ABSTRACT
The design and synthesis of a novel scaffold for potent and selective PDE5 inhibitors are described. Compound 3a was more potent (PDE5 IC50=0.31 nM) and selective (>10,000-fold vs PDE1 and 160-fold selective vs PDE6) PDE5 inhibitor than sildenafil.
Subject(s)
Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacology , Phosphoric Diester Hydrolases/drug effects , 3',5'-Cyclic-GMP Phosphodiesterases , Cyclic Nucleotide Phosphodiesterases, Type 5 , Cyclic Nucleotide Phosphodiesterases, Type 6 , Drug Design , Drug Evaluation, Preclinical , Inhibitory Concentration 50 , Piperazines/pharmacology , Purines , Sildenafil Citrate , Structure-Activity Relationship , SulfonesSubject(s)
3',5'-Cyclic-GMP Phosphodiesterases/antagonists & inhibitors , Phosphodiesterase Inhibitors/chemical synthesis , Pyridines/chemical synthesis , Administration, Oral , Animals , Cyclic Nucleotide Phosphodiesterases, Type 5 , Dogs , Erectile Dysfunction/drug therapy , In Vitro Techniques , Male , Muscle Relaxation/drug effects , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Penis/drug effects , Penis/physiology , Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacokinetics , Phosphodiesterase Inhibitors/pharmacology , Pyridines/chemistry , Pyridines/pharmacokinetics , Pyridines/pharmacology , Rabbits , Rats , Structure-Activity RelationshipABSTRACT
A previous report from these laboratories identified the N-3-benzylimidazoquinazolinone nucleus as a more selective PDE5 inhibitor template compared to the pyrazolopyrimidine of sildenafil. This paper describes in detail the structure-activity relationships of a set of sulfonamide analogues, several of which are both more potent and more selective PDE5 inhibitors in vitro than sildenafil. The synthesis, in vitro enzyme activity and selectivity, and in vitro functional and preclinical pharmacokinetic assessment of molecules in this series are described.
Subject(s)
Phosphodiesterase Inhibitors/chemical synthesis , Phosphoric Diester Hydrolases/metabolism , Quinazolines/chemical synthesis , 3',5'-Cyclic-GMP Phosphodiesterases , Animals , Cattle , Cyclic Nucleotide Phosphodiesterases, Type 5 , Dogs , Drug Evaluation, Preclinical , Humans , In Vitro Techniques , Male , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Muscles , Penis/drug effects , Penis/physiology , Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacokinetics , Phosphodiesterase Inhibitors/pharmacology , Quinazolines/chemistry , Quinazolines/pharmacokinetics , Quinazolines/pharmacology , Rabbits , Rats , Structure-Activity RelationshipABSTRACT
Phosphodiesterase type 5 (PDE5) inhibitors with improved PDE isozyme selectivity relative to sildenafil may result in agents for the treatment of male erectile dysfunction (MED) with a lower incidence of PDE-associated adverse effects. This paper describes the discovery of 14, a PDE5 inhibitor with improved potency and selectivity in vitro compared to sildenafil. This compound shows activity in a functional assay of erectile function comparable to that of sildenafil.
Subject(s)
3',5'-Cyclic-GMP Phosphodiesterases/antagonists & inhibitors , Erectile Dysfunction/drug therapy , Imidazoles/chemical synthesis , Penis/drug effects , Phosphodiesterase Inhibitors/chemical synthesis , Quinazolines/chemical synthesis , Animals , Cyclic Nucleotide Phosphodiesterases, Type 5 , Imidazoles/chemistry , Imidazoles/pharmacology , In Vitro Techniques , Male , Penis/physiology , Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacology , Piperazines/pharmacology , Purines , Purinones/chemistry , Quinazolines/chemistry , Quinazolines/pharmacology , Rabbits , Sildenafil Citrate , Structure-Activity Relationship , SulfonesABSTRACT
Reovirus S4 RNA codes for the dsRNA-binding polypeptide sigma 3, a major virion outer capsid component that also has translational effects in both infected and transfected mammalian cells. To compare the composition and properties of the three different serotypes of sigma 3, a DNA copy of the type 2 gene was cloned and sequenced. The total lengths (1196) and the sequences of leader (33 nucleotides) and trailer (66 nucleotides) regions are highly conserved among the three S4 serotypes. The type 1 and 3 S4 genes are highly related (77 mismatches). However, the type 2 gene contains many mismatches relative to the type 1 and 3 genes (260 and 270 positions, respectively). Most of the mismatches are third position changes, resulting in sigma 3 polypeptides that are 90% or more identical. Transient expression vectors, constructed by replacing the chloramphenicol acetyltransferase (CAT) gene in pRSVCAT with S4 DNA, were used to test the effects of polypeptide sigma 3 on CAT expression in cotransfected COS cells. Transfection with the correctly oriented DNAs resulted in synthesis of the corresponding sigma 3 polypeptides which enhanced CAT expression. The type 2 and type 3 S4 genes were considerably more stimulatory than type 1 when compared to CAT DNA alone. However, with all three serotypes the CAT activity was significantly higher in cells cotransfected with S4 DNA in the correct orientation as compared to the reverse arrangement.
Subject(s)
Capsid/genetics , Genes, Viral , RNA-Binding Proteins/genetics , Reoviridae/genetics , Amino Acid Sequence , Base Sequence , Blotting, Northern , Capsid/chemistry , Chloramphenicol O-Acetyltransferase/genetics , Chloramphenicol O-Acetyltransferase/metabolism , Cloning, Molecular , Gene Expression/genetics , Molecular Sequence Data , Protein Biosynthesis/genetics , RNA-Binding Proteins/chemistry , Reoviridae/chemistry , Reoviridae/classification , SerotypingABSTRACT
Reovirus mRNAs synthesized by the virion-associated RNA polymerase contain a 5'-terminal cap that is added to nascent transcripts by polypeptide lambda 2, a structural component of virions encoded by double-stranded RNA genome segment L2. The complete, 3916-nucleotide sequence of a full-length reovirus type 3 L2 DNA clone was determined by the dideoxy chain terminator method. The sequence has a single long open reading frame extending from the second A-T-G at nucleotide 14 to a termination codon at position 3881. On this basis, the 1289-amino acid sequence of polypeptide lambda 2, the reovirus mRNA guanylyltransferase, was deduced and compared to other GTP-binding proteins. Two different, lysine-containing lambda 2 peptide sequences closely resemble predicted amino acid stretches in vaccinia virus guanylyltransferase and potentially form part of active sites in the viral mRNA capping enzymes.
Subject(s)
DNA, Viral/analysis , Genes, Viral , Nucleotidyltransferases/genetics , RNA, Messenger/analysis , Reoviridae/genetics , Amino Acid Sequence , Base Sequence , Codon , Molecular Sequence DataABSTRACT
A full-length cDNA copy of reovirus double-stranded RNA genome segment S4 which codes for a major virion structural polypeptide, sigma 3, has been completely sequenced. The 1,196-nucleotide cDNA contains a single long open reading frame in the plus strand extending 1,095 nucleotides from the 5'-proximal A-T-G to a single stop codon. This corresponds to translation of 92% of the S4 gene. The inferred sigma 3 polypeptide is hydrophilic and consists of 365 amino acids, totalling 41,164 daltons.
