Development of Triplex-Forming Oligonucleotides to Inhibit Expression of the c-myc Oncogene in Breast Cancer Cells
Abstract
Triple helix-forming oligonucleotides (TFOs) bind with high affinity and specificity to homopurine/homopyrimidine sequences in double-stranded DNA. Oligonucleotide- directed triplex formation in gene promoter regions has been shown to inhibit transcription of targeted genes. C-myc is a growth%-promoting oncogene that is deregulated and overexpressed in breast and other cancers. Our research is designed to assess TFO-mediated reduction of c-myc expression as a means of decreasing breast tumor growth. The purpose of the present work was to optimize the binding affinity and nuclease resistance of a previously studied myc-targeted TFO. A novel chimeric TFO was designed, consisting of two portions with dissimilar nucleotide content and opposite polarity. This TFO bound with approximately tenfold higher affinity than the TFO used in our previous study, and its double 5, ends conferred increased resistance to degradation by nucleases in vitro. Studies of the chimeric TFO's anti-gene activity in vitro and in cells are in progress. Further modifications may be added to enhance nuclease resistance in cells. In another series of experiments, we found that conjugation of a short experimental TFO to daunomycin, an intercalating agent, resulted in more stable triplex without loss of binding specificity. Further testing of daunomycin- conjugated TFOs is planned.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADA391394
Entities
People
- Carlo V. Catapano
- Eileen M. Mcguffie
Organizations
- Medical University of South Carolina