Nanomolar Cellular Antisense Activity of Peptide Nucleic Acid (PNA) Cholic Acid ("Umbrella") and Cholesterol Conjugates Delivered by Cationic Lipids

Takehiko Shiraishi, Peter E Nielsen

34 Citationer (Scopus)

Abstract

Limited cellular uptake and low bioavailability of peptide nucleic acids (PNAs) have restricted widespread use of PNAs as antisense/antigene agents for cells in culture and not least for in vivo applications. We now report the synthesis and cellular antisense activity in cultured HeLa pLuc705 cells of cholesterol and cholic acid ("umbrella") derivatives of splice correction antisense PNA oligomers. While the conjugates alone were practically inactive up to 1 µM, their activity was dramatically improved when delivered by a cationic lipid transfection agent (LipofectAMINE2000). In particular, PNAs, conjugated to cholesterol through an ester hemisuccinate linker or to cholic acid, exhibited low nanomolar activity (EC(50) ~ 25 nM). Excellent sequence specificity was retained, as mismatch PNA conjugates did not show any significant antisense activity. Furthermore, we show that increasing the transfection volume improved transfection efficiency, suggesting that accumulation (condensation) of the PNA/lipid complex on the cellular surface is part of the uptake mechanism. These results provide a novel, simple method for very efficient cellular delivery of PNA oligomers, especially using PNA-cholic acid conjugates which, in contrast to PNA-cholesterol conjugates, exhibit sufficient water solubility. The results also question the generality of using cholic acid "umbrella" derivatives as a delivery modality for antisense oligomers.
OriginalsprogEngelsk
TidsskriftBioconjugate Chemistry
Vol/bind23
Udgave nummer2
Sider (fra-til)196-202
Antal sider7
ISSN1043-1802
DOI
StatusUdgivet - 15 feb. 2012

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