Estrogen receptor aα enhances the transcriptional activity of ETS-1 and promotes the proliferation, migration and invasion of neuroblastoma cell in a ligand dependent manner

Abstract

Background: It is well known that estrogen receptor aα (ERaα) participates in the pathogenic progress of breast cancer, hepatocellular carcinoma and head and neck squamous cell carcinoma. In neuroblastoma cells and related cancer clinical specimens, moreover, the ectopic expression of ERaα has been identified. However, the detailed function of ERaα in the proliferation of neuroblastoma cell is yet unclear. Methods: The transcriptional activity of ETS-1 (E26 transformation specific sequence 1) was measured by luciferase analysis. Western blot assays and Real-time RT-PCR were used to examine the expression of ERaα, ETS-1 and its targeted genes. The protein-protein interaction between ERaα and ETS-1 was determined by co-IP and GST-Pull down assays. The accumulation of ETS-1 in nuclear was detected by western blot assays, and the recruitment of ETS-1 to its targeted gene's promoter was tested by ChIP assays. Moreover, SH-SY5Y cells' proliferation, anchor-independent growth, migration and invasion were quantified using the MTT, soft agar or Trans-well assay, respectively. Results: The transcriptional activity of ETS-1 was significantly increased following estrogen treatment, and this effect was related to ligand-mediated activation of ERaα. The interaction between the ERaα and ETS-1 was identified, and enhancement of ERaα activation would up-regulate the ETS-1 transcription factor activity via modulating its cytoplasm/nucleus translocation and the recruitment of ETS-1 to its target gene's promoter. Furthermore, treatment of estrogen increased proliferation, migration and invasion of neuroblastoma cells, whereas the antagonist of ERaα reduced those effects. Conclusions: In this study, we provided evidences that activation of ERaα promoted neuroblastoma cells proliferation and up-regulated the transcriptional activity of ETS-1. By investigating the role of ERaα in the ETS-1 activity regulation, we demonstrated that ERaα may be a novel ETS-1 co-activator and thus a potential therapeutic target in human neuroblastoma treatment.