In vitro anticancer activity of gold(III) complexes with some esters of (S,S)-ethylenediamine-N,N '-di-2-propanoic acid

Five novel gold(III) complexes of general formulas [AuCl2{(S,S)-R(2)eddip}]PF6, ((S,S)-eddip = (S,S)-ethylenediamine-N,N'-di-2-propanoate, R = n-Bu, n-Pe, i-Bu, i-Am, cPe; 1-5, respectively) were synthesized and characterized by UV/Vis, IR and NMR spectroscopy and mass spectrometry. DFT calculations indicated that (R,R)-N,N'-configuration diastereoisomers were the most stable for 1-5. 3 is stable in DMSO for at least 24 h, but immediate hydrolysis in PBS occurs. 3 is readily reduced with ascorbic acid and forms adducts with bovine serum albumin (BSA). In vitro anticancer activity of the gold(III) complexes against human cervix adenocarcinoma HeLa, human myelogenous leukemia K562, human melanoma Fem-x tumor cell lines, as well as against non-cancerous human embryonic lung fibroblast cell line MRC5 was determined using MIT assay. Complex 4 showed highest activity and selectivity (IC50(Femx) = 1.3 +/- 0.2; IC50(MRC-5)/IC50(Fem-x) = 72.5 +/- 12.4), 4 times more active and 28 times more selective than cisplatin. Complexes induced apoptotic mode of death in a time-dependent manner in HeLa cells