ABSTRACT
The adenosinergic pathway represents an attractive new therapeutic approach in cancer immunotherapy. In this pathway, ecto-5-nucleotidase CD73 has the unique function of regulating production of immunosuppressive adenosine (ADO) through the hydrolysis of AMP. CD73 is overexpressed in many cancers, resulting in elevated levels of ADO that correspond to poor patient prognosis. Therefore, reducing the level of ADO via inhibition of CD73 is a potential strategy for treating cancers. Based on the binding mode of adenosine 5'-(α,ß-methylene)diphosphate (AOPCP) with human CD73, we designed a series of novel monophosphonate small-molecule CD73 inhibitors. Among them, OP-5244 (35) proved to be a highly potent and orally bioavailable CD73 inhibitor. In preclinical studies, 35 completely inhibited ADO production in both human cancer cells and CD8+ T cells. Furthermore, 35 lowered the ratio of ADO/AMP significantly and reversed immunosuppression in mouse models, indicating its potential as an in vivo tool compound for further development.
Subject(s)
5'-Nucleotidase/antagonists & inhibitors , Adenosine/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Immunologic Factors/pharmacology , Nucleosides/pharmacology , Organophosphonates/pharmacology , Administration, Oral , Animals , CD8-Positive T-Lymphocytes/drug effects , Cell Line, Tumor , Dogs , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , GPI-Linked Proteins/antagonists & inhibitors , Humans , Immunologic Factors/administration & dosage , Immunologic Factors/chemical synthesis , Immunologic Factors/pharmacokinetics , Macaca fascicularis , Mice, Inbred BALB C , Molecular Structure , Nucleosides/administration & dosage , Nucleosides/chemical synthesis , Nucleosides/pharmacokinetics , Organophosphonates/administration & dosage , Organophosphonates/chemical synthesis , Organophosphonates/pharmacokinetics , Rats , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Structure-based modification of mifepristone (1) led to the discovery of novel mifepristone derivatives with improved selectivity profile. Addition of a methyl group at the C10 position of the steroid has a significant impact on progesterone receptor (PR) and androgen receptor (AR) activity. Within this series, OP-3633 (15) emerged as a glucocorticoid receptor (GR) antagonist with increased selectivity against PR and AR, improved cytochrome P450 inhibition profile, and significantly improved pharmacokinetic properties compared to 1. Furthermore, 15 demonstrated substantial inhibition of GR transcriptional activity in the GR positive HCC1806 triple negative breast cancer xenograft model. Overall, compound 15 is a promising GR antagonist candidate to clinically evaluate the impact of GR inhibition in reversal or prevention of therapy resistance.
Subject(s)
Mifepristone/analogs & derivatives , Mifepristone/pharmacology , Receptors, Glucocorticoid/antagonists & inhibitors , Androgen Receptor Antagonists/chemistry , Androgen Receptor Antagonists/pharmacology , Drug Discovery , Humans , Models, Molecular , Receptors, Androgen/metabolism , Receptors, Glucocorticoid/metabolism , Receptors, Progesterone/antagonists & inhibitors , Receptors, Progesterone/metabolismABSTRACT
The glucocorticoid receptor (GR) has been linked to therapy resistance across a wide range of cancer types. Preclinical data suggest that antagonists of this nuclear receptor may enhance the activity of anticancer therapy. The first-generation GR antagonist mifepristone is currently undergoing clinical evaluation in various oncology settings. Structure-based modification of mifepristone led to the discovery of ORIC-101 (28), a highly potent steroidal GR antagonist with reduced androgen receptor (AR) agonistic activity amenable for dosing in androgen receptor positive tumors and with improved CYP2C8 and CYP2C9 inhibition profile to minimize drug-drug interaction potential. Unlike mifepristone, 28 could be codosed with chemotherapeutic agents readily metabolized by CYP2C8 such as paclitaxel. Furthermore, 28 demonstrated in vivo antitumor activity by enhancing response to chemotherapy in the GR+ OVCAR5 ovarian cancer xenograft model. Clinical evaluation of safety and therapeutic potential of 28 is underway.
Subject(s)
Drug Discovery , Hormone Antagonists/pharmacology , Ovarian Neoplasms/drug therapy , Receptors, Glucocorticoid/antagonists & inhibitors , Animals , Female , Hormone Antagonists/chemistry , Hormone Antagonists/pharmacokinetics , Humans , Mice , Ovarian Neoplasms/metabolism , Ovarian Neoplasms/pathology , Rats , Swine , Swine, Miniature , Tissue Distribution , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
JAK (Janus family of cytoplasmic tyrosine kinases) family tyrosine kinase 2 (TYK2) participates in signaling through cytokine receptors involved in immune responses and inflammation. JAKs are characterized by dual kinase domain: a tyrosine kinase domain (JH1) that is preceded by a pseudokinase domain (JH2). The majority of disease-associated mutations in JAKs map to JH2, demonstrating its central regulatory function. JH2s were considered catalytically inactive, but JAK2 JH2 was found to have low autoregulatory catalytic activity. Whether the other JAK JH2s share ATP binding and enzymatic activity has been unclear. Here we report the crystal structure of TYK2 JH2 in complex with adenosine 5'-O-(thiotriphosphate) (ATP-γS) and characterize its nucleotide binding by biochemical and biophysical methods. TYK2 JH2 did not show phosphotransfer activity, but it binds ATP and the nucleotide binding stabilizes the protein without inducing major conformational changes. Mutation of the JH2 ATP-binding pocket increased basal TYK2 phosphorylation and downstream signaling. The overall structural characteristics of TYK2 JH2 resemble JAK2 JH2, but distinct stabilizing molecular interactions around helix αAL in the activation loop provide a structural basis for differences in substrate access and catalytic activities among JAK family JH2s. The structural and biochemical data suggest that ATP binding is functionally important for both TYK2 and JAK2 JH2s, whereas the regulatory phosphorylation appears to be a unique property of JAK2. Finally, the co-crystal structure of TYK2 JH2 complexed with a small molecule inhibitor demonstrates that JH2 is accessible to ATP-competitive compounds, which offers novel approaches for targeting cytokine signaling as well as potential therapeutic applications.
Subject(s)
TYK2 Kinase/chemistry , TYK2 Kinase/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Crystallography, X-Ray , Enzyme Activation , Enzyme Stability , Humans , Janus Kinase 1/chemistry , Janus Kinase 2/chemistry , Models, Molecular , Molecular Sequence Data , Mutation , Phosphorylation , Protein Conformation , Protein Structure, Tertiary , Sequence Homology, Amino Acid , Structural Homology, Protein , TYK2 Kinase/geneticsABSTRACT
p53 is a critical tumor suppressor and is the most frequently inactivated gene in human cancer. Inhibition of the interaction of p53 with its negative regulator MDM2 represents a promising clinical strategy to treat p53 wild-type tumors. AMG 232 is a potential best-in-class inhibitor of the MDM2-p53 interaction and is currently in clinical trials. We characterized the activity of AMG 232 and its effect on p53 signaling in several preclinical tumor models. AMG 232 binds the MDM2 protein with picomolar affinity and robustly induces p53 activity, leading to cell-cycle arrest and inhibition of tumor cell proliferation. AMG 232 treatment inhibited the in vivo growth of several tumor xenografts and led to complete and durable regression of MDM2-amplified SJSA-1 tumors via growth arrest and induction of apoptosis. Therapeutic combination studies of AMG 232 with chemotherapies that induce DNA damage and p53 activity resulted in significantly superior antitumor efficacy and regression, and markedly increased activation of p53 signaling in tumors. These preclinical data support the further evaluation of AMG 232 in clinical trials as both a monotherapy and in combination with standard-of-care cytotoxics.
Subject(s)
Acetates/pharmacology , Antineoplastic Agents/pharmacology , Cytotoxins/pharmacology , Piperidones/pharmacology , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/metabolism , Animals , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Female , HCT116 Cells , HT29 Cells , Humans , MCF-7 Cells , Mice , Mice, Nude , Xenograft Model Antitumor Assays/methodsABSTRACT
Structure-based rational design and extensive structure-activity relationship studies led to the discovery of AMG 232 (1), a potent piperidinone inhibitor of the MDM2-p53 association, which is currently being evaluated in human clinical trials for the treatment of cancer. Further modifications of 1, including replacing the carboxylic acid with a 4-amidobenzoic acid, afforded AM-7209 (25), featuring improved potency (KD from ITC competition was 38 pM, SJSA-1 EdU IC50 = 1.6 nM), remarkable pharmacokinetic properties, and in vivo antitumor activity in both the SJSA-1 osteosarcoma xenograft model (ED50 = 2.6 mg/kg QD) and the HCT-116 colorectal carcinoma xenograft model (ED50 = 10 mg/kg QD). In addition, 25 possesses distinct mechanisms of elimination compared to 1.
Subject(s)
Antineoplastic Agents/pharmacology , Cell Proliferation/drug effects , Colonic Neoplasms/drug therapy , Drug Discovery , Protein Binding/drug effects , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Female , Humans , Mice , Mice, Nude , Models, Molecular , Molecular Structure , Proto-Oncogene Proteins c-mdm2/metabolism , Structure-Activity Relationship , Tumor Cells, Cultured , Tumor Suppressor Protein p53/metabolismABSTRACT
Continued optimization of the N-substituent in the piperidinone series provided potent piperidinone-pyridine inhibitors 6, 7, 14, and 15 with improved pharmacokinetic properties in rats. Reducing structure complexity of the N-alkyl substituent led to the discovery of 23, a potent and simplified inhibitor of MDM2. Compound 23 exhibits excellent pharmacokinetic properties and substantial in vivo antitumor activity in the SJSA-1 osteosarcoma xenograft mouse model.
ABSTRACT
Cytochrome P450 4F12 is a drug-metabolizing enzyme that is primarily expressed in the liver, kidney, colon, small intestine, and heart. The properties of CYP4F12 that may impart an increased catalytic selectivity (decreased promiscuity) were explored through in vitro metabolite elucidation, kinetic isotope effect experiments, and computational modeling of the CYP4F12 active site. By using astemizole as a probe substrate for CYP4F12 and CYP3A4, it was observed that although CYP4F12 favored astemizole O-demethylation as the primary route of metabolism, CYP3A4 was capable of metabolizing astemizole at multiple sites on the molecule. Deuteration of astemizole at the site of O-demethylation resulted in an isotope effect of 7.1 as well as an 8.3-fold decrease in the rate of clearance for astemizole by CYP4F12. Conversely, although an isotope effect of 3.8 was observed for the formation of the O-desmethyl metabolite when deuterated astemizole was metabolized by CYP3A4, there was no decrease in the clearance of astemizole. Development of a homology model of CYP4F12 based on the crystal structure of cytochrome P450 BM3 predicted an active site volume for CYP4F12 that was approximately 76% of the active site volume of CYP3A4. As predicted, multiple favorable binding orientations were available for astemizole docked into the active site of CYP3A4, but only a single binding orientation with the site of O-demethylation oriented toward the heme was identified for CYP4F12. Overall, it appears that although CYP4F12 may be capable of binding similar ligands to other cytochrome P450 enzymes such as CYP3A4, the ability to achieve catalytically favorable orientations may be inherently more difficult because of the increased steric constraints of the CYP4F12 active site.
Subject(s)
Aryl Hydrocarbon Hydroxylases/chemistry , Aryl Hydrocarbon Hydroxylases/metabolism , Astemizole/metabolism , Biotransformation , Catalytic Domain , Cytochrome P-450 CYP3A/metabolism , Humans , In Vitro Techniques , Models, Molecular , Substrate SpecificityABSTRACT
We describe the structural optimization of a lead compound 1 that exhibits dual inhibitory activities against FLT3 and CDK4. A series of pyrido[4',3':4,5]pyrrolo[2,3-d]pyrimidine derivatives was synthesized, and SAR analysis, using cell-based assays, led to the discovery of 28 (AMG 925), a potent and orally bioavailable dual inhibitor of CDK4 and FLT3, including many FLT3 mutants reported to date. Compound 28 inhibits the proliferation of a panel of human tumor cell lines including Colo205 (Rb(+)) and U937 (FLT3(WT)) and induced cell death in MOLM13 (FLT3(ITD)) and even in MOLM13 (FLT3(ITD, D835Y)), which exhibits resistance to a number of FLT3 inhibitors currently under clinical development. At well-tolerated doses, compound 28 leads to significant growth inhibition of MOLM13 xenografts in nude mice, and the activity correlates with inhibition of STAT5 and Rb phosphorylation.
Subject(s)
Cyclin-Dependent Kinase 4/antagonists & inhibitors , Heterocyclic Compounds, 3-Ring/chemical synthesis , Naphthyridines/chemical synthesis , Protein Kinase Inhibitors/chemical synthesis , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Animals , Cyclin-Dependent Kinase 6/antagonists & inhibitors , Cytochrome P-450 CYP3A , Cytochrome P-450 CYP3A Inhibitors , Dogs , Drug Discovery , Heterocyclic Compounds, 3-Ring/pharmacology , Humans , Macaca fascicularis , Naphthyridines/pharmacology , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/pharmacology , Rats , Structure-Activity Relationship , U937 Cells , fms-Like Tyrosine Kinase 3/geneticsABSTRACT
We previously reported the discovery of potent and selective morpholinone and piperidinone inhibitors of the MDM2-p53 interaction. These inhibitors have in common a carboxylic acid moiety that engages in an electrostatic interaction with MDM2-His96. Our continued search for potent and diverse inhibitors led to the discovery of novel replacements for these acids uncovering new interactions with the MDM2 protein. In particular, using pyridine or thiazole as isosteres of the carboxylic acid moiety resulted in very potent analogues. From these, AM-6761 (4) emerged as a potent inhibitor with remarkable biochemical (HTRF IC50 = 0.1 nM) and cellular potency (SJSA-1 EdU IC50 = 16 nM), as well as favorable pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 11 mg/kg. Optimization efforts toward the discovery of these inhibitors as well as the new interactions observed with the MDM2 protein are described herein.
Subject(s)
Acetates/pharmacology , Antineoplastic Agents/pharmacology , Carboxylic Acids/pharmacology , Cell Proliferation/drug effects , Myocytes, Smooth Muscle/drug effects , Piperidones/pharmacology , Protein Interaction Domains and Motifs/drug effects , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/antagonists & inhibitors , Acetates/chemistry , Animals , Bone Neoplasms/drug therapy , Carboxylic Acids/chemistry , Cells, Cultured , Crystallography, X-Ray , Drug Design , Female , Humans , Hydrogen Bonding , Mice , Mice, Nude , Models, Molecular , Molecular Structure , Osteosarcoma/drug therapy , Piperidones/chemistry , Protein Binding , Proto-Oncogene Proteins c-mdm2/metabolism , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, Cultured , Tumor Suppressor Protein p53/metabolism , Xenograft Model Antitumor AssaysABSTRACT
We previously reported the discovery of AMG 232, a highly potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Our continued search for potent and diverse analogues led to the discovery of novel morpholinone MDM2 inhibitors. This change to a morpholinone core has a significant impact on both potency and metabolic stability compared to the piperidinone series. Within this morpholinone series, AM-8735 emerged as an inhibitor with remarkable biochemical potency (HTRF IC50 = 0.4 nM) and cellular potency (SJSA-1 EdU IC50 = 25 nM), as well as pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 41 mg/kg. Lead optimization toward the discovery of this inhibitor as well as key differences between the morpholinone and the piperidinone series will be described herein.
Subject(s)
Acetates/chemical synthesis , Acetates/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Morpholines/chemical synthesis , Morpholines/pharmacology , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Proto-Oncogene Proteins c-mdm2/chemistry , Tumor Suppressor Protein p53/antagonists & inhibitors , Tumor Suppressor Protein p53/chemistry , Animals , Cell Line, Tumor , Crystallography, X-Ray , Drug Discovery , Humans , Indicators and Reagents , Mice , Models, Molecular , Molecular Conformation , Morpholines/pharmacokinetics , Rats , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
Acute myeloid leukemia (AML) remains a serious unmet medical need. Despite high remission rates with chemotherapy standard-of-care treatment, the disease eventually relapses in a major proportion of patients. Activating Fms-like tyrosine kinase 3 (FLT3) mutations are found in approximately 30% of patients with AML. Targeting FLT3 receptor tyrosine kinase has shown encouraging results in treating FLT3-mutated AML. Responses, however, are not sustained and acquired resistance has been a clinical challenge. Treatment options to overcome resistance are currently the focus of research. We report here the preclinical evaluation of AMG 925, a potent, selective, and bioavailable FLT3/cyclin-dependent kinase 4 (CDK4) dual kinase inhibitor. AMG 925 inhibited AML xenograft tumor growth by 96% to 99% without significant body weight loss. The antitumor activity of AMG 925 correlated with the inhibition of STAT5 and RB phosphorylation, the pharmacodynamic markers for inhibition of FLT3 and CDK4, respectively. In addition, AMG 925 was also found to inhibit FLT3 mutants (e.g., D835Y) that are resistant to the current FLT3 inhibitors (e.g., AC220 and sorafenib). CDK4 is a cyclin D-dependent kinase that plays an essential central role in regulating cell proliferation in response to external growth signals. A critical role of the CDK4-RB pathway in cancer development has been well established. CDK4-specific inhibitors are being developed for treating RB-positive cancer. AMG 925, which combines inhibition of two kinases essential for proliferation and survival of FLT3-mutated AML cells, may improve and prolong clinical responses.
Subject(s)
Cyclin-Dependent Kinase 4/antagonists & inhibitors , Heterocyclic Compounds, 3-Ring/administration & dosage , Leukemia, Myeloid, Acute/drug therapy , Naphthyridines/administration & dosage , Protein Kinase Inhibitors/administration & dosage , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Animals , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Heterocyclic Compounds, 3-Ring/pharmacokinetics , Heterocyclic Compounds, 3-Ring/therapeutic use , Humans , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Mice , Mice, Nude , Naphthyridines/pharmacokinetics , Naphthyridines/therapeutic use , Neoplasms, Experimental , Niacinamide/analogs & derivatives , Niacinamide/pharmacology , Phenylurea Compounds/pharmacology , Piperazines/pharmacology , Protein Kinase Inhibitors/pharmacokinetics , Pyridines/pharmacology , Signal Transduction/drug effects , Sorafenib , U937 Cells , Xenograft Model Antitumor AssaysABSTRACT
We recently reported the discovery of AM-8553 (1), a potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Continued research investigation of the N-alkyl substituent of this series, focused in particular on a previously underutilized interaction in a shallow cleft on the MDM2 surface, led to the discovery of a one-carbon tethered sulfone which gave rise to substantial improvements in biochemical and cellular potency. Further investigation produced AMG 232 (2), which is currently being evaluated in human clinical trials for the treatment of cancer. Compound 2 is an extremely potent MDM2 inhibitor (SPR KD = 0.045 nM, SJSA-1 EdU IC50 = 9.1 nM), with remarkable pharmacokinetic properties and in vivo antitumor activity in the SJSA-1 osteosarcoma xenograft model (ED50 = 9.1 mg/kg).
Subject(s)
Acetates/pharmacology , Antineoplastic Agents/pharmacology , Piperidones/pharmacology , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/antagonists & inhibitors , Acetates/chemistry , Administration, Oral , Antineoplastic Agents/chemistry , Biological Availability , Crystallography, X-Ray , Drug Discovery , Humans , Piperidones/chemistry , Protein ConformationABSTRACT
We describe the discovery of a series of arylsulfonyl 3-(pyridin-2-yloxy)anilines as GPR119 agonists derived from compound 1. Replacement of the three methyl groups in 1 with metabolically stable moieties led to the identification of compound 34, a potent and efficacious GPR119 agonist with improved pharmacokinetic (PK) properties.
Subject(s)
Aniline Compounds/chemistry , Aniline Compounds/pharmacology , Receptors, G-Protein-Coupled/agonists , Aniline Compounds/chemical synthesis , Animals , Diabetes Mellitus, Type 2/drug therapy , Drug Discovery , Humans , Mice , Models, Molecular , Receptors, G-Protein-Coupled/chemistry , Structure-Activity RelationshipABSTRACT
The discovery, structure-based design, synthesis, and optimization of NIK inhibitors are described. Our work began with an HTS hit, imidazopyridinyl pyrimidinamine 1. We utilized homology modeling and conformational analysis to optimize the indole scaffold leading to the discovery of novel and potent conformationally constrained inhibitors such as compounds 25 and 28. Compounds 25 and 31 were co-crystallized with NIK kinase domain to provide structural insights.
Subject(s)
Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Alkynes/chemical synthesis , Alkynes/chemistry , Alkynes/pharmacology , Amines/chemical synthesis , Amines/chemistry , Amines/pharmacology , Drug Design , HT29 Cells , Humans , Hydrogen Bonding , Imidazoles/chemical synthesis , Imidazoles/chemistry , Imidazoles/pharmacology , Models, Molecular , Protein Kinase Inhibitors/chemical synthesis , Protein Serine-Threonine Kinases/chemistry , Pyridines/chemical synthesis , Pyridines/chemistry , Pyridines/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Pyrimidines/pharmacology , Structure-Activity Relationship , NF-kappaB-Inducing KinaseABSTRACT
Protein kinases are recognized as important drug targets due to the pivotal roles they play in human disease. Many kinase inhibitors are ATP competitive, leading to potential problems with poor selectivity and significant loss of potency in vivo due to cellular ATP concentrations being much higher than K(m). Consequently, there has been growing interest in the development of ATP-noncompetitive inhibitors to overcome these problems. There are challenges to identifying ATP-noncompetitive inhibitors from compound library screens because ATP-noncompetitive inhibitors are often weaker and commonly excluded by potency-based hit selection criteria in favor of abundant and highly potent ATP-competitive inhibitors in screening libraries. Here we report the development of a time-resolved fluorescence resonance energy transfer (TR-FRET) assay for protein kinase cyclin-dependent kinase 4 (CDK4) and the identification of ATP-noncompetitive inhibitors by high-throughput screening after employing a strategy to favor this type of inhibitors. We also present kinetic characterization that is consistent with the proposed mode of inhibition.
Subject(s)
Adenosine Triphosphate/metabolism , Cyclin-Dependent Kinase 4/antagonists & inhibitors , Fluorescence Resonance Energy Transfer/methods , Protein Kinase Inhibitors/pharmacology , Cell Line, Tumor , Chromatography, High Pressure Liquid , Cyclin-Dependent Kinase 4/metabolism , Humans , Kinetics , Mass Spectrometry , Models, MolecularABSTRACT
In the quest for safe, efficacious kinase inhibitors as drugs, selectivity is often assessed early using kinase profiling panels. Here we present a selectivity index based on thermodynamics principles that can help in analysis of the resulting data. The "partition" selectivity index is easy to calculate and is applicable in certain situations where other widely used indices are not. It is uniquely useful in analysis of small, focused selectivity panel data frequently encountered in medicinal chemistry hit-to-lead and lead optimization. For larger "kinome" panels, the partition index allows assessment of selectivity relative to a kinase or multiple kinases of interest.
Subject(s)
Drug Evaluation, Preclinical/methods , Protein Kinase Inhibitors/pharmacology , Protein Kinases/metabolism , Inhibitory Concentration 50 , Substrate Specificity , ThermodynamicsABSTRACT
A novel approach to the synthesis of substituted 5-amino- and 3-amino-1,2,4-thiadiazoles beginning from a common precursor has been achieved. Derivatization by palladium-catalyzed Suzuki-Miyaura coupling enables the rapid preparation of analogs around this pharmaceutically relevant core. FMO calculations rationalize the observed chemoselectivity for coupling at chlorine.
Subject(s)
Palladium/chemistry , Thiadiazoles/chemical synthesis , Catalysis , Combinatorial Chemistry Techniques , Hydrocarbons, Brominated/chemical synthesis , Hydrocarbons, Brominated/chemistry , Molecular Structure , Thiadiazoles/chemistryABSTRACT
A novel class of PARP-1 inhibitors was identified containing a non-aromatic heterocycle or carbocycle fused to a pyrazolo pyridin-2-one. Compounds displayed low nanomolar binding activity in the PARP-1 binding assay and submicromolar activity in a cell based chemosensitization assay.
Subject(s)
Enzyme Inhibitors , Poly(ADP-ribose) Polymerase Inhibitors , Pyrazoles , Pyridones , Animals , Chickens , Combinatorial Chemistry Techniques , Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Molecular Structure , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Pyrazoles/pharmacology , Pyridones/chemical synthesis , Pyridones/chemistry , Pyridones/pharmacology , Structure-Activity RelationshipABSTRACT
P-glycoprotein (Pgp) mediated drug efflux affects the absorption, distribution, and clearance of a broad structural variety of drugs. Early assessment of the potential of compounds to interact with Pgp can aid in the selection and optimization of drug candidates. To differentiate nonsubstrates from substrates of Pgp, a robust predictive pharmacophore model was targeted in a supervised analysis of three-dimensional (3D) pharmacophores from 163 published compounds. A comprehensive set of pharmacophores has been generated from conformers of whole molecules of both substrates and nonsubstrates of P-glycoprotein. Four-point 3D pharmacophores were employed to increase the amount of shape information and resolution, including the ability to distinguish chirality. A novel algorithm of the pharmacophore-specific t-statistic was applied to the actual structure-activity data and 400 sets of artificial data (sampled by decorrelating the structure and Pgp efflux activity). The optimal size of the significant pharmacophore set was determined through this analysis. A simple classification tree using nine distinct pharmacophores was constructed to distinguish nonsubstrates from substrates of Pgp. An overall accuracy of 87.7% was achieved for the training set and 87.6% for the external independent test set. Furthermore, each of nine pharmacophores can be independently utilized as an accurate marker for potential Pgp substrates.