Glycoconjugate Journal (1996) 13:391-399 In vivo growth conditions suppress the expression of ganglioside GM2 and favour that of lacto series gangliosides in the human glioma D-54MG cell line PAM FREDMAN l*, CAROL J WIKSTRAND 2, JAN-ERIC MANSSON 1 GUIDO REIFENBERGER 3, SANDY H, BIGNER 2, AHMED RASHEED 2, LARS SVENNERHOLM 1 and DARELL D BIGNER 2 1Institute of Clinical Neuroscience, Department of Psychiatry and Neurochemistry, GO'teborg University, M6lndal Hospital, S-431 80 Sweden :Department of Pathology and Preuss Laboratory for Brain Tumor Research, Duke University Medical Cente~ Box 3156, Durham, NC 27710, USA ~Department of Neuropathology, Heinrich-Heine University, Box 101007, D-40001 Diisseldorf Germany Received 4 August 1995, revised 23 October 1995 The human glioma D-54MG cell line grown in vitro primarily expresses ganglio series gangliosides, particularly GM2. Subcutaneous injection of these cells into nude mice produced xenografts with an increased content of the human glioma-associated lacto series gangliosides, primarily 3'-isoLM1, an alteration that was dose dependent, with the highest dose (1 × 108) resulting in a phenotype that was most like that of the inoculum. After one passage in vivo, the lacto series dominated and reached a proportional level that was kept throughout the 10 passages. The mRNA levels of the GM2-synthase clearly coincided with GM2 expression and was 20 times higher in cells grown in vitro than in those grown in vivo. These results support the view that ganglioside expression in human gliomas is strongly influenced by environmental factors. Keywords: Ganglioside antigens, gliomas, ganglioside metabolism, glioma cell line Abbreviations: The gangliosides have been designated according to Svennerholm (Eur J Biochem (1977) 79:11- 21) GM3, II3NeuAc-LacCer; GM2, II3NeuAc-GgOse3Cer; GM1, II3NeuAc-GgOse4Cer; GD3, II3(NeuAc)2-LacCer; GD2, II3(NeuAc)2-GgOse3Cer; GDla, IV3NeuAc, II3NeuAc-GgOse4Cer; GDlb, II3(NeuAc)2-GgOseaCer; GTlb, IV3NeuAc, II3(NeuAc)2-GgOse4Cer; 3'-LM1, IV3NeuAc-nLcOse4Cer; 3'-isoLM1, IV3NeuAc-LcOse4Cer; 3',6'- isoLD1, IV3NeuAc, III6NeuAc-LcOse4Cer; 3'8'-LM1, IV3(NeuAc)2-nLcOse4Cer. MAb(s), monoclonal antibody (ies); the designation LM1 is used when both 3'-isoLM1 and 3'-LM1 and LD1, when both 3'6'-isoLDl and 3'8'- LD1 are included. Introduction When serially transplanted as subcutaneous xenografts in nude mice the D-54MG cell line predominantly expresses the lacto series gangliosides 3'-isoLM1 and 3',6'-isoLD1 [1,2]. These ganglioside antigens have been shown to be associated with the primary brain tumours, human malignant glioma and medulloblastoma, but not with human meningiomas [2-4]. Analyses of autopsy brains from individuals with malignant gliomas showed that 3'- isoLM1 appeared in highest concentrations in areas *To whom correspondenceshould be addressed. 0282-0080 © 1996 Chapman & Hall surrounding macroscopic tumour tissue and in anatomical structures along which tumour cells may migrate [2, 5]. The expression of 3'-isoLM1 and 3'6'-isoLD1 is not exclusively found in primary brain tumours, but in human normal brain they are restricted to the developmental periods with astroglial proliferation [6]. The fetal expres- sion of lacto series gangliosides has also been demon- strated in primary cultures of rat fetal astrocytes [7]. Recent studies have shown that human glioma cells and fetal rat astrocytes invade normal rat brain in a similar manner [8, 9]. These results support the hypothesis that 3'- isoLM1 and 3'6'-isoLD1 are associated with proliferative astrocytes, either neoplastic or non-neoplastic, and may