ERRα is involved in TFG-β induced transcription of Snail in osteosarcoma cells. MG-63 and HOS cells were treated with increasing concentrations of XCT-790 (A) or transfected with si-ERRα for 24 h, the expression of Snail mRNA were analyzed by qRT-PCR; (C) MG-63 cells were treated with TFG-β (20 ng/ml), XCT-790 (2 μM) or both of them for 24 h, the expression of Snail mRNA were analyzed by qRT-PCR; (D) MG-63 cells were transfected with si-ERRα or si-NC for 24 h and then treated with TFG-β (20 ng/ml) for 24 h, the expression of Snail mRNA were analyzed by qRT-PCR; MG-63 (E) or HOS (F) cells were transfected with siNC or si-Snail for 24 h and then further treated with TFG-β (20 ng/ml) for another 24 h, the mRNA expression of ERRα were measured by use of qRT-PCR. Data were presented as means ± SD of 3 independent experiments. **p < 0.01 compared with control.