Inhibition of the erbB-2 tyrosine kinase receptor in breast cancer cells by phosphoromonothioate and phosphorodithioate antisense oligonucleotides.
Antisense activity against erbB-2 of a variety of sulfur-modified oligonucleotides was examined in a breast cancer cell line which overexpresses this oncogene. Using a 15 base anti-erbB-2 sequence previously shown to be effective, various backbone configurations containing phosphoromonothioate or phosphorodithioate linkages were evaluated for antisense activity by a two-color flow cytometric assay. This sequence was effective in inhibiting the production of erbB-2 protein when it was configured as a monothioate at each linkage and as an alternating dithioate/phosphodiester. Both of these compounds were also able to specifically inhibit erbB-2 mRNA expression, indicative of RNase H-mediated activity. The same sequence protected by either three dithioate or three monothioate linkages at each end was ineffective as an antisense reagent, suggesting that endonuclease activity is a significant determinant of the stability of oligonucleotides. Finally, the erbB-2 sequence target was shifted in an effort to improve antisense activity. A new lead sequence was identified that was significantly more effective in inhibiting erbB-2 protein levels and retained activity at lower concentrations.
Vaughn
J P
JP
Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA.
Stekler
J
J
Demirdji
S
S
Mills
J K
JK
Caruthers
M H
MH
Iglehart
J D
JD
Marks
J R
JR
D001483:Base Sequence; D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured
D016376:Oligonucleotides, Antisense; D020794:Receptor Protein-Tyrosine Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases