ABSTRACT
As a continuation of our SAR studies of dipeptidyl aspartyl-fmk as caspase inhibitors, we explored the replacement of the P(2) amino acid by a 2-aminoaryl acid or other non-natural amino acids. Several of these compounds, such as 6l and 6p, were found to have good activities with inhibition potencies of around 100 nM in a caspase-3 enzyme assay. EP1113, Z-Val-(2-aminobenzoyl)-Asp-fmk (9b), is identified as a potent broad-spectrum caspase inhibitor with IC(50) values of 6-60 nM in different caspases. EP1113 also has good activity in a cell apoptosis protection assay.
Subject(s)
Amino Acids/chemistry , Benzamides/pharmacology , Caspase Inhibitors , Dipeptides/pharmacology , Ketones/pharmacology , Molecular Mimicry , Apoptosis/drug effects , Aspartic Acid/chemistry , Benzamides/chemistry , Caspases/chemistry , Dipeptides/chemical synthesis , Dipeptides/chemistry , Drug Evaluation, Preclinical , Fluorine/chemistry , HeLa Cells , Humans , Inhibitory Concentration 50 , Ketones/chemistry , Molecular Structure , Structure-Activity RelationshipABSTRACT
A novel set of azabicyclic aryl amides have been identified as potent and selective agonists of the alpha7 nAChR. A two-pronged approach was taken to improve the potential hERG liability of previously disclosed alpha7 nAChR agonist, PNU-282,987, while maintaining the compound's other desirable pharmacological properties. The first approach involved further exploration of the aryl carboxylic acid fragment of PNU-282,987, while the second approach focused on modification of the azabicyclic amine portion of PNU-282,987. The best compounds from each series are characterized by rapid brain penetration, good oral bioavailability in rat, and demonstrate in vivo efficacy in a rat P50 auditory sensory gating assay. At least one analog from each series (1h, 1o, 2a, 9a, and 18a) shows an improved hERG safety profile over PNU-282,987.
Subject(s)
Brain/metabolism , Drug Design , Nicotinic Agonists/pharmacology , Receptors, Nicotinic/chemistry , Animals , Bungarotoxins , Cells, Cultured , Electrophysiology , Evoked Potentials, Auditory/drug effects , Hippocampus/drug effects , Ion Channel Gating/drug effects , Molecular Structure , Motor Activity/drug effects , Neurons/drug effects , Nicotinic Agonists/chemical synthesis , Nicotinic Agonists/chemistry , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Synapses/drug effects , Synapses/physiology , alpha7 Nicotinic Acetylcholine ReceptorABSTRACT
N-[(3R)-1-Azabicyclo[2.2.2]oct-3-yl]furo[2,3-c]pyridine-5-carboxamide (14, PHA-543,613), a novel agonist of the alpha7 neuronal nicotinic acetylcholine receptor (alpha7 nAChR), has been identified as a potential treatment of cognitive deficits in schizophrenia. Compound 14 is a potent and selective alpha7 nAChR agonist with an excellent in vitro profile. The compound is characterized by rapid brain penetration and high oral bioavailability in rat and demonstrates in vivo efficacy in auditory sensory gating and, in an in vivo model to assess cognitive performance, novel object recognition.
Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis , Cognition Disorders/drug therapy , Nicotinic Agonists/chemical synthesis , Nootropic Agents/chemical synthesis , Quinuclidines/chemical synthesis , Receptors, Nicotinic/metabolism , Schizophrenia/drug therapy , Animals , Biological Availability , Brain/metabolism , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Drug Stability , Ether-A-Go-Go Potassium Channels/drug effects , Evoked Potentials, Auditory/drug effects , Humans , In Vitro Techniques , Learning/drug effects , Male , Memory/drug effects , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Neurons/drug effects , Neurons/physiology , Nicotinic Agonists/pharmacokinetics , Nicotinic Agonists/pharmacology , Nootropic Agents/pharmacokinetics , Nootropic Agents/pharmacology , Patch-Clamp Techniques , Quinuclidines/chemistry , Quinuclidines/pharmacology , Radioligand Assay , Rats , Rats, Sprague-Dawley , Receptors, Nicotinic/physiology , Recognition, Psychology/drug effects , Stereoisomerism , Structure-Activity Relationship , alpha7 Nicotinic Acetylcholine ReceptorABSTRACT
As a continuation of our efforts to discover and develop the apoptosis inducing 4-aryl-4H-chromenes as novel anticancer agents, we explored the SAR of 4-aryl-4H-chromenes with modifications at the 7- and 5-, 6-, 8-positions. It was found that a small hydrophobic group, such as NMe2, NH2, NHEt, and OMe, is preferred at the 7-position. Di-substitution at either the 5,7-positions or the 6,7-positions generally led to a large decrease in potency. Di-substitution at the 7,8-positions, in general, was found to result in potent compounds. 7-NMe2, 7-NHEt, 7-OMe, and 7,8-di-NH2 analogs were found to have similar SAR for the 4-aryl group, and several 7-substituted and 7,8-di-substituted analogs were found to have similar potencies as the lead compound MX58151 (2a) both as caspase activators and inhibitors of cell proliferation.
Subject(s)
Antineoplastic Agents/chemical synthesis , Apoptosis/drug effects , Benzopyrans/chemical synthesis , Antineoplastic Agents/pharmacology , Benzopyrans/pharmacology , Caspases/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Drug Evaluation, Preclinical/methods , Enzyme Activation/drug effects , Humans , Hydrophobic and Hydrophilic Interactions , Structure-Activity RelationshipABSTRACT
As a continuation of our SAR studies of dipeptidyl aspartyl-fmk as caspase inhibitors, we explored the replacement of the P2 alpha-amino acid by a peptidomimetic alpha-hydroxy acid. These alpha-carbamoyl-alkylcarbonyl-aspartyl fluoromethylketones were found to be potent caspase inhibitors, and the SAR of these compounds is similar to the corresponding dipeptidyl aspartyl-fmk. MX1153, (S)-3-methyl-2-(phenylcarbamoyl)butanoyl-Asp-fmk, is identified as a potent broad-spectrum caspase inhibitor, and is selective for caspases versus other proteases. MX1153 also has good activity in the cell apoptosis protection assays and is active in the mouse liver apoptosis model.
Subject(s)
Amino Acids/chemistry , Caspase Inhibitors , Cysteine Proteinase Inhibitors/chemical synthesis , Hydroxy Acids/chemistry , Ketones/chemical synthesis , Animals , Apoptosis/drug effects , Aspartic Acid/chemistry , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/pharmacology , Dipeptides/chemistry , Humans , Ketones/chemistry , Ketones/pharmacology , Mice , Molecular Structure , Structure-Activity RelationshipABSTRACT
By applying a novel cell- and caspase-based HTS assay, 2-amino-3-cyano-7-(dimethylamino)-4-(3-methoxy-4,5-methylenedioxyphenyl)-4H-chromene (1a) has been identified as a potent apoptosis inducer. Compound 1a was found to induce nuclear fragmentation and PARP cleavage, as well as to arrest cells at the G(2)/M stage and to induce apoptosis as determined by the flow cytometry analysis assay in multiple human cell lines (e.g. Jurkat, T47D). Through structure-activity relationship (SAR) studies of the 4-aryl group, a 4- and 7-fold increase in potency was obtained from the screening hit 1a to the lead compounds 2-amino-4-(3-bromo-4,5-dimethoxyphenyl)-3-cyano-7-(dimethylamino)-4H-chromene (1c) and 2-amino-3-cyano-7-(dimethylamino)-4-(5-methyl-3-pyridyl)-4H-chromene (4e), with an EC(50) of 19 and 11 nM in the caspase activation assay in T47D breast cancer cells, respectively. The 2-amino-4-aryl-3-cyano-7-(dimethylamino)-4H-chromenes also were found to be highly active in the growth inhibition MTT assay, with GI(50) values in the low nanomolar range for compound 1c. Significantly, compound 1c was found to have a GI(50) value of 2 nM in the paclitaxel resistant, p-glycoprotein overexpressed, MES-SA/DX5 tumor cells. Functionally, compound 1c was found to be a potent inhibitor of tubulin polymerization and to effectively inhibit the binding of colchicine to tubulin. These results confirm that the cell-based caspase activation assay is a powerful tool for the discovery of potent apoptosis inducers and suggest that the 4-aryl-4H-chromenes have the potential to be developed into future anticancer agents.
Subject(s)
Antineoplastic Agents/chemistry , Apoptosis , Benzopyrans/chemistry , Caspases/metabolism , Dioxoles/chemistry , Antineoplastic Agents/pharmacology , Benzopyrans/pharmacology , Biopolymers , Cell Line, Tumor , Cell Nucleus/drug effects , Cell Proliferation/drug effects , Dioxoles/pharmacology , Drug Screening Assays, Antitumor , Enzyme Activation , Humans , Poly(ADP-ribose) Polymerases/metabolism , Structure-Activity Relationship , Tubulin/chemistryABSTRACT
This article describes the synthesis and biological evaluation of a group of N-protected Val-Asp-fmk as caspase inhibitors. The protecting group was found to contribute to caspase-3 inhibiting activity, and compounds with a large group such as Cbz are more active than compounds with a small group such as Ac. Compounds with more hydrophobic protecting groups were found to be more active in cell apoptosis protection assays, probably due to increased cell permeability. MX1122, 2,4-di-Cl-Cbz-Val-Asp-fmk, is identified as a potent broad-spectrum caspase inhibitor and is selective for caspases versus other proteases, with good activity in the cell apoptosis protection assays as well as good efficacy in the mouse liver apoptosis model.
Subject(s)
Amino Acid Chloromethyl Ketones/chemical synthesis , Caspase Inhibitors , Dipeptides/chemical synthesis , Ketones/chemical synthesis , Protease Inhibitors/chemical synthesis , Amino Acid Chloromethyl Ketones/chemistry , Amino Acid Chloromethyl Ketones/pharmacology , Animals , Apoptosis/drug effects , Caspase 3 , Caspases/metabolism , Dipeptides/chemistry , Dipeptides/pharmacology , HeLa Cells , Humans , Ketones/chemistry , Ketones/pharmacology , Liver/cytology , Liver/drug effects , Liver/enzymology , Mice , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Structure-Activity Relationship , Survival RateABSTRACT
By applying a novel cell- and caspase-based HTS assay, a series of N-phenyl nicotinamides has been identified as a new class of potent inducers of apoptosis. Through SAR studies, a 20-fold increase in potency was achieved from a screening hit N-(4-methoxy-2-nitrophenyl)pyridine-3-carboxamide (1) to lead compound 6-methyl-N-(4-ethoxy-2-nitrophenyl)pyridine-3-carboxamide (10), with an EC(50) of 0.082 microM in the caspase activation assay in T47D breast cancer cells. The N-phenyl nicotinamides also were found to be active in the growth inhibition assay where compound 10 had a GI(50) value of 0.21 microM in T47D cells. More importantly, compound 10 was found to be equipotent in MES-SA cells and paclitaxel-resistant, p-glycoprotein overexpressed MES-SA/DX5 cells. Compounds 1 and 6-chloro-N-(4-ethoxy-2-nitrophenyl)pyridine-3-carboxamide (8), a more potent analogue, were found to arrest T47D cells in G(2)/M phase of the cell cycle followed by induction of apoptosis as measured by flow cytometry. Compound 8, which was more potent than 1 in the caspase activation assay, also was found to be more potent in G(2)/M arrest and apoptosis assay. These data confirm that the cell-based caspase activation assay is useful for screening for inducers of apoptosis, as well as for SAR studies and lead optimization. Upon further characterization, N-phenyl nicotinamides were found to be inhibitors of microtubule polymerization in vitro. The identification of N-phenyl nicotinamides as a novel series of inducers of apoptosis demonstrates that our cell- and caspase-based HTS assay is useful for the discovery and optimization of potentially novel anticancer agents.
