Enhancement of in vitro chemotherapeutic activity by dimethylsulfoxide

The effects of the differentiation-inducing polar solvent dimethylsulfoxide (DMSO) on the in vitro response of murine hepatocarcinoma cells to cisplatinum, BCNU, and melphalan were investigated using the sister chromatid exchange (SCE) and cell survival assays. Growth of cells in medium containing 2 per cent DMSO enhanced drug-induced SCEs and cell kill. In order for the enhancement to occur, cells had to be exposed to DMSO for at least 48 h prior to drug treatment. The presence of DMSO during drug treatment did not affect cell response to the three chemotherapeutic agents. The enhancement of chemosensitivity was eliminated within 24 h of DMSO removal. These data suggest that the differentiation-inducing polar solvents may provide antineoplastic benefits when administered in combination with standard chemotherapeutic agents.