Androgen enhances the activity of ETS-1 and promotes the proliferation of HCC cells

The expression of androgen receptor (AR) has been detected in hepatocellular cancer (HCC). However, there is no universal model detailing AR's function and mechanism in HCC. This study's results show that treatment with dihydrotestosterone (DHT), an endogenous androgen, promoted HCC cells' proliferation and up-regulated the transcription factor activity of ETS-1 (E26 transformation specific sequence 1), which mediates the migration and invasion of cancer cells via protein-protein interaction between AR and ETS-1. Results from luciferase assays showed that ETS-1's activity was significantly up-regulated following androgen treatment. AR mediated ETS-1's DHT-induced transcription factor activity. A potential protein-protein interaction between ETS-1 and AR was identified via glutathione S-transferase (GST) pull-down and co-immunoprecipitation assays. The mechanisms' data indicated that enhancing AR activity increases ETS-1's activity by modulating its cytoplasmic/nuclear translocation and recruiting ETS-1 to its target genes' promoter. Moreover, while overexpression of AR significantly increased the proliferation or in vitro migration or invasion of HepG2 cells in the presence of androgen, inhibiting AR's activity reduced these abilities. Thus, AR's function as a novel ETS-1 co-activator or potentially therapeutic target of HCC has been demonstrated.