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Title: Specific Inhibition of Estrogen Receptor Alpha Function by Antisense Oligodeoxyribonucleotides
Authors: Taylor, Anthony H.
Pringle, J. H.
Bell, Stephen C.
Al-Azzawi, Farook
First Published: 2001
Publisher: Mary Ann Liebert, Inc., on behalf of the Oligonucleotide Therapeutics Society (OTS)
Citation: Antisense and Nucleic Acid Drug Development, 2001, 11 (4), pp.219-231
Abstract: We have tested the effect of a range of antisense oligodeoxyribonucleotides (ODN) directed against the human estrogen receptor alpha (ERα) on ERα protein expression and function. Antisense ERα ODN transfected into the ERα-positive human breast carcinoma cell line MCF7-K2 showed variable responses dependent on the oligo used. The most active antisense ODN (oligo 7) decreased the levels of ERα protein by 61% as measured by Western blot analysis. Exogenous 17β-estradiol (17β-E2), but not 17α-E2, augmented this effect, with a threshold effect at 10-8 M 17β-E2. The inhibitory effect of antisense ERα oligo 7 was confirmed by measurement of functional ERα protein. 3H-17β-E2 binding to MCF7 cell extracts was inhibited to approximately 40% of control values in the presence of oligo 7. Antisense-transfected MCF7-K2 cell cultures produced a further 30% binding reduction in the presence of exogenous 17β-E2. An inhibitory effect on 17β-E2-dependent cell function was confirmed by the demonstration that ERα oligo 7-transfected MCF7-K2 cells failed to exhibit 17β-E2-stimulated cell proliferation. Exogenous 17β-E2 enhanced the inhibitory effect of the antisense ODN by increasing ODN transfection efficiency but without ERα catabolism via the proteosomal pathway, suggesting an effect of 17β-E2 on the plasma membrane and the existence of different ERα degradation pathways in the MCF7-K2 cell subclone. As 17β-E2 had no effect on ER α protein degradation, we conclude that the observed reduction of ER α protein levels is due solely to the presence of the antisense ERα ODN. Antisense ERα ODN molecules, therefore, may form the basis of effective therapies against ERα-dependent malignancies.
DOI Link: 10.1089/108729001317022223
ISSN: 1545-4576
eISSN: 1557-8526
Version: Publisher version
Status: Peer reviewed
Type: Article
Rights: Copyright © 2001 Mary Ann Liebert, Inc. Deposited with reference to the publisher's archiving policy available on the SHERPA/RoMEO website. This is a copy of an article published in Antisense and Nucleic Acid Drug Development (now Nucleic Acid Therapeutics). Antisense and Nucleic Acid Drug Development is available online at:
Appears in Collections:Published Articles, Dept. of Cancer Studies and Molecular Medicine

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