In order for cancer cells to survive during metastasis, they must overcome anoikis, a caspase-dependent cell death process triggered by extracellular matrix (ECM) detachment, and rectify detachment-induced metabolic defects that compromise cell survival. However, the precise signals used by cancer cells to facilitate their survival during metastasis remain poorly understood. We have discovered that oncogenic Ras facilitates the survival of ECM-detached cancer cells by using distinct effector pathways to regulate metabolism and block anoikis. Surprisingly, we find that while Ras-mediated phosphatidylinositol (3)-kinase signaling is critical for rectifying ECM-detachment-induced metabolic deficiencies, the critical downstream effector is serum and glucocorticoid-regulated kinase-1 (SGK-1) rather than Akt. Our data also indicate that oncogenic Ras blocks anoikis by diminishing expression of the phosphatase PHLPP1 (PH Domain and Leucine-Rich Repeat Protein Phosphatase 1), which promotes anoikis through the activation of p38 MAPK. Thus, our study represents a novel paradigm whereby oncogene-initiated signal transduction can promote the survival of ECM-detached cells through divergent downstream effectors. Cell Death and Differentiation (2016) 23, 1271-1282 doi:10.1038/cdd.2016 published online 26 February 2016 Cancer metastasis, the spread of cancer cells to distant parts of the body, accounts for~90% of cancer-related deaths and represents an inherently difficult clinical challenge.1,2 It has become clear that for successful metastasis to occur, cells must overcome a caspase-dependent cell death mechanism, anoikis, which is triggered by detachment from the extracellular matrix (ECM).3 In addition to anoikis evasion, cancer cells must also contend with anoikis-independent cellular alterations that can compromise cellular viability. 4 Chief among these alterations are metabolic deficiencies that are induced by ECM detachment. [5][6][7] These metabolic alterations involve deficiencies in ATP generation, elevated levels of reactive oxygen species, and the induction of autophagy. 6,8,9 Although recent studies have begun to unravel the strategies used by cancer cells to ameliorate metabolic deficiencies during ECM detachment, 10 the signal-transduction cascades responsible for regulating metabolism during ECM detachment in cancer cells remain almost entirely unexplored.The activation of oncogenic signaling pathways is critical to anchorage-independent growth and ultimately to the survival of a variety of distinct cancer cell types during ECM detachment. 4,11 Presumably, this oncogenic signaling is also necessary for resolving the aforementioned ECM-detachment-induced metabolic deficiencies. ErbB2 overexpression in mammary epithelial cells results in a stimulation of phosphatidylinositol (3)-kinase (PI(3)K)/Akt signaling to promote glucose uptake and ATP generation.6 These data raise the question as to how cancer cells that lack ErbB2 overexpression rectify metabolic deficiencies during ECM detachment. Does activation o...

1 The endothelium-dependent relaxation of blood vessels induced by P2y-purinoceptor activation has often been shown to involve prostacyclin and/or nitric oxide (NO) release. In this work, we have investigated the mechanisms involved in the relaxant effect of the P2y agonist, adenosine -5'-O-(2-thiodiphosphate) (ADPflS) using two complementary preparations: rat pancreatic vascular bed and aortic ring.2 On the pancreatic vascular bed, ADPPS (1.5 and 15 gM) infused for 30 min induced a concentrationdependent vasodilatation; it was progressive during the first 10 min (first period) and sustained from 10 to 30 min (second period). Indomethacin (10 gM) delayed ADPBS-induced vasodilatation (1.5 and 15 guM) by about 6 min. N()-nitro-L-arginine methyl ester (L-NAME) (200 gM) suppressed the relaxation for about 5 min but thereafter ADPBS at the two concentrations progressively induced an increase in the flow rate. Even the co-administration of L-NAME and indomethacin did not abolish the ADPPSinduced vasorelaxation. 3 On 5-hydroxy tryptamine (5-HT) precontracted rings mounted in isometric conditions in organ baths, we observed that ADPPS induced a concentration-dependent relaxation of rings with a functional endothelium; this effect was stable for 25 min. The ADPPS relaxant effect was strongly inhibited by Reactive Blue 2 (30 gM) and was suppressed by pretreatment of rings with saponin (0.05 mg ml-' for 30 min), which also abolished the acetylcholine-induced relaxation. 4 ADPBS-induced relaxation of 5-HT precontracted rings is largely inhibited by indomethacin (100 or 10 pM) or L-NAME (100 gM). 5 We conclude that: the ADPBS-induced relaxation is endothelium-dependent, mediated by P2Y-purinoceptors, and at least in part linked to NO and prostacyclin release, depending on the preparation used. Furthermore, on the pancreatic vascular bed, (an)other mechanism(s) than prostacyclin and NO releases may be involved in ADPPS-induced vasodilatation.

Highlights d SGK1 promotes energy generation and anchorageindependent growth d SGK1 stimulates glucose uptake due to elevated GLUT1 transcription d Pentose phosphate pathway flux is necessary for SGK1mediated energy generation d Defects in SGK1-mediated ATP generation are rescued by GAPDH activation

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