A potential method to improve the in vitro cytotoxicity of half-sandwich Os(ii) complexes against A2780 cells. Issue 16 (10th April 2018)

• Record Type: Journal Article
• Authors: Štarha, Pavel; Trávníček, Zdeněk; Herchel, Radovan; Jewula, Pawel; Dvořák, Zdeněk
• Is Part Of: Dalton transactions. Volume 47:Issue 16(2018)
• Page Start: 5714
• Page End: 5724
• Publication Date: 2018-04-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt00193f
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : [Os(η 6 - p cym)(dpa)(VP)]PF6 (1-VP ), containing the histone deacetylase inhibitor valproate, shows ca. 3-fold higher in vitro cytotoxicity against the A2780 human ovarian carcinoma cells than its chlorido analogue [Os(η 6 - p cym)(dpa)Cl]PF6 (1-Cl ). Abstract : The [Os(η 6 - p cym)(dpa)(VP)]PF6 (1-VP ) complex contains the histone deacetylase (HDAC) inhibitor valproate (2-propylpentanoate; VP) as a monodentate O-donor ligand and shows ca. 3-fold higher in vitro cytotoxicity against A2780 human ovarian carcinoma cells than its chlorido analogue [Os(η 6 - p cym)(dpa)Cl]PF6 (1-Cl ); p cym = 1-methyl-4-(propan-2-yl)benzene ( p -cymene), dpa = 2, 2′-dipyridylamine. The complex1-VP showed promising selectivity towards the A2780 ovarian carcinoma cell line (IC50 = 20.9 μM) over normal human hepatocytes (IC50 > 200.0 μM). Moreover, the complex1-VP was found to be inactive against MCF-7 (breast adenocarcinoma), PANC-1 (pancreatic adenocarcinoma) and HT-29 (colon carcinoma) up to a concentration of 100 μM. Detailed flow cytometry studies indicated that treatment of A2780 cells with complex1-VP led to induction of apoptosis, production of reactive oxygen species (ROS) and superoxide (SO) anion radicals, as well as mitochondrial membrane potential depletion and cell cycle perturbations. The microscopic assessment (standard hematoxylin/eosin staining) revealed signs of morphological changes associated with the progression of apoptosis in A2780 cells treated with the IC50 concentration of the complex1-VP . Consistent with the intracellular production of ROS and SO, the complex1-VP induced hydroxyl radical formation, as proved by EPR spin trapping experiments. This case study suggests that replacement of the chlorido ligand of half-sandwich Os(ii ) complexes by a releasable monodentate biologically active ligand ( e.g., VP used in this study) is an effective strategy for the development of novel non-platinum cytotoxic agents.