Activity of lysosomal exoglycosidases in human gliomas

Abstract

There is a lot of data suggesting that modifications of cell glycoconjugates may be important in progression of cancer. In the present work we studied activities of lysosomal exoglycosidases: beta-hexosaminidase and its isoenzymes A and B, beta-galactosidase and alpha-mannosidase, in human gliomas. Enzyme activity was determined spectrophotometrically based on the release of p-nitrophenol from p-nitrophenyl-derivative of appropriate sugars. The activities of the exoglycosidases tested were significantly higher in malignant glial tumors than in control tissue (normal brain tissue) and non-glial tumors. The highest activities of exoglycosidases were observed in high-grade gliomas, and a positive correlation of enzyme activities and degree of malignancy was noted. Our results suggest that lysosomal exoglycosidases may participate in the progression and dynamical development of glial tumors.

O-GlcNAcylation enhances anaplastic thyroid carcinoma malignancy

“…The lysosomal β-N-acetylglucosaminidase is a type of O-GlcNAcase. The enhancement of its degradative activity has been observed to be associated with O-GlcNAcylation level in a variety of human cancer types (21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Additionally, a previous study proposed OGA activity to be significantly higher and O-GlcNAcylation to be lower in tumor tissue compared with corresponding normal tissue (31).…”

Elevation of nucleocytoplasmic β-N-acetylglucosaminidase (O-GlcNAcase) activity in thyroid cancers

“…The enhancement of lysosomal ß-N-acetylglucosaminidase degradative activity in different human cancers, i.e. gastric, renal, breast, lung, glial and salivary gland is well documented (6)(7)(8)(9)(10)(11)(12)(13)(14)(15).…”

“…Two major lysosomal hexosaminidase isozymes, A and B were extensively studied because dysfunction of either of them results in the accumulation of gangliosides and other glycoconjugates within the lysosome causing the neurodegenerative disorders known as Tay-Sachs and Sandhoff disease (2,5). Moreover, the enhancement of ß-hexosaminidase degradative activity in different human cancer tissues and in serum or urine of patients with cancers is well documented (6)(7)(8)(9)(10)(11)(12)(13)(14)(15).…”

Activity of Hydrolytic Enzymes in Various Regions of Normal Human Brain Tissue

“…Several studies have earlier highlighted the importance of studying hydrolytic enzymes in a variety of pathological conditions such as brain tumors [2,3], neurodegenerative diseases such as Alzheimer's disease [4] and inherited metabolic disorders [5]. Among all the hydrolase's, two phosphomonoesterases viz., alkaline and acid phosphatase(s) have been extensively studied in tumors [6] then esterase's were studied [7].…”