Fig. 9.

SIRT1 regulates DNMT1-mediated silencing of TSGs. (A and B) MDA-MB-231 (A) and MCF-7 (B) cells were treated with 0.3 μM TSA for 12 h, 15 mM nicotinamide for 12 h, 300 μM splitomicin for 24 h, or 1 μM EX-527 for 6 h. Some cultures also received 50 μM 5-aza-dC for 48 h. (C) MDA-MB-231 cells with plasmids that express either Myc-SIRT1 or SIRT1 shRNA. Expressions of ESR1 and CDH1 mRNA were determined by quantitative real-time PCR. The RNA of untreated MCF-7 cells was used as positive control and for generation of a standard curve. 18S RNA was used as the internal control. Amounts of PCR-amplified ESR1 mRNA and CDH1 mRNA were determined from the standard curve and normalized to the amount of 18S RNA. Results from averages of three experiments with standard deviations are depicted as fold of untreated control. SIRT1 protein expressions were assessed using Western blot assays (right).