Figure 4.

Proangiogenic role of MMP2 in tumor metastasis and skeletal development. MMP2 promotes angiogenesis in multiple ways: 1, Degradation of vascular basement membrane and extracellular matrix, and cell-cell adhesion cleavage; 2, Detachment of pericytes and migration of endothelial cells; 3, increased release and activation of ECM-bound angiogenic growth factors, such as VEGF, bFGF and TGF-β; 4, potential increase in the secretion of PDGF-BB through induction of osteoclast differentiation and maturation. Angiogenesis is coupled with osteogenesis during skeletal development, but supports tumor cell-induced osteolysis during metastasis. bFGF, basic fibroblast growth factor; CatK, cathepsin K; ECM, extracellular matrix; MMP, matrix metalloproteinase; TRAP, tartrate-resistant acid phosphatase.