PT  - JOURNAL ARTICLE
AU  - Christopher M. Coulis
AU  - Chunja Lee
AU  - Violet Nardone
AU  - Rebecca D. Prokipcak
TI  - Inhibition of c-&lt;em&gt;myc&lt;/em&gt; Expression in Cells by Targeting an RNA-Protein Interaction Using Antisense Oligonucleotides
AID  - 10.1124/mol.57.3.485
DP  - 2000 Mar 01
TA  - Molecular Pharmacology
PG  - 485--494
VI  - 57
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/57/3/485.short
4100  - http://molpharm.aspetjournals.org/content/57/3/485.full
SO  - Mol Pharmacol2000 Mar 01; 57
AB  - Antisense oligodeoxynucleotides (ODNs) are designed to bind to and inhibit a target mRNA. We used a novel approach for the design of ODNs to the c-myc mRNA using protein binding sites as targets for ODN action. Our strategy was to identify ODNs that could interfere with the coding region determinant-binding protein (CRD-BP), a protein that binds to the CRD region of the c-myc mRNA. Using an in vitro gel shift assay, we show that ODN molecules can occlude the CRD-BP from the mRNA. The best ODN, CRD-ODN4, was able to inhibit RNA binding of the CRD-BP by 75%. This effect was sequence-specific and concentration dependent. K562 cells treated with a 2′-O-methyl derivative of CRD-ODN4 showed a concentration-dependent decrease in both c-myc mRNA and protein levels, with a maximal 65% inhibition of protein expression at 200 nM CRD-ODN4. In contrast, a 2′-O-methyl ODN derivative targeting the translation initiation codon (antimyc-aug) reduced c-myc protein but actually increased mRNA levels, an effect resulting at least partly from stabilization of the c-myc mRNA. CRD-ODN4 treatment did not alter the c-myc mRNA half-life. CRD-ODN4 was more effective in inhibiting K562 cell growth than antimyc-aug, reducing cell number by ≈70% after 48 h of exposure to 750 nM. The correlation between ODN effects on RNA-protein interactions in vitro and those observed in cells supports the hypothesis that CRD-ODN4 inhibits the interaction between the CRD-BP and the c-myc mRNA and that disrupting this RNA-protein interaction reduces c-mycexpression in cells.