Invasion of ras-transformed breast epithelial cells depends on the proteolytic activity of cysteine and aspartic proteinases

Biol Chem. 2001 May;382(5):853-7. doi: 10.1515/BC.2001.104.


It has been suggested that the lysosomal proteinases cathepsin B, L and D participate in tumour invasion and metastasis. Whereas for cathepsins B and L the role of active enzyme in invasion processes has been confirmed, cathepsin D was suggested to support tumour progression via its pro-peptide, rather than by its proteolytic activity. In this study we have compared the presence of active cathepsins B, L and D in ras-transformed human breast epithelial cells (MCF-10A neoT) with their ability to invade matrigel. In this cell line high expression of all three cathepsins was detected by immunofluorescence microscopy. The effect of proteolytic activity on cell invasion was studied by adding various natural and synthetic cysteine and aspartic proteinase inhibitors. The most effective compound was chicken cystatin, a general natural inhibitor of cysteine proteinases, (82.8+/-1.6% inhibition of cell invasion), followed by the synthetic inhibitor trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E-64). CLIK-148, a specific inhibitor of cathepsin L, showed a lower effect than chicken cystatin and E-64. Pepstatin A weakly inhibited invasion, whereas the same molar concentrations of squash aspartic proteinase (SQAPI)-like inhibitor, isolated from squash Cucurbita pepo, showed significant inhibition (65.7+/-1.8%). We conclude that both cysteine and aspartic proteinase activities are needed for invasion by MCF-10A neoT cells in vitro.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Aspartic Acid Endopeptidases / antagonists & inhibitors
  • Aspartic Acid Endopeptidases / metabolism
  • Aspartic Acid Endopeptidases / pharmacology*
  • Breast / cytology
  • Breast / drug effects
  • Breast / enzymology
  • Breast Neoplasms / enzymology*
  • Breast Neoplasms / etiology
  • Breast Neoplasms / pathology
  • Cathepsins / antagonists & inhibitors
  • Cathepsins / metabolism
  • Cathepsins / pharmacology
  • Cell Line
  • Cell Transformation, Neoplastic / chemically induced
  • Cell Transformation, Neoplastic / metabolism*
  • Cell Transformation, Neoplastic / pathology
  • Chickens
  • Collagen
  • Cystatins / antagonists & inhibitors
  • Cystatins / pharmacology
  • Cysteine Endopeptidases / metabolism
  • Cysteine Endopeptidases / pharmacology*
  • Cysteine Proteinase Inhibitors / pharmacology
  • Drug Combinations
  • Epithelial Cells / drug effects
  • Epithelial Cells / enzymology
  • Epithelial Cells / pathology
  • Female
  • Humans
  • Laminin
  • Microscopy, Fluorescence
  • Neoplasm Invasiveness*
  • Proteoglycans
  • ras Proteins / pharmacology


  • Cystatins
  • Cysteine Proteinase Inhibitors
  • Drug Combinations
  • Laminin
  • Proteoglycans
  • matrigel
  • Collagen
  • Cathepsins
  • Cysteine Endopeptidases
  • Aspartic Acid Endopeptidases
  • ras Proteins