Ampk Alpha 1 Deletion In Fibroblasts Promotes Tumorigenesis In Athymic Nude Mice By P52-Mediated Elevation Of Erythropoietin And Cdk2

Angiogenesis is essential for tumor development. Accumulating evidence suggests that adenosine monophosphate-activated protein kinase (AMPK), an energy sensor and redox modulator, is associated with cancer development. However, the effect of AMPK on tumor development is controversial, and whether AMPK affects tumor angiogenesis has not been resolved. We show that deletion of AMPK alpha 1, but not AMPK alpha 2, upregulates non-canonical nuclear factor kappa B2 (NF-kappa B2)/p52-mediated cyclin-dependent kinase 2 (CDK2), which is responsible for the anchorage-independent cell growth of immortalized mouse embryo fibroblasts (MEFs). Co-culture with AMPK alpha 1 knockout MEFs (or their conditioned medium) enhances the migration and network formation of human microvascular endothelial cells, which is dependent on p52-upregulated erythropoietin (Epo). AMPK alpha 1 deletion stimulates cellular proliferation of allograft MEFs, angiogenesis, and tumor development in athymic nu/nu mice, which is partly ameliorated by antibody-mediated Epo neutralization. Therefore, the AMPK alpha 1-p52-Epo pathway may be involved in stromal fibroblast-mediated angiogenesis and tumorigenesis.