Design and In Vitro Biological Evaluation of a Novel Organotin(IV) Complex with 1-(4-Carboxyphenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione

Hindawi Journal of Chemistry Volume 2019, Article ID 2905840, 8 pages https://doi.org/10.1155/2019/2905840 Research Article Design and In Vitro Biological Evaluation of a Novel Organotin(IV) Complex with 1-(4-Carboxyphenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione Nebojša Ð. Pantelić ,1,2 Bojana B. Zmejkovski,3 Željko Žižak,4 Nebojša R. Banjac,2 Bojan Ð. Božić,5 Tatjana P. Stanojković ,4 and Goran N. Kalud�erović 1 1 Department of Engineering and Natural Sciences, University of Applied Sciences Merseburg, Eberhard-Leibnitz-Strasse 2, 06217 Merseburg, Germany 2 Department of Chemistry and Biochemistry, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11000 Belgrade-Zemun, Serbia 3 Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Studentski Trg 14, 11000 Belgrade, Serbia 4 Institute of Oncology and Radiology, 11000 Belgrade, Serbia 5 Institute of Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski Trg 16, 11000 Belgrade, Serbia Correspondence should be addressed to Nebojša Ð. Pantelić; and Goran N. KaluCerović; Received 24 September 2018; Accepted 3 December 2018; Published 17 January 2019 Academic Editor: Maolin Guo Copyright © 2019 Nebojša Ð. Pantelić et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A novel triphenyltin(IV) compound with 1-(4-carboxyphenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione was synthesized and characterized by IR, NMR spectroscopy, mass spectrometry, and elemental analysis. In vitro anticancer activity of ligand precursor and synthesized organotin(IV) compound was determined against tumor cell lines: human adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human breast cancer (MDA-MB-453), using microculture tetrazolium test (MTT) assay. The results indicate that complex exhibited very high antiproliferative activity against all tested cell lines with IC50 values in the range of 0.22 to 0.53 µM. The highest activity organotin(IV) compound expressed against the HeLa cells (IC50 � 0.22 ± 0.04 µM). The ligand precursor did not show anticancer activity (IC50 > 200 µM). Furthermore, fluorescence microscopy analysis of HeLa cells reveal that organotin(IV) complex induced apoptosis as a mode of cell death, which is consistent with the increase of cells in the sub-G1 phase. 1. Introduction Metal complexes have been successfully applied in medicine for the treatment of human diseases such as cancer, rheumatoid arthritis, and gastric and duodenal ulcers and also are in widespread use as imaging agents as diagnostics tools [1]. One of the most expanding areas in medicinal bioinorganic chemistry is research on the synthesis of new metal-based compounds and their applications in medicine as drugs [2‒4]. Nowadays, cancer is one of the most threatening mankind diseases. During last five decades, over 500,000 synthetic chemical compounds have been tested for their antitumor activity, but only about 25 of these are in worldwide use today [5]. The application of the first and most worldwide used metal-based anticancer drug, cisplatin, discovered by Rosenberg, is limited by severe side effects such as neuro-, nephro-, and ototoxicity [6‒11], and therefore, the research of novel metal-based complexes with reduced toxicity and improved clinical efficacy is the subject of intensive studies into anticancer drug investigations [12‒16]. Recent studies have shown very promising in vitro antitumor properties of organotin(IV) compounds, against a wide panel of tumor cell lines of human origin [17‒21]. The organotin(IV) complexes with carboxylate [22‒29], thiolato 2 [30‒36], and dithiocarbamato [37] ligands have been extensively studied, and it was found that (carboxylato)triphenyltin(IV) and tetraorganotin(IV) compounds show the highest cytotoxic activity [22, 38]. However, the possible application of the synthesized organotin(IV) derivatives was very limited due to their poor water solubility [39]. Also, significant biological studies of organotin(IV) derivatives with benzoic acids have been reported [40‒46]. Many studies demonstrated that cyclic imides such as succinimides (pyrrolidine-2,5-diones) have promising biological properties such as nephrotoxic [47], anticonvulsant [48], antimutagenic [49], and analgesic [50] activities. Additionally, it was found that they inhibit a selective monoglyceride lipase and psychiatric disorders such as anxiety and depression [51]. Therefore, attention herein was drawn to aryl-N-succinimide with a carboxylate substituent as ligand compound. There are numerous reports showing that there is no single or well-defined number of ways in which organotin(IV) compounds interact with the cell membrane or constituents within the cell [52–55]. Thus, the mechanism of action of organotin(IV) compounds in effecting cell death remains unclear, and further work is necessary to identify the real apoptotic or necrotic pathways that cells treated with these compounds follow to their death. In this study, the synthesis and characterization of a triphenyltin(IV) compound containing 1-(4-carboxyphenyl)3-ethyl-3-methylpyrrolidine-2,5-dione anion (CEMPD–) is reported. The evaluation of cytotoxic activity against tumor cell lines human cervix adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human breast cancer (MDA-MB-453) has been performed. Additionally, the mode of cell death and cell cycle distribution of HeLa cells induced by synthesized complex were studied. 2. Materials and Methods 2.1. Chemicals and Methods. The ligand 1-(4-carboxyphenyl)3-ethyl-3-methylpyrrolidine-2,5-dione, a racemate, was synthesized as described previously [56]. Elemental analyses were performed on an elemental vario EL III microanalyzer. A Nicolet 6700 FT-IR spectrometer and ATR technique were used for recording midinfrared spectra (4000–400 cm−1) for complex. NMR spectra were recorded on Bruker Avance III 500 spectrometer. Chemical shifts for 1H, 13C, and spectra were referenced to internal standard TMS. Mass spectra of the compound were recorded with an Orbitrap LTQ XL instrument (Thermo Scientific, Bremen, Germany) in CH3CN [57]. Reagents and solvents were of commercial reagent grade quality and used without further purification. 2.2. Synthesis of Complex. A suspension of the 1-(4carboxyphenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione (50 mg; 0.191 mmol) in distilled water (10 mL) was treated with LiOH·H2O (8.1 mg; 0.191 mmol), the mixture was stirred for 3 h at 40°C, and a clear solution was formed. Then, 5 mL of Ph3SnCl (73.8 mg; 0.191 mmol) methanolic solution was added dropwise into the reaction mixture. Afterwards, the solution was stirred for 3 h and white precipitate was Journal of Chemistry formed. The precipitate was filtered off, washed with 5 mL of distilled water, and then d (...truncated)