Showing papers by "Alan P. Kozikowski published in 2009"

HDAC6 is a target for protection and regeneration following injury in the nervous system

Abstract: Central nervous system (CNS) trauma can result in tissue disruption, neuronal and axonal degeneration, and neurological dysfunction. The limited spontaneous CNS repair in adulthood and aging is often insufficient to overcome disability. Several investigations have demonstrated that targeting HDAC activity can protect neurons and glia and improve outcomes in CNS injury and disease models. However, the enthusiasm for pan-HDAC inhibition in treating neurological conditions is tempered by their toxicity toward a host of CNS cell types -a biological extension of their anticancer properties. Identification of the HDAC isoform, or isoforms, that specifically mediate the beneficial effects of pan-HDAC inhibition could overcome this concern. Here, we show that pan-HDAC inhibition not only promotes neuronal protection against oxidative stress, a common mediator of injury in many neurological conditions, but also promotes neurite growth on myelin-associated glycoprotein and chondroitin sulfate proteoglycan substrates. Real-time PCR revealed a robust and selective increase in HDAC6 expression due to injury in neurons. Accordingly, we have used pharmacological and genetic approaches to demonstrate that inhibition of HDAC6 can promote survival and regeneration of neurons. Consistent with a cytoplasmic localization, the biological effects of HDAC6 inhibition appear transcription-independent. Notably, we find that selective inhibition of HDAC6 avoids cell death associated with pan-HDAC inhibition. Together, these findings define HDAC6 as a potential nontoxic therapeutic target for ameliorating CNS injury characterized by oxidative stress-induced neurodegeneration and insufficient axonal regeneration.

A series of halogenated heterodimeric inhibitors of prostate specific membrane antigen (PSMA) as radiolabeled probes for targeting prostate cancer.

Abstract: Prostate specific membrane antigen (PSMA) is a validated molecular marker for prostate cancer. A series of glutamate-urea (Glu-urea-X) heterodimeric inhibitors of PSMA were designed and synthesized where X = epsilon-N-(o-I, m-I, p-I, p-Br, o-Cl, m-Cl, p-Cl, p-F, H)-benzyl-Lys and epsilon-(p-I, p-Br, p-Cl, p-F, H)-phenylureido-Lys. The affinities for PSMA were determined by screening in a competitive binding assay. PSMA binding of the benzyllysine series was significantly affected by the nature of the halogen substituent (IC(50) values, Cl < I = Br << F = H) and the ring position of the halogen atom (IC(50) values, p-I < o-I << m-I). The halogen atom had little affect on the binding affinity in the para substituted phenylureido-Lys series. Two lead iodine compounds were radiolabeled with (123)I and (131)I and demonstrated specific PSMA binding on human prostate cancer cells, warranting evaluation as radioligands for the detection, staging, and monitoring of prostate cancer.

Structure-activity relationships for a series of quinoline-based compounds active against replicating and nonreplicating Mycobacterium tuberculosis.

Abstract: Tuberculosis (TB) remains as a global pandemic that is aggravated by a lack of health care, the spread of HIV, and the emergence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) strains New anti-TB drugs are urgently required to shorten the long 6−12 month treatment regimen and to battle drug-resistant Mtb strains We have identified several potent quinoline-based anti-TB compounds, bearing an isoxazole containing side-chain The most potent compounds, 7g and 13, exhibited submicromolar activity against the replicating bacteria (R-TB), with minimum inhibitory concentrations (MICs) of 077 and 095 μM, respectively In general, these compounds also had micromolar activity against the nonreplicating persistent bacteria (NRP-TB) and did not show toxicity on Vero cells up to 128 μM concentration Compounds 7g and 13 were shown to retain their anti-TB activity against rifampin, isoniazid, and streptomycin resistant Mtb strains The results suggest that quinoline−isoxazole-based an

The amino terminus of tau inhibits kinesin-dependent axonal transport: Implications for filament toxicity

Abstract: The neuropathology of Alzheimer's disease (AD) and other tauopathies is characterized by filamentous deposits of the microtubule-associated protein tau, but the relationship between tau polymerization and neurotoxicity is unknown. Here, we examined effects of filamentous tau on fast axonal transport (FAT) using isolated squid axoplasm. Monomeric and filamentous forms of recombinant human tau were perfused in axoplasm, and their effects on kinesin- and dynein-dependent FAT rates were evaluated by video microscopy. Although perfusion of monomeric tau at physiological concentrations showed no effect, tau filaments at the same concentrations selectively inhibited antero-grade (kinesin-dependent) FAT, triggering the release of conventional kinesin from axoplasmic vesicles. Pharmacological experiments indicated that the effect of tau filaments on FAT is mediated by protein phosphatase 1 (PP1) and glycogen synthase kinase-3 (GSK-3) activities. Moreover, deletion analysis suggested that these effects depend on a conserved 18-amino-acid sequence at the amino terminus of tau. Interestingly, monomeric tau isoforms lacking the C-terminal half of the molecule (including the microtubule binding region) recapitulated the effects of full-length filamentous tau. Our results suggest that pathological tau aggregation contributes to neurodegeneration by altering a regulatory pathway for FAT.

From a Natural Product Lead to the Identification of Potent and Selective Benzofuran-3-yl-(indol-3-yl)maleimides as Glycogen Synthase Kinase 3β Inhibitors That Suppress Proliferation and Survival of Pancreatic Cancer Cells

Abstract: Recent studies have demonstrated that glycogen synthase kinase 3beta (GSK-3beta) is overexpressed in human colon and pancreatic carcinomas, contributing to cancer cell proliferation and survival. Here, we report the design, synthesis, and biological evaluation of benzofuran-3-yl-(indol-3-yl)maleimides, potent GSK-3beta inhibitors. Some of these compounds show picomolar inhibitory activity toward GSK-3beta and an enhanced selectivity against cyclin-dependent kinase 2 (CDK-2). Selected GSK-3beta inhibitors were tested in the pancreatic cancer cell lines MiaPaCa-2, BXPC-3, and HupT3. We determined that some of these compounds, namely compounds 5, 6, 11, 20, and 26, demonstrate antiproliferative activity against some or all of the pancreatic cancer cells at low micromolar to nanomolar concentrations. We found that the treatment of pancreatic cancer cells with GSK-3beta inhibitors 5 and 26 resulted in suppression of GSK-3beta activity and a distinct decrease of the X-linked inhibitor of apoptosis (XIAP) expression, leading to significant apoptosis. The present data suggest a possible role for GSK-3beta inhibitors in cancer therapy, in addition to their more prominent applications in CNS disorders.

Novel Inhibitors of Human Histone Deacetylase (HDAC) Identified by QSAR Modeling of Known Inhibitors, Virtual Screening, and Experimental Validation

Abstract: Inhibitors of histone deacetylases (HDACIs) have emerged as a new class of drugs for the treatment of human cancers and other diseases because of their effects on cell growth, differentiation, and apoptosis. In this study we have developed several quantitative structure−activity relationship (QSAR) models for 59 chemically diverse histone deacetylase class 1 (HDAC1) inhibitors. The variable selection k nearest neighbor (kNN) and support vector machines (SVM) QSAR modeling approaches using both MolconnZ and MOE chemical descriptors generated from two-dimensional rendering of compounds as chemical graphs have been employed. We have relied on a rigorous model development workflow including the division of the data set into training, test, and external sets and extensive internal and external validation. Highly predictive QSAR models were generated with leave-one-out cross-validated (LOO-CV) q2 and external R2 values as high as 0.80 and 0.87, respectively, using the kNN/MolconnZ approach and 0.93 and 0.87, re...

Putting the ‘HAT’ back on survival signalling: the promises and challenges of HDAC inhibition in the treatment of neurological conditions

Abstract: Decreased histone acetyltransferase activity and transcriptional dysfunction have been implicated in almost all neurodegenerative conditions. Increasing net histone acetyltransferase activity through inhibition of the histone deacetylases (HDACs) has been shown to be an effective strategy to delay or halt progression of neurological disease in cellular and rodent models. These findings have provided firm rationale for Phase I and Phase II clinical trials of HDAC inhibitors in Huntington's disease, spinal muscular atrophy, and Freidreich's ataxia. In this review, we discuss the current findings and promise of HDAC inhibition as a strategy for treating neurological disorders. Despite the fact that HDAC inhibitors are in an advanced stage of development, we suggest other approaches to modulating HDAC function that may be less toxic and more efficacious than the canonical agents developed so far.

Searching for New Cures for Tuberculosis: Design, Synthesis, and Biological Evaluation of 2-Methylbenzothiazoles

Abstract: The actual development and clinical use of new therapeutics for tuberculosis (TB) have remained stagnant for years because of the complexity of the disease process, the treatment of which at present requires the administration of drug combinations over a 6 month period. There is thus an urgent need for the discovery and development of novel, more active, and less toxic anti-TB agents. In this study, we report on the chemistry and biology of a series of potent 5-(2-methylbenzothiazol-5-yloxymethyl)isoxazole-3-carboxamide derivatives, which proved to be active against replicating Mycobacterium tuberculosis (Mtb) H37Rv. The most potent compounds 7j and 7s were found to inhibit Mtb growth at micromolar concentrations, with MIC values of 1.4 and 1.9 μM, respectively. Impressively, all active compounds were nontoxic toward Vero cells (IC50 > 128 μM). Moreover, the best of these compounds were also tested against protozoan parasites, and some of these compounds were found to show activity, especially against Pla...

Selective 5-Hydroxytryptamine 2C Receptor Agonists Derived from the Lead Compound Tranylcypromine: Identification of Drugs with Antidepressant-Like Action

Abstract: We report here the design, synthesis, and pharmacological properties of a series of compounds related to tranylcypromine (9), which itself was discovered as a lead compound in a high-throughput screening campaign. Starting from 9, which shows modest activity as a 5-HT2C agonist, a series of 1-aminomethyl-2-phenylcyclopropanes was investigated as 5-HT2C agonists through iterative structural modifications. Key pharmacophore feature of this new class of ligands is a 2-aminomethyl-trans-cyclopropyl side chain attached to a substituted benzene ring. Among the tested compounds, several were potent and efficacious 5-HT2C receptor agonists with selectivity over both 5-HT2A and 5-HT2B receptors in functional assays. The most promising compound is 37, with 120- and 14-fold selectivity over 5-HT2A and 5-HT2B, respectively (EC50 = 585, 65, and 4.8 nM at the 2A, 2B, and 2C subtypes, respectively). In animal studies, compound 37 (10−60 mg/kg) decreased immobility time in the mouse forced swim test.

Studies of Benzamide- and Thiol-Based Histone Deacetylase Inhibitors in Models of Oxidative-Stress-Induced Neuronal Death: Identification of Some HDAC3-Selective Inhibitors

Abstract: Less stress: We compare three structurally different classes of histone deacetylase (HDAC) inhibitors that contain benzamide, hydroxamate, or thiol groups as the zinc binding group (ZBG) for their ability to protect cortical neurons in culture from cell death induced by oxidative stress. Novel benzamide-based ligands selectively inhibit HDAC3 but provide no neuroprotection in the HCA–cortical neuron model of oxidative stress. We compare three structurally different classes of histone deacetylase (HDAC) inhibitors that contain benzamide, hydroxamate, or thiol groups as the zinc binding group (ZBG) for their ability to protect cortical neurons in culture from cell death induced by oxidative stress. This study reveals that none of the benzamide-based HDAC inhibitors (HDACIs) provides any neuroprotection whatsoever, in distinct contrast to HDACIs that contain other ZBGs. Some of the sulfur-containing HDACIs, namely the thiols, thioesters, and disulfides present modest neuroprotective activity but show toxicity at higher concentrations. Taken together, these data demonstrate that the HDAC6-selective mercaptoacetamides that were reported previously provide the best protection in the homocysteic acid model of oxidative stress, thus further supporting their study in animal models of neurodegenerative diseases.

Synthesis, biological evaluation, and structure-activity relationships for 5-[(E)-2-arylethenyl]-3-isoxazolecarboxylic acid alkyl ester derivatives as valuable antitubercular chemotypes.

Abstract: Tuberculosis (TB), mostly caused by Mycobacterium tuberculosis (Mtb), is one of the leading causes of death from infectious disease worldwide. Its coinfection with HIV and the emergence of multidru...

Searching for Disease Modifiers—PKC Activation and HDAC Inhibition—A Dual Drug Approach to Alzheimer's Disease that Decreases Aβ Production while Blocking Oxidative Stress

Abstract: A series of benzolactam compounds were synthesized, some of which caused a concentration-dependent increase in sAPPalpha and decrease in Abeta production in the concentration range of 0.1-10 microM. Moreover, some compounds showed neuroprotective effects in the 10-20 microM range in the HCA cortical neuron model of oxidative stress and no toxicity in measurements of neuron viability by MTT assay, even at the highest concentrations tested (20 microM). Alzheimer's disease (AD) is a well-studied neurodegenerative process characterized by the presence of amyloid plaques and neurofibrillary tangles. In this study, a series of protein kinase C (PKC) activators were investigated, some of which also exhibit histone deacetylase (HDAC) inhibitory activity, under the hypothesis that such compounds might provide a new path forward in the discovery of drugs for the treatment of AD. The PKC-activating properties of these drugs were expected to enhance the alpha-secretase pathway in the processing of amyloid precursor protein (APP), while their HDAC inhibition was anticipated to confer neuroprotective activity. We found that benzolactams 9 and 11-14 caused a concentration-dependent increase in sAPPalpha and decrease in beta-amyloid (Abeta) production in the concentration range of 0.1-10 microM, consistent with a shift of APP metabolism toward the alpha-secretase-processing pathway. Moreover, compounds 9-14 showed neuroprotective effects in the 10-20 microM range in the homocysteate (HCA) cortical neuron model of oxidative stress. In parallel, we found that the most neuroprotective compounds caused increased levels of histone acetylation (H4), thus indicating their likely ability to inhibit HDAC activity. As the majority of the compounds studied also show nanomolar binding affinities for PKC, we conclude that it is possible to design, de novo, agents that combine both PKC-activating properties along with HDAC inhibitory properties. Such agents would be capable of modulating amyloid processing while showing neuroprotection. These findings may offer a new approach to therapies that exhibit disease-modifying effects, as opposed to symptomatic relief, in the treatment of AD.

Chemistry and pharmacology of nicotinic ligands based on 6-[5-(azetidin-2-ylmethoxy)pyridin-3-yl]hex-5-yn-1-ol (AMOP-H-OH) for possible use in depression.

Abstract: AMOP-H-OH (sazetidine-A; 6-[5-(azetidin-2-ylmethoxy)pyridin-3-yl]hex-5-yn-1-ol) and some sulfur-bearing analogues were tested for their activities in vitro against human alpha4beta2-, alpha4beta4-, alpha3beta4*- and alpha1*-nicotinic acetylcholine receptors (nAChRs). AMOP-H-OH was also assessed in an antidepressant efficacy model. AMOP-H-OH and some of its analogues have high potency and selectivity for alpha4beta2-nAChRs over other nAChR subtypes. Effects are manifested as partial agonism, perhaps reflecting selectivity for high sensitivity (alpha4)(3)(beta2)(2)-nAChRs. More prolonged exposure to AMOP-H-OH and its analogues produces inhibition of subsequent responses to acute challenges with full nicotinic agonists, again selectively for alpha4beta2-nAChRs over other nAChR subtypes. The inhibition is mediated either via antagonism or desensitization of nAChR function, but the degree of inhibition of alpha4beta2-nAChRs is limited by the partial agonist activity of the drugs. Certain aspects of the in vitro pharmacology suggest that AMOP-H-OH and some of its analogues have a set of binding sites on alpha4beta2-nAChRs that are distinct from those for full agonists. The in vitro pharmacological profile suggests that peripheral side effects of AMOP-H-OH or its analogues would be minimal and that their behavioral effects would be dominated by central nAChR actions. AMOP-H-OH also has profound and high potency antidepressant-like effects in the forced swim test. The net action of prolonged exposure to AMOP-H-OH or its analogues, as for nicotine, seems to be a selective decrease in alpha4beta2-nAChR function. Inactivation of nAChRs may be a common neurochemical endpoint for nicotine dependence, its treatment, and some of its manifestations, including relief from depression.

Use of molecular modeling, docking, and 3D-QSAR studies for the determination of the binding mode of benzofuran-3-yl-(indol-3-yl)maleimides as GSK-3β inhibitors

Abstract: Molecular modeling and docking studies along with three-dimensional quantitative structure relationships (3D-QSAR) studies have been used to determine the correct binding mode of glycogen synthase kinase 3beta (GSK-3beta) inhibitors. The approaches of comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) are used for the 3D-QSAR of 51 substituted benzofuran-3-yl-(indol-3-yl)maleimides as GSK-3beta inhibitors. Two binding modes of the inhibitors to the binding site of GSK-3beta are investigated. The binding mode 1 yielded better 3D-QSAR correlations using both CoMFA and CoMSIA methodologies. The three-component CoMFA model from the steric and electrostatic fields for the experimentally determined pIC(50) values has the following statistics: R(2)(cv) = 0.386 nd SE(cv) = 0.854 for the cross-validation, and R(2) = 0.811 and SE = 0.474 for the fitted correlation. F (3,47) = 67.034, and probability of R(2) = 0 (3,47) = 0.000. The binding mode suggested by the results of this study is consistent with the preliminary results of X-ray crystal structures of inhibitor-bound GSK-3beta. The 3D-QSAR models were used for the estimation of the inhibitory potency of two additional compounds.

Benzofuran-3-yl(indol-3-yl) maleimides as potent GSK3 inhibitors

Abstract: Compounds of formula: and pharmaceutically acceptable salts, esters and solvates thereof, where variables are defined in the specification, useful generally as inhibitors of protein kinases and particularly useful for inhibition of GSK-3. Pharmaceutically compositions and medicaments containing a compound of the invention are provided. The invention provides methods of treatment of protein kinase-related disease, disorders or conditions. The invention provides methods of treatment of GSK-3-related diseases, disorders or conditions. More specifically, methods of treatment of bipolar disorder, including mania, schizophrenia, stroke, epilepsy, motor neuron disease, cranial or spinal trauma, neurodegenerative disorders, including multiple sclerosis (MS), Alzheimer's disease, Fragile X syndrome, autism, Huntington's disease, Parkinson's disease, amylotrophic lateral sclerosis (ALS), AIDS-associated dementia, diabetes, particularly type II diabetes, cardiomycete hypertrophy, reperfusion/ischemia, cancer, particularly colorectal cancer, pancreatic cancer, allergies and/or asthma and hair loss or baldness.

Stereoselective HDAC inhibition from cysteine-derived zinc-binding groups.

Abstract: A series of small-molecule histone deacetylase (HDAC) inhibitors, which feature zinc binding groups derived from cysteine, were synthesized. These inhibitors were tested against multiple HDAC isoforms, and the most potent, compound 10, was determined to have IC(50) values below 1 microM. The compounds were also tested in a cellular assay of oxidative stress-induced neurodegeneration. Many of the inhibitors gave near-complete protection against cell death at 10 microM without the neurotoxicity seen with hydroxamic acid-based inhibitors, and were far more neuroprotective than HDAC inhibitors currently in clinical trials. Both enantiomers of cysteine were used in the synthesis of a variety of novel zinc-binding groups (ZBGs). Derivatives of L-cysteine were active in the HDAC inhibition assays, while the derivatives of D-cysteine were inactive. Notably, the finding that both the D- and L-cysteine derivatives were active in the neuroprotection assays suggests that multiple mechanisms are working to protect the neurons from cell death. Molecular modeling was employed to investigate the differences in inhibitory activity between the HDAC inhibitors generated from the two enantiomeric forms of cysteine.

Nicotinic acetylcholine receptor ligands and the uses thereof

Abstract: The invention relates to pyridinyl nicotinic acetylcholine receptor ligands, compositions comprising an effective amount of a pyridinyl nicotinic acetylcholine receptor ligand and methods to treat or prevent a condition, such as depression and nicotine dependence, comprising administering to an animal in need thereof an effective amount of a pyridinyl nicotinic acetylcholine receptor ligand.