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The state of differentiation of HT‐29 colon carcinoma cells alters the secretion of cathepsin D and of plasminogen activator
Author(s) -
Huet Guillemette,
Zerimech Farid,
Dieu MarieClaire,
Hemon Brigitte,
Grard Georges,
Balduyck Malika,
Janin Anne,
Lafyatis Robert,
Degand Pierre
Publication year - 1994
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910570617
Subject(s) - plasminogen activator , extracellular , biology , cell culture , cathepsin , cathepsin b , cellular differentiation , secretion , population , cathepsin d , microbiology and biotechnology , endocrinology , biochemistry , medicine , enzyme , environmental health , gene , genetics
We have studied the cellular content and the extracellular release of cathepsins B and D, and of plasminogen activator, in 2 different tumor cell populations before confluence and after late confluence: the HT‐29 colon carcinoma cell line, which contains primarily undifferentiated cells, and a subpopulation derived from this cell line, which contains cells committed to differentiation into mucus‐secreting goblet cells after confluence. In both populations, cellular cathepsin‐B activity increased after confluence, and latent cathepsin B was found in all culture media. In the parental cell line, cellular cathepsin D activity decreased after confluence; however, cathepsin D was secreted at high levels into the extracellular medium. In contrast, in the subpopulation of cells committed to differentiation, cellular cathepsin D activity increased after confluence, and cathepsin D was not secreted into the extracellular medium, but was immunolocalized in the apical brush border of the differentiated cells. Plasminogen activator of urokinase type was identified by immunocytochemistry. Both subconfluent cell populations, and the post‐confluent undifferentiated cell population, produced plasminogen activator activity at similar levels. In contrast, in the differentiated postconfluent cells, the production of plasminogen activator activity was markedly lower. Our data show that the differentiation of HT‐29 colon carcinoma cells into mucus‐secreting cells impairs the secretion of plasminogen activator and cathepsin D, but does not affect cathepsin B. © 1994 Wiley‐Liss, Inc.