Protein accumulation in cultures of hepatic tumor cells exposed to dimethylsulfoxide

The effect of the differentiation-inducing agent dimethylsulfoxide (DMSO) on the protein composition of hepatic tumor cells was evaluated using the BW77-1 line of murine hepatoma cells previously determined to be DMSO-inducible for enhanced liver function. DMSO-mediated suppression of BW77-1 proliferation was accompanied by a stimulated uptake of [35S]-methionine and incorporation of the isotope into acid-insoluble product. DMSO produced a quantitative increase in the major cellular and secreted protein species per 10(6) cells although qualitatively the pattern of major peptides among control and DMSO-treated populations was basically similar; increases in two minor peptides of 90,000 and 110,000 daltons was noted, however, in the secreted protein fraction of DMSO-treated cells relative to controls. The data collectively suggest that the enhanced levels of differentiated liver cell gene products previously observed as a consequence of DMSO exposure reflects a stimulation in the synthesis, accumulation and secretion of at least all of the major proteins normally produced by BW77-1 hepatoma cells.