Recent findings indicate that tumor-associated macrophages are important drivers of tumor angiogenesis. Here, we review the essential role played by Tie2-expressing monocytes (TEM) in this phenomenon. TEMs are present in human blood and tumors and their elimination in various tumor models suppresses tumor angiogenesis. A ligand for Tie2, angiopoietin-2 (Ang-2), is produced by angiogenic tumor vessels and is a chemoattractant for TEMs. Hypoxia up-regulates Tie2 expression on TEMs and, together with Ang-2, down-regulates their antitumor functions. Learning more about the regulation of TEMs by the tumor microenvironment may yield new strategies to ablate the tumor vasculature.
Michele De Palma, Douglas Hanahan
Freddy Radtke, Nadine Fournier, Etienne Meylan, Justine Pascual, Amber Dawn Bowler, Anita Bodac, Vincent Roh
Didier Trono, Priscilla Turelli, Sandra Eloise Kjeldsen, Evaristo Jose Planet Letschert, Filipe Amândio Brandão Sanches Vong Martins, Florian Huber, Cyril David Son-Tuyên Pulver, Olga Marie Louise Rosspopoff, Romain Forey, Joana Carlevaro Fita