Expression of attractin and its differential enzyme activity in glioma cells

Attractin/mahogany protein was previously shown to be involved in a number of physiological and pathological events, including immune system regulatio n, body weight control, pigmentation, myelinization, and tumor susceptibili ty. Human attractin has an enzymatic activity resembling dipeptidyl peptida se IV (DPP-IV). In the central nervous system, attractin has been detected in neurons but not in glial, cells up to now. We show the expression of att ractin mRNA and protein in glioma cell lines at different degree of transfo rmation. In human U373 and U87 glioma cells (Grades III and TV), membrane-b ound attractin displays hydrolytic activity amounting to 5 and 25% of total cellular DPP-TV-like enzyme activity, respectively. Such activity has not been observed in the rat Cg glioma cells (Grade I). Attractin presence in g lioma, but not in normal glial cells, together with its differential enzyma tic activity, suggests its role in growth properties of tumors of glial cel l origin, (C) 2001 Academic Press.