Vanadium in cancer treatment

Vanadium 8-hydroxyquinoline derivatives in medicine: current state and future outlook

Vanadium complexes featuring 8-hydroxyquinoline ligands and their derivatives have emerged as a promising class of compounds with potential therapeutic applications, particularly as antimicrobial and anticancer agents. This comprehensive review offers a timely and insightful analysis of the current landscape of vanadium complexes with HQ ligand or its derivatives, whether alone or in combination with organic coligands. This review covers synthetic strategies, and mechanisms that underlie their antibacterial and anticancer activities. A significant focus of this review is the thorough evaluation of the antibacterial and anticancer properties of these complexes, providing an invaluable resource for researchers in the interdisciplinary fields of inorganic chemistry, medicinal chemistry, and drug discovery. By compiling and synthesizing the existing knowledge on vanadium-8-hydroxyquinoline (VO-8HQ) complexes, this review addresses a critical gap in the literature. Ongoing research, including rigorous preclinical and clinical evaluations, is essential for fully exploring the therapeutic potential of this promising class of metallodrugs.

Interaction of VVO2-hydrazonates with lysozyme

Vanadium compounds (VCs) exhibit a broad range of pharmacological properties, with their most significant medical applications being in the treatment of cancer and diabetes. The therapeutic effects and mode of action of VCs may be associated with their ability to bind proteins and, consequently, understanding the VC-protein interaction is of paramount importance. Among the promising VCs, the VVO2 complex with the aroylhydrazone furan-2-carboxylic acid ((3-ethoxy-2-hydroxybenzylidene)hydrazide, hereafter denoted as VC1), deserves attention, since it exhibits cytotoxicity against various cancer cell lines, including HeLa. The interaction between VC1 and its analogue, denoted as VC2 (the dioxidovanadium(V) complex with (E)-N'-(1-(2-hydroxy-5-methoxyphenyl)ethylidene)furan-2-carbohydrazide), and hen egg white lysozyme (HEWL) was examined by UV-vis spectroscopy, fluorescence, circular dichroism, and X-ray crystallography. The interaction of VC1 and VC2 with HEWL does not alter the protein secondary and tertiary structure. Crystallographic studies indicate that the two metal complexes or V-containing fragments originating from VC1 and VC2 bind the protein via non-covalent interactions. Furthermore, when bound to HEWL, two VC1 molecules and two VC2 molecules form a supramolecular association stabilized by stacking interactions. This type of interaction could favour the binding of similar compounds to proteins and affect their biological activity.

Hydrolysis, Ligand Exchange, and Redox Properties of Vanadium Compounds: Implications of Solution Transformation on Biological, Therapeutic, and Environmental Applications

Vanadium is a transition metal with important industrial, technological, biological, and biomedical applications widespread in the environment and in living beings. The different reactions that vanadium compounds (VCs) undergo in the presence of proteins, nucleic acids, lipids and metabolites under mild physiological conditions are reviewed. In the environment vanadium is present naturally or through anthropogenic sources, the latter having an environmental impact caused by the dispersion of VCs in the atmosphere and aquifers. Vanadium has a versatile chemistry with interconvertible oxidation states, variable coordination number and geometry, and ability to form polyoxidovanadates with various nuclearity and structures. If a VC is added to a water-containing environment it can undergo hydrolysis, ligand-exchange, redox, and other types of changes, determined by the conditions and speciation chemistry of vanadium. Importantly, the solution is likely to differ from the VC introduced into the system and varies with concentration. Here, vanadium redox, hydrolytic and ligand-exchange chemical reactions, the influence of pH, concentration, salt, specific solutes, biomolecules, and VCs on the speciation are described. One of our goals with this work is highlight the need for assessment of the VC speciation, so that beneficial or toxic species might be identified and mechanisms of action be elucidated.

Ultrathin ALD Coatings of Zr and V Oxides on Anodic TiO2 Nanotube Layers: Comparison of the Osteoblast Cell Growth

The current study investigates and compares the biological effects of ultrathin conformal coatings of zirconium dioxide (ZrO2) and vanadium pentoxide (V2O5) on osteoblastic MG-63 cells grown on TiO2 nanotube layers (TNTs). Coatings were achieved by the atomic layer deposition (ALD) technique. TNTs with average tube diameters of 15, 30, and 100 nm were fabricated on Ti substrates (via electrochemical anodization) and were used as primary substrates for the study. The MG-63 cell growth and proliferation after 48 h of incubation on hybrid TNTs/ZrO2 and TNTs/V2O5 surfaces was evaluated in comparison to the uncoated TNTs of each diameter. The density of viable MG-63 cells was assessed for all the TNT surfaces, along with the cell morphology and the spreading behavior (i.e., the cell length). The ultrathin coatings retained the original morphology of the TNTs but changed the surface chemical composition, wettability, and cell behavior, whose interplay is the subject of the present investigation. These findings offer interesting views on the influence of the composition of biomedical implant surfaces, triggered by ALD ultrathin coatings on them. The outcomes of this work shed light on the assessment of the biocompatibility of the two different ALD coatings.

Cytotoxicity of Vanadium(IV) and Vanadium(V) on Caco-2 Cells: The Important Influence of Vanadium Speciation

Exposure to vanadium (V) occurs through the ingestion of contaminated water, polluted soil, V-containing foods and medications, and the toxicity and absorption during the small intestine phase after oral ingestion play crucial roles in the ultimate health hazards posed by V. In this study, the human colon adenocarcinoma (Caco-2) cells were selected as an intestinal absorption model to investigate the uptake and cytotoxicity of vanadyl sulfate (VOSO4) and sodium orthovanadate (Na3VO4). Our results confirmed the cytotoxic effects of V(IV) and V(V) and revealed a greater toxicity of V(IV) than V(V) towards Caco-2 cells. Cell viability correlated linearly with V(V) concentration, whereas it exhibited a non-monotonic dose-response curve with V(IV) concentration. Moreover, exposures to V(IV) and V(V) induced oxidative stress in Caco-2 cells. Under experimental conditions, Caco-2 cells exhibited greater uptake of V(IV) compared to V(V). Morphological experiments further substantiated the adverse effects of V(IV) on Caco-2 cells, manifested as alterations in cellular morphology and disruption of cell monolayer structure. In conclusion, these results indicate that V(IV) exerts stronger negative effects on Caco-2 cells, with a more complex mechanism of action. Altogether, studying intestinal cytotoxicity of V provides deeper insights into the potential health risks posed by oral V exposure.

Insights into the Theranostic Activity of Nonoxido VIV: Lysosome-Targeted Anticancer Metallodrugs

Developing new anticancer agents can be useful, with the ability to diagnose and treat cancer worldwide. Previously, we focused on examining the effects of nonoxidovanadium(IV) complexes on insulin mimetic and cytotoxicity activity. In this study, in addition to the cytotoxic activity, we evaluated their bioimaging properties. This study investigates the synthesis of four stable nonoxido VIV complexes [VIV(L1-4)2] (1-4) using aroylhydrazone ligands (H2L1-4) and their full characterization in solid state and the solution phase stability using various physicochemical techniques. The biomolecular (DNA/HSA) interaction of the complexes was evaluated by using conventional methods. The in vitro cytotoxicity of 1-4 was studied against A549 and LN-229 cancer cell lines and found that drug 2 displayed the highest activity among the four. Since 1-4 are fluorescently active, live cell imaging was used to evaluate their cellular localization activity. Complexes specifically target the lysosome and damage lysosome integrity by producing an excessive amount (9.7-fold) of reactive oxygen species (ROS) compared to the control, which may cause cell apoptosis. Overall, this study indicates that 2 has the greatest potential for the development of multifunctional theranostic agents that combine imaging capabilities and anticancer properties of nonoxidovanadium(IV)-based metallodrugs.

In-Depth Mass Spectrometry Study of Vanadium(IV) Complexes with Model Peptides

Investigating the speciation of vanadium complexes in the presence of potential biomolecular targets under physiological conditions remains challenging, and further experimental techniques are needed to better understand the mechanism of action of potential metallodrugs. The interaction of two model peptides (angiotensin I and angiotensin II) with three well-known oxidovanadium(IV) compounds with antidiabetic and/or anticancer activity, [VIVO(pic)2(H2O)], [VIVO(ma)2], and [VIVO(dhp)2] (where pic, ma, and dhp are picolinate, maltolate, and 1,2-dimethyl-3-hydroxy-4(1H)-pyridinonate anions, respectively), was investigated by ESI-MS/MS (electrospray ionization tandem mass spectrometry) and complemented by EPR (electron paramagnetic resonance) spectroscopy measurements and theoretical calculations at the DFT (density functional theory) level. The results demonstrated that vanadium-peptide bonds are preserved after HCD (higher energy collisional dissociation) fragmentation, allowing for the identification of binding sites through a detailed analysis of the fragmentation spectra. Angiotensin I (AT1) and angiotensin II (AT2) exhibited different coordination behaviors. AT1, with two His residues (His6, His9), prefers to form [AT1 + VOL] adducts with both histidine residues coordinated to the metal ion, while AT2, which has only His6, can bind the metal in a monodentate fashion, forming also [AT2 + VOL2] adducts. Insights from this study pave the way to ESI-MS/MS investigations of more complex systems, including target proteins and further development of vanadium-based drugs.

Establishment of XRD fourier fingerprint identification method of realgar decoction pieces and its anti-tumor activity in tumor-in-situ transplanted mice

ETHNOPHARMACOLOGICAL RELEVANCE

Realgar, a traditional mineral Chinese medicine, has been used in China for more than 2000 years. It has been recorded in many ancient and modern works that it has anti-cancer and anti-tumor effects. Of course, colon cancer is also within the scope of its treatment. Realgar needs to be processed into realgar decoction pieces by water grinding before being used for medicine. To ensure the consistency of efficacy and quality of realgar decoction pieces, modern methods need to be used for further quality control.

AIM OF THE STUDY

The research of traditional mineral Chinese medicine is relatively difficult, and the related research is less. The purpose of this study is to control the quality of realgar decoction pieces by modern analytical technology and analyze its components. On this basis, its anti-colon cancer activity was discussed.

MATERIALS AND METHODS

Several batches of realgar decoction pieces were analyzed by XRD, and the components of realgar decoction pieces were obtained. The quality control fingerprints of realgar decoction pieces were established by processing XRD spectra and similarity evaluation. Then, the effects of realgar decoction pieces on apoptosis of CT26 and HTC-116 cells were observed in vitro by Hoechst 33258 staining, flow cytometry, measurement of mitochondrial membrane potential and Western blot; In vivo, the mouse model of tumor-in-situ transplantation of colon cancer was established, and the related indexes were observed.

RESULT

The explorations showed that the XRD Fourier fingerprints of realgar decoction pieces samples that had the same phase revealed 10 common peaks, respectively. The similarity evaluation of the established XRD Fourier fingerprint was greater than 0.900. We also demonstrated that realgar decoction pieces can promote apoptosis and inhibit tumor growth in colon cancer cells, its activating effect on p53 protein, and its safety when used within reasonable limits.

CONCLUSION

The quality control of realgar decoction pieces by XRD is scientific and has the inhibitory effect on colon cancer, which has the development potential.

Effect of roasting process on the V (anti-tumor agent) recovery from the slag of the electric arc furnace (EAF)

Due to the lack of mineral sources of Vanadium (V) in many parts of the world and its recent applications in the field of medicine (as an anti-tumor agent), one of the biggest sources of V is the extraction of V as V2O5 from steel slag in melting process. In this study, the pyro-hydrometallurgical process has been investigated for the extraction of V from steel slag created in a convertor. To get an optimum process of salt roasting, the effect of roasting temperature, time, salt value, slag particle size, and cooling method have been investigated. For this purpose, slag samples were roasted with sodium carbonate and then dissolved in water. The amount of V2O5 obtained by optical spectrometry is the efficiency criterion of this process. Results showed that the optimum condition for the extraction of V2O5 from steel slag was 15 wt % of Na2CO3 as a salt roasting agent and hating for 60 min at 1100 °C.

Search for new biologically active compounds: in vitro studies of antitumor and antimicrobial activity of dirhodium(II,II) paddlewheel complexes

Four neutral Rh1-Rh4 complexes of the general formula [Rh2(CH3COO)4L2], where L is an N-alkylimidazole ligand, were synthesized and characterized using various spectroscopic techniques, and in the case of Rh4 the crystal structure was confirmed. Investigation of the interactions of these complexes with HSA by fluorescence spectroscopy revealed that the binding constants Kb are moderately strong (∼104 M-1), and site-marker competition experiments showed that the complexes bind to Heme site III (subdomain IB). Competitive binding studies for CT DNA using EB and HOE showed that the complexes bind to the minor groove, which was also confirmed by viscosity experiments. Molecular docking confirmed the experimental data for HSA and CT DNA. Antimicrobial tests showed that the Rh2-Rh4 complexes exerted a strong inhibitory effect on G+ bacteria B. cereus and G- bacteria V. parahaemolyticus as well as on the yeast C. tropicalis, which showed a higher sensitivity compared to fluconazole. The cytotoxic activity of Rh1-Rh4 complexes tested on three cancer cell lines (HeLa, HCT116 and MDA-MB-231) and on healthy MRC-5 cells showed that all investigated complexes elicited more efficient cytotoxicity on all tested tumor cells than on control cells. Investigation of the mechanism of action revealed that the Rh1-Rh4 complexes inhibit cell proliferation via different mechanisms of action, namely apoptosis (increase in expression of the pro-apoptotic Bax protein and caspase-3 protein in HeLa and HCT116 cells; changes in mitochondrial potential and mitochondrial damage; release of cytochrome c from the mitochondria; cell cycle arrest in G2/M phase in both HeLa and HCT116 cells together with a decrease in the expression of cyclin A and cyclin B) and autophagy (reduction in the expression of the protein p62 in HeLa and HCT116 cells).

EGCG-vanadium nanomedicine with neutral pH Fenton reaction activity inhibits heat shock proteins for enhanced photothermal/chemodynamic therapy

A burgeoning interest has recently focused on the development of nanomedicine to integrate noninvasive photothermal therapy (PTT) and chemodynamic therapy (CDT) for synergistic tumor treatments, owing to PTT's amplification effect on CDT. However, challenges emerge as hyperthermia often induces an unwarranted overexpression of cytoprotective heat shock proteins (HSPs), thereby curtailing PTT efficacy. Additionally, the nearly neutral tumor intracellular pH (pHi ≈ 7.2) that handicaps the Fenton reaction poses a leading limitation to CDT. Addressing these hurdles, we introduce EVP, a nanomedicine developed through the straightforward assembly of epigallocatechin gallate (EGCG), vanadium sulfate (VOSO4), and Pluronic F-127 (PF127). EVP comprehensively downregulates overexpressed HSPs (HSP 60, 70, 90) through the collaborative action of EGCG and vanadyl (VO2+). Moreover, the tumor intracellular pH-processed Fenton-like reaction by VO2+ ensures highly efficient hydroxyl radicals (OH) production in cytosols, overcoming the stringent acidity requirement for CDT. Additionally, the hyperthermia induced by PTT augments OH production, further enhancing CDT efficacy. In vitro and in vivo experiments validate EVP's excellent biocompatibility and potent tumor inhibition, highlighting its substantial potential in tumor therapy.

Evaluation of genotoxic damage, production reactive oxygen and nitrogen species in Plasmodium yoelii yoelii exposed to sodium metavanadate

Malaria represents the greatest global health burden among all parasitic diseases, with drug resistance representing the primary obstacle to control efforts. Sodium metavanadate (NaVO3) exhibits antimalarial activity against the Plasmodium yoelii yoelii (Pyy), yet its precise antimalarial mechanism remains elusive. This study aimed to assess the antimalarial potential of NaVO3, evaluate its genotoxicity, and determine the production of reactive oxygen and nitrogen species (ROS/RNS) in Pyy. CD-1 mice were infected and divided into two groups: one treated orally with NaVO3 (10 mg/kg/day for 4 days) and the other untreated. A 50% decrease in parasitemia was observed in treated mice. All experimental days demonstrated DNA damage in exposed parasites, along with an increase in ROS and RNS on the fifth day, suggesting a possible parasitostatic effect. The results indicate that DNA is a target of NaVO3, but further studies are necessary to fully elucidate the mechanisms underlying its antimalarial activity.

In-vitro and in-silico analysis and antitumor studies of novel Cu(II) and V(V) complexes of N-p-Tolylbenzohydroxamic acid

Copper(L2Cu) and vanadium(L2VOCl) complexes of N-p-tolylbenzohydroxamic acid (LH) ligand have been investigated for DNA binding efficacy by multiple analytical, spectral, and computational techniques. The results revealed that complexes as groove binders as evidenced by UV absorption. Fluorescence studies including displacement assay using classical intercalator ethidium bromide as fluorescent probe also confirmed as groove binders. The viscometric analysis too supports the inferences as strong groove binders for both the complexes. Molecular docking too exposed DNA as a target to the complexes which precisely binds L2Cu, in the minor groove region while L2VOCl in major groove region. Molecular dynamic simulation performed on L2Cu complex revealing the interaction of complex with DNA within 20 ns time. The complex stacked into the nitrogen bases of oligonucleotides and the bonding features were intrinsically preserved for longer simulation times. In-vitro cytotoxicity study was undertaken employing MTT assay against the breast cancer cell line (MCF-7). Potential cytotoxic activities were observed for L2Cu and L2VOCl complexes with IC50 values of showing 71 % and 74 % of inhibition respectively.

Mitochondria-targeted BODIPY dyes for small molecule recognition, bio-imaging and photodynamic therapy

Mitochondria are essential for a diverse array of biological functions. There is increasing research focus on developing efficient tools for mitochondria-targeted detection and treatment. BODIPY dyes, known for their structural versatility and excellent spectroscopic properties, are being actively explored in this context. Numerous studies have focused on developing innovative BODIPYs that utilize optical signals for imaging mitochondria. This review presents a comprehensive overview of the progress made in this field, aiming to investigate mitochondria-related biological events. It covers key factors such as design strategies, spectroscopic properties, and cytotoxicity, as well as mechanism to facilitate their future application in organelle imaging and targeted therapy. This work is anticipated to provide valuable insights for guiding future development and facilitating further investigation into mitochondria-related biological sensing and phototherapy.

Cytotoxicity of vanadium dioxide nanoparticles to human embryonic kidney cell line: Compared with vanadium(IV/V) ions

Vanadium dioxide (VO2) is a class of thermochromic material with potential applications in various fields. Massive production and wide application of VO2 raise the concern of its potential toxicity to human, which has not been fully understood. Herein, a commercial VO2 nanomaterial (S-VO2) was studied for its potential toxicity to human embryonic kidney cell line HEK293, and two most common vanadium ions, V(IV) and V(V), were used for comparison to reveal the related mechanism. Our results indicate that S-VO2 induces dose-dependent cellular viability loss mainly through the dissolved V ions of S-VO2 outside the cell rather than S-VO2 particles inside the cell. The dissolved V ions of S-VO2 overproduce reactive oxygen species to trigger apoptosis and proliferation inhibition via several signaling pathways of cell physiology, such as MAPK and PI3K-Akt, among others. All bioassays indicate that the differences in toxicity between S-VO2, V(IV), and V(V) in HEK293 cells are very small, supporting that the toxicity is mainly due to the dissolved V ions, in the form of V(V) and/or V(IV), but the V(V)'s behavior is more similar to S-VO2 according to the gene expression analysis. This study reveals the toxicity mechanism of nanosized VO2 at the molecular level and the role of dissolution of VO2, providing valuable information for safe applications of vanadium oxides.

Effects of the tetravanadate [V4O12]4- anion on the structural, magnetic, and biological properties of copper/phenanthroline complexes

The aim to access linked tetravanadate [V4O12]4- anion with mixed copper(II) complexes, using α-amino acids and phenanthroline-derived ligands, resulted in the formation of four copper(II) complexes [Cu(dmb)(Gly)(OH2)]2[Cu(dmb)(Gly)]2[V4O12]·9H2O (1) [Cu(dmb)(Lys)]2[V4O12]·8H2O (2), [Cu(dmp)2][V4O12]·C2H5OH·11H2O (3), and [Cu(dmp)(Gly)Cl]·2H2O (4), where dmb = 4,4'-dimethioxy-2,2'-bipyridine; Gly = glycine; Lys = lysine; and dmp = 2,9-dimethyl-1,10-phenanthroline. The [V4O12]4- anion is functionalized with mixed copper(II) units in 1 and 2; while in 3, it acts as a counterion of two [Cu(dmp)]2+ units. Compound 4 crystallized as a unit that did not incorporate the vanadium cluster. All compounds present magnetic couplings arising from Cu⋯O/Cu⋯Cu bridges. Stability studies of water-soluble 3 and 4 by UV-Vis spectroscopy in cell culture medium confirmed the robustness of 3, while 4 appears to undergo ligand scrambling over time, resulting partially in the stable species [Cu(dmp)2]+ that was also identified by electrospray ionization mass spectrometry at m/z = 479. The in vitro cytotoxicity activity of 3 and 4 was determined in six cancer cell lines; the healthy cell line COS-7 was also included for comparative purposes. MCF-7 cells were more sensitive to compound 3 with an IC50 value of 12 ± 1.2 nmol. The tested compounds did not show lipid peroxidation in the TBARS assay, ruling out a mechanism of action via reactive oxygen species formation. Both compounds inhibited cell migration at 5 µM in wound-healing assays using MCF-7, PC-3, and SKLU-1 cell lines, opening a new window to study the anti-metastatic effect of mixed vanadium-copper(II) systems.

Ultrastructural alterations due to sodium metavanadate treatment in the blood stages of Plasmodium yoelii yoelii

Malaria is a potentially mortal disease caused by parasites of the genus Plasmodium spp. It has a wide distribution in the world and unfortunately there are several factors that make its control difficult; among which the development of pharmacological resistance to the different drugs used to treat this disease stands out, which makes it necessary to design new compounds that have an antimalarial effect. Previous studies have shown that vanadium has a broad antiparasitic spectrum and is also safe for the host, so the objective of this research was to evaluate the antimalarial potential of sodium metavanadate (SM) and to analyze the ultrastructural changes in parasites exposed. The method consisted of inoculating CD-1 male mice with Plasmodium yoelii yoelii and administering a 10 mg/kg/day dose of SM orally for 4 days. On the fifth day, whole blood samples were obtained, processed for ultrastructural analysis, and the changes in the different parasite stages were compared against the control. Our results showed that SM decreased parasitemia compared to the group that did not receive treatment and modified the ultrastructure in all parasitic stages because it damaged the membranes, causing alterations mainly in the nucleus and in the mitochondria as well as the loss of cellular organization, which could affect the integrity of these parasites and decrease its viability.

Substitution Kinetics, Albumin and Transferrin Affinities, and Hypoxia All Affect the Biological Activities of Anticancer Vanadium(V) Complexes

Limited stability of most transition-metal complexes in biological media has hampered their medicinal applications but also created a potential for novel cancer treatments, such as intratumoral injections of cytotoxic but short-lived anticancer drugs. Two related V(V) complexes, [VO(Hshed)(dtb)] (1) and [VO(Hshed)(cat)] (2), where H2shed = N-(salicylideneaminato)-N'-(2-hydroxyethyl)-1,2-ethanediamine, H2dtb = 3,5-di-tert-butylcatechol, and H2cat = 1,2-catechol, decomposed within minutes in cell culture medium at 310 K (t1/2 = 43 and 9 s for 1 and 2, respectively). Despite this, both complexes showed high antiproliferative activities in triple-negative human breast cancer (MDA-MB-231) cells, but the mechanisms of their activities were radically different. Complex 1 formed noncovalent adducts with human serum albumin, rapidly entered cells via passive diffusion, and was nearly as active in a short-term treatment (IC50 = 1.9 ± 0.2 μM at 30 min) compared with a long-term treatment (IC50 = 1.3 ± 0.2 μM at 72 h). The activity of 1 decreased about 20-fold after its decomposition in cell culture medium for 30 min at 310 K. Complex 2 showed similar activities (IC50 ≈ 12 μM at 72 h) in both fresh and decomposed solutions and was inactive in a short-term treatment. The activity of 2 was mainly due to the reactions among V(V) decomposition products, free catechol, and O2 in cell culture medium. As a result, the activity of 1 was less sensitive than that of 2 to the effects of hypoxic conditions that are characteristic of solid tumors and to the presence of apo-transferrin that acts as a scavenger of V(V/IV) decomposition products in blood serum. In summary, complex 1, but not 2, is a suitable candidate for further development as an anticancer drug delivered via intratumoral injections. These results demonstrate the importance of fine-tuning the ligand properties for the optimization of biological activities of metal complexes.

Vanadium in the Environment: Biogeochemistry and Bioremediation

Vanadium(V) is a highly toxic multivalent, redox-sensitive element. It is widely distributed in the environment and employed in various industrial applications. Interactions between V and (micro)organisms have recently garnered considerable attention. This Review discusses the biogeochemical cycling of V and its corresponding bioremediation strategies. Anthropogenic activities have resulted in elevated environmental V concentrations compared to natural emissions. The global distributions of V in the atmosphere, soils, water bodies, and sediments are outlined here, with notable prevalence in Europe. Soluble V(V) predominantly exists in the environment and exhibits high mobility and chemical reactivity. The transport of V within environmental media and across food chains is also discussed. Microbially mediated V transformation is evaluated to shed light on the primary mechanisms underlying microbial V(V) reduction, namely electron transfer and enzymatic catalysis. Additionally, this Review highlights bioremediation strategies by exploring their geochemical influences and technical implementation methods. The identified knowledge gaps include the particulate speciation of V and its associated environmental behaviors as well as the biogeochemical processes of V in marine environments. Finally, challenges for future research are reported, including the screening of V hyperaccumulators and V(V)-reducing microbes and field tests for bioremediation approaches.

Bioactive Vanadium Disulfide Nanostructure with "Dual" Antitumor Effects of Vanadate and Gas for Immune-Checkpoint Blockade-Enhanced Cancer Immunotherapy

Bioactive inorganic nanomaterials and the biological effects of metal ions have attracted extensive attention in tumor therapy in recent years. Vanadium (V), as a typical bioactive metal element, regulates a variety of biological functions. However, its role in antitumor therapy remains to be revealed. Herein, biodegradable vanadium disulfide (VS2) nanosheets (NSs) were prepared as a responsive gas donor and bioactive V source for activating cancer immunotherapy in combination with immune-checkpoint blockade therapy. After PEGylation, VS2-PEG exhibited efficient glutathione (GSH) depletion and GSH-activated hydrogen sulfide (H2S) release. Exogenous H2S caused lysosome escape and reduced adenosine triphosphate (ATP) synthesis in tumor cells by interfering with the mitochondrial membrane potential and inducing acidosis. In addition, VS2-PEG degraded into high-valent vanadate, leading to Na+/K+ ATPase inhibition, potassium efflux, and interleukin (IL)-1β production. Together with further induction of ferroptosis and immunogenic cell death, a strong antitumor immune response was stimulated by reversing the immunosuppressive tumor microenvironment. Moreover, the combined treatment of VS2-PEG and α-PD-1 amplified antitumor therapy, significantly suppressed tumor growth, and further elicited robust immunity to effectively defeat tumors. This work highlights the biological effects of vanadium for application in cancer treatment.

Medicinal applications of vanadium complexes with Schiff bases

Many transition metal complexes have been explored for their therapeutic properties after the discovery of cisplatin. Schiff bases have an efficient complexation tendency with the transition metals and several medicinal properties have been reported. However, fewer studies have reported the medicinal utility of vanadium and its Schiff base complexes. This paper provides a comprehensive overview of vanadium complexes with Schiff bases along with their mechanistic insight. Vanadium complexes in + 4 and + 5 oxidation states have exhibited well-defined geometry and found to be thermodynamically stable. The studies have reported the G0/G1 phase cell cycle arrest and decreased delta psi m, inducing mitochondrial membrane depolarization in cancer cell lines along with the alterations in the metabolism of the cancer cells upon dosing with the vanadium complexes. Cancer cell invasion and growth are also found to be markedly reduced by peroxo complexes of vanadium. The studies included in the review paper have been taken from leading indexing databases and focus was laid on recent reports in literature. The biological potential of vanadium complexes of Schiff bases opens new horizons for future interdisciplinary studies and investigation focussed on understanding the biochemistry of these complexes, along with designing new complexes which have better bioavailability, solubility and low or non-toxicity.

Encapsulated Oxovanadium(IV) and Dioxovanadium(V) Complexes into Solid Lipid Nanoparticles Increase Cytotoxicity Against MDA-MB-231 Cell Line

Introduction

Solid lipid nanoparticles (SLN) have been considered lately as promising drug delivery system in treatment of many human diseases including cancers. We previously studied potential drug compounds that were effective inhibitors of PTP1B phosphatase - possible target for breast cancer treatment. Based on our studies, two complexes were selected for encapsulation into the SLNs, the compound 1 ([VO(dipic)(dmbipy)] · 2 H₂O) and compound 2 ([VOO(dipic)](2-phepyH) · H₂O). Here, we investigate the effect of encapsulation of those compounds on cell cytotoxicity against MDA-MB-231 breast cancer cell line. The study also included the stability evaluation of the obtained nanocarriers with incorporated active substances and characterization of their lipid matrix. Moreover, the cell cytotoxicity studies against the MDA-MB-231 breast cancer cell line in comparison and in combination with vincristine have been performed. Wound healing assay was carried out to observe cell migration rate.

Methods

The properties of the SLNs such as particle size, zeta potential (ZP), and polydispersity index (PDI) were investigated. The morphology of SLNs was observed by scanning electron microscopy (SEM), while the crystallinity of the lipid particles was analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The cell cytotoxicity of complexes and their encapsulated forms was carried out against MDA-MB-231 breast cancer cell line using standard MTT protocols. The wound healing assay was performed using live imaging microscopy.

Results

SLNs with a mean size of 160 ± 25 nm, a ZP of -34.00 ± 0.5, and a polydispersity index of 30 ± 5% were obtained. Encapsulated forms of compounds showed significantly higher cytotoxicity also in co-incubation with vincristine. Moreover, our research shows that the best compound was complex 2 encapsulated into lipid nanoparticles.

Conclusion

We observed that encapsulation of studied complexes into SLNs increases their cell cytotoxicity against MDA-MB-231 cell line and enhanced the effect of vincristine.

Therapeutic Properties of Vanadium Complexes

Vanadium is a hard, silver-grey transition metal found in at least 60 minerals and fossil fuel deposits. Its oxide and other vanadium salts are toxic to humans, but the toxic effects depend on the vanadium form, dose, exposure duration, and route of intoxication. Vanadium is used by some life forms as an active center in enzymes, such as the vanadium bromoperoxidase of ocean algae and nitrogenases of bacteria. The structure and biochemistry of vanadate resemble those of phosphate, hence vanadate can be regarded as a phosphate competitor in a variety of biochemical enzymes such as kinases and phosphatases. In this review, we describe the biochemical pathways regulated by vanadium compounds and their potential therapeutic benefits for a range of disorders including type 2 diabetes, cancer, cardiovascular disease, and microbial pathology.

Emergence of nutrigenomics and dietary components as a complementary therapy in cancer prevention

Cancer is an illness characterized by abnormal cell development and the capability to infiltrate or spread to rest of the body. A tumor is the term for this abnormal growth that develops in solid tissues like an organ, muscle, or bone and can spread to other parts of the body through the blood and lymphatic systems. Nutrition is a critical and immortal environmental component in the development of all living organisms encoding the relationship between a person's nutrition and their genes. Nutrients have the ability to modify gene expression and persuade alterations in DNA and protein molecules which is researched scientifically in nutrigenomics. These interactions have a significant impact on the pharmacokinetic properties of bioactive dietary components as well as their site of action/molecular targets. Nutrigenomics encompasses nutrigenetics, epigenetics, and transcriptomics as well as other "omic" disciplines like proteomics and metabolomics to explain the vast disparities in cancer risk among people with roughly similar life style. Clinical trials and researches have evidenced that alternation of dietary habits is potentially one of the key approaches for reducing cancer risk in an individual. In this article, we will target how nutrigenomics and functional food work as preventive therapy in reducing the risk of cancer.

Tuning the Biological Activity of Camphorimine Complexes through Metal Selection

The cytotoxic activity of four sets of camphorimine complexes based on the Cu(I), Cu(II), Ag(I), and Au(I) metal sites were assessed against the cisplatin-sensitive A2780 and OVCAR3 ovarian cancer cells. The results showed that the gold complexes were ca. one order of magnitude more active than the silver complexes, which in turn were ca. one order of magnitude more active than the copper complexes. An important finding was that the cytotoxic activity of the Ag(I) and Au(I) camphorimine complexes was higher than that of cisplatin. Another relevant aspect was that the camphorimine complexes did not interact significantly with DNA, in contrast with cisplatin. The cytotoxic activity of the camphorimine complexes displayed a direct relationship with the cellular uptake by OVCAR3 cells, as ascertained by PIXE (particle-induced X-ray emission). The levels of ROS (reactive oxygen species) formation exhibited an inverse relationship with the reduction potentials for the complexes with the same metal, as assessed by cyclic voltammetry. In order to gain insight into the toxicity of the complexes, their cytotoxicity toward nontumoral cells (HDF and V79 fibroblasts) was evaluated. The in vivo cytotoxicity of complex 5 using the nematode Caenorhabditis elegans was also assessed. The silver camphorimine complexes displayed the highest selectivity coefficients (activity vs. toxicity).

Relationship between structure and cytotoxicity of vanadium and molybdenum complexes with pyridoxal derived ligands

In this work four vanadium complexes (compounds 1, 2, 3 and 4) and one molybdenum complex (compound 5) with hydrazone ligands derived from pyridoxal were synthesized and characterized. All compounds are mononuclear species, two of them (compounds 3 and 5) are dioxide complexes and the other three (compounds 1, 2 and 4) monoxide complexes. The vanadium atom of the compound 3 is five-coordinated and all the other compounds have a six coordinated environment polyhedron. The poses for the potential intercalation of the compounds 2 and 3 with DNA were obtained by using AutoDock software. Optimizations were also performed at PM6-D3H4 semi-empirical level whereas the study of the nature of the interaction was carried out by means of the Energy Decomposition Analysis and the Non-Covalent Interaction index by using in both cases Density Functional Theory computations. The cytotoxicity in lung cancer cells (A549 cell line) of all the compounds was also evaluated. After 24 h of treatment, vanadium complexes showed high values of IC₅₀, between 419.93 ± 22.58 and 685.88 ± 46.55 μM. After 48 h, the results showed that the compound 3 had the lowest IC₅₀ value, 65.32 ± 9.95 μM, and the compound 2 the highest value, 375.28 ± 32.09 μM. The molybdenum complex showed the lowest IC₅₀ value at 48 h (11.22 ± 1.34 μM). The toxicity of the compounds 3, 4 and 5 was tested in vivo, using zebrafish model, and the molybdenum complex showed higher toxic effects than the studied vanadium complexes.

Oxidative stress imposed in vivo anticancer therapeutic efficacy of novel imidazole-based oxidovanadium (IV) complex in solid tumor

Vanadium is a transitional metal having several therapeutic aspects that can be exploited for its anticancer activity. Herein, we have verified anticancer effectivity of synthesized novel water soluble mononuclear dipicolinic acid-1-allyl imidazole-based oxidovanadium (IV) complex [VOL(1-allylimz)2] with respect to anticancer effectivity of known standard platinum-based anticancer agent cisplatin. In current work, we have verified VOL(1-allylimz)2 as highly potential anticancer agent selectively against human breast cancer cells. VOL(1-allylimz)2 has been noticed to elicit dose dependent cytotoxicity in MCF-7 cell line through induction of intracellular oxidative stress and mitochondrial membrane potential. Apart from in vitro validation, in vivo studies in male Swiss Albino mice also have seen to portray dose-dependent anticancer effect of [VOL(1-allylimz)2], where indications of oxidative stress induction became prominent too. Besides, both mitochondrial as well as extra-mitochondrial apoptosis in tumor cells have been shown to be induced by [VOL(1-allylimz)2] treatment, together enforcing its anticancer potency. In contrast to cisplatin, which shows high chances of nephrotoxicity in cancer patients, [VOL(1-allylimz)2] has been found to be comparatively safe for in vivo studies.

Dependency of EGFR activation in vanadium-based sensitization to oncolytic virotherapy

Oncolytic virotherapy is a clinically validated approach to treat cancers such as melanoma; however, tumor resistance to virus makes its efficacy variable. Compounds such as sodium orthovanadate (vanadate) can overcome viral resistance and synergize with RNA-based oncolytic viruses. In this study, we explored the basis of vanadate mode of action and identified key cellular components in vanadate’s oncolytic virus-enhancing mechanism using a high-throughput kinase inhibitor screen. We found that several kinase inhibitors affecting signaling downstream of the epidermal growth factor receptor (EGFR) pathway abrogated the oncolytic virus-enhancing effects of vanadate. EGFR pathway inhibitors such as gefitinib negated vanadate-associated changes in the phosphorylation and localization of STAT1/2 as well as NF-κB signaling. Moreover, gefitinib treatment could abrogate the viral sensitizing response of vanadium compounds in vivo. Together, we demonstrate that EGFR signaling plays an integral role in vanadium viral sensitization and that pharmacological EGFR blockade can counteract vanadium/oncolytic virus combination therapy.

New oxovanadium(IV) complexes overcame drug resistance and increased in vitro cytotoxicity by an apoptotic pathway in breast cancer cells

In order to examine the anticancer potential of oxovanadium(IV) complexes with thiosemicarbazone, two new complexes were prepared starting from 2-thenoyltrifluoroacetone-S-methylthiosemicarbazone. The complexes with tetradentate thiosemicarbazone ligand were characterized by elemental analysis, IR, ESI MS, and single-crystal X-ray diffraction analysis. Cytotoxicity on breast cancer cells, MDA-MB-231 and MCF-7, was determined by MTT assay. Cisplatin was positive control and the results were compared with those of the normal cells, HUVEC and 3T3. The complexes exhibited greater activity on cancer cells than cisplatin, but they were cytotoxic at several times higher concentrations in the healthy cells. In our study, the presence of thiophene and fluoro groups in the oxovanadium(IV) complexes with thiosemicarbazone increased greatly the cytotoxic activity of the complexes on breast cancer cells. Moreover, the complexes induced apoptosis-mediated cell death and also reduced the expression of MDR-1 or P-glycoprotein and ABCG2. As a result, the findings indicated that the complexes have selective cytotoxicity on breast cancer cells and can overcome multidrug resistance. These properties of the complexes make it possible to be a potential anticancer drug candidate for breast cancer treatment.

Theoretical Investigation by DFT and Molecular Docking of Synthesized Oxidovanadium(IV)-Based Imidazole Drug Complexes as Promising Anticancer Agents

Vanadium compounds have been set in various fields as anticancer, anti-diabetic, anti-parasitic, anti-viral, and anti-bacterial agents. This study reports the synthesis and structural characterization of oxidovanadium(IV)-based imidazole drug complexes by the elemental analyzer, molar conductance, magnetic moment, spectroscopic techniques, as well as thermal analysis. The obtained geometries were studied theoretically using density functional theory (DFT) under the B3LYP level. The DNA-binding nature of the ligands and their synthesized complexes has been studied by the electronic absorption titrations method. The biological studies were carried with in-vivo assays and the molecular docking method. The EPR spectra asserted the geometry around the vanadium center to be a square pyramid for metal complexes. The geometries have been confirmed using DFT under the B3LYP level. Moreover, the quantum parameters proposed promising bioactivity of the oxidovanadium(IV) complexes. The results of the DNA-binding revealed that the investigated complexes bind to DNA via non-covalent mode, and the intrinsic binding constant (K_b) value for the [VO(SO₄)(MNZ)₂] H₂O complex was promising, which was 2.0 × 10⁶ M⁻¹. Additionally, the cytotoxic activity of the synthesized complexes exhibited good inhibition toward both hepatocellular carcinoma (HepG-2) and human breast cancer (HCF-7) cell lines. The results of molecular docking displayed good correlations with experimental cytotoxicity findings. Therefore, these findings suggest that our synthesized complexes can be introduced as effective anticancer agents.

Biological Properties of Transition Metal Complexes with Metformin and Its Analogues

Metformin is a widely prescribed medication for the treatment and management of type 2 diabetes. It belongs to a class of biguanides, which are characterized by a wide range of diverse biological properties, including anticancer, antimicrobial, antimalarial, cardioprotective and other activities. It is known that biguanides serve as excellent N-donor bidentate ligands and readily form complexes with virtually all transition metals. Recent evidence suggests that the mechanism of action of metformin and its analogues is linked to their metal-binding properties. These findings prompted us to summarize the existing data on the synthetic strategies and biological properties of various metal complexes with metformin and its analogues. We demonstrated that coordination of biologically active biguanides to various metal centers often resulted in an improved pharmacological profile, including reduced drug resistance as well as a wider spectrum of activity. In addition, coordination to the redox-active metal centers, such as Au(III), allowed for various activatable strategies, leading to the selective activation of the prodrugs and reduced off-target toxicity.

An Overview of Vanadium and Cell Signaling in Potential Cancer Treatments

Vanadium is an ultratrace element present in higher plants, animals, algae, and bacteria. In recent years, vanadium complexes have been studied to be considered as a representative of a new class of nonplatinum metal anticancer drugs. Nevertheless, the study of cell signaling pathways related to vanadium compounds has scarcely been reported on and reviewed thus far; this information is highly critical for identifying novel targets that play a key role in the anticancer activity of these compounds. Here, we perform a review of the activity of vanadium compounds over cell signaling pathways on cancer cells and of the underlying mechanisms, thereby providing insight into the role of these proteins as potential new molecular targets of vanadium complexes.

A family of amphiphilic dioxidovanadium(V) hydrazone complexes as potent carbonic anhydrase inhibitors along with anti-diabetic and cytotoxic activities

A family of dioxidovanadium(V) complexes (1-4) of the type [Na(H₂O)_x]⁺[V^VO₂(HL^1-4)]^- (x = 4, 4.5 and 7) where HL^2- represents the dianionic form of 2-hydroxybenzoylhydrazone of 2-hydroxyacetophenone (H₂L¹, complex 1), 2-hydroxy-5-methylacetophenone (H₂L², complex 2), 2-hydroxy-5-methoxyacetophenone (H₂L³, complex 3) and 2-hydroxy-5-chloroacetophenone (H₂L⁴, complex 4), have been synthesized and characterized by analytical and spectral methods. These complexes exhibited the potential abilities to suppress the erythrocytes carbonic anhydrase enzymatic activity in type 1 and type 2 diabetic patients (in vitro), promising antidiabetic activity against T2 diabetic mice (in vivo). They also exhibited significant cytotoxic activity against cervical cancer (SiHa) cells (in vitro) as the IC₅₀ value of complexes 1, 2 and 4 is substantially lower than the value found for cisplatin while that of 3 is comparable and follow the order: 4 < 1 < 2 < 3 and can kill the cells by apoptosis via the generation of reactive oxygen species (ROS). The complexes are soluble both in water and octanol media and also non-toxic at working concentrations. The antidiabetic activity of these four complexes follows the order: 4 > 2 > 1 > 3 while both the carbonic anhydrase and cytotoxic activity follow the order: 4 > 1 > 2 > 3 suggesting that complex 4, containing electron withdrawing Cl atom is the most reactive while 3 with electron donating OCH₃ group is the least reactive species. The molecular docking study on hCA-I and hCA-II demonstrates that complexes interact via hydrogen bonding as well as different types of π-stacking.

QSAR Modeling, Molecular Docking and Cytotoxic Evaluation for Novel Oxidovanadium(IV) Complexes as Colon Anticancer Agents

Four new drug-based oxidovanadium (IV) complexes were synthesized and characterized by various spectral techniques, including molar conductance, magnetic measurements, and thermogravimetric analysis. Moreover, optimal structures geometry for all syntheses was obtained by the Gaussian09 program via the DFT/B3LYP method and showed that all of the metal complexes adopted a square-pyramidal structure. The essential parameters, electrophilicity (ω) value and expression for the maximum charge that an electrophile molecule may accept (ΔN_max) showed the practical biological potency of [VO(CTZ)₂] 2H₂O. The complexes were also evaluated for their propensity to bind to DNA through UV–vis absorption titration. The result revealed a high binding ability of the [VO(CTZ)₂] 2H₂O complex with K_b = 1.40 × 10⁶ M⁻¹. Furthermore, molecular docking was carried out to study the behavior of the VO (II) complexes towards colon cancer cell (3IG7) protein. A quantitative structure–activity relationship (QSAR) study was also implemented for the newly synthesized compounds. The results of validation indicate that the generated QSAR model possessed a high predictive power (R² = 0.97). Within the investigated series, the [VO(CTZ)₂] 2H₂O complex showed the greatest potential the most selective compound comparing to the stander chemotherapy drug.

Effective topical treatments of innovative NNO-tridentate vanadium (IV) complexes-mediated photodynamic therapy in psoriasis-like mice model

Psoriasis is a chronic inflammatory skin disease that can significantly impact the quality of human life. Various drug treatments with long-term severe side effects limit those drugs usage. Photodynamic therapy...