Inhibition of transcription of the human c-myc protooncogene by intermolecular triplex.


Triplex-forming oligonucleotides (TFOs) have been shown to inhibit both transcription in vitro and the expression of target genes in cell culture by binding to polypurine/polypyrimidine sequences in several human gene promoters. The c-myc protooncogene is overexpressed in a variety of human cancers and appears to play an important role in the proliferation of these cells. In an attempt to assay the ability of triplex-forming oligonucleotides to inhibit expression of a target gene in vivo, we have developed a cellular system involving transfection of a c-myc promoter-driven luciferase reporter plasmid with triplex-forming oligonucleotides targeted to the human c-myc protooncogene. To increase the stability of the TFO, we have used modified phosphorothioate oligonucleotides. Triplex formation with a modified phosphorothioate oligonucleotide occurs with approximately equal binding affinity as that seen using a phosphodiester oligonucleotide. Phosphorothioate-modified TFOs targeted to c-myc inhibit transcription of the c-myc promoter in HeLa cells as demonstrated by a decrease in luciferase expression from a luciferase reporter gene construct. These results suggests that triplex formation may represent a gene-specific means of inhibiting specific protooncogene expression.

Cite this paper

@article{Kim1998InhibitionOT, title={Inhibition of transcription of the human c-myc protooncogene by intermolecular triplex.}, author={Hyung Gyoon Kim and James F Reddoch and Charles A Mayfield and Scot W . Ebbinghaus and Nadarajah Vigneswaran and Steve Thomas and Douglas E. Jones and Daniel Menachem Miller}, journal={Biochemistry}, year={1998}, volume={37 8}, pages={2299-304} }