Characterization and cytotoxic effect of aqua-(2,2',2''-nitrilotriacetato)-oxo-vanadium salts on human osteosarcoma cells

Metallocompounds as anticancer agents against osteosarcoma

Metallocompounds are a class of anticancer compounds largely used in the treatment of several types of solid tumors, including bone cancer. Osteosarcoma (OS) is a primary malignant bone tumor that frequently affects children, adolescents and young adults. It is a very invasive type of tumor, so ∼40% of patients develop distant metastases, showing elevated mortality rates. In this review, we present an outline of the chemistry and antitumor properties of metal-based compounds in preclinical (in vitro and in vivo) and clinical OS models, focusing on the relationship between structure-activity, molecular targets and the study of the mechanism of action involved in metallocompound anticancer activity.

Exploring the Antitumor Efficacy of N-Heterocyclic Nitrilotriacetate Oxidovanadium(IV) Salts on Prostate and Breast Cancer Cells

The crystal structures of two newly synthesized nitrilotriacetate oxidovanadium(IV) salts, namely [QH][VO(nta)(H2O)](H2O)2 (I) and [(acr)H][VO(nta)(H2O)](H2O)2 (II), were determined. Additionally, the cytotoxic effects of four N-heterocyclic nitrilotriacetate oxidovanadium(IV) salts-1,10-phenanthrolinium, [(phen)H][VO(nta)(H2O)](H2O)0.5 (III), 2,2'-bipyridinium [(bpy)H][VO(nta)(H2O)](H2O) (IV), and two newly synthesized compounds (I) and (II)-were evaluated against prostate cancer (PC3) and breast cancer (MCF-7) cells. All the compounds exhibited strong cytotoxic effects on cancer cells and normal cells (HaCaT human keratinocytes). The structure-activity relationship analysis revealed that the number and arrangement of conjugated aromatic rings in the counterion had an impact on the antitumor effect. The compound (III), the 1,10-phenanthrolinium analogue, exhibited the greatest activity, whereas the acridinium salt (II), with a different arrangement of three conjugated aromatic rings, showed the lowest toxicity. The increased concentrations of the compounds resulted in alterations to the cell cycle distribution with different effects in MCF-7 and PC3 cells. In MCF-7 cells, compounds I and II were observed to block the G2/M phase, while compounds III and IV were found to arrest the cell cycle in the G0/G1 phase. In PC3 cells, all compounds increased the rates of cells in the G0/G1 phase.

In silico and in vitro analysis of FAK/MMP signaling axis inhibition by VO-clioquinol in 2D and 3D human osteosarcoma cancer cells

The study of novel mechanisms of action of vanadium compounds is critical to elucidating the role and importance of these kinds of compounds as antitumor and antimetastatic agents. This work deals with in silico and in vitro studies of one clioquinol oxidovanadium(iv) complex [VO(clioquinol)2], VO(CQ)2, and its regulation of FAK. In particular, we focus on elucidating the relationship of the FAK inhibition, MMP activity and antimetastatic effects of the complex in human bone cancer cells.

The effect of vanadium(IV) complexes on development of Arabidopsis thaliana subjected to H2O2-induced stress

The impact of oxydiacetate oxidovanadium(IV) complexes on plants is currently unknown. This report demonstrates the influence of these complexes on Arabidopsis thaliana (L.) Heynh. In the presence of 10-6M vanadium(IV) complexes, plants proceeded through their entire life cycle, with the occurrence of proper morphological and cytological organisation of leaf and root tissues. The addition of 10-1M H2O2 caused root damage, leaf necrosis, and plant death at around the seventh day, due to the destruction of the root system. Pretreatment of the plants with 10-6M of vanadium(IV) compounds: VOSO4 and VO(oda), alleviated the effects of H2O2 to some extent. Plants pretreated with 10-6M vanadium(IV) complexes survived longer despite the presence of H2O2. Considering the higher rate of plant survival in the presence of VOSO4, and the relatively high photosynthetic parameters and anthocyanin contents in the cells, we conclude that this vanadium(IV) compound can have positive effects on plants that are grown under stress conditions.

Vanadium Compounds as Enzyme Inhibitors with a Focus on Anticancer Effects

Vanadium salts and coordination compounds have desirable cellular anticancer effects, and although they have been investigated in detail as a potential treatment for diabetes, less attention has been given to the anticancer effects. The inhibition of some signal transduction enzymes is known, and studies of the metabolism and activation pathways both in vitro and in vivo are important for future investigations and development of vanadium's role as a new potential drug. In addition, a new approach has demonstrated that the enhancement of oncolytic viruses using vanadium salts and coordination complexes for immunotherapy is very promising. Some differences exist between this approach and current antidiabetic and anticancer studies because vanadium(iv) complexes have been found to be most potent in the latter approach, but the few compounds investigated with oncolytic viruses show that vanadium(v) systems are more effective. We conclude that recent studies demonstrate effects on signal transduction enzymes and anticancer pathways, thus suggesting potential applications of vanadium as anticancer agents in the future both as standalone treatments as well as combination therapies.

New Oxidovanadium(IV) Coordination Complex Containing 2-Methylnitrilotriacetate Ligands Induces Cell Cycle Arrest and Autophagy in Human Pancreatic Ductal Adenocarcinoma Cell Lines

Pancreatic cancer is characterized by one of the lowest five-year survival rates. In search for new treatments, some studies explored several metal complexes as potential anticancer drugs. Therefore, we investigated three newly synthesized oxidovanadium(IV) complexes with 2-methylnitrilotriacetate (bcma3-), N-(2-carbamoylethyl)iminodiacetate (ceida3-) and N-(phosphonomethyl)-iminodiacetate (pmida4-) ligands as potential anticancer compounds using pancreatic cancer cell lines. We measured: Cytotoxicity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR) and lactate dehydrogenase (LDH) assay; antiproliferative activity by bromodeoxyuridine BrdU assay; reactive oxygen species (ROS) generation and cell cycle analysis by flow cytometry; protein level by Western blot and cellular morphology by confocal laser scanning microscopy. The results showed that these oxidovanadium(IV) complexes were cytotoxic on pancreatic cancer cells (PANC-1 and MIA PaCa2), but not on non-tumor human immortalized pancreas duct epithelial cells (hTERT-HPNE) over the concentration range of 10⁻25 μM, following 48 h incubation. Furthermore, molecular mechanisms of cytotoxicity of [4-NH₂-2-Me(Q)H][VO(bcma)(H₂O)]2H₂O (T1) were dependent on antiproliterative activity, increased ROS generation, cell cycle arrest in G2/M phase with simultaneous triggering of the p53/p21 pathway, binucleation, and induction of autophagy. Our study indicates that oxidovanadium(IV) coordination complexes containing 2-methylnitrilotriacetate ligand are good candidates for preclinical development of novel anticancer drugs targeting pancreatic cancer.

In-depth synthetic, physicochemical and in vitro biological investigation of a new ternary V(IV) antioxidant material based on curcumin

Curcumin is a natural product with a broad spectrum of beneficial properties relating to pharmaceutical applications, extending from traditional remedies to modern cosmetics. The biological activity of such pigments, however, is limited by their solubility and bioavailability, thereby necessitating new ways of achieving optimal tissue cellular response and efficacy as drugs. Metal ion complexation provides a significant route toward improvement of curcumin stability and biological activity, with vanadium being a representative such metal ion, amply encountered in biological systems and exhibiting exogenous bioactivity through potential pharmaceuticals. Driven by the need to optimally increase curcumin bioavailability and bioactivity through complexation, synthetic efforts were launched to seek out stable species, ultimately leading to the synthesis and isolation of a new ternary V(IV)-curcumin-(2,2'-bipyridine) complex. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetry (TGA), UV-Visible, NMR, ESI-MS, Fluorescence, X-rays) portrayed the solid-state and solution properties of the ternary complex. Pulsed-EPR spectroscopy, in frozen solutions, suggested the presence of two species, cis- and trans-conformers. Density Functional Theory (DFT) calculations revealed the salient features and energetics of the two conformers, thereby complementing EPR spectroscopy. The well-described profile of the vanadium species led to its in vitro biological investigation involving toxicity, cell metabolism inhibition in S. cerevisiae cultures, Reactive Oxygen Species (ROS)-suppressing capacity, lipid peroxidation, and plasmid DNA degradation. A multitude of bio-assays and methodologies, in comparison to free curcumin, showed that it exhibits its antioxidant potential in a concentration-dependent fashion, thereby formulating a bioreactivity profile supporting development of new efficient vanado-pharmaceuticals, targeting (extra)intra-cellular processes under (patho)physiological conditions.

Synthesis, in vitro cytotoxicity, and structure-activity relationships (SAR) of multidentate oxidovanadium(iv) complexes as anticancer agents

Multidentate oxidovanadium(iv) complexes with different geometric configurations [VO(ox)(bpy)(H2O)] 1, [VO(ox)(phen)(H2O)] 2, [VO(ida)(bpy)]·2H2O 3, (phen)[VO(ida)(phen)]·4H2O 4, and (Hphen)[VO(H2O)(nta)]·2H2O 5 [ox = oxalic acid, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, ida = iminodiacetic acid, nta = nitrilotriacetic acid] have been obtained from the reactions of oxidovanadium sulfate or vanadium pentoxide with oxalates, amino-polycarboxylates and N-heterocyclic ligands in neutral solution by the hydrothermal method, and have been fully characterized by elemental, thermogravimetric analyses and single crystal X-ray diffraction, as well as a wide range of spectroscopic techniques such as FT-IR, UV/Vis, NMR, ESI-MS. The anti-tumor properties of oxidovanadium compounds 1-5 were further evaluated in human HepG2 and SMMC-7721 hepatocellular carcinoma cell lines in vitro. The profiles of cytotoxicity, cell cycle distribution, as well as cell apoptosis upon test compound exposure, were determined by MTT and flow cytometry assays. Compound 2 exhibited a much higher anti-tumor activity than others. The IC50 values of 2 were 5.34 ± 0.034 μM and 29.07 ± 0.017 μM in SMMC-7721 and HepG2 cells after 48 h treatment, respectively. Furthermore, compound 2 could significantly arrest the cell cycle in the S and G2/M phases and further induce cell apoptosis in a dose-dependent manner. The structure-activity relationship (SAR) studies revealed that structural elements, for example, metal components, variations of coordination mode, labile water molecules, chelated ligands etc., probably exert an essential cooperative effect on the antitumor activity. In short, these findings not only provide an accessible model system to exploit V-based complexes as potential simple, safe and effective multifunctional antitumor agents, but also open up a rational approach to shed new light on the selection and optimization of ideal drug candidates.