Fig. 4

Unmethylated THOR decreases reporter gene expression. A Schematic representation of the TERT promoter and the luciferase constructs with and without the presence of THOR and/or C228T TERTpmut are shown. THOR (gray) is a transcriptional regulatory element located upstream of the hTERT core promoter (yellow). B Normalized fold changes in hTERT promoter activity are shown for the specified luciferase constructs transfected into the BC cell lines MCF-7, MDA-MB-231, and BT-20. The addition of THOR to the hTERT core promoter significantly decreases reporter gene expression when compared to the hTERT core promoter alone, in the absence or presence of C228T mutation. Column bars represent the mean of 3 independent experiments ± SD. P values were determined using two-tailed, unpaired Student’s t test, *P < 0.05; **P < 0.01; ***P < 0.001. pGL4 empty vector, Core-hTERT core promoter, Core + Thor-hTERT core promoter plus THOR region, CoreM-hTERT core promoter with C228T mutation, CoreM + Thor-hTERT core promoter with C228T mutation plus THOR region