Neutrophil granulocyte derived MMP-9 is a VEGF independent functional component of the angiogenic switch in pancreatic ductal adenocarcinoma

Abstract

Background Vascular endothelial growth factor (VEGF) that is secreted by tumor cells plays a key role in angiogenesis. Matrix metalloproteinase 9 (MMP-9) is produced by inflammatory cells, such as stromal granulocytes (PMN), remodels the extracellular matrix and is known to promote angiogenesis indirectly by interacting with VEGF. The aim of this study was to determine the role of PMN-derived MMP-9, its interaction with VEGF, and the efficacy of anti-angiogenic therapy targeting MMP-9 with oral Doxycycline and VEGF with Bevacizumab in pancreatic cancer (PDAC). Methodology/principal findings Inhibitors to MMP-9 (Doxycycline) and VEGF (Bevacizumab) were used alone or in combination in an in vitro angiogenesis assay to test their effect on angiogenesis caused by MMP-9, VEGF, PMN and PDAC cells. In an in vivo model of xenografted PDAC, treatment effects after 14 days under monotherapy with oral Doxycycline or Bevacizumab and a combination of both were evaluated. In vitro, PMN-derived MMP-9 had a direct and strong proangiogenic effect that was independent and additive to PDAC-derived VEGF. Complete inhibition of angiogenesis required the inhibition of VEGF and MMP-9. In vivo, co-localization of MMP-9, PMN and vasculature was observed. MMP inhibition with oral Doxycycline alone resulted in a significant decrease in PDAC growth and mean vascular density comparable to VEGF inhibition alone. Conclusions/significance PMN derived MMP-9 acts as a potent, direct and VEGF independent angiogenic factor in the context of PDAC. MMP-9 inhibition is as effective as VEGF inhibition. Targeting MMP-9 in addition to VEGF is therefore likely to be important for successful anti-angiogenic treatment in pancreatic cancer.

Late SV40 Factor (LSF) Enhances Angiogenesis by Transcriptionally Up-regulating Matrix Metalloproteinase-9 (MMP-9)

“…The source of pro-angiogenic MMP-9 might be the tumor cells themselves. Studies from mouse models also suggest bone marrow-derived cells, neutrophils or osteoclasts as potential sources of MMP-9 facilitating tumor angiogenesis (25)(26)(27)(28). We document that the angiogenic properties of conditioned media (CM) from MMP-9 knockdown HCC cells in an LSF-overexpression background were significantly compromised suggesting that MMP-9 plays a key role in the angiogenic function of LSF.…”

IL-6 Cooperates with G-CSF To Induce Protumor Function of Neutrophils in Bone Marrow by Enhancing STAT3 Activation

“…Neutrophils have been found to exert a dual influence on blood vessel formation by producing proangiogenic or antiangiogenic factors. Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis (43). However, VEGF secreted from cells is sequestered to the extracellular matrix (3).…”

Angiogenic capacity of M1- and M2-polarized macrophages is determined by the levels of TIMP-1 complexed with their secreted proMMP-9

“…[19][20][21][22][23] Accumulated evidence demonstrates that among granulocytic leukocytes, the neutrophils constitute a critical myeloid cell type delivering angiogenesis-inducing proMMP-9. [24][25][26][27][28][29][30] The high angiogenic potential of neutrophil proMMP-9 has been linked to its unique tissue inhibitor of metalloproteinase (TIMP)-free status. 31 Because neutrophils do not express TIMP-1, the natural inhibitor of MMP-9 enzyme and negative regulator of proMMP-9 activation, 32 Submitted May 9, 2013; accepted October 21, 2013.…”