Figure 8.

When solid tumors reach a few millimeters in diameter, hypoxic stress is induced, which leads to ADAM8 induction resulting in strong pro-angiogenic signaling, in part via VEGF-A release into the extracellular compartment, and endothelial cell recruitment. ADAM8 also promotes β1-integrin activation on tumor cells needed for their adhesion onto and transmigration through the blood vessel wall, which supports dissemination of CTCs and development of metastases. Importantly, here we demonstrate that if the induction of ADAM8 is blocked or its activity inhibited with antibody, there is an insufficient angiogenic response, leading to tumor mass dormancy or slowing of growth, as well as to a striking reduction of CTCs and metastases.