Arsenic Induces Functional Re-Expression of Estrogen Receptor α by Demethylation of DNA in Estrogen Receptor-Negative Human Breast Cancer
Figure 1
ERα mRNA and protein re-expression induced by arsenic trioxide in MDA-MB-231 cells (A) and Hs578T cells (B).
ERα protein re-expression induced by AZA (2.5 μmol/L for 4 days) in MDA-MB-231 cells (C). RT-PCR and Western blotting analysis showed the re-expression of ER mRNA and protein after exposure of cells to arsenic trioxide (1, 2, 4 μmol/L for 6 days), whereas SAM (200 μmol/L for 6 days) reduced the degree of re-expression. The ER-positive prototype, MCF-7, was used as a positive control; untreated ER-negative MDA-MB-231 cells were used as a negative control. GAPDH and β-Actin provided a control for the amount of intact RNA and protein used in the reactions. ## P<0.01 compared with control cells. # P<0.05 compared with control cells. *P<0.05 compared with cells exposed to 1 μM arsenic trioxide.