Crystal structure and cytotoxic activities of a bis(pyrrolyl-imine) gold(III) complex

Synthesis, structural characterization, docking simulation and in vitro antiproliferative activity of the new gold(III) complex with 2-pyridineethanol

Gold(III) complex containing 2-pyridineethanol has been synthesized and characterized structurally by single crystal X-ray diffraction, vibrational spectroscopy, ¹H NMR spectroscopy, electrochemical study, and DFT calculations. The Au(III) ion is four coordinated with one N-donor ligand (L) and three Cl anions. The Okuniewski's (τ'₄₌0.018) has been used to estimate the angular distortion from ideal square planar geometry. The vibrational spectroscopy studies, in the solid state and DMSO solution and cyclic voltammetry, have been performed to determine its stability and redox activity, respectively. A complete assignment of the IR and Raman spectra has been made based on the calculated potential energy distribution (PED). The theoretical calculations have been made for two functionals and several basis sets. The compound has been evaluated for its antiproliferative properties in a human lung adenocarcinoma cell line (A549), mouse colon carcinoma (CT26), human breast adenocarcinoma (MCF-7), human prostate carcinoma derived from the metastatic site in the brain (DU-145), and PANC-1 human pancreas/duct carcinoma cell line and non-tumorigenic cell lines: HaCat (human keratinocyte), and HEK293T (human embryonic kidney). Au(III) complex cytotoxicity is significantly against A549 and MCF-7 cells as in the reference drug: cisplatin. Studies of the interactions of Au(III) complex with DNA, HSA (human serum albumin) have been performed. The results from modeling docking simulations indicate that the title complex exerts anticancer effects in vitro based on different mechanisms of action to compare with cisplatin.

Linear gold(I) complex with tris-(2-carboxyethyl)phosphine (TCEP): Selective antitumor activity and inertness toward sulfur proteins

The search for modulating ligand substitution reaction in gold complexes is essential to find new active metallo compounds for medical applications. In this work, a new linear and hydrosoluble gold^I complex with tris-(2-carboxyethylphosphine) (AuTCEP). The two phosphines coordinate linearly to the metal as solved by single crystal X-ray diffraction. Complete spectroscopic characterization is also reported. In vitro growth inhibition (GI₅₀) in a panel of nine tumorigenic and one non-tumorigenic cell lines demonstrated the complex is highly selective to ovarium adenocarcinoma (OVCAR-03) with GI₅₀ of 3.04 nmol mL^-1. Moreover, non-differential uptake of AuTCEP was observed between OVCAR-03 (tumor) and HaCaT (non-tumor) two cell lines. Biophysical evaluation with the sulfur-rich biomolecules showed the compound does not interact with two types of zinc fingers, bovine serum albumin, N-acetyl-l-cysteine and also l-histidine, revealing to be inert to ligand substitution reactions with these molecules. However, AuTCEP demonstrated to cleave plasmidial DNA, suggesting DNA as a possible target. No antibacterial activity was observed in the strains evaluated. Besides, it inhibits 15% of the activity of a mixture of serine-β-lactamase and metallo-β-lactamase from Bacillus cereus in the enzymatic activity assay, similarly to EDTA. These results suggest AuTCEP is selective to metallo-β-lactamase but the cell uptake is hindered, and the compound does not reach the periplasmic space of Gram-positive bacteria. The unique inert behavior of AuTCEP is interesting and represent the modulation of the reactivity through coordination chemistry to decrease the toxicity associated with Au^I complexes and its lack of specificity, generating very selective compounds with unexpected targets.