Study of Interactions between Metallothionein and Cisplatin by using Differential Pulse Voltammetry Brdickás reaction and Quartz Crystal Microbalance

Molecular mechanisms underlying cisplatin-induced nephrotoxicity and the potential ameliorative effects of essential oils: A comprehensive review

Since the Middle Ages, essential oils (EO) have been widely used for bactericidal, virucidal, fungicidal, insecticidal, medicinal and cosmetic applications, nowadays in pharmaceutical, agricultural and food industries. Recently, EO have emerged as promising adjuvant therapies to mitigate the toxicities induced by anti - cancerous drugs; among them cisplatin induced renal damage amelioration remain remarkable. Cisplatin (cis-diaminedichloroplatinum II, CDDP) is renowned as one of the most effective anti-neoplastic agents, widely used as a broad-spectrum anti-tumor agent for various solid tumors. However, its clinical use is hampered by several side effects, notably nephrotoxicity and acute kidney injury, which arise from the accumulation of CDDP in the proximal tubular epithelial cells (PTECs). To better understand and analyze the molecular mechanisms of CDDP-induced renal damage, it is crucial to investigate potential interventions to protect against cisplatin-mediated nephrotoxicity. These EO have shown the ability to counteract oxidative stress, reduce inflammation, prevent apoptosis, and exert estrogenic effects, all contributing to renal protection. In this review, we have made an effort to summarize the molecular mechanisms and exploring new interventions by which we can pave the way for safer and more effective cancer management in the future.

A chemometric-assisted voltammetric analysis of free and Zn(II)-loaded metallothionein-3 states

We focused on the application of mass spectrometry and electrochemical methods combined with a chemometric analysis for the characterization of partially metallothionein-3 species. The results showed decreased Cat1 and Cat2 signals for the Zn(II)-loaded MT3 species with respect to the metal-free protein, which might be explained by the arrangement of tetrahedral metal-thiolate coordination environments and the formation of metal clusters. Moreover, there was a decrease in the Cat1 and Cat2 signals, and a plateau was reached with 4-5 Zn(II) ions that corresponded to the formation of the C-terminal α-domain. Regarding the Zn_7-xMT3 complexes, we observed three different electrochemical behaviours for the Zn_1-2MT3, Zn_3-6MT3 and Zn₇MT3 species. The difference for Zn_1-2MT3 might be explained by the formation of independent ZnS₄ cores in this stage that differ with respect to the formation of Zn_xCys_y clusters with an increased Zn(II) loading. The binding of the third Zn(II) ion to MT3 resulted in high sample heterogeneity due the co-existence of Zn_3-6MT3. Finally, the Zn₇MT3 protein showed a third type of behaviour. The fact that there were no free Cys residues might explain this phenomenon. Thus, this research identifies the major proteins responsible for zinc buffering in the cell.

Isolated domains of recombinant human apo-metallothionein 1A are folded at neutral pH: a denaturant and heat-induced unfolding study using ESI-MS

Metallothioneins (MTs) are characterized by their high metal loading capacity, small molecular weight, and abundant cysteine residues. It has long been thought that metal-free, or apo-MT peptides were unstructured and only adopted as a distinct conformation upon forming the metal clusters, described as metal-induced folding. More recent studies have suggested that the presence of a globular, yet loosely defined structure actually exists that can be disrupted or unfolded. Residue modification and ion-mobility ESI (IM-ESI)-MS have been used to examine this unusual unfolding process. The structure of apo-MT plays a critical role as the starting point in the flexible metalation pathways that can accommodate numerous soft metals. ESI-MS measurements of the product species formed following the cysteine alkylation of the isolated domain fragments of recombinant human apo-MT 1A with n-ethylmaleimide (NEM) were used in the present study to monitor the denaturant- and heat-induced unfolding at physiological pH. The results indicate that these apo-MT fragments adopt distinct structures at neutral pH that react co-operatively with NEM when folded and non-cooperatively when heated or exposed to high concentrations of the denaturant guanidinium chloride (GdmCl). From these studies, we can conclude that at neutral pH, the domain fragments are folded into globular structures where some of the free cysteine residues are buried within the core and are stabilized by hydrogen bonds. Metalation therefore, must take place from the folded conformation.

The Application of Curve Fitting on the Voltammograms of Various Isoforms of Metallothioneins-Metal Complexes

The translation of metallothioneins (MTs) is one of the defense strategies by which organisms protect themselves from metal-induced toxicity. MTs belong to a family of proteins comprising MT-1, MT-2, MT-3, and MT-4 classes, with multiple isoforms within each class. The main aim of this study was to determine the behavior of MT in dependence on various externally modelled environments, using electrochemistry. In our study, the mass distribution of MTs was characterized using MALDI-TOF. After that, adsorptive transfer stripping technique with differential pulse voltammetry was selected for optimization of electrochemical detection of MTs with regard to accumulation time and pH effects. Our results show that utilization of 0.5 M NaCl, pH 6.4, as the supporting electrolyte provides a highly complicated fingerprint, showing a number of non-resolved voltammograms. Hence, we further resolved the voltammograms exhibiting the broad and overlapping signals using curve fitting. The separated signals were assigned to the electrochemical responses of several MT complexes with zinc(II), cadmium(II), and copper(II), respectively. Our results show that electrochemistry could serve as a great tool for metalloproteomic applications to determine the ratio of metal ion bonds within the target protein structure, however, it provides highly complicated signals, which require further resolution using a proper statistical method, such as curve fitting.

Ecotoxicological assessment of the anticancer drug cisplatin in the polychaete Nereis diversicolor

Anticancer drugs are designed to inhibit tumor cell proliferation by interacting with DNA and altering cellular growth factors. When released into the waterbodies of municipal and hospital effluents these pharmaceutical compounds may pose a risk to non-target aquatic organisms, due to their mode of action (cytotoxic, genotoxic, mutagenic and teratogenic). The present study aimed to assess the ecotoxicological potential of the alkylating agent cisplatin (CisPt) to the polychaete Nereis diversicolor, at a range of relevant environmental concentrations (i.e. 0.1, 10 and 100ngPtL^-1). Behavioural impairment (burrowing kinetic impairment), ion pump effects (SR Ca²⁺-ATPase), neurotoxicity (AChE activity), oxidative stress (SOD, CAT and GPXs activities), metal exposure (metallothionein-like proteins - MTLP), biotransformation (GST), oxidative damage (LPO) and genotoxicity (DNA damage), were selected as endpoints to evaluate the sublethal responses of the ragworms after 14-days of exposure in a water-sediment system. Significant burrowing impairment occurred in worms exposed to the highest CisPt concentration (100ngPtL^-1) along with neurotoxic effects. The activity of antioxidant enzymes (SOD, CAT) and second phase biotransformation enzyme (GST) was inhibited but such effects were compensated by MTLP induction. Furthermore, LPO levels also increased. Results showed that the mode of action of cisplatin may pose a risk to this aquatic species even at the range of ngL^-1.

Quartz-Crystal Microbalance (QCM) for Public Health: An Overview of Its Applications

Nanobiotechnologies, from the convergence of nanotechnology and molecular biology and postgenomics medicine, play a major role in the field of public health. This overview summarizes the potentiality of piezoelectric sensors, and in particular, of quartz-crystal microbalance (QCM), a physical nanogram-sensitive device. QCM enables the rapid, real time, on-site detection of pathogens with an enormous burden in public health, such as influenza and other respiratory viruses, hepatitis B virus (HBV), and drug-resistant bacteria, among others. Further, it allows to detect food allergens, food-borne pathogens, such as Escherichia coli and Salmonella typhimurium, and food chemical contaminants, as well as water-borne microorganisms and environmental contaminants. Moreover, QCM holds promises in early cancer detection and screening of new antiblastic drugs. Applications for monitoring biohazards, for assuring homeland security, and preventing bioterrorism are also discussed.

Serum metallothionein in patients with testicular cancer

PURPOSE

Metallothioneins (MTs) have been disclosed as a useful diagnostic factor for tumour progression and drug resistance in a variety of malignancies. Increased levels of MT in blood serum have been found in patients with several types of cancer, but there is no available information on serum MT levels in patients with testicular germ cell tumour (TGCT). The aim of the study was to determine MT levels in serum of patients with TGCT and to evaluate the portion of platinum (Pt) that binds to MT after cisplatin administration since MTs could be involved in drug resistance.

METHODS

Concentration of total MT was determined in serum of 25 men with newly diagnosed TGCT by differential pulse voltammetry. The fractionation of serum was carried out by size exclusion high-performance liquid chromatography (SE-HPLC), while concentration of Pt in collected fractions was determined by inductively coupled plasma mass spectrometry.

RESULTS

Concentration of serum MT was significantly higher in TGCT patients than in healthy volunteers. The results of SE-HPLC analysis showed that only a small amount of Pt was bound to proteins in the area of MT elution.

CONCLUSIONS

Significant increase in MT levels in individuals with TGCT indicates certain health problem and, in combination with other commonly used diagnostic tools, could improve early diagnosis.

Synthesis of carbon quantum dots for DNA labeling and its electrochemical, fluorescent and electrophoretic characterization

Nanoparticles as a progressively developing branch offer a tool for studying the interaction of carbon quantum dots (CQDs) with DNA. In this study, fluorescent CQDs were synthesized using citric acid covered with polyethylene glycol (PEG) as the source of carbon precursors. Furthermore, interactions between CQDs and DNA (double-stranded DNA and single-stranded DNA) were investigated by spectral methods, gel electrophoresis, and electrochemical analysis. Primarily, the fluorescent behavior of CQDs in the presence of DNA was monitored and major differences in the interaction of CQDs with tested single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) were observed at different amounts of CQDs (μg mL

The effects on soil/water/plant/animal systems by platinum group elements

Emissions of toxic substances such as oxides of carbon, nitrogen, sulphur, and, in addition, aromatic hydrocarbons, aldehydes and heavy metals are the most serious problem of road traffic affecting landscape. Platinum group elements (PGE), which are the main component of the catalyst, are one of the main sources of heavy metals in the environment. Here, we review the way by which emissions and forms of the emitted PGE end up in the environment especially to the soil-water-plant-animal system. The major points discussed are the following: 1) the main sources of PGE emission are automobile exhaust catalysts; 2) hospitals, where platinum is widely used to treat malignant neoplasm, and urban waste water belonging to other important sources of PGE in the environment; 3) soil is one of the most important components of the environment that may be contaminated with platinum metals; 4) phytotoxicity of PGE depends on the following conditions: the concentration of metals in the soil, time of exposure, the chemical form of metal, the chemical composition of exposed soil and plant species; 5) animals are also endangered by the increasing concentration of PGE in the environment. Moreover, we pay our attention to thiol-based mechanisms of how an organism protects itself against platinum group elements.

Bio-sensing of cadmium(II) ions using Staphylococcus aureus

Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health due to its undesirable effects (oxidative stress, changes in activities of many enzymes, interactions with biomolecules including DNA and RNA) and consequent potential risk, making its detection very important. New and unique technological and biotechnological approaches for solving this problems are intensely sought. In this study, we used the commonly occurring potential pathogenic microorganism Staphylococcus aureus for the determination of markers which could be used for sensing of cadmium(II) ions. We were focused on monitoring the effects of different cadmium(II) ion concentrations (0, 1.25, 2.5, 5, 10, 15, 25 and 50 μg mL(-1)) on the growth and energetic metabolism of Staphylococcus aureus. Highly significant changes have been detected in the metabolism of thiol compounds-specifically the protein metallothionein (0.79-26.82 mmol/mg of protein), the enzyme glutathione S-transferase (190-5,827 μmol/min/mg of protein), and sulfhydryl groups (9.6-274.3 μmol cysteine/mg of protein). The ratio of reduced and oxidized glutathione indicated marked oxidative stress. In addition, dramatic changes in urease activity, which is connected with resistance of bacteria, were determined. Further, the effects of cadmium(II) ions on the metabolic pathways of arginine, β-glucosidase, phosphatase, N-acetyl β-d-glucosamine, sucrose, trehalose, mannitol, maltose, lactose, fructose and total proteins were demonstrated. A metabolomic profile of Staphylococcus aureus under cadmium(II) ion treatment conditions was completed seeking data about the possibility of cadmium(II) ion accumulation in cells. The results demonstrate potential in the application of microorganisms as modern biosensor systems based on biological components.

An adsorptive transfer technique coupled with brdicka reaction to reveal the importance of metallothionein in chemotherapy with platinum based cytostatics

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.