Inhibition of MDR1 gene expression by chimeric HNA antisense oligonucleotides.
Hexitol nucleic acids (HNAs) are nuclease resistant and provide strong hybridization to RNA. However, there is relatively little information on the biological properties of HNA antisense oligonucleotides. In this study, we compared the antisense effects of a chimeric HNA 'gapmer' oligonucleotide comprising a phosphorothioate central sequence flanked by 5' and 3' HNA sequences to conventional phosphorothioate oligonucleotides and to a 2'-O-methoxyethyl (2'-O-ME) phosphorothioate 'gapmer'. The antisense oligomers each targeted a sequence bracketing the start codon of the message of MDR1, a gene involved in multi-drug resistance in cancer cells. Antisense and control oligonucleotides were delivered to MDR1-expressing cells using transfection with the cationic lipid Lipofectamine 2000. The anti-MDR1 HNA gapmer was substantially more potent than a phosphorothioate oligonucleotide of the same sequence in reducing expression of P-glycoprotein, the MDR1 gene product. HNA and 2'-O-ME gapmers displayed similar potency, but a pure HNA antisense oligonucleotide (lacking the phosphorothioate 'gap') was ineffective, indicating that RNase H activity was likely required. Treatment with anti-MDR1 HNA gapmer resulted in increased cellular accumulation of the drug surrogate Rhodamine 123 that correlated well with the reduced cell surface expression of P-glycoprotein. Thus, HNA gapmers may provide a valuable additional tool for antisense-based investigations and therapeutic approaches.
Kang
Hyunmin
H
Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
Fisher
Michael H
MH
Xu
Dong
D
Miyamoto
Yuko J
YJ
Marchand
Arnaud
A
Van Aerschot
Arthur
A
Herdewijn
Piet
P
Juliano
Rudolph L
RL
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D041681:NIH 3T3 Cells; D016376:Oligonucleotides, Antisense / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D020112:Rhodamine 123 / Q000378:metabolism; D013402:Sugar Alcohols / Q000737:chemistry; D013873:Thionucleotides / Q000737:chemistry
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D005456:Fluorescent Dyes; D016376:Oligonucleotides, Antisense; D013402:Sugar Alcohols; D013873:Thionucleotides; D020112:Rhodamine 123