Location of tumour cells in colon tissue by Texas red labelled pentosan polysulphate, an inhibitor of a cell surface protease.

Abstract

Pentosan polysulphate (PPS), a highly negatively charged polysaccharide, is a significant inhibitor of an isoenzymic form of a cell surface protease referred to as guanidinobenzoatase GB, associated with colonic carcinoma tissues in frozen sections and free GB in solution, in a concentration-dependent manner. However PPS failed to recognise and bind to the isoenzymic form of GB associated with normal colon epithelial cell surfaces. Texas red labelled PPS (TR-PPS) binds to the tumour cell surfaces of colonic carcinoma and colonic polyps and these cells fluoresce red, whilst the normal colon cell surfaces failed to bind the TR-PPS, and hence lacked red fluorescence. Polysulphonated suramin also selectively recognised and inhibited the colonic carcinoma GB isoenzyme. The kinetic data indicated that this inhibition was not caused by a mere polyanionic effect, since highly sulphated heparin failed to show a significant inhibition of colonic carcinoma GB, however trypan blue did show 50% inhibition. Kinetic studies have also shown that PPS is a non-competitive, reversible inhibitor of colonic carcinoma GB, with an apparent Km 6.8 x 10(-7) M. Gel analysis has shown that PPS binds to another site, distinct from the active centre, and after binding PPS changed the conformation of GB. These studies suggest that TR-PPS is a potent inhibitor of colonic carcinoma GB, and can be used as a novel fluorescent probe for the location of tumour cells in frozen sections of human colon tissues. PSS could also have potential as a vehicle for the transport of cytotoxic compounds to carcinoma cells of the colon.

• Authors: M Anees
• Journal: Journal of enzyme inhibition (J Enzyme Inhib) Vol. 10 Issue 3 Pg. 203-14 ( 1996) ISSN: 8755-5093 [Print] Switzerland
• PMID: 8835946 (Publication Type: Journal Article)

Chemical References

• 4-methylumbelliferylguanidinobenzoate
• Dansyl Compounds
• Fluorescent Dyes
• Isoenzymes
• Protease Inhibitors
• Xanthenes
• dansyl fluoride
• Pentosan Sulfuric Polyester
• Hymecromone
• Suramin
• Texas red
• Heparin
• Carboxylic Ester Hydrolases
• guanidinobenzoate esterase
• Endopeptidases
• Trypan Blue

Topics

• Carboxylic Ester Hydrolases (pharmacology)
• Cell Membrane (enzymology)
• Chromatography, Affinity
• Colonic Neoplasms (metabolism)
• Dansyl Compounds (metabolism)
• Electrophoresis, Polyacrylamide Gel
• Endopeptidases (pharmacology)
• Fluorescent Dyes (metabolism)
• Heparin (pharmacology)
• Humans
• Hymecromone (analogs & derivatives, metabolism)
• Isoenzymes (antagonists & inhibitors, metabolism)
• Kinetics
• Microscopy, Fluorescence
• Pentosan Sulfuric Polyester (analogs & derivatives, pharmacology)
• Protease Inhibitors (pharmacology)
• Protein Conformation
• Suramin (pharmacology)
• Trypan Blue (pharmacology)
• Xanthenes (metabolism)