Effects of Specific Gangliosides on the In Vitro Proliferation of MPTP-Susceptible Cells

Abstract: To determine which portion of a ganglioside molecule might be necessary for the enhancement of recovery from MPTP-induced lesions, the ability of specific gangliosides to stimulate proliferation of MPTP-treated 140–3 cells was investigated. The results indicate that of the gangliosides tested, GM1 was the most effective. Although GD1 a and GT1 b were able to enhance the proliferation of MPTP-treated cells, twice as much GT1b was needed to induce the same effect seen with GM1. In contrast, asialo-GM1, GM2, and GM3 were ineffective at promoting proliferation of MPTP-treated cells. The isolated oligosaccharide of GM1 had little effect. These results indicate that in addition to the sialosyl residue, at least the Gal(β1–3)Gal-NAc portion of the oligosaccharide chain and the ceramide moiety are essential for the induction of proliferation of the MPTP-treated cells. Investigation of the time of addition of GM1 on its ability to counteract the MPTP-induced inhibition of 140–3 cell proliferation indicated that addition of GM1 before or concomitantly with MPTP resulted in a significant reduction in MPTP-induced inhibition of cell proliferation.     

Neuronal and non-neuronal properties of neuroblastoma cells.

Three different mouse neuroblastoma cell lines (S20Y, N2CL10, N115) were examined for acetylcholinesterase activity, ganglioside composition, cell processes, and affinity for protargol silver (i.e., argyrophilia). Assays were made on cloned cells, corresponding tumors which developed after subcutaneous injection of $\text{A}\text{J}$ strain male mice with 2 × 10⁶ cells, and primary and secondary cultures. Acetylcholinesterase activity was present in all cells assayed, with maximal activity noted in cloned cells. Ganglioside patterns of neuroblastoma cells differed from those of neural cells, but remained qualitatively unchanged for a given cell line grown in vivo or in vitro. Some cells were stained with protargol silver in primary cultures, but few cells in cloned or secondary cultures, or those in in vivo tissues, were impregnated with protargol silver. These findings show that while neuroblastoma cell lines maintain some neuronal characteristics (i.e., high acetylcholinesterase levels, cell processes), they do not express other accepted neuronal properties (i.e., ganglioside patterns, argyrophilia), and suggest that direct analogies between normal neurons and “differentiated” neuroblastoma cells should be made with caution.