Effects of Gangliosides on DNA Synthesis in U1242 MG Glioma Cells

J Korean Neurol Assoc > Volume 13(4); 1995 > Article

Journal of the Korean Neurological Association 1995;13(4): 749-761.

Ganglilosides가 U242 MG 신경교세포의 DNA합성에 미치는 영향

조광호, 이민철

원광대학교 신경과, 전남대학교 병리학교실

Effects of Gangliosides on DNA Synthesis in U1242 MG Glioma Cells

Kwang-Ho Cho, M.D., Min-Choel Lee, M.D

Department of Neurology, College of Medicine, Wonkwang University, Dept of Patology, College of Medicine, Choonnam University

Abstract

Exogenously added gangliosides modulate the growth and differentiation of a variety of cells in vitro including human gliomas. GM1, Gdla and GTlb gangliosides inhibit both PDGF-stimulated and serum-stimulated DNA synthesis of Swiss 3T3 cells and U1242 MG cells in a dose responsive manner. The inhibitory effect is counteracted in a dose-responsive fashion by serum, and that ganglioside-induced inhibition is essentially abolished in 10% serum. Because of the potentially important role that gangliosides play in growth regulation of human gliomas, this phenomenon was studied in detail using the human glioma cell line U1242 MG. Low doses of serum stimulate DNA synthesis of U1242 MG cells which is inhibited in a dose-responsive fashion by ganglioside GMI. However, serum itself counteracts the inhibitory effect of ganglioside in a dose-responsive way. On the other hand GM,, Gdla and GTlb stimulate DNA synthesis in quiescent U1242 MG cells in both sparse and confluent conditions, indicating that ganglioside-stimulated DNA synthesis is dependent on the phase of cellular growth rather than celluar density. The growth stimulatory effect of the three gangliosides is more potent on quiescent, confluent cells than quiescent, sparse cells. Gangliosides stimulate radiolabeling of and 35% of nuclei with (3H) thymidine in quiescent, sparse and quiescent, confluent cells respectively. These results demonstrate that exogenously added gangliosides can have different effects on progression of human glioma cells, support of the bimodal behavior model of gangliosides. The effects are mainly related to cell cycle depending on the growth phase of the cells rather than the cell density.