The present review deals with prefractionation protocols used in proteomic investigation in preparation for mass spectrometry (MS) or two-dimensional electrophoresis (2-DE) map analysis. Briefly, reported methods focus on cell organelle differential centrifugation and on chromatographic approaches, to continue in extenso with a panoply of electrophoretic methods. In the case of chromatography, procedures useful as a prefractionation step, including affinity, ion-exchange, and reversed-phase resins, revealed several hundreds of new species, previously undetected in unfractionated samples. Novel chromatographic prefractionation methods are also discussed such as a multistaged fractionation column, consisting in a set of immobilized chemistries, serially connected in a stack format (an assembly of seven blocks), each capable of harvesting a given protein population. Such a method significantly simplifies the complexity of treated samples while concentrating species, all resulting in a larger number of visible proteins by MS or 2-DE. Electrophoretic prefractionation protocols include all those electrokinetic methodologies which are performed in free solution, essentially all relying on isoelectric focusing steps (although some approaches based on gels and granulated media are also discussed). Devices associated with electrophoretic separation are multichamber apparatus, such as the multicompartment electrolyzers equipped with either isoelectric membranes or with isoelectric beads. Multicup device electrophoresis and several others, exploiting the conventional technique of carrier ampholyte focusing, are reviewed. This review also reports approaches for sample treatments in order to detect low-abundance species. Among others, a special emphasis is made on the reduction of concentration difference between proteins constituting a sample. This latter consists in a library of combinatorial ligands coupled to small beads. Such a library comprises hexameric ligands composed of 20 amino acids, resulting in millions of different structures. When these beads are impregnated with complex proteomes (e.g., human sera) of widely differing protein compositions, they are able to significantly reduce the concentration differences, thus greatly enhancing the possibility to evidence low-abundance species. It is felt that this panoply of methods could offer a strong step forward in "mining below the tip of the iceberg" for detecting the "unseen proteome".

The human urinary proteome has been reassessed and re-evaluated via a novel concentration/equalization technique, exploiting beads coated with hexameric peptide ligand libraries. These beads act by capturing the whole protein spectra contained in the sample, by drastically reducing the level of the most abundant species, while strongly concentrating the more dilute and rare ones. In a control urine sample, 134 unique proteins could be identified. The first bead eluate (in thiourea, urea, and CHAPS) permitted the identification of 317 gene products, whereas the second eluate (in 9 M urea, pH 3.8) allowed the identification of another 95 unique proteins. By eliminating redundancies, a total of 383 unique gene products could be identified in human urines. This represents a major increment as compared to data reported in recent literature. By comparing our data with those reported to the present, an additional 251 proteins could be added to the list, thus bringing the total unique gene products so far identified in human urines to ca. 800 species.

Background/Aims-Patients with chronic hepatitis C (CHC) often have increased liver iron, a condition associated with reduced sustained response to antiviral therapy, more rapid progression to cirrhosis, and development of hepatocellular carcinoma. The hepatic hormone hepcidin is the major regulator of iron metabolism and inhibits iron absorption and recycling from erythrophagocytosis. Hepcidin decrease is a possible pathophysiological mechanism of iron overload in CHC, but studies in humans have been hampered so far by the lack of reliable quantitative assays for the 25-amino acid bioactive peptide in serum (s-hepcidin).Methods-Using a recently validated immunoassay, we measured s-hepcidin levels in 81 untreated CHC patients and 57 controls with rigorous definition of normal iron status. All CHC patients underwent liver biopsy with histological iron score.Results-S-hepcidin was significantly lower in CHC patients than in controls (geometric means with 95% confidence intervals: 33.7, 21.5-52.9 vs. 90.9, 76.1-108.4 ng/mL, respectively; p < 0.001). In CHC patients, s-hepcidin significantly correlated with serum ferritin and histological total iron score, but not with s-interleukin-6. After stratification for ferritin quartiles, s-hepcidin increased significantly across quartiles in both controls and CHC patients (chi for trend, p < 0.001). However, in CHC patients, s-hepcidin was significantly lower than in controls for each corresponding quartile (analysis of variance, p < 0.001).Conclusions-These results, together with very recent studies in animal and cellular models, indicate that although hepcidin regulation by iron stores is maintained in CHC, the suppression of

The present review deals with a number of prefractionation protocols in preparation for two-dimensional map analysis, both in the fields of chromatography and in the field of electrophoresis. In the first case, Fountoulaki's groups has reported just about any chromatographic procedure useful as a prefractionation step, including affinity, ion-exchange, and reversed-phase resins. As a result of the various enrichment steps, several hundred new species, previously undetected in unfractionated samples, could be revealed for the first time. Electrophoretic prefractionation protocols include all those electrokinetic methodologies which are performed in free solution, essentially all relying on isoelectric focusing steps. The devices here reviewed include multichamber apparatus, such as the multicompartment electrolyzer with Immobiline membranes, Off-Gel electrophoresis in a multicup device and the Rotofor, an instrument also based on a multichamber system but exploiting the conventional technique of carrier-ampholyte-focusing. Other instruments of interest are the Octopus, a continuous-flow device for isoelectric focusing in a upward flowing liquid curtain, and the Gradiflow, where different pI cuts are obtained by a multistep passage through two compartments buffered at different pH values. It is felt that this panoply of methods could offer a strong step forward in "mining below the tip of the iceberg" for detecting the "unseen proteome".

Iron deficiency, with or without anemia, is extremely frequent worldwide, representing a major public health problem. Iron replacement therapy dates back to the seventeenth century, and has progressed relatively slowly until recently. Both oral and intravenous traditional iron formulations are known to be far from ideal, mainly because of tolerability and safety issues, respectively. At the beginning of this century, the discovery of hepcidin/ferroportin axis has represented a turning point in the knowledge of the pathophysiology of iron metabolism disorders, ushering a new era. In the meantime, advances in the pharmaceutical technologies are producing newer iron formulations aimed at minimizing the problems inherent with traditional approaches. The pharmacokinetic of oral and parenteral iron is substantially different, and diversities have become even clearer in light of the hepcidin master role in regulating systemic iron homeostasis. Here we review how iron therapy is changing because of such important advances in both pathophysiology and pharmacology.

Since drug resistance is a complex and multifactorial event involving activation/repression of multiple biochemical pathways, we used a proteomic approach to study cisplatin resistance and drug response in human tumor cell lines. The cervix squamous cell carcinoma cell line A431 and its cisplatin‐resistant subline, A431/Pt, were used as a model system. The experimental set‐up involved not just a two‐way comparison of the control vs. the drug‐resistant cell line, but also an acute cisplatin treatment of both cell lines, leading to a four‐way comparison, as follows: 1) A431 vs. A431/Pt cells; 2) A431 vs. A431 cisplatin exposed cells; 3) A431/Pt vs. A431/Pt cisplatin exposed cells; 4) A431 cisplatin exposed cells vs. A431/Pt cisplatin exposed cells. We found modulation of proteins, which could be classified under various categories, such as molecular chaperones (e.g. heat‐shock proteins HSP60, HSP90, HSC71, heat‐shock cognate 71 kDa protein), Ca2plus;‐binding proteins (e.g. calmodulin, calumenin), proteins involved in drug detoxification (such as peroxiredoxins PRX 2 and PRX 6, and glutathione‐S‐transferase, GST), anti‐apoptotic proteins (such as 14‐3‐3 switched on in cisplatin‐exposed cells) and ion channels (such as VDAC‐1, voltage‐dependent anion‐selective channel). In particular, the basal levels of HSC71 and HSP60 were increased in A431/Pt cells as compared to A431 cells, and cisplatin exposure resulted in up‐regulation of HSP60 and HSP90 only in A431 cells. Moreover, cisplatin exposure up‐regulated the anti‐apoptotic 14‐3‐3 protein in both cell lines, GST in sensitive cells and PRX6 in A431/Pt cells. These findings are consistent with a constitutive expression of defence factors by resistant cells and with activation by cisplatin of mechanisms acting to protect cells from drug‐induced damage. This pattern of response, also observed in parental cells, could reflect an intrinsic resistance of this tumor type.

Anemia in cancer patients is quite common, with remarkable negative impacts on quality of life and overall prognosis. The pathogenesis is complex and typically multifactorial, with iron deficiency (ID) often being a major and potentially treatable contributor. In turn, ID in cancer patients can be due to multiple concurring mechanisms, including bleeding (e.g., in gastrointestinal cancers or after surgery), malnutrition, medications, and hepcidin-driven iron sequestration into macrophages with subsequent iron-restricted erythropoiesis. Indeed, either absolute or functional iron deficiency (AID or FID) can occur. While for absolute ID there is a general consensus regarding the laboratory definition (that is ferritin levels <100 ng/mL ± transferrin saturation (TSAT) <20%), a shared definition of functional ID is still lacking. Current therapeutic options in cancer anemia include iron replacement, erythropoietic stimulating agents (ESAs), and blood transfusions. The latter should be kept to a minimum, because of concerns regarding risks, costs, and limited resources. Iron therapy has proved to be a valid approach to enhance efficacy of ESAs and to reduce transfusion need. Available guidelines focus mainly on patients with chemotherapy-associated anemia, and generally suggest intravenous (IV) iron when AID or FID is present. However, in the case of FID, the upper limit of ferritin in association with TSAT <20% at which iron should be prescribed is a matter of controversy, ranging up to 800 ng/mL. An increasingly recognized indication to IV iron in cancer patients is represented by preoperative anemia in elective oncologic surgery. In this setting, the primary goal of treatment is to decrease the need of blood transfusions in the perioperative period, rather than improving anemia-related symptoms as in chemotherapy-associated anemia. Protocols are mainly based on experiences of Patient Blood Management (PBM) in non-oncologic surgery, but no specific guidelines are available for oncologic surgery. Here we discuss some possible approaches to the management of ID in cancer patients in different clinical settings, based on current guidelines and recommendations, emphasizing the need for further research in the field.

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