Structure and functions of proteases which cleave human C3 and are expressed on normal or tumor human cells: Some are involved in tumorigenic and metastatic properties of human melanoma cells

  • Frade R
  • 2


    Mendeley users who have this article in their library.
  • 19


    Citations of this article.


Human C3 is a multipotent molecule which participates to different events involved in immune response as complement activation, antigen presentation, cell-cell interactions and cell proliferation. Thus, proteinases which cleave C3 may modify C3-dependent cellular functions. This led us to identify two membrane-associated proteinases which cleave human C3: (a) A p57 serine proteinase expressed on human erythrocyte membranes - This p57 proteinase shared antigenic determinants with ankyrine and may be involved in clearance of immune complexes; (b) A p41 cysteine proteinase, which shares antigenic determinants, amino-acid sequence and specific activity with procathepsin-L - This p41 C3-cleaving cyteine proteinase is also involved in tumorigenic and metastatic properties of human melanoma in nude mice. Indeed, pretreatment of highly tumorigenic and metastatic melanoma cells with anti-p39 Ab totally abolished their tumorigenicity and significantly decreased the number of experimental lung metastases in nude mice. Furthermore, overexpression of procathepsin-L in nonmetastatic melanoma cells increased their tumorigenicity and switched their phenotype to highly metastatic cells in nude mice. Altogether, these data support that expression and secretion of procathepsin-L, which cleaves human C3, might be one of the multiple mechanisms by which tumor cells escape the immune surveillance.

Author-supplied keywords

  • Human C3
  • Melanoma
  • Metastasis
  • Proteinases
  • Tumorigenic

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Raymond Frade

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free