Blockade of MMP14 activity in murine breast carcinomas: implications for macrophages, vessels, and radiotherapy

J Natl Cancer Inst. 2015 Feb 20;107(4):djv017. doi: 10.1093/jnci/djv017. Print 2015 Apr.


Background: Matrix metalloproteinase (MMP) 14 may mediate tumor progression through vascular and immune-modulatory effects.

Methods: Orthotopic murine breast tumors (4T1 and E0771 with high and low MMP14 expression, respectively; n = 5-10 per group) were treated with an anti-MMP14 inhibitory antibody (DX-2400), IgG control, fractionated radiation therapy, or their combination. We assessed primary tumor growth, transforming growth factor β (TGFβ) and inducible nitric oxide synthase (iNOS) expression, macrophage phenotype, and vascular parameters. A linear mixed model with repeated observations, with Mann-Whitney or analysis of variance with Bonferroni post hoc adjustment, was used to determine statistical significance. All statistical tests were two-sided.

Results: DX-2400 inhibited tumor growth compared with IgG control treatment, increased macrophage numbers, and shifted the macrophage phenotype towards antitumor M1-like. These effects were associated with a reduction in active TGFβ and SMAD2/3 signaling. DX-2400 also transiently increased iNOS expression and tumor perfusion, reduced tissue hypoxia (median % area: control, 20.2%, interquartile range (IQR) = 6.4%-38.9%; DX-2400: 1.2%, IQR = 0.2%-3.2%, P = .044), and synergistically enhanced radiation therapy (days to grow to 800mm(3): control, 12 days, IQR = 9-13 days; DX-2400 plus radiation, 29 days, IQR = 26-30 days, P < .001) in the 4T1 model. The selective iNOS inhibitor, 1400W, abolished the effects of DX-2400 on vessel perfusion and radiotherapy. On the other hand, DX-2400 was not capable of inducing iNOS expression or synergizing with radiation in E0771 tumors.

Conclusion: MMP14 blockade decreased immunosuppressive TGFβ, polarized macrophages to an antitumor phenotype, increased iNOS, and improved tumor perfusion, resulting in reduced primary tumor growth and enhanced response to radiation therapy, especially in high MMP14-expressing tumors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amidines / pharmacology*
  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • Antibodies, Monoclonal / therapeutic use
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Benzylamines / pharmacology*
  • Breast Neoplasms / blood supply
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / immunology
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / radiotherapy*
  • Cell Line, Tumor
  • Dose Fractionation, Radiation
  • Enzyme Inhibitors / pharmacology*
  • Enzyme Inhibitors / therapeutic use*
  • Female
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Immunoglobulin G / blood
  • Macrophages / drug effects*
  • Macrophages / enzymology
  • Mammary Neoplasms, Experimental
  • Matrix Metalloproteinase 14 / drug effects*
  • Matrix Metalloproteinase 14 / metabolism*
  • Mice
  • Neovascularization, Pathologic
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • Nitric Oxide Synthase Type II / drug effects*
  • Nitric Oxide Synthase Type II / metabolism
  • Phenotype
  • Signal Transduction / drug effects
  • Smad2 Protein / metabolism
  • Smad3 Protein / metabolism
  • Transforming Growth Factor beta / metabolism
  • Up-Regulation


  • Amidines
  • Antibodies, Monoclonal
  • Antineoplastic Agents
  • Benzylamines
  • Enzyme Inhibitors
  • Immunoglobulin G
  • N-(3-(aminomethyl)benzyl)acetamidine
  • SMAD2 protein, human
  • SMAD3 protein, human
  • Smad2 Protein
  • Smad3 Protein
  • Transforming Growth Factor beta
  • NOS2 protein, human
  • Nitric Oxide Synthase Type II
  • MMP14 protein, human
  • Matrix Metalloproteinase 14