Innovative Proteomics for the Discovery of Systemically Accessible Cancer Biomarkers Suitable for Imaging and Targeted Therapies

in American Journal of Pathology (2011), 178(1), 12-18

The discovery of biomarkers that are readily accessible through the circulating blood and are selectively overexpressed in pathological tissues has become a major research objective, particularly in the ... [more ▼]

The discovery of biomarkers that are readily accessible through the circulating blood and are selectively overexpressed in pathological tissues has become a major research objective, particularly in the field of oncology. Indisputably, this group of molecules has a high potential to serve as an innovative tool for effective imaging and targeted cancer therapy approaches. In this attractive therapeutic concept, specific cancer proteins are reached by intravenously administered ligands that are coupled to cytotoxic drugs. Such compounds are able to induce cancer destruction while sparing normal tissues. Owing to the performance of mass spectrometry technology, current high-throughput proteomic analysis allows for the identification of a high number of proteins that are differentially expressed in the cancerous tissues. However, such approaches provide no information regarding the effective accessibility of the biomarkers and, therefore, the possibility for these discovered proteins to be targeted. To bypass this major limitation, which clearly slows the discovery of such biomarkers, innovative methodological strategies have been developed to enrich the clinical specimens before the mass spectrometry analysis. The focus is laid on the group of proteins that are necessarily located either at the exterior face of the plasma membrane or in the extracellular matrix. The present review addresses the current technologies meant for the discovery and analysis of accessible antigens from clinically relevant samples. [less ▲]

Levels and trends of PCDD/Fs and PCBs in camel milk (Camelus bactrianus and Camelus dromedarius) from Kazakhstan

in Chemosphere (2011), 85

To date, despite the fact it represents a very important part of the national dairy production, no data are available concerning the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs ... [more ▼]

To date, despite the fact it represents a very important part of the national dairy production, no data are available concerning the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in camel milk from the Republic of Kazakhstan. Selected PCDDs, PCDFs, and PCBs were measured in pools of milk from camels (n = 15) located in various places of Kazakhstan (Almaty, Atyrau, Aralsk, Shymkent) and sampled at two different seasons for two different species (Camelus bactrianus and Camelus dromedarius). Non-dioxin-like (NDL- )PCB concentrations (6.3 ± 2.7 ng gÿ1 fat, median 5.1 ng gÿ1 fat, range 0.6–17.4 ng gÿ1 fat) were far below the maximum value of 40 ng gÿ1 fat proposed by the EU. Dioxin-like (DL-)PCB concentrations (1.7 ± 0.7 ng gÿ1 fat, median 1.5 ng gÿ1 fat, range 0.3–4.2 ng gÿ1 fat) and the NDL-PCB to DL-PCB ratio (4.3) were similar to what is reported in EU for cow-based dairy products. PCB 52 and PCB 101 appeared to be proportionally more present in Kazakh camel milk samples (>60% of the sum of the 6 indicator NDL-PCBs) than in European cow milk samples (<10% of the sum of the 6 indicator NDL-PCBs), indicating possible differences in the route of exposure to PCBs in Kazakhstan. PCB 105 and PCB 118 appeared to be present at higher concentrations in camel milk (>80% of the sum of the 12 DL-PCBs). PCB 105, PCB 118 and PCB 156 were the major congeners for DL-PCBs, accounting for 92% of the sum of concentrations of DL-PCBs (88% for Belgian cows). In terms of TEQ, PCB 126 and PCB 118 are the major contributors and represent, respectively, 80% and 14% of the DL-PCB TEQWHO05 concentrations. No significant interracial or geographical trends were observed for NDL- and DL-PCB profiles. However, concentrations of all DL-PCBs appeared to be significantly higher for samples collected in Atyrau region. 2,3,7,8-TCDD level (mean 0.08 ± 0.07 pg gÿ1 fat, median 0.08 pg gÿ1 fat, range 0.00–0.18 pg gÿ1 fat, 60% > LOQs) were very low for all samples and 2,3,4,7,8-PeCDF was the major contributor (27%) to the PCDD/F TEQWHO05. Considering the total TEQWHO05 (sum of DL-PCBs and PCDD/Fs), DL-PCB and PCDD/F contributed for 73% and 27%, respectively. A decrease of only 1% of the total TEQ was observed when using the TEFWHO05 scale instead of the TEFWHO98 scale. Two samples collected in the region of Atyrau exceeded the EU maximum level value of 6.00 pg TEQWHO98 gÿ1 fat (6.4 pg TEQWHO05 gÿ1 fat and 6.9 pg TEQWHO05 gÿ1 fat). Both samples exceeded the EU action level for the sum of DL-PCBs. Based on the fact that camel milk is used to prepare popular traditional fermented drinks like shubat, this suggests that the human exposure in the Caspian Sea region of Atyrau should be expected to be higher than in the other regions studied here. [less ▲]

Fibulin-3 fragments (FIB3-1 and FIB3-2) are potential new biomarkers for the diagnosis of osteoarthritis

in Annals of the Rheumatic Diseases (2011), 70(Suppl 3), 354

A specific inorganic triphosphatase from Nitrosomonas europaea: structure and catalytic mechanism

in Journal of Biological Chemistry (2011), 286

The CYTH superfamily of proteins is named after its two founding members, the CyaB adenylyl cyclase from Aeromonas hydrophila and the human 25-kDa thiamine triphosphatase. Because these proteins often ... [more ▼]

The CYTH superfamily of proteins is named after its two founding members, the CyaB adenylyl cyclase from Aeromonas hydrophila and the human 25-kDa thiamine triphosphatase. Because these proteins often form a closed β-barrel, they are also referred to as “Triphosphate Tunnel Metalloenzymes” (TTM). Functionally, they are characterized by their ability to bind triphosphorylated substrates and divalent metal ions. These proteins exist in most organisms and catalyze different reactions, depending on their origin. Here we investigate structural and catalytic properties of the recombinant TTM protein from Nitrosomonas europaea (NeuTTM), a 19-kDa protein. Crystallographic data show that it crystallizes as a dimer and that, in contrast to other TTM proteins, it has an open β-barrel structure. We demonstrate that NeuTTM is a highly specific inorganic triphosphatase, hydrolyzing tripolyphosphate (PPPi) with high catalytic efficiency in the presence of Mg2+. These data are supported by native mass spectrometry analysis showing that the enzyme binds PPPi (and Mg-PPPi) with high affinity (Kd < 1.5 μM), while it has a low affinity for ATP or thiamine triphosphate. In contrast to Aeromonas and Yersinia CyaB proteins, NeuTTM has no adenylyl cyclase activity, but it shares several properties with other enzymes of the CYTH superfamily, e.g. heat-stability, alkaline pH optimum and inhibition by Ca2+ and Zn2+ ions. We suggest a catalytic mechanism involving a catalytic dyad formed by K52 and Y28. The present data provide the first characterization of a new type of phosphohydrolase (unrelated to pyrophosphatases or exopolyphosphatases), able to hydrolyze inorganic triphosphate with high specificity. [less ▲]

Furan formation in baby food model system via lipid oxidation and sugar degradation

in Communications in Agricultural and Applied Biological Sciences (2011), 76(1), 107-110

Mass spectrometry: major improvements and new concepts in food analysis

Conference (2011)

ION MOBILITY – MASS SPECTROMETRY AS A NEW APPROACH FOR THE SCREENING OF PESTICIDE RESIDUES IN FOOD

in Organohalogen Compounds (2011)

Pesticide residue analysis requires methods that can determine hundreds of compounds at low levels in complex food matrices. This challenge has given rise to multi residue methods, the only efficient ... [more ▼]

Pesticide residue analysis requires methods that can determine hundreds of compounds at low levels in complex food matrices. This challenge has given rise to multi residue methods, the only efficient analytical approach. This type of analytical method entails a “generic” extraction followed by a soft or no purification step to avoid any analytes looses. With over a 1000 active compounds with different physical chemical properties, gas and liquid chromatography are used as complementary separative techniques. In the past decade, the determination has been performed on tandem mass analyzers, a powerful tool to overcome co-eluting compounds with excellent sensitivity. Nevertheless, these instruments can guarantee these results per acquisition cycles for more or less 150 compounds. This represents a serious limitation when the number of pesticides to be sought for monitoring and MRL enforcement is growing each year. As multiple injections from the same sample are not viable for laboratories, alternative options have to be explored. We propose the investigation of ion mobility (IM) coupled with mass spectrometry as a new approach for pesticide residue analysis in food. [less ▲]

Automated Procedures in Iso17025 Routine Dioxin Laboratory:Impact on the Throughput

in Organohalogen Compounds (2011), 73

Reproduction of European eel jeopardised by high levels of dioxins and dioxin-like PCBs

in Science of the Total Environment (2011), 409

ioxins, furans and dioxin-like polychlorinated biphenyls (PCBs) were analysed in muscle tissue from yellow phased European eel (Anguilla anguilla) from 38 sites in Belgium. Dioxin concentrations in eel ... [more ▼]

ioxins, furans and dioxin-like polychlorinated biphenyls (PCBs) were analysed in muscle tissue from yellow phased European eel (Anguilla anguilla) from 38 sites in Belgium. Dioxin concentrations in eel vary considerably between sampling locations, indicating that yellow eel is a good indicator of local pollution levels. Measured levels of dioxin-like PCBs are much higher than those of the dioxins and furans. In the majority of the sites, eel has levels considered to be detrimental for their reproduction. Field levels of dioxin and dioxin-like PCBs are therefore suggested as an additional causal factor contributing to the decline of the European eel. 42% of the sampling sites show especially dioxin-like PCB levels exceeding the European consumption level (with a factor 3 on average). Human consumption of eel, especially in these highly contaminated sites, seems unjustified. [less ▲]

d(CGGTGGT) forms an octameric parallel G-quadruplex via stacking of unusual G(:C):G(:C):G(:C):G(:C) octads

in Nucleic Acids Research (2011)

Among non-canonical DNA secondary structures, G-quadruplexes are currently widely studied because of their probable involvement in many pivotal biological roles, and for their potential use in ... [more ▼]

Among non-canonical DNA secondary structures, G-quadruplexes are currently widely studied because of their probable involvement in many pivotal biological roles, and for their potential use in nanotechnology. The overall quadruplex scaffold can exhibit several morphologies through intramolecular or intermolecular organization of G-rich oligodeoxyribonucleic acid strands. In particular, several G-rich strands can form higher order assemblies by multimerization between several G-quadruplex units. Here, we report on the identification of a novel dimerization pathway. Our Nuclear magnetic resonance, circular dichroism, UV, gel electrophoresis and mass spectrometry studies on the DNA sequence dCGGTGGT demonstrate that this sequence forms an octamer when annealed in presence of K+ or NH4+ ions, through the 5′-5′ stacking of two tetramolecular G-quadruplex subunits via unusual G(:C):G(:C):G(:C):G(:C) octads. [less ▲]