DIFFERENTIAL REGULATION OF GLYCOSPHINGOLIPID BIOSYNTHESIS IN PHENOTYPICALLY DISTINCT BURKITTS-LYMPHOMA CELL-LINES

Earlier studies have shown that Burkitt's lymphoma (BL) cell lines can be divided into 2 major groups: group I, which retain the original BL biopsy phenotype with expression of CD10 and CD77 antigens and lack o f B-cell activation markers, and group III, which, after several in vi tro passages, progress toward an ''LCL-like'' phenotype with loss of C D10 and CD77 expression and up-regulation of B-cell activation antigen s. In previous studies we have shown that several glycolipid molecules constitute stage-specific antigens for B cells and that sequential sh ifts in the 3 major glycolipid series ave observed during B-cell diffe rentiation, these changes being mostly due to sequential activations o f the corresponding glycosyltransferases. In the present work, 10 BL c ell lines with group I or group III phenotype have been examined for c ell surface expression of 5 glycolipid antigens (LacCer, GM3, Gb3/CD77 , Gb4 and GM2), total glycolipid content and enzymatic activities of 4 glycosyltransferases (GM3, Gb3, Gb4 and GM2 synthetases). We now repo rt that group I and group III BL cells differ in their glycolipid meta bolism and express either mostly globoseries or ganglioseries compound s. Indeed, Gb3 is the major glycolipid of group I cells, whereas GM3 a nd GM2 are the 2 major components of group III cells, and these phenot ypic differences are mainly due to differential activities of the corr esponding glycosyltransferases: group I cells have high Gb3 synthetase activities and low or no GM3 and GM2 synthetase activities, whereas g roup III cells have high GM3 and GM2 synthetase activities and low Gb3 synthetase activities. Finally, we also show that, unlike LCL, group III BL cells do not synthesize Gb4. (C) 1995 Wiley-Liss, Inc.