Effect of dimethylsulfoxide on human gliomas: correlations between the nuclear magnetic resonance spectra and the transformed phenotypes of the tumor cells.

Prolonged in vitro induction of six established human glioma cell lines with dimethylsulfoxide (DMSO) generated an adherent human fibroblastoid phenotype. The development of contact-inhibited cell growth coincided with the decreased colony-forming potential of these cells in semisolid medium and with the reduction or elimination of tumorigenicity when transplanted in athymic nude mice. These DMSO-induced changes persisted for at least 19 passages after removal of the inducer from the medium. High-resolution natural-abundance 13C nuclear magnetic resonance spectroscopy showed specific spectral differences between the cell lines with more or less malignant transformed phenotypes: the glioma cells with a higher degree of tumorigenicity and colony-forming potential exhibited more intense myoinositol signals than those with the more benign phenotype.