A novel enediynyl peptide inhibitor of furin that blocks processing of proPDGF-A, B and proVEGF-C.
BACKGROUND
Furin represents a crucial member of secretory mammalian subtilase, the Proprotein Convertase (PC) or Proprotein Convertase Subtilisin/Kexin (PCSK) superfamily. It has been linked to cancer, tumorgenesis, viral and bacterial pathogenesis. As a result it is considered a major target for intervention of these diseases.


RESULTS
Herein, we report, for the first time, the synthesis and biological evaluation of a newly designed potent furin inhibitor that contains a highly reactive beta-turn inducing and radical generating "enediynyl amino acid" (Eda) moiety. "Eda" was inserted between P1 and P1' residues of hfurin(98-112) peptide, derived from the primary cleavage site of furin's own prodomain. The resulting hexadecapeptide derivative inhibited furin in vitro with IC(50) approximately 40 nM when measured against the fluorogenic substrate Boc-RVRR-MCA. It also inhibited furin-mediated cleavage of a fluorogenic peptide derived from hSARS-CoV spike protein with IC(50) approximately 193 nM. Additionally it also blocked furin-processing of growth factors proPDGF-A, B and VEGF-C that are linked to tumor genesis and cancer. Circular dichroism study showed that this inhibitor displayed a predominantly beta-turn structure while western blots confirmed its ability to protect furin protein from self degradation.


CONCLUSIONS
These findings imply its potential as a therapeutic agent for intervention of cancer and other furin-associated diseases.
Basak
Ajoy
A
Department of Biochemistry, Chronic Diseases Program, Regional Protein Chemistry Center, Ottawa Hospital Research Institute, University of Ottowa, Ottawa, Canada. abasak@ohri.ca
Khatib
Abdel-Majid
AM
Mohottalage
Dayani
D
Basak
Sarmistha
S
Kolajova
Maria
M
Bag
Subhendu Sekhar
SS
Basak
Amit
A
D000595:Amino Acid Sequence; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002942:Circular Dichroism; D003374:Coumarins / Q000737:chemistry; D015195:Drug Design; D045683:Furin / Q000037:antagonists & inhibitors*; D006801:Humans; D020128:Inhibitory Concentration 50; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism*; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism*
D003374:Coumarins; D009842:Oligopeptides; D010455:Peptides; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; C467486:VEGFC protein, human; D042582:Vascular Endothelial Growth Factor C; C075278:platelet-derived growth factor A; C089959:tert-butoxycarbonyl-arginyl-valyl-arginyl-arginyl-methylcoumarin amide; D045683:Furin