In vitro antitumor activity, metal uptake and reactivity with ascorbic acid and BSA of some gold(III) complexes with N,N′-ethylenediamine bidentate ester ligands

Four novel gold(III) complexes of general formulae [AuCl2{(S,S)-R(2)eddl}]PF6 (R(2)eddl = O,O'-dialkyl-(S,S)-ethylenediamine-N,N'-di-2-(4-methyl)pentanoate, R= n-Pr, n-Bu, n-Pe, i-Bu; 1-4, respectively), were synthesized and characterized by elemental analysis, UV/Vis, IR, and NMR spectroscopy, as well as high resolution mass spectrometry. Density functional theory calculations pointed out that (R,R)-N,N'-configuration diastereoisomers were energetically the most favorable. Duo to high cytotoxic activity complex 3 was chosen for stability study in DMSO, no decomposition occurs within 24 h, and for the reaction with ascorbic acid in which was reduced immediately. Additionally, 3 interacts with bovine serum albumin (BSA) as proven by UV/Vis spectroscopy. In vitro antitumor activity was determined against human cervix adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human melanoma (Fem-x) cancer cell lines, as well as against non-cancerous human embryonic lung fibroblast cells MRC-5. The highest activity was observed against K562 cells (IC50: 5.04-6.51 mu M). Selectivity indices showed that these complexes are less toxic than cisplatin. 3 had a similar viability kinetics on HeLa cells as cisplatin. Drug accumulation studies in HeLa cells showed that the total gold uptake increased much faster than that of cisplatin pointing out that 3 more efficiently enters the cells than cisplatin. Furthermore, morphological and cell cycle analysis reveal that gold(III) complexes induced apoptosis in time- and dose-dependent manner.This is the peer-reviewed version of the following article: Pantelić, N.; Zmejkovski, B. B.; Kolundžija, B.; Crnogorac, M. Đ.; Vujić, J. M.; Dojčinović, B.; Trifunović, S. R.; Stanojković, T. P.; Sabo, T. J.; Kaluđerović, G. N. In Vitro Antitumor Activity, Metal Uptake and Reactivity with Ascorbic Acid and BSA of Some Gold(III) Complexes with N,N′-Ethylenediamine Bidentate Ester Ligands. Journal of Inorganic Biochemistry 2017, 172, 55–66. [https://doi.org/10.1016/j.jinorgbio.2017.04.001]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3071