Dimethyl sulfoxide-induced differentiation does not alter tumorigenicity of neuroblastoma cells.

It has been shown that agents that are known to be scavengers of hydroxyl radicals may induce differentiation and inhibit growth of murine neuroblastoma cells in tissue culture. The present study tests dimethyl sulfoxide as a differentiation agent of the human neuroblastoma cell lines LA-N-1 and murine neuroblastoma NIE-115. Results indicate that DMSO induces morphologic and biochemical differentiation of neuroblastoma cells coupled to growth inhibition and inhibition of colony formation in semi liquid tissue culture systems. DMSO treatment in vitro had no effect on tumorigenicity of NIE-115 cells. In vivo DMSO treatment of athymic nude mice with transplanted LA-N-1 human neuroblastoma tumors has not affected tumor size or animal survival. No diminishing effect of natural killer cell activity could be attributed to DMSO treatment.