TKT and breast cancer: To test whether our novel ERRα ligand antagonizes the constitutive transcriptional activity of ERRα, we cotransfected MCF-7 breast cancer cells with the reporter plasmid p3xERE-TK-Luc or the ERE-negative control plasmid (pGL2 Luc) together with the control parental vector pcDNA3.1 and phRL-TK renilla plasmid for normalization.