SGK1 Signaling Promotes Glucose Metabolism and Survival in Extracellular Matrix Detached Cells

Abstract

Loss of integrin-mediated attachment to extracellular matrix (ECM) proteins can trigger a variety of cellular changes that impact cell viability. Foremost among these is the activation of anoikis, caspase-mediated cell death induced by ECM-detachment. In addition to anoikis, loss of ECM-attachment causes profound alterations in cellular metabolism that can lead to anoikis-independent cell death. Here, we describe a surprising role for serum and glucocorticoid kinase-1 (SGK1) in the promotion of energy production when cells are detached. Our data demonstrate that SGK1 activation is necessary and sufficient for ATP generation during ECM-detachment and anchorage-independent growth. More specifically, SGK1 promotes a substantial elevation in glucose uptake due to elevated GLUT1 transcription. In addition, carbon flux into the pentose phosphate pathway (PPP) is necessary to accommodate elevated glucose uptake and PPP-mediated glyceraldehyde-3-phosphate (G3P) is necessary for ATP production. Thus, our data unmask SGK1 as master regulator of glucose metabolism and cell survival during ECM-detached conditions.