mTORC2 mediates CXCL12-induced angiogenesis.
The chemokine CXCL12, through its receptor CXCR4, positively regulates angiogenesis by promoting endothelial cell (EC) migration and tube formation. However, the relevant downstream signaling pathways in EC have not been defined. Similarly, the upstream activators of mTORC2 signaling in EC are also poorly defined. Here, we demonstrate for the first time that CXCL12 regulation of angiogenesis requires mTORC2 but not mTORC1. We find that CXCR4 signaling activates mTORC2 as indicated by phosphorylation of serine 473 on Akt and does so through a G-protein- and PI3K-dependent pathway. Significantly, independent disruption of the mTOR complexes by drugs or multiple independent siRNAs reveals that mTORC2, but not mTORC1, is required for microvascular sprouting in a 3D in vitro angiogenesis model. Importantly, in a mouse model, both tumor angiogenesis and tumor volume are significantly reduced only when mTORC2 is inhibited. Finally, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), which is a key regulator of glycolytic flux, is required for microvascular sprouting in vitro, and its expression is reduced in vivo when mTORC2 is targeted. Taken together, these findings identify mTORC2 as a critical signaling nexus downstream of CXCL12/CXCR4 that represents a potential link between mTORC2, metabolic regulation, and angiogenesis.
The Department of Molecular Biology and Biochemistry, University of California Irvine, 3219 McGaugh Hall, Mail Code: 3900, Irvine, CA, 92697, USA.
Mary E
ME
Ziegler
The Department of Molecular Biology and Biochemistry, University of California Irvine, 3219 McGaugh Hall, Mail Code: 3900, Irvine, CA, 92697, USA.
Michaela M S
MM
Hatch
The Department of Molecular Biology and Biochemistry, University of California Irvine, 3219 McGaugh Hall, Mail Code: 3900, Irvine, CA, 92697, USA.
Nan
N
Wu
The Department of Molecular Biology and Biochemistry, University of California Irvine, 3219 McGaugh Hall, Mail Code: 3900, Irvine, CA, 92697, USA.
Steven A
SA
Muawad
The Department of Molecular Biology and Biochemistry, University of California Irvine, 3219 McGaugh Hall, Mail Code: 3900, Irvine, CA, 92697, USA. cchughes@uci.edu.|The Department of Biomedical Engineering, University of California Irvine, Irvine, CA, 92697, USA. cchughes@uci.edu.|The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, Irvine, CA, 92697, USA. cchughes@uci.edu.
Christopher C W
CC
Hughes
D000818:Animals; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000502:physiology*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1 / Q000502:physiology; D000076225:Mechanistic Target of Rapamycin Complex 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D051379:Mice; D009389:Neovascularization, Pathologic / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D018919:Neovascularization, Physiologic; D025481:Phosphofructokinase-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D019718:Receptors, CXCR4 / Q000502:physiology; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology
D054377:Chemokine CXCL12; D034741:RNA, Small Interfering; D019718:Receptors, CXCR4; C000595376:PFKFB3 protein, mouse; D025481:Phosphofructokinase-2; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D020123:Sirolimus
Akt; Angiogenesis; CXCL12; CXCR4; mTOR; mTORC2