Inhibition of interferon-gamma-induced intercellular adhesion molecule-1 expression on human keratinocytes by phosphorothioate antisense oligodeoxynucleotides is the consequence of antisense-specific and antisense-non-specific effects.
Expression of intercellular adhesion molecule-1 (ICAM-1) by keratinocytes is an important event in the pathogenesis of T-cell-mediated inflammatory skin diseases. To determine if ICAM-1 expression could be selectively modulated, two antisense phosphorothioate oligonucleotides (S-ODN) targeting the translation initiation and 3' untranslated regions of ICAM-1 mRNA were added as lipid complexes to cultures of keratinocytes. Interferon-gamma was added after 24 h to induce ICAM-1 expression, which was quantitated by flow cytometry after 48 h. The S-ODN targeting the translation initiation site did not inhibit ICAM-1 expression at 0.2-20.0 microM. In contrast, 0.2-1.0 microM of the S-ODN targeting a site in the 3' untranslated region abrogated ICAM-1 expression in up to 75% of the keratinocytes; this inhibition was reversible when complementary sense S-ODN was added. Phosphodiester ODN (PD-ODN) targeting the same sites did not inhibit ICAM-1 expression on keratinocytes, most likely as a consequence of rapid degradation. Inhibition of ICAM-1 by the antisense S-ODN was selective; expression of beta 2-microglobulin, alpha 3-integrin, and beta 1-integrin remained largely unaffected and interferon-gamma-induced HLA-DR expression was inhibited to a much lesser extent than ICAM-1. Antisense-non-specific inhibition was also noted in that two scrambled S-ODN with an identical nucleotide (14 of 20 cytosines) composition inhibited ICAM-1 expression in up to 44% of the keratinocytes, whereas a degenerate S-ODN did not. The data demonstrate the complex effects exerted by antisense S-ODN in that ICAM-1 expression was inhibited via antisense-non-specific mechanisms probably due to the intrinsic properties of the S-ODN as well as via the anticipated sequence-specific mechanisms.
Hertl
M
M
Dermatology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA.
Neckers
L M
LM
Katz
S I
SI
D001483:Base Sequence; D003872:Dermatitis / Q000503:physiopathology; D006684:HLA-DR Antigens / Q000502:physiology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000187:drug effects* / Q000502:physiology*; D007371:Interferon-gamma / Q000494:pharmacology*; D015603:Keratinocytes / Q000737:chemistry*; D008081:Liposomes; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010714:Phosphatidylethanolamines / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology*; D015854:Up-Regulation / Q000502:physiology
D006684:HLA-DR Antigens; D008081:Liposomes; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D010714:Phosphatidylethanolamines; D013873:Thionucleotides; D018799:Intercellular Adhesion Molecule-1; C020888:1,2-dielaidoylphosphatidylethanolamine; D007371:Interferon-gamma