Publications by authors named "Alzir A Batista"

72 Publications

Ruthenium (II)/allopurinol complex inhibits breast cancer progression via multiple targets.

J Biol Inorg Chem 2021 Apr 10. Epub 2021 Apr 10.

Laboratório de Genética Molecular E Citogenética Humana, sala 213, Departamento de Genética, Instituto de Ciências Biológicas I, Campus Samambaia, Universidade Federal de Goiás, Avenida Esperança, s/n, Cx Postal: 131, Goiânia, Goiás, CEP 74690-900, Brazil.

Metal complexes based on ruthenium have established excellent activity with less toxicity and great selectivity for tumor cells. This study aims to assess the anticancer potential of ruthenium(II)/allopurinol complexes called [RuCl(allo)(PPh)] (1) and [RuCl(allo)(dppb)] (2), where allo means allopurinol, PPh is triphenylphosphine and dppb, 1,4-bis(diphenylphosphino)butane. The complexes were synthesized and characterized by elemental analysis, IR, UV-Vis and NMR spectroscopies, cyclic voltammetry, molar conductance measurements, as well as the X-ray crystallographic analysis of complex 2. The antitumor effects of compounds were determined by cytotoxic activity and cellular and molecular responses to cell death mechanisms. Complex 2 showed good antitumor profile prospects because in addition to its cytotoxicity, it causes cell cycle arrest, induction of DNA damage, morphological and biochemical alterations in the cells. Moreover, complex 2 induces cell death by p53-mediated apoptosis, caspase activation, increased Beclin-1 levels and decreased ROS levels. Therefore, complex 2 can be considered a suitable compound in antitumor treatment due to its cytotoxic mechanism.
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http://dx.doi.org/10.1007/s00775-021-01862-yDOI Listing
April 2021

Ruthenium complexes show promise when submitted to toxicological safety tests using alternative methodologies.

Eur J Med Chem 2021 Apr 15;216:113262. Epub 2021 Feb 15.

Instituto de Ciências Biológicas, Universidade Federal de Goiás (UFG), CEP 74045-155, Goiânia, GO, Brazil. Electronic address:

The number of cancer cases continues to increase worldwide, and unfortunately the main systemic treatments available have numerous of side effects. Ruthenium complexes have shown to be promising chemotherapeutic agents, since they present low toxicity and are more selective for tumor tissues. We report the synthesis, characterization and biological properties of two new ruthenium (II) complexes containing Lapachol and Lawsone as ligands: (1) [Ru(Law)(dppb)(phen)]PF and (2) [Ru(Lap)(dppb)(phen)]PF, where Law = Lawsone, Lap = Lapachol, dppb = 1,4-bis(diphenylphosphine)butane and phen = 1,10-phenanthroline. The ability of the complexes (1) and (2) to interact with CT-DNA (Calf Thymus) was investigated, and the results indicate that the complexes have shown a weak interaction with this macromolecule. Complexes (1) and (2) showed a moderate interaction with BSA, via a spontaneous process with the involvement of van der Waals and hydrogen bond interactions. Both complexes were tested against human lung cancer cell lines, chronic human myeloid leukemia, murine melanoma and human cervical and non-tumoral murine fibroblast adenocarcinoma, human lung fibroblasts and monkey kidney epithelia. The potential for cytotoxicity was tested out using the MTT assay and the neutral red test, to calculate inhibitory concentrations (IC50) and selectivity indices (IS). Both complexes showed a higher selectivity index of 1.17 and 10.91, respectively, for the HeLa tumor line. Studies of toxicological evaluation, using the micronucleus test and the comet assay against non-tumor cells, as well as an assessment of the potential for acute toxicity and neurotoxicity in zebrafish (Danio rerio). In the in vitro micronucleus test, complex (1) showed the least genotoxic potential, and in the in vitro comet assay both compounds had revealed a genotoxic potential at 0.5 and 1.0 mg L, with no difference between 24 h and 48 h exposure times. In the acute toxicity tests on zebrafish embryos, complex (1) showed sublethal effects such as decreased blood circulation and heartbeat rate, which were less pronounced than with complex (2). In contrast to complex 2, which caused lethality even before 48h, complex (1) did not cause the death of the embryos at concentrations up to (2.0 mg L). Complex (2) also lead to a delay in the embryo. Cell based in vitro methods thus proved able to provide specific toxicological data, allowing a significant reduction in ∖animal experimentation. Given that in vitro tests cannot completely replace animal tests, the use of less advanced developmental stages such as zebrafish embryos, which - at least in the European Union - are not regarded protected, could be shown to be an excellent alternative for testing with, e.g., mammals.
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http://dx.doi.org/10.1016/j.ejmech.2021.113262DOI Listing
April 2021

A novel ruthenium(ii) gallic acid complex disrupts the actin cytoskeleton and inhibits migration, invasion and adhesion of triple negative breast tumor cells.

Dalton Trans 2021 Jan 11;50(1):323-335. Epub 2020 Dec 11.

Departamento de Química, Universidade Federal de São Carlos - UFSCar, Rodovia Washington Luís Km 235, CP 676, 13561-901, São Carlos, SP, Brazil.

This work describes the synthesis of three new ruthenium(ii) complexes with gallic acid and derivatives of the general formula [Ru(L)(dppb)(bipy)]PF, where L = gallate (GAC), benzoate (BAC), and esterified-gallate (EGA), bipy = 2,2'-bipyridine and dppb = 1,4-bis(diphenylphosphino)butane. The complexes were characterized by elemental analysis, molar conductivity, NMR, cyclic voltammetry, UV-vis and IR spectroscopy, and two of them by X-ray crystallography. Cell viability assays show promising results, indicating higher cytotoxicity of the complexes in MDA-MB-231 cells, a triple-negative breast cancer (TNBC) cell line, compared with the hormone-dependent MCF-7 cell line. Studies in vitro with the MDA-MB-231 cell line showed that only Ru(BAC) and Ru(GAC) interacted with BSA. Besides that, the Ru(GAC) complex, which has a polyphenolic acid, interacted in an apo-Tf structure and function dependent manner and it was able to inhibit the formation of reactive oxygen species. Ru(GAC) was able to cause damage to the cellular cytoskeleton leading to inhibition of some cellular processes of TNBC cells, such as invasion, migration, and adhesion.
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http://dx.doi.org/10.1039/d0dt03490hDOI Listing
January 2021

Lapachol in the Design of a New Ruthenium(II)-Diphosphine Complex as a Promising Anticancer Metallodrug.

J Inorg Biochem 2021 Jan 23;214:111289. Epub 2020 Oct 23.

Departamento de Química, Universidade Federal de São Carlos (UFSCar), CP 676, CEP 13565-905 São Carlos, SP, Brazil. Electronic address:

The preparation of two new Ru(II)/diphosphine complexes containing Lapachol (Lap) and Lawsone (Law): (1) [Ru(Lap)(dppm)]PF and (2) [Ru(Law)(dppm)]PF, where dppm = bis(diphenylphosphino)methane, is reported here. The complexes were synthetized and fully characterized by elemental analyses, molar conductivity, UV-Vis, IR, P{H}, H and C NMR, and the crystal structure of the complex (1) was determined by X-ray diffraction. Complexes (1) and (2) showed high in vitro cytotoxicity against four cancer cells (MDA-MB-231, MCF-7, A549 and DU-145), with IC values in the micromolar range (0.03 to 2.70 μM). Importantly, complexes (1) and (2) were more active than the cisplatin, the drug used as a reference in the cytotoxic assays. Moreover, complex (1) showed high selectivity to triple-negative breast cancer cells (MDA-MB-231). Studies of the mechanism of action in MDA-MB-231 cancer cells showed that complex (1) inhibits cell migration, colony formation, and induces cell cycle arrest and apoptosis by activation of the mitochondrial pathway through the loss of mitochondrial membrane potential (ΔΨm). Furthermore, complex (1) induces ROS (Reactive Oxygen Species) generation in MDA-MB-231 cells, which can cause DNA damage. Finally, complexes (1) and (2) interact with DNA by minor grooves and show a moderate interaction with BSA (Bovine Serum Albumin), with the involvement of hydrophobic interactions. Essentially, Ru(II)/diphosphine-naphthoquinone complexes have remarkable cytotoxic effects with high selectivity to triple-negative breast cancer (MDA-MB-231) and could be promising anticancer candidates for cancer treatment. SYNOPSIS: The naphthoquinones Lapachol and Lawsone can form new ruthenium compounds with promising anticancer properties.
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http://dx.doi.org/10.1016/j.jinorgbio.2020.111289DOI Listing
January 2021

Ruthenium(II) Phosphine/Mercapto Complexes: Their in Vitro Cytotoxicity Evaluation and Actions as Inhibitors of Topoisomerase and Proteasome Acting as Possible Triggers of Cell Death Induction.

Inorg Chem 2020 Oct 30;59(20):15004-15018. Epub 2020 Sep 30.

Departamento de Química, Universidade Federal de São Carlos, CEP 13565-905 São Carlos, São Paulo, Brazil.

In this paper, a series of new ruthenium complexes of the general formula [Ru(NS)(dpphpy)(dppb)]PF (-), where dpphpy = diphenyl-2-pyridylphosphine, NS ligands = 2-thiazoline-2-thiol (tzdt, ), 2-mercaptopyrimidine (pySm, ), and 4,6-diamino-2-mercaptopyrimidine (damp, ), and dppb = 1,4-bis(diphenylphosphino)butane, were synthesized and characterized by elemental analysis, spectroscopic techniques (IR, UV/visible, and 1D and 2D NMR), and X-ray diffraction. In the characterization, the correlation between the phosphorus atoms and their respective aromatic hydrogen atoms of the compounds in the assignment stands outs, by H-P HMBC experiments. The compounds show anticancer activities against A549 (lung) and MDA-MB-231 (breast) cancer cell lines, higher than the clinical drug cisplatin. All of the complexes are more cytotoxic against the cancer cell lines than against the MRC-5 (lung) and MCF-10A (breast) nontumorigenic human cell lines. For A549 tumor cells, cell cycle analysis upon treatment with showed that it inhibits the mitotic phase because arrest was observed in the Sub-G1 phase. Additionally, the compound induces cell death by an apoptotic pathway in a dose-dependent manner, according to annexin V-PE assay. The multitargeted character of the compounds was investigated, and the biomolecules were DNA, topoisomerase IB, and proteasome, as well as the fundamental biomolecule in the pharmacokinetics of drugs, human serum albumin. The experimental results indicate that the complexes do not target DNA in the cells. At low concentrations, the compounds showed the ability to partially inhibit the catalytic activity of topoisomerase IB in the process of relaxation of the DNA plasmid. Among the complexes assayed in cultured cells, complex was able to diminish the proteasomal chymotrypsin-like activity to a greater extent.
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http://dx.doi.org/10.1021/acs.inorgchem.0c01835DOI Listing
October 2020

Ru(II)/diclofenac-based complexes: DNA, BSA interaction and their anticancer evaluation against lung and breast tumor cells.

Dalton Trans 2020 Sep;49(36):12643-12652

Departamento de Química, ICEB, Universidade Federal de Ouro Preto (UFOP), CEP 35400-000, Ouro Preto, MG, Brazil.

Ruthenium(ii) diclofenac-based complexes of the general formula [Ru(dicl)(P-P)(bpy)]PF6 [dicl = diclofenac, bpy = 2,2'-bipyridine, and P-P = 1,4'-bis(diphenylphosphino)butane (dppb) (1), 1,2'-bis(diphenylphosphino)ethane (dppe) (2), 1,3'-bis(diphenylphosphino)propane (dppp) (3) and 1,1'-bis(diphenylphosphino)ferrocene (dppf) (4)] are synthesized. The complexes (1-4) are characterized by elemental analyses, infrared, NMR, and UV-vis spectroscopy and (3) and (4) are characterized by single crystal X-ray diffraction. The DNA binding of complexes (1-4), studied by circular dichroism (CD) and Hoechst 33 258 staining assay, indicates their binding with the minor grooves. The complexes interact with BSA with binding constants (Kb) in the range of 2.5 × 103-5.5 × 104 M-1. The complexes exhibit high cytotoxicity against the tumor cell lines A549, MDA-MB-231, and MCF-7 with IC50 values ranging from 0.56 to 15.28 μM. The complexes are more selective for the hormone-dependent MCF-7 breast tumor cell line and complex (1) is the most potent one. The study demonstrates the anticancer activity of ruthenium(ii)/diclofenac-based complexes.
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http://dx.doi.org/10.1039/d0dt01591aDOI Listing
September 2020

On the Cytotoxicity of Chiral Ruthenium Complexes Containing Sulfur Amino Acids Against Breast Tumor Cells (MDA-231 and MCF-7).

Anticancer Agents Med Chem 2020 Aug 24. Epub 2020 Aug 24.

Departamento de Química, Universidade Federal de São Carlos - UFSCar, São Carlos, SP. Brazil.

Background: Breast cancer is one of the most common types among women. Its incidence progressively increases with age, especially after age 50. Platinum compounds are not efficient in the treatment of breast cancer, highlighting the use of other metals for the development of new chemotherapeutic agents.

Objective: This paper aims to obtain three new ruthenium compounds that incorporate sulfur amino acids in their structures and to investigate their cytotoxic activity in breast tumor cell lines.

Methods: Complexes with general formula [Ru(AA)(dppb)(bipy)] (complexes 1 and 2) or [Ru(AA)(dppb)(bipy)]PF6 (complex 3), where AA = L-cysteinate (1), D-penicillaminate (2), and L-deoxyalliinate (3), dppb = 1,4- bis(diphenylphosphino)butane and 2,2´-bipyridine, were obtained from the cis-[RuCl2(dppb)(bipy)] precursor. The cytotoxicity of the complexes on MDA-MB-231 (triple negative human breast cancer); MCF-7 (double positive human breast cancer) and V79 (hamster lung fibroblast) were performed by the MTT (4,5-dimethylthiazol-2-yl-2,5- diphenyltetrazolium bromide) method. The control agent was the cisplatin, which is a commercially available drug for cancer treatment.

Results: In complexes (1) and (2), the ligands are coordinated to the metal center by nitrogen and sulfur atoms, while in complex (3) coordination is through the oxygen and nitrogen atoms. These suggestions are based on the infrared and 31P{1H} NMR data. For complexes (1) and (2), their X-ray structures were determined confirming this suggestion. The three complexes are stable in a mixture of DMSO (80 %) and biological medium (20 %) for at least 48 h and presented cytotoxicity against the MDA-MB-231 and MCF-7 tumor cells with reasonable selectivity indexes.

Conclusion: Our work demonstrated that ruthenium complexes containing sulfur amino acids, bipyridines and bisphosphines showed cytotoxicity against the MDA-MB-231 and MCF-7 cancer cell lines, in vitro, and that they interact weakly with the DNA (Deoxyribonucleic Acid) and the HSA (Human Serum Albumin) biomolecules.

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http://dx.doi.org/10.2174/1871520620666200824114816DOI Listing
August 2020

Cytotoxicity of ruthenium-N,N-disubstituted-N'-acylthioureas complexes.

Mater Sci Eng C Mater Biol Appl 2020 Oct 20;115:111106. Epub 2020 May 20.

Departamento de Química, Universidade Federal de São Carlos - UFSCar, São Carlos, SP, Brazil. Electronic address:

Five new complexes with general formula [Ru(L)(PP)(bipy)]PF, where L = N,N'-dimethyl-N-Acyl thiourea, and P-P: 1,2-bis(diphenylphosphino)ethane (dppe) or 1,4-bis(diphenylphosphino)butane (dppb)) were synthesized and characterized by elemental analysis, molar conductivity, cyclic voltammetry, IR, NMR (H, C{H} and P{H}), and single crystal X-ray diffractometry. The cytotoxicity of compounds against lung and breast tumor cell lines was significant, where two complexes, [Ru(L)(bipy)(dppe)]PF (3) and [Ru(L)(bipy)(dppb)]PF (6), were selected to evaluate changes in morphology, inhibition of migration and cell death in the MDA-MB-231 lineage. The complexes caused alterations in the cell morphology and were able to inhibit cell migration at the concentrations evaluated, induce the cell cycle arrested in the Sub-G1 phase, and induced cell death by apoptosis. All the complexes presented interaction with HSA, and the interaction studies with DNA suggested weak interactions, probably by the minor groove.
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http://dx.doi.org/10.1016/j.msec.2020.111106DOI Listing
October 2020

Ru(II)-Naphthoquinone complexes with high selectivity for triple-negative breast cancer.

Dalton Trans 2020 Nov;49(45):16193-16203

Departamento de Química, Universidade Federal de São Carlos - UFSCar, Rodovia Washington Luiz, KM 235 CP 676, CEP 13561-901, São Carlos, SP, Brazil.

Six new ruthenium(ii) complexes with lapachol (Lap) and lawsone (Law) with the general formula [Ru(L)(P-P)(bipy)]PF6, where L = Lap or Law, P-P = 1,2'-bis(diphenylphosphino)ethane (dppe), 1,4'-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf) and bipy = 2,2'-bipyridine, were synthesized, fully characterized by elemental analysis, molar conductivity, NMR, cyclic voltammetry, UV-vis, IR spectroscopies and three of them by X-ray crystallography. All six complexes were active against breast (MCF-7 and MDA-MB-231) and prostate (DU-145) cancer cell lines with lower IC50 values than cisplatin. Complex [Ru(Lap)(dppe)(bipy)]PF6 (1a) showed significant selectivity for MDA-MB-231, a model of triple-negative breast cancer (TNBC), as compared to the "normal-like" human breast epithelial cell line, MCF-10A. Complex (1a) inhibited TNBC colony formation and induced loss of cellular adhesion. Furthermore, the complex (1a) induced mitochondrial dysfunction and generation of ROS, as is involved in the apoptotic cell death pathway. Preferential cellular uptake of complex (1a) was observed in MDA-MB-231 cells compared to MCF-10A cells, consistent with the observed selectivity for tumorigenic vs. non-tumorigenic cells. Taken together, these results indicate that ruthenium complexes containing lapachol and lawsone as ligands are promising candidates as chemotherapeutic agents.
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http://dx.doi.org/10.1039/d0dt01091jDOI Listing
November 2020

Selective Coordination Mode of Acylthiourea Ligands in Half-Sandwich Ru(II) Complexes and Their Cytotoxic Evaluation.

Inorg Chem 2020 Apr 25;59(7):5072-5085. Epub 2020 Mar 25.

Departamento de Química, Universidade Federal de São Carlos-UFSCar, Rodovia Washington Luís KM 235, CP 676, 13561-901 São Carlos, SP, Brazil.

In this study, half-sandwich Ru(II) complexes containing acylthiourea ligands of the general type [Ru(η--cymene)(PPh)(S)Cl]PF (-) and [Ru(η--cymene)(PPh)(S-O)]PF (-) where S/S-O = -disubstituted acylthiourea were synthesized and characterized (via elemental analyses, IR spectroscopy, H NMR spectroscopy, C{H} NMR spectroscopy, and X-ray diffractometry), and their cytotoxic activity was evaluated. The different coordination modes of the acylthiourea ligands, monodentately via S (-) and bidentately via S,O (-), to ruthenium were modulated from different synthetic routes. The cytotoxicity of the complexes was evaluated in five human cell lines (DU-145, A549, MDA-MB-231, MRC-5, and MCF-10A) by MTT assay. The IC values for prostate cancer cells (2.89-7.47 μM) indicated that the complexes inhibited cell growth, but that they were less cytotoxic than cisplatin (2.00 μM). Unlike for breast cancer cells (IC = 0.28-0.74 μM) and lung cancer cells (IC = 0.51-1.83 μM), the complexes were notably more active than the reference drug, and a remarkable selectivity index (SI 4.66-19.34) was observed for breast cancer cells. Based on both the activity and selectivity, complexes and , as well as their respective analogous complexes in the monodentate coordination and , were chosen for further investigation in the MDA-MB-231 cell line. These complexes not only induced morphology changes but also were able to inhibit colony formation and migration. In addition, the complexes promoted cell cycle arrest at the sub-G phase inducing apoptosis. Interaction studies by viscosity measurements, gel electrophoresis, and fluorescence spectroscopy indicated that the complexes interact with the DNA minor groove and exhibit an HSA binding affinity.
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http://dx.doi.org/10.1021/acs.inorgchem.0c00319DOI Listing
April 2020

Evaluation of the biological potential of ruthenium(II) complexes with cinnamic acid.

J Inorg Biochem 2020 05 14;206:111021. Epub 2020 Feb 14.

Departamento de Química, Universidade Federal de São Carlos, CEP 13565-905 São Carlos, SP, Brazil. Electronic address:

In this work, we present the synthesis and characterization of five new ruthenium compounds with general formula [Ru(L)(dppb)(bipy)]PF, where L = cinnamic acid derivatives, dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2'-bipyridine. The cytotoxicity of the complexes was evaluated against human breast tumor cells from the lines MCF-7, MDA-MB-231 and in human (MCF-10A) or mouse (L929) non-tumor cells. Complexes Ru(L)(dppb)(bipy)]PF (4) (L = 4-hydroxycinnamic acid) and [Ru(L)(dppb)(bipy)]PF (5) (L = 3,4-dihydroxycinnamic acid) were the most selective, presenting the highest values of selectivity indexes besides inhibited some processes related to tumor progression in vitro, such as invasion, migration, and adhesion in the MDA-MB-231 cell line. In addition, the complexes 4 and 5 were able to interact with Bovine Serum Albumin (BSA) and complex 5 showed antioxidant activity.
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http://dx.doi.org/10.1016/j.jinorgbio.2020.111021DOI Listing
May 2020

Heterobimetallic Ru(ii)/Fe(ii) complexes as potent anticancer agents against breast cancer cells, inducing apoptosis through multiple targets.

Metallomics 2020 04 28;12(4):547-561. Epub 2020 Feb 28.

Department of Chemistry, Federal University of São Carlos, CP 676, CEP 13565-905, São Carlos, São Paulo, Brazil.

Antimetastatic activity, high selectivity and cytotoxicity for human tumor cell lines make ruthenium(ii) complexes attractive for the development of new chemotherapeutic agents for cancer treatment. In this study, cytotoxic activities and the possible mechanism of cell death induced by three ruthenium complexes were evaluated, [Ru(MIm)(bipy)(dppf)]PF (1), [RuCl(Im)(bipy)(dppf)]PF (2) and [Ru(tzdt)(bipy)(dppf)]PF (3). The results showed high cytotoxicity and selectivity indexes for the human triple-negative breast tumor cell line (MDA-MB-231) with IC value and selectivity index for complex 1 (IC = 0.33 ± 0.03 μM, SI = 4.48), complex 2 (IC = 0.80 ± 0.06 μM, SI = 2.31) and complex 3 (IC = 0.48 ± 0.02 μM, SI = 3.87). The mechanism of cell death induced in MDA-MB-231 cells, after treatment with complexes 1-3, indicated apoptosis of the cells as a consequence of the increase in the percentage of cells in the Sub-G1 phase in the cell cycle analysis, characteristic morphological changes and the presence of apoptotic cells labeled with Annexin-V. Multiple targets of action were identified for complexes 1 and 3 with an induction of DNA damage in cells treated with complexes 1 and 3, mitochondrial depolarization with a reduction in mitochondrial membrane potential, an increase in reactive oxygen species levels and increased expression levels of caspase 3 and p53. In addition, antimetastatic activities for complexes 1 and 3 were observed by inhibition of cell migration by the wound healing assay and Boyden chamber assay, as well as inhibition of angiogenesis caused by MDA-MB-231 tumor cells in the CAM model.
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http://dx.doi.org/10.1039/c9mt00272cDOI Listing
April 2020

Nucleobase Derivatives as Building Blocks to Form Ru(II)-Based Complexes with High Cytotoxicity.

ACS Omega 2020 Jan 3;5(1):122-130. Epub 2020 Jan 3.

Departamento de Química, Instituto de Ciências Exatas e Biológicas-Campus Morro do Cruzeiro, Universidade Federal de Ouro Preto-UFOP, CEP 35400-000 Ouro Preto, MG, Brazil.

Two new Ru(II)-based complexes containing 2-thiouracil derivatives, known as 2-thiouracil (2TU) and 6-methyl-2-thiouracil (6m2TU), were synthesized using [RuCl(PPh)(bipy)] as a precursor. The obtained compounds with a general formula [Ru(2TU)(PPh)(bipy)]PF () and [Ru(6m2TU)(PPh)(bipy)]PF () were characterized by analytical techniques such as NMR, UV-vis, and IR spectroscopies, elementary analysis, mass spectrometry, and single-crystal X-ray diffraction. Moreover, the investigation of the complexes-DNA interaction were carried out using spectrophotometric titrations and showed that the complexes present a weak interaction with this biomolecule. The compounds were evaluated against HL-60, K-562, HepG2, and B16-F10 cancer cells and against noncancer cells (PBMCs). The results of the biological assay revealed that complex is more promising than complex . Finally, the present study suggests that complexes and causes cell death by apoptosis, significantly increasing the percentage of apoptotic HL-60 cells, in which the compounds altered the cell cycle, reducing the cells in G/G, G/M, and S phases.
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http://dx.doi.org/10.1021/acsomega.9b01921DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963899PMC
January 2020

Synthesis and structural characterization of a series of ternary copper(II)-L-dipeptide-neocuproine complexes. Study of their cytotoxicity against cancer cells including MDA-MB-231, triple negative breast cancer cells.

J Inorg Biochem 2020 02 18;203:110930. Epub 2019 Nov 18.

Facultad de Química, Universidad de la República, Av. General Flores 2124, Montevideo, Uruguay. Electronic address:

This work presents the synthesis and characterization of eight copper complexes [Cu(L-dipeptide)(neo)]·nHO (neo = neocuproine) and their cytotoxic activities against tumor cell lines. The crystalline structure of [Cu(gly-val)(neo)]·3HO, [Cu(gly-leu)(neo)]·HO, [Cu(ala-gly)(neo)]·4HO, [Cu(val-phe)(neo)]·4.5HO and [Cu(phe-phe)(neo)]·3HO were determined by single crystal X-ray diffraction. In all of them, the Cu(II) is pentacoordinated, in a square pyramidal environment. The coordination observed in solid state was retained in the major species in aqueous solution, as suggested by Electronic Paramagnet Resonance and UV-vis spectroscopies. The complexes were shown to have affinity for isolated DNA, as determined by Circular Dichroism experiments. Furthermore, biological experiments showed that all the complexes present high cytotoxic activity against the cell lines: MDA-MB-231, MCF-7 (human metastatic breast adenocarcinomas, the first triple negative), MCF-10A (human normal breast cells), A549 (human lung epithelial carcinoma) and MRC-5 (human lung epithelial cells). Together, these results suggest that these compounds are promising steps towards new effective drugs to treat cancer.
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http://dx.doi.org/10.1016/j.jinorgbio.2019.110930DOI Listing
February 2020

Palladium(ii) complexes with thiosemicarbazones derived from pyrene as topoisomerase IB inhibitors.

Dalton Trans 2019 Nov;48(44):16509-16517

São Carlos Institute of Chemistry, University of São Paulo, 13560-970, São Carlos, Brazil.

New palladium complexes with thiosemicarbazonate ligands derived from pyrene exhibit potent antiproliferative activity against A2780 and cisplatin-resistant A2780Cis human ovarian cancer cells, which is dependent on substituent groups of the thiosemicarbazone ligands. Cellular accumulation and distribution studies confirmed that palladium enters the cell nucleus. DNA and topoisomerase IB studies show that one complex is a potent TopIB inhibitor, with selectivity for cancer versus normal cells.
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http://dx.doi.org/10.1039/c9dt02570gDOI Listing
November 2019

Non-mutagenic Ru(ii) complexes: cytotoxicity, topoisomerase IB inhibition, DNA and HSA binding.

Dalton Trans 2019 Oct;48(39):14885-14897

Dipartimentodi Biologia, UniversitàTorVergatadi Roma, 00133 Rome, Italy.

Herein we discuss five ruthenium(ii) complexes with good cytotoxicity against cancer cells. These complexes are named [Ru(tzdt)(bipy)(dppb)]PF6 (1), [Ru(mmi)(bipy)(dppb)]PF6 (2), [Ru(dmp)(bipy)(dppb)]PF6 (3), [Ru(mpca)(bipy)(dppb)]PF6 (4) and [Ru(2mq)(bipy)(dppb)]PF6 (5), where tzdt = 1,3-thiazolidine-2-thione, mmi = mercapto-1-methyl-imidazole, dmp = 4,6-diamino-2-mercaptopyrimidine, mpca = 6-mercaptopyridine-3-carboxylic acid, 2mq = 2-mercapto-4(3H)-quinazolinone, bipy = 2,2'-bipyridine and dppb = 1,4-bis(diphenylphosphino)butane. In vitro cell culture experiments revealed significant cytotoxic activity for 1-5 against MDA-MB-231, MCF-7, A549, DU-145 and HepG2 tumor cells, higher than that for the standard anticancer drug cisplatin. Compound/DNA interaction studies were carried out showing that 1-5 interact with DNA by electrostatic force of attraction or by hydrogen bonding. Moreover, the complexes interact, moderately and spontaneously, with human serum albumin (HSA) through the hydrophobic region. The five complexes are able to inhibit the DNA supercoiled relaxation mediated by human topoisomerase IB (TopIB), and complex 1 is found to be the most efficient TopIB inhibitor among the five compounds. The inhibitory effect and analysis of different steps of the TopIB catalytic cycle indicate that complex 1 inhibits the cleavage reaction impeding the binding of the enzyme to DNA and has no effect on the religation step. Complexes 1, 2 and 3 did not show mutagenic activity when they were evaluated by the cytokinesis-block micronucleus cytome assay in HepG2 cells and the Ames test in the presence and absence of mouse liver S9 metabolic activation. Therefore, it is necessary to perform further in-depth analysis of the therapeutic potential of these promising ruthenium complexes as anticancer drugs.
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http://dx.doi.org/10.1039/c9dt01905gDOI Listing
October 2019

Ruthenium(II) complexes with 6-methyl-2-thiouracil selectively reduce cell proliferation, cause DNA double-strand break and trigger caspase-mediated apoptosis through JNK/p38 pathways in human acute promyelocytic leukemia cells.

Sci Rep 2019 08 7;9(1):11483. Epub 2019 Aug 7.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Bahia, Brazil.

Ruthenium(II) complexes with 6-methyl-2-thiouracil cis-[Ru(6m2tu)(PPh)] (1) and [Ru(6m2tu)(dppb)] (2) (where PPhtriphenylphosphine; dppb = 1,4-bis(diphenylphosphino)butane; and 6m2tu = 6-methyl-2-thiouracil) are potent cytotoxic agents and able to bind DNA. The aim of this study was to evaluate in vitro cellular underlying mechanism and in vivo effectiveness of these ruthenium(II) complexes in human acute promyelocytic leukemia HL-60 cells. Both complexes displayed potent and selective cytotoxicity in myeloid leukemia cell lines, and were detected into HL-60 cells. Reduction of the cell proliferation and augmented phosphatidylserine externalization, caspase-3, -8 and -9 activation and loss of mitochondrial transmembrane potential were observed in HL-60 cells treated with both complexes. Cotreatment with Z-VAD(OMe)-FMK, a pan-caspase inhibitor, reduced Ru(II) complexes-induced apoptosis. In addition, both metal complexes induced phosphorylation of histone H2AX (S139), JNK2 (T183/Y185) and p38α (T180/Y182), and cotreatment with JNK/SAPK and p38 MAPK inhibitors reduced complexes-induced apoptosis, indicating DNA double-strand break and activation of caspase-mediated apoptosis through JNK/p38 pathways. Complex 1 also reduced HL-60 cell growth in xenograft model. Overall, the outcome indicated the ruthenium(II) complexes with 6-methyl-2-thiouracil as a novel promising antileukemic drug candidates.
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http://dx.doi.org/10.1038/s41598-019-47914-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686011PMC
August 2019

Ru(II)-thymine complex causes DNA damage and apoptotic cell death in human colon carcinoma HCT116 cells mediated by JNK/p38/ERK1/2 via a p53-independent signaling.

Sci Rep 2019 07 31;9(1):11094. Epub 2019 Jul 31.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Bahia, 40296-710, Brazil.

Ru(II)-thymine complex [Ru(PPh)(Thy)(bipy)]PF (where PPh = triphenylphosphine, Thy = thyminate and bipy = 2,2'-bipyridine) is a potent cytotoxic agent with ability to bind to DNA, inducing caspase-mediated apoptosis in leukemia cells. In this study, we investigated the mechanism underlying the cell death induction by Ru(II)-thymine complex in human colon carcinoma HCT116 cells, as well as its effect in xenograft tumor model. The Ru(II)-thymine complex increased significantly the percentage of apoptotic HCT116 cells. Co-treatment with a JNK/SAPK inhibitor, p38 MAPK inhibitor and MEK inhibitor, which inhibit the activation of ERK1/2, caused a marked reduction of the percentage of complex-induced apoptotic cells. Moreover, the Ru(II)-thymine complex induced an increase in phospho-JNK2 (T183/Y185), phospho-p38α (T180/Y182) and phospho-ERK1 (T202/Y204) levels in HCT116 cells. Treatment with the Ru(II)-thymine complex increased significantly the phospho-histone H2AX (S139) expression, a DNA damage marker. The expression of phospho-p53 (S15) and MDM2 were not changed, and the co-treatment with a p53 inhibitor (cyclic pifithrin-α) did not reduce the complex-induced apoptosis in HCT116 cells, indicating that the Ru(II)-thymine complex induces DNA damage-mediated apoptosis by JNK/p38/ERK1/2 via a p53-independent signaling. The Ru(II)-thymine complex (1 and 2 mg/kg/day) also inhibited HCT116 cell growth in a xenograft model, reducing the tumor mass at 32.6-40.1%. Altogether, indicate that the Ru(II)-thymine complex is a promising anti-colon cancer drug candidate.
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http://dx.doi.org/10.1038/s41598-019-47539-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668648PMC
July 2019

Ruthenium Complexes Containing Heterocyclic Thioamidates Trigger Caspase-Mediated Apoptosis Through MAPK Signaling in Human Hepatocellular Carcinoma Cells.

Front Oncol 2019 9;9:562. Epub 2019 Jul 9.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil.

Herein, ruthenium complexes containing heterocyclic thioamidates [Ru(mmi)(bipy)(dppb)]PF (), [Ru(tzdt)(bipy)(dppb)]PF (), [Ru(dmp)(bipy)(dppb)]PF () and [Ru(mpca)(bipy)(dppb)]PF () were investigated for their cellular and molecular effects in cancer cell lines. Complexes and were the most potent of the four compounds against a panel of different cancer cell lines in monolayer cultures and showed potent cytotoxicity in a 3D model of multicellular spheroids that formed from human hepatocellular carcinoma HepG2 cells. In addition, both complexes were able to bind to DNA in a calf thymus DNA model. Compared to the controls, a reduction in cell proliferation, phosphatidylserine externalization, internucleosomal DNA fragmentation, and the loss of the mitochondrial transmembrane potential were observed in HepG2 cells that were treated with these complexes. Additionally, coincubation with a pan-caspase inhibitor (Z-VAD(OMe)-FMK) reduced the levels of apoptosis that were induced by these compounds compared to those in the negative controls, indicating that cell death through apoptosis occurred via a caspase-dependent pathway. Moreover, these complexes also induced the phosphorylation of ERK1/2, and coincubation with an MEK inhibitor (U0126), which is known to inhibit the activation of ERK1/2, but not JNK/SAPK and p38 MAPK inhibitors, reduced the complexes-induced apoptosis compared to that in the negative controls, indicating that the induction of apoptotic cell death occurred through ERK1/2 signaling in HepG2 cells. On the other hand, no increase in oxidative stress was observed in HepG2 cells treated with the complexes, and the complexes-induced apoptosis was not reduced with coincubation with the antioxidant N-acetylcysteine or a p53 inhibitor compared to that in the negative controls, indicating that apoptosis occurred via oxidative stress- and p53-independent pathways. Finally, these complexes also reduced the growth of HepG2 cells that were engrafted in C.B-17 SCID mice compared to that in the negative controls. These results indicated that these complexes are novel anticancer drug candidates for liver cancer treatment.
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http://dx.doi.org/10.3389/fonc.2019.00562DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6629894PMC
July 2019

Ruthenium Complexes With Piplartine Cause Apoptosis Through MAPK Signaling by a p53-Dependent Pathway in Human Colon Carcinoma Cells and Inhibit Tumor Development in a Xenograft Model.

Front Oncol 2019 3;9:582. Epub 2019 Jul 3.

Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil.

Ruthenium complexes with piplartine, [Ru(piplartine)(dppf)(bipy)](PF) () and [Ru(piplartine)(dppb)(bipy)](PF) () (dppf = 1,1-bis(diphenylphosphino) ferrocene; dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2'-bipyridine), were recently synthesized and displayed more potent cytotoxicity than piplartine in different cancer cells, regulated RNA transcripts of several apoptosis-related genes, and induced reactive oxygen species (ROS)-mediated apoptosis in human colon carcinoma HCT116 cells. The present work aimed to explore the underlying mechanisms through which these ruthenium complexes induce cell death in HCT116 cells , as well as their action in a xenograft model. Both complexes significantly increased the percentage of apoptotic HCT116 cells, and co-treatment with inhibitors of JNK/SAPK, p38 MAPK, and MEK, which inhibits the activation of ERK1/2, significantly reduced the apoptosis rate induced by these complexes. Moreover, significant increase in phospho-JNK2 (T183/Y185), phospho-p38α (T180/Y182), and phospho-ERK1 (T202/Y204) expressions were observed in cells treated with these complexes, indicating MAPK-mediated apoptosis. In addition, co-treatment with a p53 inhibitor (cyclic pifithrin-α) and the ruthenium complexes significantly reduced the apoptosis rate in HCT116 cells, and increased phospho-p53 (S15) and phospho-histone H2AX (S139) expressions, indicating induction of DNA damage and p53-dependent apoptosis. Both complexes also reduced HCT116 cell growth in a xenograft model. Tumor mass inhibition rates were 35.06, 29.71, and 32.03% for the complex (15 μmol/kg/day), complex (15 μmol/kg/day), and piplartine (60 μmol/kg/day), respectively. These data indicate these ruthenium complexes as new anti-colon cancer drugs candidates.
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http://dx.doi.org/10.3389/fonc.2019.00582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6616125PMC
July 2019

Ru(II) complexes containing uracil nucleobase analogs with cytotoxicity against tumor cells.

J Inorg Biochem 2019 09 9;198:110751. Epub 2019 Jun 9.

Departamento de Química, Universidade Federal de São Carlos - UFSCar, Rodovia Washington Luiz, KM 235 CP 676, CEP 13561-901 São Carlos, SP, Brazil; Instituto de Química, Universidade Federal de Goiás - UFG, CEP 74690-900 Goiânia, GO, Brazil. Electronic address:

We report on chemistry and cytotoxic studies of four new ruthenium (II) complexes containing uracil derivatives. All compounds are neutral, presenting the formula [Ru(PPh)(2TU)] (1), [Ru(PPh)(6m2TU)] (2), [Ru(dppb)(2TU)] (3) and [Ru(dppb)(6m2TU)] (4), where PPh = triphenylphosphine; dppb = 1,4-bis(diphenylphosphino)butane, 2TU = 2-thiouracil and 6m2TU = 6-methyl-2-thiouracil. They were characterized using NMR, UV-vis and IR spectroscopies, microanalytical analysis and mass spectrometry. Furthermore, the crystal structures of 1-4 were determined by single-crystal X-ray diffraction. The coordination of 2-thiouracil derivatives with ruthenium increases regions able to carry out hydrogen bonds with the biological targets, such as DNA. We evaluated the interaction of the complexes with DNA by UV/Vis spectrophotometric titration, and as a result, the values of DNA-binding constants are in the range of 0.8-1.8 × 10 M. Moreover, the interaction of the complexes with BSA was investigated. In vitro, activities against B16-F10 (mouse melanoma), HepG2 (human hepatocellular carcinoma), HL-60 (human promyelocytic leukemia) and K562 (human chronic myelocytic leukemia) and non-tumor cells: PBMC (human peripheral blood mononuclear cells activated with concanavalin A - human lymphoblast) were carried out. Cytotoxicity assays revealed that complexes (2) and (4) present biological activity against tumor cells comparable with oxaliplatin, the reference platinum drug, revealing that they are promising molecules for developing new antitumor compounds.
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http://dx.doi.org/10.1016/j.jinorgbio.2019.110751DOI Listing
September 2019

Magnetic-field-tuned phase transition of a molecular material from the isolated-spin to the coupled-spin regime.

Phys Chem Chem Phys 2019 Feb;21(8):4394-4407

CEITEC - Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic.

We report the preparation, X-ray structure, chemical properties, and electron paramagnetic resonance (EPR) studies at Q and X-bands and temperature (mainly) T = 293 K of powder and oriented single crystal samples of the new compound [Cu(N',N'-dimethyl-N'-benzoylthiourea)(2,2'-bipyridine)Cl], called CuBMB. The EPR spectra of single crystal samples at the Q-band display abrupt merging and narrowing of the peaks corresponding to two rotated copper sites as a function of magnetic field (B0) orientation. This behaviour indicates a quantum transition from an array of quasi-isolated spins to a quantum-entangled spin array associated with exchange narrowing processes and produced by weak intermolecular exchange interactions Ji between neighbour copper spins. This transition occurs when the magnitudes of the anisotropic contributions to the Zeeman couplings, tuned with the direction of B0, approach these |Ji| and produce level crossings. The exchange couplings between neighbour spins are estimated from the angular variation of the single crystal EPR results at the Q-band. We analyse the quantum behaviour and phase transitions of the spin system and discuss the magnitudes of the exchange couplings in terms of the structure of the chemical paths connecting Cu neighbours. The single crystal data at the Q-band indicates an uncommon ground electronic state of CuII which is discussed and compared with the results of DFT calculations. The spectrum of polycrystalline (powder) samples at the Q-band is a sum of contributions of microcrystals in each phase, and the fraction F of the entangled phase depends on the microwave frequency. The X-band spectrum is compatible with the Q-band results, but does not display a transition, and the spin system is in the quantum-entangled phase for all field orientations. This behaviour is further studied with a simple geometric model giving basic predictions. The crystal structure of CuBMB is monoclinic, space group P21/n, with a = 11.9790(3) Å, b = 14.0236(5) Å, c = 12.1193(3) Å, β = 104.952(2)° and Z = 4, and the copper ions are equatorially bonded to the benzoylthiourea and bipyridine ligands in a heavily distorted square pyramidal structure.
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http://dx.doi.org/10.1039/c8cp06719hDOI Listing
February 2019

In vitro cytotoxicity and in vivo zebrafish toxicity evaluation of Ru(ii)/2-mercaptopyrimidine complexes.

Dalton Trans 2019 May;48(18):6026-6039

Laboratory of Molecular Genetics and Cytogenetics, Institute of Biological Sciences, Federal University of Goias-UFG, CEP 74690-900 Goiania, Goias, Brazil.

In this paper, four new ruthenium complexes, [Ru(N-S)(dppm)2]PF6 (1), [Ru(N-S)(dppe)2]PF6 (2), [Ru(N-S)2(dppp)] (3) and [Ru(N-S)2(PPh3)2] (4) [dppm = 1,1-bis(diphenylphosphino)methane, dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, PPh3 = triphenylphosphine and N-S = 2-mercaptopyrimidine anion] were synthesized and characterized using spectroscopy techniques, molar conductance, elemental analysis, electrochemical techniques and X-ray diffraction. The DNA binding studies were investigated using voltammetry and spectroscopy techniques. The results show that all complexes exhibit a weak interaction with DNA. HSA interaction with the complexes was studied using fluorescence emission spectroscopy, where the results indicate a spontaneous interaction between the species by a static quenching mechanism. The cytotoxicity of the complexes was evaluated against A549, MDA-MB-231 and HaCat cells by MTT assay. Complexes (1) and (2), which are very active against triple negative MDA-MB-231, were subjected to further biological tests with this cell line. The cytotoxic activity triggered by the complexes was confirmed by clonogenic assay. Cell cycle analyses demonstrated marked anti-proliferative effects, especially at the G0/G1 and S phases. The morphological detection of apoptosis and necrosis - HO/PI and Annexin V-FITC/PI assay, elucidated that the type of cell death triggered by these complexes was probably by apoptosis. The in vivo toxicological assessment performed on zebrafish embryos revealed that complexes (1) and (2) did not present embryotoxic or toxic effects during embryonic and larval development showing that they are promising new prototypes of safer and more effective drugs for triple negative breast cancer treatment.
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http://dx.doi.org/10.1039/c8dt03738hDOI Listing
May 2019

Ru(II)/N-N/PPh complexes as potential anticancer agents against MDA-MB-231 cancer cells (N-N = diimine or diamine).

J Inorg Biochem 2019 04 18;193:70-83. Epub 2019 Jan 18.

Universidade Federal de São Carlos, Departamento de Química, São Carlos, SP, Brazil. Electronic address:

The rational design of anticancer agents that acts in specific biological targets is one of the most effective strategies for developing chemotherapeutic agents. Aiming at obtaining new ruthenium (II) compounds with good cytotoxicity against tumor cells, a series of new complexes of general formula [RuCl(PPh)(Hdpa)(NN)]Cl [PPh = triphenylphosphine, N-N = 2,2'-dipyridylamine (Hdpa) (1), 1,2-diaminoethane (en) (2), 2,2'-bipyridine (bipy) (3), 5,5'-dimethyl-2,2'-bipyridine (dmbipy) (4), 1,10-phenanthroline (phen) (5) and 4,7-diphenyl-1,10-phenanthroline (dphphen) (6)] were synthesized. The complexes were characterized by elemental analysis and spectroscopic techniques (IR, UV/Visible, and 1D and 2D NMR) and three of their X-ray structures were determined: [RuCl(PPh)(Hdpa)]Cl, [RuCl(PPh)(Hdpa)(en)]Cl and [RuCl(PPh)(Hdpa)(dmbipy)]Cl. All the complexes are more cytotoxic against the cancer cell line than against the non-tumor cell line, highlighting complexes 1 and 5, which have an index selectivity of 18 and 15, respectively. The binding constants of compounds 1-6 with human serum albumin (HSA) were determined by tryptophan fluorescence quenching, indicating moderate to strong interactions. The binding mode of the complexes to calf thymus (CT) DNA was explored by several techniques, which reveal that only the dphphen compound 6 causes distortions in the secondary and tertiary structures of DNA. The studies demonstrated that the nature of the NN co-ligand and the presence of the PPh and Hdpa ligands are features that can influence the binding affinity of the complexes by the biomolecules and in the cytotoxic activity of the complexes. Overall, the complexes with diimine co-ligand are much more cytotoxic than compound 2 with the aliphatic diamine.
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http://dx.doi.org/10.1016/j.jinorgbio.2019.01.006DOI Listing
April 2019

Transport of the Ruthenium Complex [Ru(GA)(dppe)]PF into Triple-Negative Breast Cancer Cells Is Facilitated by Transferrin Receptors.

Mol Pharm 2019 03 25;16(3):1167-1183. Epub 2019 Jan 25.

Campus of Exact Sciences and Technology (CCET) , State University of Goiás , CEP 75132-903 Anápolis , GO , Brazil.

The triple-negative breast cancer subtype (TNBC) is highly aggressive and metastatic and corresponds to 15-20% of diagnosed cases. TNBC treatment is hampered, because these cells usually do not respond to hormonal therapy, and they develop resistance to chemotherapeutic drugs. On the other hand, the severe side effects of cisplatin represent an obstacle for its clinical use. Ruthenium (Ru)-based complexes have emerged as promising antitumor and antimetastatic substitutes for cisplatin. In this study, we demonstrated the effects of a Ru/biphosphine complex, containing gallic acid (GA) as a ligand, [Ru(GA)(dppe)]PF, hereafter called Ru(GA), on a TNBC cell line, and compared them to the effects in a nontumor breast cell line. Ru(GA) complex presented selective cytotoxicity against TNBC over nontumor cells, inhibited its migration and invasion, and induced apoptosis. These effects were associated with the increased amount of transferrin receptors (TfR) on tumor cells, compared to nontumor ones. Silencing of TfR decreased Ru(GA) effects on TNBC cells, demonstrating that these receptors were at least partially responsible for Ru(GA) delivery into tumor cells. The Ru(GA) compound must be further studied in different in vivo assays in order to investigate its antitumor properties and its toxicity in complex biological systems.
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http://dx.doi.org/10.1021/acs.molpharmaceut.8b01154DOI Listing
March 2019

Remarkable Electronic Effect on the meso-Tetra(thienyl)porphyrins.

Inorg Chem 2019 Jan 3;58(2):1030-1039. Epub 2019 Jan 3.

Departamento de Química , Universidade Federal de São Carlos , CP 676, CEP 13565-905 , São Carlos , São Paulo , Brazil.

Complexes derived from meso-tetra(thienyl)porphyrins (TThP) and meso-tetra(pyridyl)porphyrin (TPyP) containing peripheral ruthenium complexes with general formulas {TPyP[RuCl(dppb)(5,5'-Mebipy)]}(PF), {TThP[RuCl(dppb)(5,5'-Mebipy)]}(PF), and {TThP-me-[RuCl(dppb)(5,5'-Mebipy)]}(PF) [5,5'-Mebipy = 5,5'-dimethyl-2,2'-bipyridine and dppb = 1,4-bis(diphenylphosphino)butane] were synthesized and characterized by spectroscopy techniques (H- and P{H}-NMR, IR, UV/vis, fluorescence, and electron paramagnetic resonance (EPR)), cyclic voltammetry, coulometry, molar conductivity, and elemental analysis. Voltammetry and UV/vis studies demonstrated differentiated electronic properties for ruthenium appended with TThP and TThP-me when compared to ruthenium appended with TPyP. The UV/vis analysis for the ruthenium complex derived from TThP and TThP-me, as well as the Soret and Q bands, characteristics of porphyrins, showed a band at 700 nm referring to the Ru → S electronic transition, and porphyrin TThP-me showed another band at 475 nm from the Ru-N transition. The attribution of these bands was confirmed by spectroelectrochemical analysis. Cyclic voltammetry analysis for the ruthenium complex derived from TPyP exhibited only an electrochemical process with E = 0.47 V assigned to the Ru(II)/Ru(III) redox pair (Fc/Fc). On the other hand, two processes were observed for the ruthenium complexes derived from TThP and TThP-me, with E around 0.17 and 0.47 V, which were attributed to the formation of a mixed valence tetranuclear species containing Ru(II) and Ru(III) ions, showing that the peripheral groups are not oxidized at the same potential. Fluorescence spectroscopic experiments show the existence of a mixed state of emission in the supramolecular porphyrin moieties. The results suggest the formation of Ru(II)-Ru(III) mixed valence complexes when oxidation potential was applied around 0.17 V in the {TThP[RuCl(dppb)(5,5'-Mebipy)]}(PF) and {TThP-me-[RuCl(dppb)(5,5'-Mebipy)]}(PF) species.
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http://dx.doi.org/10.1021/acs.inorgchem.8b01032DOI Listing
January 2019

Determination of in vitro absorption in Caco-2 monolayers of anticancer Ru(II)-based complexes acting as dual human topoisomerase and PARP inhibitors.

Biometals 2019 02 30;32(1):89-100. Epub 2018 Nov 30.

Center of Exact Sciences and Technology, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil.

Due to their unique and versatile biochemical properties, ruthenium-based compounds have emerged as promising anticancer agents. Previous studies showed that three ruthenium(II) compounds: [Ru(pySH)(bipy)(dppb)]PF (1), [Ru(HSpym)(bipy)(dppb)]PF (2) and Ru[(SpymMe)(bipy)(dppb)]PF (3) presented anticancer properties higher than doxorubicin and cisplatin and acted as human topoisomerase IB (Topo I) inhibitors. Here, we focused our studies on in vitro intestinal permeability and anticancer mechanisms of these three complexes. Caco-2 permeation studies showed that 1 did not permeate the monolayer of intestinal cells, suggesting a lack of absorption on oral administration, while 2 and 3 permeated the cells after 60 and 120 min, respectively. Complexes 2 and 3 fully inhibited Topo II relaxation activity at 125 µM. In previously studies, 3 was the most potent inhibitor of Topo I, here, we concluded that it is a dual topoisomerase inhibitor. Moreover, it presented selectivity to cancer cells when evaluated by clonogenic assay. Thus, 3 was selected to gene expression assay front MDA-MB-231 cells from triple-negative breast cancer (TNBC), which represents the highly aggressive subgroup of breast cancers with poor prognosis. The analyses revealed changes of 27 out of 84 sought target genes. PARP1 and PARP2 were 5.29 and 1.83 times down-regulated after treatment with 3, respectively. PARPs have been attractive antitumor drug targets, considering PARP inhibition could suppress DNA damage repair and sensitize tumor cells to DNA damage agents. Recent advances in DNA repair studies have shown that an approach that causes cell lethality using synthetic PARP-inhibiting drugs has produced promising results in TNBC.
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http://dx.doi.org/10.1007/s10534-018-0160-0DOI Listing
February 2019

Study of the cytotoxic and genotoxic potential of the carbonyl ruthenium(II) compound, ct-[RuCl(CO)(dppb)(bipy)]PF [dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2'-bipyridine], by in vitro and in vivo assays.

J Appl Toxicol 2019 04 20;39(4):630-638. Epub 2018 Nov 20.

Laboratório de Mutagênese, Universidade de Franca, Pq. Universitario, CEP, 14404-600, Franca, SP, Brazil.

Considering the promising previous results of ct-[RuCl(CO)(dppb)(bipy)]PF (where dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2'-bipyridine) as an antitumor agent, novel biological assays evaluating its toxicogenic potential were performed. The genotoxicity of the compound was evaluated by the in vitro micronucleus test (V79, Chinese hamster lung fibroblasts; HepG2, hepatocellular carcinoma cells), in vivo bone marrow micronucleus test and comet assay in hepatocytes (Swiss mice). The animals were treated with 0.63, 1.25, 2.5 and 5.0 mg/kg body weight (bw) of the compound. Negative (water) and positive (cisplatin, 1.5 mg/kg bw; methyl methanesulfonate, 40 mg/kg bw) controls were included. The parameters considered in the comet assay were the percentage of tail DNA, tail moment and tail length. The results of the in vitro micronucleus tests showed the absence of genotoxicity in V79 cells, while the compound was genotoxic in HepG2 cells at a concentration of 1.25 μm. In the in vivo micronucleus test, the compound was not genotoxic at the different doses evaluated. In the comet assay, only the dose of 5.0 mg/kg bw resulted in a significant increase in the frequency of DNA damage in hepatocytes when compared to the negative control. The genotoxic effect observed in HepG2 cells and in the liver comet assay indicates that the compound was metabolized by hepatic cells.
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http://dx.doi.org/10.1002/jat.3753DOI Listing
April 2019

Hydrolysis reaction promotes changes in coordination mode of Ru(II)/acylthiourea organometallic complexes with cytotoxicity against human lung tumor cell lines.

J Inorg Biochem 2018 09 18;186:147-156. Epub 2018 Jun 18.

Departamento de Química, Universidade Federal de São Carlos - UFSCar, Rodovia Washington Luís KM 235, CP 676, 13565-905 São Carlos, SP, Brazil. Electronic address:

In this study, Ru(II)-arene complexes with acylthiourea ligands of the type [Ru(η‑p‑cymene)(PPh)(T)Cl]PF(1-5) and [Ru(η‑p‑cymene)(PPh)(T)]PF(1a, 4a), where PPh = triphenylphosphine and T = N‑acyl‑N'(monosubstituted)thiourea, were synthesized and characterized, and their cytotoxic properties were also evaluated. 1a and 4a were obtained from the hydrolysis reaction of 1 and 4. All complexes showed unusual coordination modes for acylthiourea ligands, which are coordinated in a monodentate fashion (S) in 1-5, while they found to be bidentate (S,N), in 1a and 4a. To the best of our knowledge, 1a and 4a are the first crystallographically reported ruthenium compounds with acylthiourea coordinated via S and N(amide) atoms. The cytotoxicity of the compounds was evaluated in human lung cells, A549 and MRC-5. The IC values ranging from 0.25 to 0.61 μM after 48 h incubation in lung cancer cells indicate that the compounds showed high cytotoxicity with values significantly lower than the reference drug, cisplatin (11.84 μM). Interaction studies were carried out using human serum albumin (HSA) and DNA. All complexes showed similar cytotoxic activity, however complex 1a, which is the hydrolysis product of 1, presented the highest activity and selectivity among all seven compounds synthesized here. Complexes 1 and 1a inhibited the colony formation decreasing the colony size and inducing morphology changes in A549 cells. These complexes induced apoptosis cell death and promoted cell cycle arrest in the Sub-G1 phase with a decrease in the cell number at the S phase.
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http://dx.doi.org/10.1016/j.jinorgbio.2018.06.007DOI Listing
September 2018

Cytotoxic activity and structural features of Ru(II)/phosphine/amino acid complexes.

J Inorg Biochem 2018 05 23;182:48-60. Epub 2017 Dec 23.

Departamento de Química, Universidade Federal de São Carlos, C.P. 676, CEP 13565-905 São Carlos, (SP), Brazil.

Thirteen new ruthenium amino acid complexes were synthesized and characterized. They were obtained by the reaction of α-amino acids (AA) with [RuCl(P-P)(N-N)], where P-P=1,4-bis(diphenylphosphino)butane (dppb) or 1,3-bis(diphenylphosphino)propane (dppp) and N-N=4,4'-dimethyl-2,2'-bipyridine (4'-Mebipy), 5,5'-dimethyl-2,2'-bipyridine (5'-Mebipy) or 4,4'-Methoxy-2-2'-bipyridine (4'-MeObipy). This afforded a family of complexes formulated as [Ru(AA-H)(P-P)(N-N)]PF, where AA=glycine (Gly), L-alanine (Ala), L-valine (Val), L-tyrosine (Tyr), L-tryptophan (Trp), L-histidine (His) and L-methionine (Met). All compounds were characterized by elemental analysis, spectroscopic and electrochemical techniques. The [Ru(AA-H)(P-P)(N-N)]PF complexes are octahedral (the AA-H ligand binding involves N-amine and O-carboxylate), diamagnetic (low-spin d, S=0) and present bands due to electronic transitions in the visible region. H, C{H} and P{H} NMR spectra of the complexes indicate the presence of C symmetry, and the identification of diastereoisomers. In vitro cytotoxicity assays of the compounds and cisplatin were carried out using MDA-MB-231 (human breast) tumor cell line and a non-tumor breast cell line (MCF-10A). Most complexes present promising results with IC values comparable with the reference drug cisplatin and high selectivity indexes were found for the complexes containing L-Trp. The binding of two Ru-precursors of the type [RuCl(dppb)(NN)] (N-N=4'-MeObipy or 4'-Mebipy) to the blood transporter protein human serum albumin (HSA) was evaluated by fluorescence and circular dichroism spectroscopy. Both complexes bind HSA, probably in the hydrophobic pocket near Trp214, and the Ru-complex containing 4'-MeObipy shows higher affinity for HSA than the 4'-Mebipy one.
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http://dx.doi.org/10.1016/j.jinorgbio.2017.12.010DOI Listing
May 2018