Fig. 3.

HIC1 is required for the transcriptional regulation of SIRT1 by 2-DG. (A) Decreased HIC1 levels in tumor cells are associated with loss of 2-DG-induced SIRT1 up-regulation. Human lung cancer cells (H1299) and primary human fibroblasts (CCD) were treated with 2-DG. Western blot (Left) shows the HIC1 and CtBP levels. SIRT1 RNA levels were measured by RT-PCR (Right). Data were normalized to 18S RNA and are represented as mean ± SEM from three independent experiments. (B) HIC1 rescues the 2-DG-induced SIRT1 up-regulation in tumor cells. H1299 lung cancer cells were transfected with HIC1, either WT or the GLDLSKK-deleted (mt) version, and treated with 2-DG. SIRT1 RNA was measured by RT-PCR and normalized to 18S RNA (Left). Data are represented as mean ± SEM from three independent experiments. Western blot shows the decreased binding of CtBP to the HIC1 GLDLSKK-deletion mutant compared with the WT (Right).