Fig. 1. miR-451 is down-regulated by tamoxifen in ER-positive breast cancer cells and its expression is inversely correlated with 14-3-3ζ in MCF7 and tamoxifen resistant (Tam^R) cells.

A) Regulation of miR-451 in MCF7 cells by the estrogen receptor ligands Tamoxifen (Tam, 1μM), Raloxifene (Ral, 1μM), estradiol (E2, 10nM), and ICI 182,780 (ICI Fulvestrant, 1μM) or 0.1μM Tam plus 3μM ICI, after 0, 4, and 24 h of treatment. ERα was also depleted from cells by treatment with siRNA for ERα prior to Tam treatment for 0, 4, and 24h. B) RNA Polymerase II (Pol II) recruitment to the transcription start site (TSS) of miR-451 in the presence of Veh or Tam for the times indicated. C) Absence of regulation of the adjacent miR-144 by the four estrogen receptor ligands. D) Levels of miR-451 in MCF7 and Tam^R breast cancer cells detected by qPCR. E-F) Change in 14-3-3ζ and miR-451 levels analyzed by quantitative RT-PCR in MCF7 and Tam^R cells after treatment with Tam. Values are fold expression compared with vehicle control. Each experiment was performed in triplicate with three experimental replicates. Insert in panel E shows 14-3-3ζ detected by Western blot.