RNAi-mediated downregulation of urokinase plasminogen activator receptor and matrix metalloprotease-9 in human breast cancer cells results in decreased tumor invasion, angiogenesis and growth

Int J Cancer. 2007 Nov 15;121(10):2307-16. doi: 10.1002/ijc.22962.

Abstract

The serine protease urokinase-type plasminogen activator (uPA) plays a significant role in tumor cell invasion and metastasis when bound to its specific receptor, uPAR (also known as CD87). In addition to the uPA-uPAR system, matrix metalloproteinases (MMPs) are involved in tumor cell invasion and metastasis. In this study, we achieved specific inhibition of uPAR and MMP-9 using RNAi technology. We introduced small interfering RNA to downregulate the expression of uPAR and MMP-9 (pUM) in breast cancer cell lines (MDA MB 231 and ZR 75 1). In vitro angiogenesis studies indicated a decrease in the angiogenic potential of the treated cells; in particular, a remarkable decrease was observed in the cells treated with bicistronic construct (pUM) in comparision to the controls. Additionally, bicistronic construct inhibited the formation of capillary-like structures in in vivo models of angiogenesis. Similarly, the invasive potential and migration decreased dramatically when treated with the bicistronic construct as shown by matrigel invasion and migration assays. These results suggest a synergistic effect from the simultaneous downregulation of uPAR and MMP-9. We also assessed the levels of phosphorylated forms of MAPK, ERK and AKT signaling pathway molecules and found reduction in the levels of these molecules in cells treated with the bicistronic construct as compared to the control cells. Furthermore, targeting both uPAR and MMP-9 totally regressed orthotopic breast tumors in nude mice. In conclusion, our results provide evidence that the simultaneous downregulation of uPAR and MMP-9 using RNAi technology may provide an effective tool for breast cancer therapy.

Publication types

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

MeSH terms

  • Animals
  • Breast Neoplasms / blood supply
  • Breast Neoplasms / enzymology*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Proliferation
  • Down-Regulation*
  • Enzyme Activation
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Matrix Metalloproteinase 9 / genetics
  • Matrix Metalloproteinase 9 / metabolism*
  • Mice
  • Mice, Nude
  • Mitogen-Activated Protein Kinases / metabolism
  • Neoplasm Invasiveness / pathology
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA, Small Interfering / genetics*
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Receptors, Urokinase Plasminogen Activator
  • Xenograft Model Antitumor Assays

Substances

  • PLAUR protein, human
  • Plaur protein, mouse
  • RNA, Small Interfering
  • Receptors, Cell Surface
  • Receptors, Urokinase Plasminogen Activator
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinases
  • Matrix Metalloproteinase 9