title: The Nitric Oxide Prodrug V-PROLI/NO Inhibits Cellular Uptake of Proline.
abstract: V-PYRRO/NO is a well studied nitric oxide (NO) prodrug which has been shown to protect human liver cells from arsenic, acetaminophen, and other toxic assaults in vivo. Its proline-based analogue, V-PROLI/NO, was designed to be a more biocompatible form that decomposes to the naturally occurring metabolites of proline, NO, and glycolaldehyde. Like V-PYRRO/NO, this cytochrome P450-activated prodrug was previously assumed to passively diffuse through the cellular membrane. Using (14)C-labeled proline in a competition assay, we show that V-PROLI/NO is transported through proline transporters into multiple cell lines. A fluorescent NO-sensitive dye (DAF-FM diacetate) and nitrite excretion indicated elevated intracellular NO release after metabolism over V-PYRRO/NO. These results also allowed us to predict and design a more permeable analogue, V-SARCO/NO. We report a proline transporter-based strategy for the selective transport of NO prodrugs that may have enhanced efficacy and aid in development of further NO prodrugs with increased permeability.
authors.affiliation: Chemistry Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at Frederick, Frederick, Maryland 21702.
authors.forename: Sam Y
authors.initials: SY
authors.lastname: Hong
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Borchert
authors.forename: Anna E
authors.initials: AE
authors.lastname: Maciag
authors.forename: Rahul S
authors.initials: RS
authors.lastname: Nandurdikar
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Saavedra
authors.forename: Larry K
authors.initials: LK
authors.lastname: Keefer
authors.forename: James M
authors.initials: JM
authors.lastname: Phang
authors.forename: Harinath
authors.initials: H
authors.lastname: Chakrapani