Protection against cis-dichlorodiammine Pt (II) cytotoxicity in vitro by cysteamine.

EMT6/SF cells exposed to cis-dichlorodiammine Pt(II) (DDP) for 1 hr in the presence of 10 mM cysteamine (MEA) survived better than cells treated with DDP alone (DMF-3.1). MEA added to cultures after removal of DDP also protected, even when the two exposures were separated by as long as 4 hr. Protection by MEA was concentration dependent: no significant protection was observed below 1 mM and maximum protection required 5 mM. When cells were incubated with 10 mM MEA immediately after removal of DDP, survival increased as a function of the length of exposure to MEA, reaching a maximum at 2 hr.