Transcriptional suppression of AMPK alpha 1 promotes breast cancer metastasis upon oncogene activation

AMP-activated protein kinase (AMPK) functions as an energy sensor and is pivotal in maintaining cellular metabolic homeostasis. Numerous studies have shown that down-regulation of AMPK kinase activity or protein stability not only lead to abnormality of metabolism but also contribute to tumor development. However, whether transcription regulation of AMPK plays a critical role in cancer metastasis remains unknown. In this study, we demonstrate that AMPK alpha 1 expression is down-regulated in advanced human breast cancer and is associated with poor clinical outcomes. Transcription of AMPK alpha 1 is inhibited on activation of PI3K and HER2 through Delta Np63 alpha. Ablation of AMPK alpha 1 expression or inhibition of AMPK kinase activity leads to disruption of E-cadherin-mediated cell-cell adhesion in vitro and increased tumor metastasis in vivo. Furthermore, restoration of AMPK alpha 1 expression significantly rescues PI3K/HER2-induced disruption of cell-cell adhesion, cell invasion, and cancer metastasis. Together, these results demonstrate that the transcription control is another layer of AMPK regulation and suggest a critical role for AMPK in regulating cell-cell adhesion and cancer metastasis.