ABSTRACT
Melanin-concentrating hormone (MCH) is an attractive target for antiobesity agents, and numerous drug discovery programs are dedicated to finding small-molecule MCH receptor 1 (MCHR1) antagonists. We recently reported novel pyridine-2(1H)-ones as aliphatic amine-free MCHR1 antagonists that structurally featured an imidazo[1,2-a]pyridine-based bicyclic motif. To investigate imidazopyridine variants with lower basicity and less potential to inhibit cytochrome P450 3A4 (CYP3A4), we designed pyridine-2(1H)-ones bearing various less basic bicyclic motifs. Among these, a lead compound 6a bearing a 1H-benzimidazole motif showed comparable binding affinity to MCHR1 to the corresponding imidazopyridine derivative 1. Optimization of 6a afforded a series of potent thiophene derivatives (6q-u); however, most of these were found to cause time-dependent inhibition (TDI) of CYP3A4. As bioactivation of thiophenes to form sulfoxide or epoxide species was considered to be a major cause of CYP3A4 TDI, we introduced electron withdrawing groups on the thiophene and found that a CF3 group on the ring or a Cl adjacent to the sulfur atom helped prevent CYP3A4 TDI. Consequently, 4-[(5-chlorothiophen-2-yl)methoxy]-1-(2-cyclopropyl-1-methyl-1H-benzimidazol-6-yl)pyridin-2(1H)-one (6s) was identified as a potent MCHR1 antagonist without the risk of CYP3A4 TDI, which exhibited a promising safety profile including low CYP3A4 inhibition and exerted significant antiobesity effects in diet-induced obese F344 rats.
Subject(s)
Anti-Obesity Agents/pharmacology , Benzimidazoles/pharmacology , Cytochrome P-450 CYP3A/metabolism , Drug Design , Obesity/drug therapy , Pyridones/pharmacology , Receptors, Somatostatin/antagonists & inhibitors , Animals , Anti-Obesity Agents/chemical synthesis , Anti-Obesity Agents/chemistry , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Dose-Response Relationship, Drug , Humans , Male , Molecular Structure , Pyridones/chemical synthesis , Pyridones/chemistry , Rats , Rats, Inbred F344 , Structure-Activity Relationship , Time FactorsABSTRACT
Aiming to discover melanin-concentrating hormone receptor 1 (MCHR1) antagonists with improved safety profiles, we hypothesized that the aliphatic amine employed in most antagonists reported to date could be removed if the bicyclic motif of the compound scaffold interacted with Asp123 and/or Tyr272 of MCHR1. We excluded aliphatic amines from our compound designs, with a cutoff value of pK(a) < 8, and explored aliphatic amine-free MCHR1 antagonists in a CNS-oriented chemical space limited by four descriptors (TPSA, ClogP, MW, and HBD count). Screening of novel bicyclic motifs with high intrinsic binding affinity for MCHR1 identified the imidazo[1,2-a]pyridine ring (represented in compounds 6a and 6b), and subsequent cyclization of the central aliphatic amide linkage led to the discovery of a potent, orally bioavailable MCHR1 antagonist 4-[(4-chlorobenzyl)oxy]-1-(2-cyclopropyl-3-methylimidazo[1,2-a]pyridin-6-yl)pyridin-2(1H)-one 10a. It exhibited low potential for hERG inhibition and phospholipidosis induction as well as sufficient brain concentration to exert antiobesity effects in diet-induced obese rats.
Subject(s)
Anti-Obesity Agents/pharmacology , Imidazoles/chemistry , Imidazoles/pharmacology , Obesity/drug therapy , Pyridones/chemistry , Pyridones/pharmacology , Receptors, Somatostatin/antagonists & inhibitors , Animals , Anti-Obesity Agents/chemical synthesis , Anti-Obesity Agents/chemistry , CHO Cells , Cricetulus , Dose-Response Relationship, Drug , Humans , Imidazoles/chemical synthesis , Male , Molecular Structure , Pyridones/chemical synthesis , Rats , Rats, Inbred F344 , Rats, Sprague-Dawley , Receptors, Somatostatin/deficiency , Structure-Activity RelationshipABSTRACT
G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) is a free fatty acid (FFA) receptor that mediates FFA-amplified glucose-stimulated insulin secretion in pancreatic ß-cells. We previously identified (2,3-dihydro-1-benzofuran-3-yl)acetic acid derivative 2 as a candidate, but it had relatively high lipophilicity. Adding a polar functional group on 2 yielded several compounds with lower lipophilicity and little effect on caspase-3/7 activity at 30 µM (a marker of toxicity in human HepG2 hepatocytes). Three optimized compounds showed promising pharmacokinetic profiles with good in vivo effects. Of these, compound 16 had the lowest lipophilicity. Metabolic analysis of 16 showed a long-acting PK profile due to high resistance to ß-oxidation. Oral administration of 16 significantly reduced plasma glucose excursion and increased insulin secretion during an OGTT in type 2 diabetic rats. Compound 16 (TAK-875) is being evaluated in human clinical trials for the treatment of type 2 diabetes.
Subject(s)
Benzofurans/pharmacology , Glucose/pharmacology , Insulin/metabolism , Receptors, G-Protein-Coupled/agonists , Sulfones/pharmacology , Animals , Benzofurans/chemical synthesis , Benzofurans/pharmacokinetics , Diabetes Mellitus, Type 2/drug therapy , Female , Glucose Tolerance Test , Hep G2 Cells , Humans , Insulin Secretion , Male , Rats , Receptors, G-Protein-Coupled/drug effects , Stereoisomerism , Sulfones/chemical synthesis , Sulfones/pharmacokineticsABSTRACT
As part of a program to identify potent GPR40 agonists with drug-like properties suitable for clinical development, the incorporation of polar substituents was explored with the intention of decreasing the lipophilicity of our recently disclosed phenylpropanoic acid derivative 1. This incorporation would allow us to mitigate the cytotoxicity issues observed with compound 1 and enable us to move away from the multifunctional free fatty acid-like structure. Substitutions on the 2',6'-dimethylbiphenyl ring were initially undertaken, which revealed the feasibility of introducing polar functionalities at the biphenyl 4'-position. Further optimization of this position and the linker led to the discovery of several 4'-alkoxybiphenyl derivatives, which showed potent GPR40 agonist activities with the best balance in terms of improved cytotoxicity profiles and favorable pharmacokinetic properties. Among them, 3-{2-fluoro-4-[({4'-[(4-hydroxy-1,1-dioxidotetrahydro-2H-thiopyran-4-yl)methoxy]-2',6'-dimethylbiphenyl-3-yl}methyl)amino]phenyl}propanoic acid (35) exhibited a robust plasma glucose-lowering effect and insulinotropic action during an oral glucose tolerance test in rats with impaired glucose tolerance.
Subject(s)
Cyclic S-Oxides/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Phenylpropionates/chemical synthesis , Receptors, G-Protein-Coupled/agonists , Animals , CHO Cells , Calcium/metabolism , Caspases/metabolism , Cell Survival , Cricetinae , Cyclic S-Oxides/pharmacokinetics , Cyclic S-Oxides/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Female , Glucose Intolerance/drug therapy , Hep G2 Cells , Humans , Hypoglycemic Agents/pharmacokinetics , Hypoglycemic Agents/therapeutic use , Inhibitory Concentration 50 , Male , Phenylpropionates/pharmacokinetics , Phenylpropionates/therapeutic use , Rats , Receptors, G-Protein-Coupled/metabolism , Structure-Activity RelationshipABSTRACT
The G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) has emerged as an attractive target for a novel insulin secretagogue with glucose dependency. We previously identified phenylpropanoic acid derivative 1 (3-{4-[(2',6'-dimethylbiphenyl-3-yl)methoxy]-2-fluorophenyl}propanoic acid) as a potent and orally available GPR40/FFA1 agonist; however, 1 exhibited high clearance and low oral bioavailability, which was likely due to its susceptibility to ß-oxidation at the phenylpropanoic acid moiety. To identify long-acting compounds, we attempted to block the metabolically labile sites at the phenylpropanoic acid moiety by introducing a fused-ring structure. Various fused-ring alkanoic acids with potent GPR40/FFA1 activities and good PK profiles were produced. Further optimizations of the lipophilic portion and the acidic moiety led to the discovery of dihydrobenzofuran derivative 53 ((6-{[4'-(2-ethoxyethoxy)-2',6'-dimethylbiphenyl-3-yl]methoxy}-2,3-dihydro-1-benzofuran-3-yl)acetic acid), which acted as a GPR40/FFA1 agonist with in vivo efficacy during an oral glucose tolerance test (OGTT) in rats with impaired glucose tolerance.
Subject(s)
Acetates/chemical synthesis , Acids, Acyclic/chemical synthesis , Benzofurans/chemical synthesis , Insulin/blood , Receptors, G-Protein-Coupled/agonists , Acetates/pharmacokinetics , Acetates/pharmacology , Acids, Acyclic/pharmacokinetics , Acids, Acyclic/pharmacology , Animals , Benzofurans/pharmacokinetics , Benzofurans/pharmacology , CHO Cells , Cricetinae , Cricetulus , Female , Glucose Intolerance/metabolism , Glucose Tolerance Test , Humans , Insulin/metabolism , Insulin Secretion , Models, Molecular , Protein Binding , Rats , Rats, Wistar , Species SpecificityABSTRACT
G protein-coupled receptor 40/free fatty acid receptor 1 (GPR40/FFA(1)) is highly expressed in pancreatic ß cells and mediates free fatty acid-induced insulin secretion. This study examined the pharmacological effects and potential for avoidance of lipotoxicity of [(3S)-6-({2',6'-dimethyl-4'-[3-(methylsulfonyl)propoxy]biphenyl-3-yl}meth-oxy)-2,3-dihydro-1-benzofuran-3-yl]acetic acid hemi-hydrate) (TAK-875), a novel, orally available, selective GPR40 agonist. Insulinoma cell lines and primary rat islets were used to assess the effects of TAK-875 in vitro. The in vivo effects of TAK-875 on postprandial hyperglycemia, fasting hyperglycemia, and normoglycemia were examined in type 2 diabetic and normal rats. In rat insulinoma INS-1 833/15 cells, TAK-875 increased intracellular inositol monophosphate and calcium concentration, consistent with activation of the Gqα signaling pathway. The insulinotropic action of TAK-875 (10 µM) in INS-1 833/15 and primary rat islets was glucose-dependent. Prolonged exposure of cytokine-sensitive INS-1 832/13 to TAK-875 for 72 h at pharmacologically active concentrations did not alter glucose-stimulated insulin secretion, insulin content, or caspase 3/7 activity, whereas prolonged exposure to palmitic or oleic acid impaired ß cell function and survival. In an oral glucose tolerance test in type 2 diabetic N-STZ-1.5 rats, TAK-875 (1-10 mg/kg p.o.) showed a clear improvement in glucose tolerance and augmented insulin secretion. In addition, TAK-875 (10 mg/kg, p.o.) significantly augmented plasma insulin levels and reduced fasting hyperglycemia in male Zucker diabetic fatty rats, whereas in fasted normal Sprague-Dawley rats, TAK-875 neither enhanced insulin secretion nor caused hypoglycemia even at 30 mg/kg. TAK-875 enhances glucose-dependent insulin secretion and improves both postprandial and fasting hyperglycemia with a low risk of hypoglycemia and no evidence of ß cell toxicity.
Subject(s)
Benzofurans/pharmacology , Diabetes Mellitus, Type 2/drug therapy , Glucose/physiology , Hyperglycemia/drug therapy , Hypoglycemic Agents , Insulin/metabolism , Receptors, G-Protein-Coupled/agonists , Sulfones/pharmacology , Animals , Blood Glucose/metabolism , CHO Cells , Calcium/metabolism , Caspase 3/metabolism , Caspase 7/metabolism , Cell Survival/drug effects , Cricetinae , Cricetulus , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Type 2/blood , Fasting/physiology , Hyperglycemia/blood , Insulin Resistance/physiology , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , Male , Postprandial Period/physiology , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effectsABSTRACT
The calcium-sensing receptor antagonist (CaSR) has been recognized as a promising target of anabolic agents for treating osteoporosis. In the course of developing a new drug candidate for osteoporosis, we found tetrahydropyrazolopyrimidine derivative 1 to be an orally active CaSR antagonist that stimulated transient PTH secretion in rats. However, compound 1 showed poor physical and chemical stability. In order to work out this compound's chemical stability and further understand its in vivo efficacy, we focused on modifying the 2-position of the tetrahydropyrazolopyrimidine. As a result of chemical modification, we discovered (5R)-N-[1-ethyl-1-(4-ethylphenyl)propyl]-2,7,7-trimethyl-5-phenyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide monotosylate 10m (TAK-075), which showed improved solubility, chemical stability, and in vivo efficacy. Furthermore, we describe that evaluating the active metabolite is important during repeated treatment with short-acting CaSR antagonists.
Subject(s)
Anabolic Agents/chemistry , Pyrazoles/chemistry , Pyrimidines/chemistry , Receptors, Calcium-Sensing/antagonists & inhibitors , Administration, Oral , Anabolic Agents/pharmacokinetics , Anabolic Agents/therapeutic use , Animals , Crystallography, X-Ray , Drug Evaluation, Preclinical , Humans , Macaca fascicularis , Molecular Conformation , Osteoporosis/drug therapy , Parathyroid Hormone/metabolism , Pyrazoles/chemical synthesis , Pyrazoles/therapeutic use , Pyrimidines/chemical synthesis , Pyrimidines/pharmacokinetics , Pyrimidines/therapeutic use , Rats , Receptors, Calcium-Sensing/metabolismABSTRACT
G protein-coupled receptor 40 (GPR40) is being recently considered to be a new potential drug target for the treatment of type 2 diabetes because of its role in the enhancement of free fatty acid-regulated glucose-stimulated insulin secretion in pancreatic ß-cells. We initially identified benzyloxyphenylpropanoic acid (1b) (EC(50) = 510 nM), which was designed based on the structure of free fatty acids, as a promising lead compound with GPR40 agonist activity. Chemical modification of compound 1b led to the discovery of 3-{4-[(2',6'-dimethylbiphenyl-3-yl)methoxy]-2-fluorophenyl}propanoic acid (4p) as a potent GPR40 agonist (EC(50) = 5.7 nM). Compound 4p exhibited acceptable pharmacokinetic profiles and significant glucose-lowering effects during an oral glucose tolerance test in diabetic rats. Moreover, no hypoglycemic event was observed even after administration of a high dose of compound 4p to normal fasted rats. These pharmacological results suggest that GPR40 agonists might be novel glucose-dependent insulin secretagogues with little or no risk of hypoglycemia.
Subject(s)
Biphenyl Compounds/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Phenylpropionates/chemical synthesis , Receptors, G-Protein-Coupled/agonists , Administration, Oral , Animals , Biphenyl Compounds/pharmacokinetics , Biphenyl Compounds/pharmacology , Blood Glucose/analysis , CHO Cells , Cricetinae , Cricetulus , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/drug therapy , Drug Design , Glucose Tolerance Test , Humans , Hypoglycemic Agents/pharmacokinetics , Hypoglycemic Agents/pharmacology , Male , Phenylpropionates/pharmacokinetics , Phenylpropionates/pharmacology , Rats , Rats, Sprague-Dawley , Stereoisomerism , Structure-Activity RelationshipABSTRACT
As part of our research for novel calcium-sensing receptor (CaSR) antagonists that can function as oral bone anabolic agents, we recently reported the discovery of a tetrahydropyrazolopyrimidine derivative featuring adamantyl group 1b with potent CaSR antagonistic activity. To explore the potential of this calcilytic congener, we introduced the gem-dialkyl benzyl group at the 3-position of the tetrahydropyrazolopyrimidine ring, forming a bioisostere of the adamantyl group by mimicking the adamantyl group's lipophilicity and bulkiness. Optimization directed toward the improvement of solubility and metabolic stability led to the discovery of compound 9e, which stimulated transient PTH secretion when orally administered to normal rats. Further, compound 9e proved to be fully effective in an osteopenic ovariectomized rat model.
Subject(s)
Bone Density Conservation Agents/chemical synthesis , Parathyroid Hormone/metabolism , Pyrazoles/chemical synthesis , Pyrimidines/chemical synthesis , Receptors, Calcium-Sensing/antagonists & inhibitors , Administration, Oral , Animals , Bone Density/drug effects , Bone Density Conservation Agents/pharmacokinetics , Bone Density Conservation Agents/pharmacology , Bone Diseases, Metabolic/drug therapy , Bone Diseases, Metabolic/physiopathology , CHO Cells , Caco-2 Cells , Cell Membrane Permeability , Cricetinae , Cricetulus , Crystallography, X-Ray , Humans , Molecular Structure , Osteocalcin/blood , Ovariectomy , Pyrazoles/pharmacokinetics , Pyrazoles/pharmacology , Pyrimidines/pharmacokinetics , Pyrimidines/pharmacology , Rats , Solubility , Stereoisomerism , Structure-Activity RelationshipABSTRACT
A series of novel tetrahydropyrazolopyrimidine derivatives containing an adamantyl group were synthesized and evaluated as potential calcium-sensing receptor (CaSR) antagonists. After chemical modification of 9a, which was identified as a hit compound in a random screening of CaSR antagonist assay, 7,7-dimethyl derivative 16c was found to be the most active compound of this new series (IC(50)=10nM). We report the synthesis of this series and their biological activities and structure-activity relationship.
Subject(s)
Pyrimidines/chemical synthesis , Receptors, Calcium-Sensing/antagonists & inhibitors , Adamantane/analogs & derivatives , Adamantane/pharmacokinetics , Adamantane/pharmacology , Animals , Inhibitory Concentration 50 , Pyrimidines/administration & dosage , Pyrimidines/pharmacokinetics , Rats , Structure-Activity RelationshipABSTRACT
GPR40, one of the G protein-coupled receptors predominantly expressed in pancreatic ß-cells, mediates enhancement of glucose-stimulated insulin secretion by free fatty acids. A potent and selective GPR40 agonist is theorized to be a safe and effective antidiabetic drug with little or no risk of hypoglycemia. Cyclization of the phenylpropanoic acid moiety of lead compound 1 produced fused phenylalkanoic acids with favorable in vitro agonist activities and pharmacokinetic profiles. Further optimization led to the discovery of dihydrobenzofuran derivative 9a ([(3S)-6-({2',6'-dimethyl-4'-[3-(methylsulfonyl)propoxy]biphenyl-3-yl}methoxy)-2,3-dihydro-1-benzofuran-3-yl]acetic acid hemi-hydrate, TAK-875) as a potent, selective, and orally bioavailable GPR40 agonist, with a pharmacokinetic profile enabling long-acting drug efficacy. Compound 9a showed potent plasma glucose-lowering action and insulinotropic action during an oral glucose tolerance test in female Wistar fatty rats with impaired glucose tolerance. Compound 9a is currently in clinical trials for the treatment of type 2 diabetes mellitus.