A dietary tomato supplement prevents prostate cancer in TRAMP mice

Transgenic adenocarcinoma of the mouse prostate (TRAMP) is a model for progressive prostate cancer that mirrors the stages of the human form. In this study, the effects of a diet enriched with processed whole tomatoes on survival, tumorigenesis, and progression of prostate cancer, and the antioxidant and inflammatory status of TRAMP mice were investigated. Tomato diet significantly increased overall survival (P < 0.01), delayed progression from prostatic intraepithelial neoplasia to adenocarcinoma, and decreased the incidence of poorly differentiated carcinoma. Biochemical data disclosed an increase in serum antioxidant activity and a reduction of serum inflammation/angiogenesis biomarkers of particular importance in prostate carcinogenesis.

Characterization of the hydrophobic substrate-binding site of the bacterial beta class glutathione transferase from Proteus mirabilis

Since their discovery, bacterial glutathione (GSH)transferases have been characterized in terms of their ability to catalyse a variety of different reactions on a large set of toxic molecules of xenobiotic or endobiotic origin. Furthermore the contribution of different residues in the GSH-binding site to GSH activation has been extensively investigated. Little is known, however, about the contribution to catalysis and overall stability of single residues shaping the hydrophobic co-substrate binding site (H-site). Here we tackle this problem by site-directed mutagenesis of residues facing the H-site in the bacterial beta class GSH transferase from Proteus mirabilis. We investigate the behaviour of these mutants under a variety of conditions and analyse their activity against several co-substrates, representative of the different reactions catalyzed by bacterial GSH transferases. Our work shows that mutations at the H-site can be used to modulate activity at the level of the different catalytic mechanisms operating on the chosen substrates, each mutation showing a different fingerprint. This work paves the way for future studies aimed at improving the catalytic properties of beta class GSH transferases against selected substrates for bioremediation purposes.

Proteome analysis of human Wharton's jelly cells during in vitro expansion

Background

The human umbilical cord contains mucoid connective tissue and fibroblast-like cells. These cells named Wharton's jelly cells, (WJCs) display properties similar to mesenchymal stem cells therefore representing a rich source of primitive cells to be potentially used in regenerative medicine.

Results

To better understand their self-renewal and potential in vitro expansion capacity, a reference 2D map was constructed as a proteomic data set. 158 unique proteins were identified. More than 30% of these proteins belong to cytoskeleton compartment. We also found that several proteins including Shootin1, Adenylate kinase 5 isoenzyme and Plasminogen activator-inhibitor 2 are no longer expressed after the 2^nd passage of in vitro replication. This indicates that the proliferative potency of these cells is reduced after the initial stage of in vitro growing. At the end of cellular culturing, new synthesized proteins, including, ERO1-like protein alpha, Aspartyl-tRNA synthetase and Prolyl-4-hydroxylase were identified. It is suggested that these new synthesized proteins are involved in the impairment of cellular surviving during replication and differentiation time.

Conclusions

Our work represents an essential step towards gaining knowledge of the molecular properties of WJCs so as to better understand their possible use in the field of cell therapy and regenerative medicine.

A computational platform for MALDI-TOF mass spectrometry data: application to serum and plasma samples

BACKGROUND

Mass spectrometry (MS) is becoming the gold standard for biomarker discovery. Several MS-based bioinformatics methods have been proposed for this application, but the divergence of the findings by different research groups on the same MS data suggests that the definition of a reliable method has not been achieved yet. In this work, we propose an integrated software platform, MASCAP, intended for comparative biomarker detection from MALDI-TOF MS data.

RESULTS

MASCAP integrates denoising and feature extraction algorithms, which have already shown to provide consistent peaks across mass spectra; furthermore, it relies on statistical analysis and graphical tools to compare the results between groups. The effectiveness in mass spectrum processing is demonstrated using MALDI-TOF data, as well as SELDI-TOF data. The usefulness in detecting potential protein biomarkers is shown comparing MALDI-TOF mass spectra collected from serum and plasma samples belonging to the same clinical population.

CONCLUSIONS

The analysis approach implemented in MASCAP may simplify biomarker detection, by assisting the recognition of proteomic expression signatures of the disease. A MATLAB implementation of the software and the data used for its validation are available at http://www.unich.it/proteomica/bioinf.

Pre-analytical factors in clinical proteomics investigations: impact of ex vivo protein modifications for multiple sclerosis biomarker discovery

Serum proteome investigations have raised an incredible interest in the research of novel molecular biomarker, nevertheless few of the proposed evidences have been translated to the clinical practice. One of the limiting factors has been the lack of generally accepted guidelines for clinical proteomics studies and the lack of a robust analytical and pre-analytical ground for the proposed classification models. Pre-analytical issues may results in a deep impact for biomarker discovery campaign. In this study we present a systematic evaluation of sample storage and sampling conditions for clinical proteomics investigations. We have developed and validated a linear MALDI-TOF-MS protein profiling method to explore the low protein molecular weight region (5-20 kDa) of serum samples. Data normalization and processing was performed using optimise peak detection routine (LIMPIC) able to describe each group under investigation. Data were acquired either from healthy volunteers and from multiple sclerosis patients in order to highlight ex vivo protein profile alteration related to different physio-pathological conditions. Our data showed critical conditions for serum protein profiles depending on storage times and temperatures: 23 degrees C, 4 degrees C, -20 degrees C and -80 degrees C. We demonstrated that upon a -20 degrees C short term storage, characteristic degradation profiles are associated with different clinical groups. Protein signals were further identified after preparative HPLC separation by peptide sequencing on a nanoLC-Q-TOF TANDEM mass spectrometer. Apolipoprotein A-IV and complement C3 protein fragments, transthyretin and the oxidized isoforms in different apolipoprotein species represent the major molecular features of such a degradation pattern.

Ratiometric-pericam-mt, a novel tool to evaluate intramitochondrial zinc

Zn(2+) can enter mitochondria and promote a plethora of physiological and patho-physiological effects. The issue of measuring changes in intramitochondrial levels is therefore critical. Past studies have employed fluorescent Zn(2+) indicators, like Rhod-2 and RhodZin-3, however, the use of these probes is impaired by their extramitochondrial sequestration. In this study, we show that the ratiometric mitochondria-targeted pericam, RPmt, can be employed to detect changes of intramitochondrial free Zn(2+) ([Zn(2+)](m)) levels. Using RPmt in neuronal and non neuronal cell lines we demonstrate that mitochondria can take up the cation mobilized from the cytosolic pool of protein-bound Zn(2+) and that mitochondrial Zn(2+) sequestration is largely mediated by the activity of the Ca(2+) uniporter.

Glutathione transferases in bacteria

Bacterial glutathione transferases (GSTs) are part of a superfamily of enzymes that play a key role in cellular detoxification. GSTs are widely distributed in prokaryotes and are grouped into several classes. Bacterial GSTs are implicated in a variety of distinct processes such as the biodegradation of xenobiotics, protection against chemical and oxidative stresses and antimicrobial drug resistance. In addition to their role in detoxification, bacterial GSTs are also involved in a variety of distinct metabolic processes such as the biotransformation of dichloromethane, the degradation of lignin and atrazine, and the reductive dechlorination of pentachlorophenol. This review article summarizes the current status of knowledge regarding the functional and structural properties of bacterial GSTs.

Glutathione transferases from Anguilla anguilla liver: identification, cloning and functional characterization

Glutathione transferases (GSTs) constitute a class of detoxifying enzymes involved in Phase II metabolism. Using GSH-affinity chromatografy followed by HPLC analysis, two GST isoforms were isolated from the Anguilla anguilla liver cytosol. The major GST belongs to the piscine-specific rho class and accounted for about 59% of total GST affinity eluted fraction, while the remaining 41% was represented by a Pi class GST. Both isoforms were cloned, heterologously expressed in Escherichia coli and their enzyme activities were characterized with respect to a broad spectrum of well-known GST substrates. Our data indicate that only a fraction of prototypical GST substrates are conjugated by these enzymes and that Pi class GST has higher specific activity than rho class GST against 1-chloro-2,4-dinitrobenzene (CDNB), ethracrynic acid, 4-nitroquinoline-1-oxide and p-nitrophenyl acetate while trans-2-nonenal is detoxified more efficiently by rho class GST. Analysis of the kinetics parameters of the conjugation against CDNB indicated that the utilization ratio K(cat)/K(m) is slightly higher for rho class GST with respect to pi class GSTs. Finally, to determine the potential for environmental inhibition of the GST isoforms, we examined the effect of the widely used herbicide atrazine as an inhibitor of catalytic activity. The inhibition studies revealed that atrazine was an effective inhibitor of GST-CDNB catalytic activities of both isoforms at micromolar concentrations, suggesting the sensitivity of these isoforms to pesticide inhibition at environmentally relevant concentrations.

Reversal of P-glycoprotein-mediated multidrug resistance in human sarcoma MES-SA/Dx-5 cells by nonsteroidal anti-inflammatory drugs

Multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) is one of the major reasons for the failure of cancer therapy. Several chemosensitizers are able to reverse in vitro MDR by inhibiting P-gp, although high toxicity limits their clinical application. In this study, we aimed to investigate the in vitro effectiveness of four common non-steroidal anti-inflammatory drugs (NSAIDs) such as Curcumin (Cur), Sulindac (Sul), Ibuprofen (Ibu) and NS-398 (NS) to inhibit P-gp activity at clinically achievable doses and to evaluate their potential use as sensitizers in anti-cancer chemotherapy. The human doxorubicin (doxo) resistant uterine sarcoma cells (MES-SA/Dx-5) expressing high levels of P-gp, were treated with different doxo concentrations in the presence or absence of NSAIDs. Cellular accumulation of doxo, cytotoxicity and apoptosis induction were measured in comparison with Verapamil, a specific P-gp inhibitor, used as a reference molecule. We found that Ibu, Cur and NS-398 enhanced significantly doxo retention, cytotoxicity and apoptosis on resistant MES-SA/Doxo-5 cells when compared with doxo alone. In contrast, no significant changes were found in resistant cells treated with Sul-doxo combinations. Our results demonstrate that Ibu, Cur and NS-398 below their therapeutic plasma concentrations were able to overcome P-gp-mediated MDR in MES-SA/Dx-5 cells. These findings provide the rationale for clinical studies of NSAIDs and/or derivatives as a new potential generation of chemosensitizers to improve effectiveness of the anti-cancer drugs in the treatment of human cancer.

Chronic exposure to 50Hz magnetic fields causes a significant weakening of antioxidant defence systems in aged rat brain

Several studies suggest that extremely low-frequency magnetic fields (ELF-MFs) may enhance the free radical endogenous production. It is also well known that one of the unavoidable consequences of ageing is an overall oxidative stress-based decline in several physiological functions and in the general resistance to stressors. On the basis of these assumptions, the aim of this study was to establish whether the ageing process can increase susceptibility towards widely present ELF-MF-mediated pro-oxidative challenges. To this end, female Sprague-Dawley rats were continuously exposed to a sinusoidal 50 Hz, 0.1 mT magnetic field for 10 days. Treatment-induced changes in the major antioxidant protection systems and in the neurotrophic support were investigated, as a function of the age of the subjects. All analyses were performed in brain cortices, due to the high susceptibility of neuronal cells to oxidative injury. Our results indicated that ELF-MF exposure significantly affects anti-oxidative capability, both in young and aged animals, although in opposite ways. Indeed, exposed young individuals enhanced their neurotrophic signalling and anti-oxidative enzymatic defence against a possible ELF-MF-mediated increase in oxygen radical species. In contrast, aged subjects were not capable of increasing their defences in response to ELF-MF treatment but, on the contrary, they underwent a significant decrease in the major antioxidant enzymatic activities. In conclusion, our data seem to suggest that the exposure to ELF-MFs may act as a risk factor for the occurrence of oxidative stress-based nervous system pathologies associated with ageing.

Cysteine 10 is critical for the activity of Ochrobactrum anthropi glutathione transferase and its mutation to alanine causes the preferential binding of glutathione to the H-site

The role of the evolutionarily conserved residue Cys10 in Ochrobactrum anthropi glutathione transferase (OaGST) has been examined by replacing it with an alanine. A double mutant C10A/S11A was also prepared. The effect of the replacements on the coniugating and thiotransferase activities, and on the thermal and chemical stability of the enzyme was analyzed. Our data support the view that in OaGST, in contrast with other beta class GSTs that display significant differences in the glutathione-binding site, Cys10 is a key residue for glutathione coniugating activity. Furthermore, analysis of the OaGST-Cys10Ala structure, crystallized in the presence of glutathione, reveals that this mutation causes a switch between the high-affinity G-site and a low-affinity H-site where hydrophobic cosubstrates bind and where we observe the presence of an unexpected glutathione.

Cleavage of cystatin C is not associated with multiple sclerosis

Recently, Irani and colleagues proposed a C-terminal cleaved isoform cystatin C (12.5 kDa) in cerebrospinal fluid as a marker of multiple sclerosis. In this study, we demonstrate that the 12.5 kDa product of cystatin C is formed by degradation of the first eight N-terminal residues. Moreover, such a degradation is not specific in the cerebrospinal fluid of multiple sclerosis, but rather is given by an inappropriate sample storage at -20 degrees C. We conclude that the use of the 12.5 kDa product of cystatin C in cerebrospinal fluid might lead to a fallacious diagnosis of multiple sclerosis. Preanalytical validation procedure is mandatory for proteomics investigations.

Fifty hertz extremely low-frequency electromagnetic field causes changes in redox and differentiative status in neuroblastoma cells

The current study was designed to establish whether extremely low-frequency electromagnetic fields might affect neuronal homeostasis through redox-sensitive mechanisms. To this end, intracellular reactive oxygen species production, antioxidant and glutathione-based detoxifying capability and genomic integrity after extremely low-frequency electromagnetic fields exposure were investigated. Moreover, we also studied potential extremely low-frequency electromagnetic fields-dependent changes in the proliferative and differentiative cellular status. Results seem to support redox-mediated extremely low-frequency electromagnetic fields effects on biological models as, although no major oxidative damage was detected, after exposure we observed a positive modulation of antioxidant enzymatic expression, as well as a significant increase in reduced glutathione level, indicating a shift of cellular environment towards a more reduced state. In addition, extremely low-frequency electromagnetic fields treatment induced a more differentiated phenotype as well as an increased expression in peroxisome proliferators-activated receptor isotype beta, a class of transcription factors related to neuronal differentiation and cellular stress response. As second point, to deepen how extremely low-frequency electromagnetic fields treatment could affect neuroblastoma cell antioxidant capacity, we examined the extremely low-frequency electromagnetic fields-dependent modifications of cell susceptibility to pro-oxidants. Results clearly showed that 50 Hz extremely low-frequency electromagnetic fields exposure reduces cell tolerance towards oxidative attacks.

Role of Ser11 in the stabilization of the structure of Ochrobactrum anthropi glutathione transferase

GSTs (glutathione transferases) are a multifunctional group of enzymes, widely distributed and involved in cellular detoxification processes. In the xenobiotic-degrading bacterium Ochrobactrum anthropi, GST is overexpressed in the presence of toxic concentrations of aromatic compounds such as 4-chlorophenol and atrazine. We have determined the crystal structure of the GST from O. anthropi (OaGST) in complex with GSH. Like other bacterial GSTs, OaGST belongs to the Beta class and shows a similar binding pocket for GSH. However, in contrast with the structure of Proteus mirabilis GST, GSH is not covalently bound to Cys10, but is present in the thiolate form. In our investigation of the structural basis for GSH stabilization, we have identified a conserved network of hydrogen-bond interactions, mediated by the presence of a structural water molecule that links Ser11 to Glu198. Partial disruption of this network, by mutagenesis of Ser11 to alanine, increases the K(m) for GSH 15-fold and decreases the catalytic efficiency 4-fold, even though Ser11 is not involved in GSH binding. Thermal- and chemical-induced unfolding studies point to a global effect of the mutation on the stability of the protein and to a central role of these residues in zippering the terminal helix of the C-terminal domain to the starting helix of the N-terminal domain.

Antioxidant vitamin supplementation in cardiovascular diseases

Cardiovascular disease is the most important adult health problem in wealthy countries, where biological factors such as obesity, hypertension, dyslipidemia, diabetes, inappropriate diet, cigarette smoking, and sedentary life-style have contributed to its dissemination. Research concerning nutritional regimens has shown that persons who consume large amounts of fruit and vegetables have lower incidences of cardiovascular diseases, stroke, and tumors, although the precise mechanisms for this protective effect are elusive. Possible explanations include (a) increased consumption of dietary fiber, (b) reduced consumption of dietary cholesterol and other lipids, and (c) increased intake of the antioxidant vitamins (A, C, and E). Numerous studies have raised the question whether vitamin supplements help to prevent cardiovascular diseases. Results of randomized controlled trials of antioxidant vitamin supplements in large numbers of participants has been ambiguous or contradictory. This minireview examines the relevant clinical reports on dietary supplements of vitamins A, C, and E to determine whether they support the premise that patients at risk of cardiovascular disease may be candidates for this therapeutic option.

An inductively coupled plasma mass spectrometry method for the quantification of yttrium-antibody based drugs using stable isotope tracing

Targeted radioimmunotherapy has been recently clinically validated and approved for the treatment of cancer by the US Food and Drug Administration. This therapeutic approach employs monoclonal antibodies directed to cancer-related, cell-surface antigens coupled to beta-emitting nuclides. 90Y is one of the most useful radioisotopes in the development of antibody based radioimmunotherapy and evaluation of the pharmacokinetic profile for 90Y-radiopharmaceuticals is usually performed by radiochemical methods. In this work we have developed an alternative radioactive-free approach to evaluate pharmacokinetic profiles based on the inductively coupled plasma mass spectrometric (ICP-MS) quantification of 89Y. A highly sensitive and rapid method for the determination of yttrium in urine is described and applied to evaluate the urinary clearance of antibody-based drugs labeled with the stable isotope of yttrium, 89Y. This approach overcomes some important limitations for pre-clinical radioanalytical methods such as radiation hazards and radioactive waste disposal. Method development was performed by determining detection and quantification limits, and precision as repeatability and trueness. These performance parameters fulfilled the acceptance criteria for bioanalytical methods.