title: Seneca Valley Virus 3Cpro Substrate Optimization Yields Efficient Substrates for Use in Peptide-Prodrug Therapy.
abstract: The oncolytic picornavirus Seneca Valley Virus (SVV-001) demonstrates anti-tumor activity in models of small cell lung cancer (SCLC), but may ultimately need to be combined with cytotoxic therapies to improve responses observed in patients. Combining SVV-001 virotherapy with a peptide prodrug activated by the viral protease 3Cpro is a novel strategy that may increase the therapeutic potential of SVV-001. Using recombinant SVV-001 3Cpro, we measured cleavage kinetics of predicted SVV-001 3Cpro substrates. An efficient substrate, L/VP4 (kcat/KM = 1932 ± 183 M(-1)s(-1)), was further optimized by a P2' N→P substitution yielding L/VP4.1 (kcat/KM = 17446 ± 2203 M(-1)s(-1)). We also determined essential substrate amino acids by sequential N-terminal deletion and substitution of amino acids found in other picornavirus genera. A peptide corresponding to the L/VP4.1 substrate was selectively cleaved by SVV-001 3Cpro in vitro and was stable in human plasma. These data define an optimized peptide substrate for SVV-001 3Cpro, with direct implications for anti-cancer therapeutic development.
authors.affiliation: Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Linde A
authors.initials: LA
authors.lastname: Miles
authors.affiliation: Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: W Nathaniel
authors.initials: WN
authors.lastname: Brennen
authors.affiliation: Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America; Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Rudin
authors.affiliation: Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: John T
authors.initials: JT
authors.lastname: Poirier
mesh_terms: D000086042:3C Viral Proteases; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D010849:Picornaviridae / Q000201:enzymology*; D013379:Substrate Specificity; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases