Inhibition of tumor cell growth in vitro by 2-mercaptoethanesulfonate (mesna) and other thiols

2-Mercaptoethanesulfonate (Mesna), which is used as a uroprotective agent during oxazaphosphorine treatment, was previously found to inhibit growth of several tumor cell lines in vitro. To test the possibility that this effect is due to the SH-group of mesna, other thiols have now been tested. It has been observed that L-cysteine, N-acetyl-L-cysteine and glutathione, on a molar basis, had effects similar to mesna on [3H]thymidine incorporations of several human tumor cell lines in vitro. The dose-response profiles were monophasic for some cell lines and biphasic for others. It is suggested that compounds with SH-groups, in relatively high concentrations, may be toxic for cells.