Fluctuating Roles of Matrix Metalloproteinase-9 in Oral Squamous Cell Carcinoma

Figure 2

Schematic picture of the events that are modulated by MMP-9 in oral cancer. Proteolytic degradation of ECM components (including types III, IV, and V collagens, as well as gelatin) by MMP-9 facilitates carcinoma cell invasion and leads to the release of growth factors, such as VEGF, that enhance angiogenesis and tumor progression. At the same time anti-antiangiogenic endostatin, angiostatin, and tumstatin are released. Processing of proinflammatory chemokines (CXCL1, -4, -8, -9, -11, -12), proforms of cytokines (proTNF-α, proIL-1β), cell adhesion proteins such as intercellular adhesion molecule-1 triggers an inflammatory reaction and modulates transcription factors leading to an epithelial-to-mesenchymal transition and enhanced carcinogenesis.