Suppression of substance P biosynthesis in sensory neurons of dorsal root ganglion by prodrug esters of potent peptidylglycine alpha-amidating monooxygenase inhibitors.
Substance P as well as many other neuropeptides are synthesized as glycine-extended precursors and converted to the biologically active C-terminal amides by posttranslational modification. The final step of posttranslational processing is catalyzed by peptidylglycine alpha-amidating monooxygenase (PAM). In a previous study, N-substituted homocysteine analogs were found to be potent inhibitors of PAM partially purified from conditioned medium of cultured rat medullary thyroid carcinoma CA-77 cells. These compounds, however, were only modest inhibitors of substance P production in cultured dorsal root ganglion cells, possibly because of poor cell penetration. Several ester derivatives of hydrocinnamoyl-phenylalanyl-homocysteine, one of the most potent PAM inhibitors, were prepared to increase the intracellular accessibility of these compounds. Hydrocinnamoyl-phenylalanyl-(S-benzoyl-homocysteine) benzyl ester was identified as the most potent compound, inhibiting substance P biosynthesis in dorsal root ganglion cells with an IC50 of 2 microM. Inhibition of PAM resulted in a concomitant increase in the glycine-extended substance p (substance P-Gly) precursor peptide. In the presence of 3 microM benzyl ester derivative, the intracellular substance P-Gly level was 2.4-fold higher while the substance P level was 2.1-fold lower than the corresponding peptides in control cells. These results suggest that PAM inhibition represents an effective method for suppression of substance P biosynthesis and, therefore, may have therapeutic utility in conditions associated with elevated substance P levels. Furthermore, PAM inhibition may also prove useful in decreasing other amidated peptides.
Jeng
A Y
AY
Research Department, Novartis Pharmaceuticals Corp., Summit, New Jersey 07901, USA. arco.jeng@pharma.novartis.com
Fujimoto
R A
RA
Chou
M
M
Tan
J
J
Erion
M D
MD
D000818:Animals; D000831:Animals, Newborn; D001205:Ascorbic Acid / Q000494:pharmacology; D018276:Carcinoma, Medullary; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology*; D004952:Esters; D005727:Ganglia, Spinal / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006710:Homocysteine / Q000031:analogs & derivatives / Q000494:pharmacology*; D007202:Indicators and Reagents; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors*; D015394:Molecular Structure; D009097:Multienzyme Complexes; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D011355:Prodrugs / Q000494:pharmacology*; D011498:Protein Precursors / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013329:Structure-Activity Relationship; D013373:Substance P / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D013964:Thyroid Neoplasms; D014407:Tumor Cells, Cultured
D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D004952:Esters; D007202:Indicators and Reagents; D009097:Multienzyme Complexes; D011355:Prodrugs; D011498:Protein Precursors; D006710:Homocysteine; D013373:Substance P; C046072:substance P, Gly(12)-; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D001205:Ascorbic Acid