Laboratory of Comparative Carcinogenesis

Frederick, MD, United States

Laboratory of Comparative Carcinogenesis

Frederick, MD, United States

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Hong S.Y.,Laboratory of Comparative Carcinogenesis | Borchert G.L.,SAIC | MacIag A.E.,SAIC | Nandurdikar R.S.,Laboratory of Comparative Carcinogenesis | And 4 more authors.
ACS Medicinal Chemistry Letters | Year: 2010

V-PYRRO/NO is a well-studied nitric oxide (NO) prodrug that 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 14C-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 the development of further NO prodrugs with increased permeability. © 2010 American Chemical Society.


Sithanandam G.,SAIC | Fornwald L.W.,SAIC | Fields J.R.,Laboratory of Comparative Carcinogenesis | Morris N.L.,SAIC | Anderson L.M.,Laboratory of Comparative Carcinogenesis
International Journal of Cancer | Year: 2012

The use of siRNAs against specific molecular targets has potential for cancer therapy but has been thought to be limited by the need for formulation to improve cellular uptake. Lung adenocarcinoma cells are markedly suppressed in culture by siRNAs to the receptor ERBB3 or its downstream signaling partner AKT2. We now demonstrate that naked, unformulated siRNAs to ERBB3 or AKT2, administered i.v. as saline solutions, 2 μg/g five times per week for 3 weeks (total dose 30 μg/g), were effective suppressors of growth of A549 human lung adenocarcinoma cell xenografts in athymic mice, 12 mice per group, in four different experiments. ERBB3 and AKT2 siRNAs each inhibited growth by 70-90% on average, compared to saline-treated or untreated controls; a nonsilencing siRNA was without significant effect. Lesser but significant effects were noted with a total dose of 12 μg/g. With the higher dose, effects persisted for several weeks after the end of treatment. Expected reductions of ERBB3 and AKT2 mRNAs and proteins occurred and correlated with decrease in tumor volume. There were no significant changes in serum cytokines. These results show that naked siRNAs to ERBB3 or AKT2 may have potential for lung cancer therapy. Copyright © 2011 UICC.

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