Role of glycosidases in human ovarian carcinoma cell mediated degradation of subendothelial extracellular matrix

Penetration of the extracellular matrix (ECM) by tumor cells, an event which occurs at various stages of the metastatic process, involves tumor cell glycosidase mediated hydrolysis of proteoglycans (PG). Recently, we observed that human ovarian carcinoma cell lines (HOCC) derived from primary tumors...

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Bibliographic Details
Published in:Cancer research (Chicago, Ill.) Ill.), 1987-09, Vol.47 (17), p.4634-4641
Main Authors: NIEDBALA, M. J, MADIYALAKAN, R, MATTA, K, CRICKARD, K, SHARMA, M, BERNACKI, R. J
Format: Article
Language:English
Subjects:
Acetylglucosamine - metabolism
beta-N-Acetylhexosaminidases - pharmacology
Biological and medical sciences
Carcinoma - metabolism
Cells, Cultured
Extracellular Matrix - metabolism
Female
Female genital diseases
Glucosamine - metabolism
Glycoside Hydrolases - metabolism
Gynecology. Andrology. Obstetrics
Humans
Hydrogen-Ion Concentration
Kinetics
Medical sciences
Ovarian Neoplasms - metabolism
Protease Inhibitors - pharmacology
Tumors
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Summary:Penetration of the extracellular matrix (ECM) by tumor cells, an event which occurs at various stages of the metastatic process, involves tumor cell glycosidase mediated hydrolysis of proteoglycans (PG). Recently, we observed that human ovarian carcinoma cell lines (HOCC) derived from primary tumors, peritoneal effusions, and distant metastases possess a varying ability to degrade radiolabeled PG of the ECM, while normal cells (human mesothelial cells or ovarian fibroblasts) fail to do so. To determine whether a quantitative relationship exists between glycosidase activity and degradation of ECM, both intracellular and extracellular glycosidase activities were measured for HOCC and normal cell lines. No relationship was found between intracellular glycosidase activities and the ability of cells to degrade ECM. However, a correlation was observed between extracellular or secretory glycosidase activities and HOCC mediated ECM degradation. In particular, a 5-8-fold increase, as compared to normal cells, was observed for HOCC extracellular beta-N-acetylglucosaminidase (EC 3.2.2.30) activity. The accumulation or secretion of this enzyme from HOCC into culture medium was found to be time dependent and not related to intracellular levels. Purified hexosaminidase derived from invasive HOCC was able to hydrolyze [3H]-glucosamine radiolabeled ECM (up to 30% radiolabel) and resulted in the cumulative release of free [3H]-N-acetylglucosamine. This enzyme mediated hydrolysis could be completely prevented with 2-acetamido-2-deoxy-1,5-D-gluconolactone, a competitive inhibitor (Ki 10(-6) M). Finally, HOCC mediated degradation of radiolabeled ECM was discerned to be dependent upon active hexosaminidase action, since tumor cell mediated degradation of ECM could be inhibited by up to 60% in the presence of this synthetic competitive inhibitor. In summary, these studies indicate a strong association between HOCC solubilization of glycoconjugates present in the ECM and extracellular levels of hexosaminidase.
ISSN:0008-5472
1538-7445