GATA6 is overexpressed in breast cancer and promotes breast cancer cell epithelial-mesenchymal transition by upregulating slug expression.

Metastasis is the leading cause of death in breast cancer (BC) patients. However, until now, the mechanisms of BC metastasis remain elusive. GATA6 is a member of the GATA transcription factor family that plays critical regulatory roles in tissue development, which has been proposed as an oncogene in many types of tumors; however, its role and underlying mechanisms in BC remain unclear. Here we show that GATA6 is elevated in BC and its expression level is positively correlated with metastasis. In addition Kaplan-Meier survival analysis showed that high expression of GATA6 was associated with decreased overall survival of BC patients. Overexpression of GATA6 in BC cells increased epithelial-mesenchymal transition. In contrast, silencing GATA6 in aggressive BC cells inhibited this process. Mechanistically, we found GATA6 exerts its function through active slug transcription. Slug knockdown blocked the GATA6-driven EMT. Furthermore, slug expression in human BC is positively correlated with GATA6 expression. Our results, for the first time, portray a pivotal role of GATA6 in regulating metastatic behaviors of BC cells, suggesting GATA6 is a potential therapeutic target in metastatic BCs.