ABSTRACT
In order to optimize the potency of the first serum-stable peptide agonist of CD47 (PKHB1) in triggering regulated cell death of cancer cells, we designed a maturation process aimed to mimic the trimeric structure of the thrombospondin-1/CD47 binding epitope. For that purpose, an N-methylation scan of the PKHB1 sequence was realized to prevent peptide aggregation. Structural and pharmacological analyses were conducted in order to assess the conformational impact of these chemical modifications on the backbone structure and the biological activity. This structure-activity relationship study led to the discovery of a highly soluble N-methylated peptide that we termed PKT16. Afterward, this monomer was used for the design of a homotrimeric peptide mimic that we termed [PKT16]3, which proved to be 10-fold more potent than its monomeric counterpart. A pharmacological evaluation of [PKT16]3 in inducing cell death of adherent (A549) and nonadherent (MEC-1) cancer cell lines was also performed.
Subject(s)
Drug Design , Peptides/chemistry , Peptides/pharmacology , Thrombospondin 1/chemistry , A549 Cells , Cell Death/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Dose-Response Relationship, Drug , Humans , Peptides/chemical synthesis , Protein Conformation , Protein Stability , Structure-Activity Relationship , Thrombospondin 1/pharmacologyABSTRACT
Carnitine palmitoyl transferase 2 (CPT2) deficiency is one of the most common inherited fatty acid oxidation (FAO) defects and represents a prototypical mitochondrial metabolic myopathy. Recent studies have suggested a pivotal role of adenosine monophosphate-activated protein kinase (AMPK) in skeletal muscle plasticity and mitochondrial homeostasis. Thus, we tested the potential of GSK773, a novel direct AMPK activator, to improve or correct FAO capacities in muscle cells from patients harboring various mutations. We used controls' and patients' myotubes and studied the parameters of FAO metabolism, of mitochondrial quantity and quality and of differentiation. We found that AMPK is constitutively activated in patients' myotubes, which exhibit both reduced FAO and impaired differentiation. GSK773 improves or corrects several metabolic hallmarks of CPT2 deficiency (deficient FAO flux and C16-acylcarnitine accumulation) by upregulating the expression of CPT2 protein. Beneficial effects of GSK773 are also likely due to stimulation of mitochondrial biogenesis and induction of mitochondrial fusion, by decreasing dynamin-related protein 1 and increasing mitofusin 2. GSK773 also induces a shift in myosin heavy chain isoforms toward the slow oxidative type and, therefore, fully corrects the differentiation process. We establish, through small interfering RNA knockdowns and pharmacological approaches, that these GSK773 effects are mediated through peroxisome proliferator-activated receptor gamma co-activator 1-alpha, reactive oxygen species and p38 mitogen-activated protein kinase, all key players of skeletal muscle plasticity. GSK773 recapitulates several important features of skeletal muscle adaptation to exercise. The results show that AMPK activation by GSK773 evokes the slow, oxidative myogenic program and triggers beneficial phenotypic adaptations in FAO-deficient myotubes. Thus, GSK773 might have therapeutic potential for correction of CPT2 deficiency.
Subject(s)
Carnitine O-Palmitoyltransferase/deficiency , Carnitine O-Palmitoyltransferase/genetics , Lipid Metabolism/genetics , Metabolism, Inborn Errors/genetics , Protein Kinases/genetics , Quinolones/pharmacology , AMP-Activated Protein Kinase Kinases , Carnitine O-Palmitoyltransferase/drug effects , Fatty Acids/metabolism , Gene Expression Regulation, Enzymologic/drug effects , Humans , Metabolism, Inborn Errors/physiopathology , Muscle Fibers, Skeletal/drug effects , Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Mutation , Myosin Heavy Chains/genetics , PPAR alpha/genetics , RNA, Small Interfering/genetics , Reactive Oxygen Species/metabolism , p38 Mitogen-Activated Protein Kinases/geneticsABSTRACT
Identification of indazole derivatives acting as dual angiotensin II type 1 (AT1) receptor antagonists and partial peroxisome proliferator-activated receptor-γ (PPARγ) agonists is described. Starting from Telmisartan, we previously described that indole derivatives were very potent partial PPARγ agonists with loss of AT1 receptor antagonist activity. Design, synthesis and evaluation of new central scaffolds led us to the discovery of pyrrazolopyridine then indazole derivatives provided novel series possessing the desired dual activity. Among the new compounds, 38 was identified as a potent AT1 receptor antagonist (IC50=0.006 µM) and partial PPARγ agonist (EC50=0.25 µM, 40% max) with good oral bioavailability in rat. The dual pharmacology of compound 38 was demonstrated in two preclinical models of hypertension (SHR) and insulin resistance (Zucker fa/fa rat).
Subject(s)
Angiotensin II/metabolism , Drug Discovery , Indazoles/pharmacology , PPAR gamma/agonists , Animals , Dose-Response Relationship, Drug , Humans , Indazoles/chemical synthesis , Indazoles/chemistry , Mice , Molecular Structure , Structure-Activity RelationshipABSTRACT
Bromodomains (BRDs) are small protein domains found in a variety of proteins that recognize and bind to acetylated histone tails. This binding affects chromatin structure and facilitates the localisation of transcriptional complexes to specific genes, thereby regulating epigenetically controlled processes including gene transcription and mRNA elongation. Inhibitors of the bromodomain and extra-terminal (BET) proteins BRD2-4 and T, which prevent bromodomain binding to acetyl-modified histone tails, have shown therapeutic promise in several diseases. We report here the discovery of 1,5-naphthyridine derivatives as potent inhibitors of the BET bromodomain family with good cell activity and oral pharmacokinetic parameters. X-ray crystal structures of naphthyridine isomers have been solved and quantum mechanical calculations have been used to explain the higher affinity of the 1,5-isomer over the others. The best compounds were progressed in a mouse model of inflammation and exhibited dose-dependent anti-inflammatory pharmacology.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Naphthyridines/pharmacology , Protein Kinase Inhibitors/pharmacology , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Chromosomal Proteins, Non-Histone , Crystallography, X-Ray , Dose-Response Relationship, Drug , Histones/chemistry , Histones/metabolism , Mice , Mice, Inbred BALB C , Models, Molecular , Molecular Structure , Naphthyridines/chemistry , Nuclear Proteins/antagonists & inhibitors , Nuclear Proteins/metabolism , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Protein Structure, Tertiary/drug effects , Structure-Activity Relationship , Transcription Factors/antagonists & inhibitors , Transcription Factors/metabolismABSTRACT
The discovery, synthesis and biological evaluation of a novel series of 7-isoxazoloquinolines is described. Several analogs are shown to increase ApoA1 expression within the nanomolar range in the human hepatic cell line HepG2.
Subject(s)
Apolipoprotein A-I/metabolism , Drug Discovery , Heterocyclic Compounds, 4 or More Rings/chemistry , Heterocyclic Compounds, 4 or More Rings/pharmacology , Nuclear Proteins/antagonists & inhibitors , Quinolines/chemistry , Up-Regulation/drug effects , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Hep G2 Cells , Histone Acetyltransferases , Histone Chaperones , Humans , Inhibitory Concentration 50 , Mice , Mice, Inbred BALB C , Nerve Tissue Proteins , Nuclear Proteins/metabolism , Quinolines/pharmacology , Rats , Structure-Activity RelationshipABSTRACT
A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 (GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.
Subject(s)
Heterocyclic Compounds, 4 or More Rings/chemistry , Isoxazoles/chemical synthesis , Nerve Tissue Proteins/antagonists & inhibitors , Quinolines/chemical synthesis , Animals , Binding Sites , Crystallography, X-Ray , Guinea Pigs , Heterocyclic Compounds, 4 or More Rings/metabolism , Inflammation/drug therapy , Isoxazoles/chemistry , Isoxazoles/pharmacology , Mice , Models, Molecular , Protein Binding/drug effects , Quinolines/chemistry , Quinolines/pharmacology , RatsABSTRACT
Starting from the structure of Telmisartan, a new series of potent and selective PPARgamma modulators was identified. The synthesis, in vitro and in vivo evaluation of the most potent compounds are reported and the X-ray structure of compound 7b bound to the PPARgamma ligand binding domain is described.