ABSTRACT
New synthetic chemical inducers of dimerization, comprising homodimeric FKBP ligands with engineered specificity for the designed point mutant F36V, have been evaluated for inducing targeted gene expression in mammalian cells. Structure-activity studies indicated that high-affinity dimerizers such as AP1903 are ineffective, perhaps due to kinetic trapping of non-productive dimers, whereas lower-affinity molecules, exemplified by AP1889 and AP1966, potently activate transcription.
Subject(s)
Cross-Linking Reagents/chemical synthesis , Cross-Linking Reagents/pharmacology , Gene Expression Regulation/drug effects , Tacrolimus/analogs & derivatives , Tacrolimus/chemical synthesis , Tacrolimus/pharmacology , Dimerization , Gene Expression Regulation/physiology , Humans , Organic ChemicalsABSTRACT
Src tyrosine kinase is a therapeutic target for bone diseases that has been validated by gene knockout studies. Furthermore, in vitro cellular studies implicate that Src has a positive regulatory role in osteoclasts and a negative regulatory role in osteoblasts. The potential use of Src inhibitors for osteoporosis therapy has been previously shown by novel bone-targeted ligands of the Src SH2 (e.g., AP22408) and non-bone-targeted, ATP-based inhibitors of Src kinase. Significant to this study, compounds 2-12 exemplify novel analogues of known pyrrolopyrimidine and pyrazolopyrimidine template-based Src kinase inhibitors that incorporate bone-targeting group modifications designed to provide tissue (bone) selectivity and diminished side effects. Accordingly, we report here the structure-based design, synthetic chemistry and biological testing of these compounds and proof-of-concept studies thereof.
Subject(s)
Adenosine Triphosphate/analogs & derivatives , Drug Design , Osteoporosis/drug therapy , Pyrimidines/chemical synthesis , src-Family Kinases/antagonists & inhibitors , Animals , Bone Diseases/drug therapy , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Humans , Inhibitory Concentration 50 , Models, Molecular , Purines/chemical synthesis , Purines/pharmacology , Pyrimidines/pharmacology , Structure-Activity RelationshipABSTRACT
Novel bone-targeted 2,6,9-trisubstituted purine template-based inhibitors of Src tyrosine kinase are described. Drug design studies of known purine compounds revealed that both positions-2 and -6 were suitable for incorporating bone-seeking moieties. A variety of bone-targeting groups with different affinity to hydroxyapatite were utilized in the study. Compound 3d was determined to be a potent Src inhibitor and was quite selective against a panel of other protein kinases.
Subject(s)
Bone Diseases/drug therapy , Purines/chemical synthesis , src-Family Kinases/antagonists & inhibitors , Adenosine Triphosphate/analogs & derivatives , Animals , Drug Delivery Systems , Drug Design , Durapatite/metabolism , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Humans , Inhibitory Concentration 50 , Purines/pharmacology , Structure-Activity RelationshipABSTRACT
The design of bone-targeted pyrido[2,3-d]pyrimidin-7-ones as Src tyrosine kinase inhibitors is described. Leveraging SAR from known compounds and using structure-based methods, we were able to rapidly incorporate bone binding components, which maintained, and even increased potency against the target enzyme. Compound 4 displayed a high affinity for hydroxyapatite, a major constituent of bone, and demonstrated antiresoprtive activity in our cell-based assay.
