Tumoral and macrophage uPAR and MMP-9 contribute to the invasiveness of B16 murine melanoma cells

Abstract

The aim of this study was to investigate whether tumor cells as well as tumor-associated macrophages (TAMs) contribute to the generation of protease activities essential to tumor cell invasiveness, such as matrix metalloproteinase 2 and 9 (MMP-2 and MMP-9), and the urokinase-type plasminogen activator (uPA) and uPA receptor (uPAR). We found that the enhanced invasiveness through Matrigel-coated filters of B16 murine melanoma cells stimulated with IFNc was associated with an higher expression of uPAR and MMP-9 in these cells. Moreover, treatment with anti-MMP-9 or anti-uPAR monoclonal antibodies abrogated the increase of invasiveness in IFNcstimulated melanoma cells, suggesting a cooperation of uPA system and MMP-9 in cytokine-stimulated invasiveness. Invasiveness through Matrigel was also enhanced in B16 melanoma cells exposed to a medium conditioned by TAMs, represented in our experimental model by thioglycollate-elicited macrophages co-cultivated with melanoma cells. Macrophages isolated from these co-cultures were found to express higher levels of uPAR and MMP-9 compared to macrophage cultures alone, and the pro-invasive activity of the co-culture-conditioned medium was abrogated by anti-MMP-9 monoclonal antibodies, but not anti-uPAR monoclonal antibodies. Furthermore, the enhanced uPAR and MMP-9 expression in macrophages cocultivated with tumor cells seems a rather specific phenomenon, generated through a cell-to-cell contact mechanism. On the whole, our data point to a cooperation between tumor cells and macrophages elicited by tumor cells themselves in generating key enzymes essential in the promotion of tumor invasiveness, such as uPAR and MMP-9.Keywords Murine melanoma cells Á Macrophages Á Cell invasiveness Á Matrix metalloproteinase 2 (MMP-2) and 9 (MMP-9) Á Urokinase-type plasminogen activator (uPA) and uPA receptor (uPAR)

A Macrophage-Dominant PI3K Isoform Controls Hypoxia-Induced HIF1α and HIF2α Stability and Tumor Growth, Angiogenesis, and Metastasis

“…5C). Consistent with this, existing literature suggests that TAMs secrete several proteins including MMP-9 (41), uPA (42), and VEGF (43), which promote tumor growth, angiogenesis, and metastasis. IL1 and TNFa are proinflammatory cytokines which are reported to be expressed at a lower level in tumor-associated M2 macrophages and are known to promote tumor suppression (44).…”

Macrophages in skin melanoma-the key element in melanomagenesis (Review)

“…TAMs additionally produces protease-like proteins which promote melanoma invasion (9,24,40). It has been demonstrated that melanoma-associated macrophages synthesize large amounts of MMP-9 and urokinase-type plasminogen activator receptor (uPAR) as a result of direct contact with melanoma cells (40).…”

“…It has been demonstrated that melanoma-associated macrophages synthesize large amounts of MMP-9 and urokinase-type plasminogen activator receptor (uPAR) as a result of direct contact with melanoma cells (40). MMP-9 decomposes collagen IV, which is main component of the basement membrane, and additionally decomposes latent TGF-β complexes, which further intensifies the EMT (2,40). uPAR is an element of the plasminogen activation system and is involved in multiple proteolytic processes that result in the reorganization and degradation of the extracellular matrix (40).…”

“…MMP-9 decomposes collagen IV, which is main component of the basement membrane, and additionally decomposes latent TGF-β complexes, which further intensifies the EMT (2,40). uPAR is an element of the plasminogen activation system and is involved in multiple proteolytic processes that result in the reorganization and degradation of the extracellular matrix (40).…”

Novel Therapeutic Approaches for Neuroblastoma

“…TAMs promote tumor growth by affecting angiogenesis, immune suppression, invasion and metastasis [101,102]. Existing literature suggests that tumor associated macrophages secrete several genes including matrix metalloproteinases-9 (MMP-9) [113], urokinasetype plasminogen activator (uPA) [114], vascular endothelial growth factor (VEGF) [115], and cyclooxygenase-2 (Cox-2] [116] which promotes tumor growth by breaking down extracellular matrix. The role of TAMs in tumor growth and progression is highlighted in Figure 3.…”