Squamous cell carcinoma antigen is a potent inhibitor of cysteine proteinase cathepsin L

FEBS Lett. 1995 Feb 6;359(1):78-80. doi: 10.1016/0014-5793(94)01456-b.

Abstract

A squamous cell carcinoma antigen (SSCA), which is a member of the serpin family of proteinase inhibitors, was purified from sera of cancer patients. It did not inhibit serine proteinases. However, it non-competitively inhibited human cathepsin L with a Ki of 0.064 nM, but not cathepsins B and H among cysteine proteinases. These results indicated that SCCA is a non-functional serpin that inhibits cathepsin L in cancer cells.

MeSH terms

  • Animals
  • Antigens, Neoplasm / blood
  • Antigens, Neoplasm / pharmacology*
  • Carcinoma, Squamous Cell / immunology
  • Cathepsin L
  • Cathepsins / antagonists & inhibitors*
  • Chromatography, Affinity
  • Cysteine Endopeptidases
  • Endopeptidases*
  • Female
  • Humans
  • Kinetics
  • Lung Neoplasms / immunology
  • Protease Inhibitors / pharmacology*
  • Serpins*
  • Swine
  • Uterine Cervical Neoplasms / immunology

Substances

  • Antigens, Neoplasm
  • Protease Inhibitors
  • Serpins
  • squamous cell carcinoma-related antigen
  • Cathepsins
  • Endopeptidases
  • Cysteine Endopeptidases
  • CTSL protein, human
  • Cathepsin L