The reaction of gold reagents [HAuCl4•3H2O], [AuCl(tht)], or cyclometalated gold(III) precursor, [C^NAuCl2] with chiral ((R,R)-(-)-2,3-bis(t-butylmethylphosphino) quinoxaline) and non-chiral phosphine (1,2-Bis(diphenylphosphino)ethane, dppe) ligands lead to distorted Au(I), (1, 2, 4, 5) and novel cyclometalated Au(III) complexes (3, 6). These gold compounds were characterized by multinuclear NMR, microanalysis, mass spectrometry, and X-ray crystallography. The inherent electrochemical properties of the gold complexes were also studied by cyclic voltammetry and theoretical insight of the complexes was gained by density functional theory and TD-DFT calculations. The complexes effectively kill cancer cells with IC50 in the range of ~0.10–2.53 μΜ across K562, H460, and OVCAR8 cell lines. In addition, the retinal pigment epithelial cell line, RPE-Neo was used as a healthy cell line for comparison. Differential cellular uptake in cancer cells was observed for the compounds by measuring the intracellular accumulation of gold using ICP-OES. Furthermore, the compounds trigger early – late stage apoptosis through potential disruption of redox homeostasis. Complexes 1 and 3 induce predominant G1 cell cycle arrest. Results presented in this report suggest that stable gold-phosphine complexes with variable oxidation states hold promise in anticancer drug discovery and need further development.
|State||Published - Dec 1 2019|
Bibliographical noteFunding Information:
Financial support was provided by the University of Kentucky (UK) start-up and UK IRC grant. This study made use of UK NMR facility, UK X-ray facility with funds from the MRI program (grants CHE-0319176 and CHE-1625732), Boston University Mass spectrometry facility, UK Environmental research training laboratory (ERTL), and UK flow cytometry core. We also thank Tyler R. Mertens for providing complexes 4 and 5.
© 2019, The Author(s).
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