Selective modulation of non-protein sulfhydryl levels in Ehrlich ascites tumor bearing mice

Thiazolidine derivatives (TD), prodrugs of L-cysteine (cys), synthesized by the condensation of cys with formaldehyde (thiazolidine-4-carboxylic acid-CF), acetaldehyde (2-methyl-thiazolidine-4-carboxylic acid-CA) and pyruvate (2-methylthiazolidine-2,4-dicarboxylic acid-CP), as well as amino acids thiocystine (T-cys) and cys, but not methionine (met) and S2O3(-2), successfully elevated non-protein sulfhydryl (NPSH) levels in livers of Ehrlich ascites tumor cells (EATC) bearing mice. At the same time, CA, promote a significant drop of NPSH concentration in EATC, whereas the other sulfur compounds (S-comp) have no effects. Thus TD and T-cys through their selective influence upon the level of NPSH in the liver and in cancer cells, seem to be the most interesting compounds for further studies on anticancer therapy.