics and nonpeptidomimetic inhibitors of the MMP active site, tetracycline derivatives, and bisphosphonates. The hydroxamate peptidomimetic inhibitor batimastat and its orally bioavailable analogue marimastat, which bind covalently to the zinc atom at the MMP-active site, were the first MMP inhibitors to be studied in detail. Marimastat is currently being studied in randomized clinical trials. The nonpeptidic MMP inhibitors were synthesized in an attempt to improve the oral bioavailability and pharmaceutical properties of the peptidic inhibitors. Several members of this class of compounds are undergoing evaluation in phase III clinical trials. The tetracyclines and, particularly, the nonantibiotic chemically modified tetracyclines, interfere with several aspects of MMP expression and activation and inhibit tumor growth and metastases in preclinical models. A representative agent of this class, Col-3, is currently undergoing phase I clinical trials. The development of the MMP inhibitors, like that of other targeted and predominantly antiproliferative compounds, poses a challenge because the paradigms that have governed the design of clinical oncology trials may not be relevant to this new class of agents. The anticipated need for long-term administration of these drugs, together with their cytostatic mechanism of action, will require novel clinical trial design strategies.

Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Agents; Biphenyl Compounds; Clinical Trials as Topic; Drugs, Investigational; Enzyme Inhibitors; Humans; Hydroxamic Acids; Imidazoles; Matrix Metalloproteinase Inhibitors; Neoplasms; Organic Chemicals; Phenylalanine; Phenylbutyrates; Protease Inhibitors; Pyrazines; Sulfonamides; Tetracycline; Tetracyclines; Thiophenes

Envenoming by the West African saw-scaled viper, Echis ocellatus resembles that of most vipers, in that it results in local blistering, necrosis and sometimes life-threatening systemic haemorrhage. While effective against systemic envenoming, current antivenoms have little or no effect against local tissue damage. The major mediators of local venom pathology are the zinc-dependant snake venom metalloproteinases (SVMPs). The high degree of structural and functional homology between SVMPs and their mammalian relatives the matrix metalloproteinases (MMPs) suggests that substrate/inhibitor interactions between these subfamilies are likely to be analogous. In this study, four recently developed MMP inhibitors (MMPIs) (Marimastat, AG-3340, CGS-270 23A and Bay-12 9566) are evaluated in addition to three metal ion chelators (EDTA, TPEN and BAPTA) for their ability to inhibit the haemorrhagic activities of the medically important E. ocellatus venom and one of its haemorrhagic SVMPs, EoVMP2. As expected, the metal ion chelators significantly inhibited the haemorrhagic activities of both whole E. ocellatus venom and EoVMP2, while the synthetic MMPIs show more variation in their efficacies. These variations suggest that individual MMPIs show specificity towards SVMPs and that their application to the neutralization of local haemorrhage may require a synthetic MMPI mixture, ensuring that a close structural component for each SVMP is represented.

Topics: Animals; Biphenyl Compounds; Chelating Agents; Chromatography, Gel; Chromatography, Liquid; Edetic Acid; Egtazic Acid; Ethylenediamines; Evaluation Studies as Topic; Hemorrhage; Hydroxamic Acids; Metalloproteases; Mice; Molecular Structure; Organic Chemicals; Phenylbutyrates; Protein Kinase Inhibitors; Pyrazines; Snake Bites; Statistics, Nonparametric; Sulfonamides; Viper Venoms

Topics: Antineoplastic Agents; Azepines; Biphenyl Compounds; Humans; Hydroxamic Acids; Metalloendopeptidases; Organic Chemicals; Phenylalanine; Phenylbutyrates; Protease Inhibitors; Pyrazines; Sulfonamides; Thiophenes