Specific Inhibition of DNMT1 by Antisense Oligonucleotides Induces Re-expression of Estrogen Receptor a (ER) in ER-negative Human Breast Cancer Cell Lines

Abstract
Recent studies have shown that changes in epigenetic regulation, such as DNA methylation and histone acetylation, are associated with silencing of the estrogen receptor _ (ER) gene in ER-negative human breast cancer cells. Treatment of these cells with the general DNMT inhibitor, 5-aza-2’deoxycytidine, led to reactivation of functional ER protein. This study addresses the hypothesis that specific inhibition of the maintenance DNA methyltransferase, DNMT1, by antisense oligonucleotides (DNMT1 ASO) is sufficient to re-express the ER gene in ER-negative human breast cancer cell lines. MDA-MB-231 and Hs578t cells were transfected with 100 nM and 150 nM DNMT1 ASO respectively for three consecutive days and evidence of DNMT1 down-regulation and functional ER re-expression was sought. Significant growth reduction was observed within 48 hr and persisted after 96 hr. DNMT1 expression was blocked after exposure to DNMT1 ASO as detected by RT-PCR, Western blot and enzymatic assay whereas a mutant DNMT1 ASO had littl...

This publication has 0 references indexed in Scilit: