Marie Paulsson

The Role of Osteopontin in Tumor Progression and Metastasis in Breast Cancer

The use of cancer biomarkers to anticipate the outlines of disease has been an emerging issue, especially as cancer treatment has made such positive steps in the last few years. Progress in the development of consistent malignancy markers is imminent because advances in genomics and bioinformatics have allowed the examination of immense amounts of data. Osteopontin is a phosphorylated glycoprotein secreted by activated macrophages, leukocytes, and activated T lymphocytes, and is present in extracellular fluids, at sites of inflammation, and in the extracellular matrix of mineralized tissues. Several physiologic roles have been attributed to osteopontin, i.e., in inflammation and immune function, in mineralized tissues, in vascular tissue, and in kidney. Osteopontin interacts with a variety of cell surface receptors, including several integrins and CD44. Binding of osteopontin to these cell surface receptors stimulates cell adhesion, migration, and specific signaling functions. Overexpression of osteopontin has been found in a variety of cancers, including breast cancer, lung cancer, colorectal cancer, stomach cancer, ovarian cancer, and melanoma. Moreover, osteopontin is present in elevated levels in the blood and plasma of some patients with metastatic cancers. Therefore, suppression of the action of osteopontin may confer significant therapeutic activity, and several strategies for bringing about this suppression have been identified. This review looks at the recent advances in understanding the possible mechanisms by which osteopontin may contribute functionally to malignancy, particularly in breast cancer. Furthermore, the measurement of osteopontin in the blood or tumors of patients with cancer, as a way of providing valuable prognostic information, will be discussed based on emerging clinical data. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1087–97)

Immunoglobulins, growth factors and growth hormone in bovine colostrum and the effects of processing

In colostrum collected 0-80 h postpartum the contents of immunoglobulins (Igs), transforming growth factor beta-2 (TGF-beta2), insulin-like growth factor-1 (IGF-1) and growth hormone (GH) were analysed. Colostrum initially contained 90 mg mL(-1) IgG1, 2.8 mg mL(-1) IgG2, 1.6 mg mL(-1) IgA, 4.5 mg mL(-1) IgM, and these concentrations declined by 92%, 87%, 93% and 84%, respectively, in the samples collected later. Of the growth factors, colostrum initially contained 289-310 ng mL(-1) TGF-beta2 and the concentration diminished to 66 ng mL(-1). The content of IGF-1 and GH postpartum decreased from 870 to 150 ng mL(-1), and from 0.17 to < 0.03 ng mL(-1), respectively. Heat treatment and freeze-drying of colostral whey decreased the content of Igs to 75%, while the contents of IGF-1 and TGF-beta2 were unaffected. A similar processing, including filtration steps reduced also the IGF-1 and TGF-beta2 by 25%. IgM seems to be the most sensitive of the Igs to processing

Thermal stability of whey proteins studied by differential scanning calorimetry

Abstract The thermal stability of the bovine whey proteins.; β-lactoglobulin (β-1g), α-lactalbumin (α-1a) and serum albumin (BSA) was studied individually and in mixtures in the temperature range 25–140°C by differential scanning calorimetry. The thermal denaturation temperature (T D ) and the transition enthalpies (ΔH app ) were determined at different pH-values (3.0–10.0) in simulated milk ultrafil-trate (SMUF). β-Lg was, except at pH 9.0 and 10.0, the most thermostable protein at all pH-values. At acidic pH-values BSA was the least thermostable. At alkaline pH-values, however, α-la had lower thermal stability than BSA. α-La exhibited double peak behaviour at acidic pH-values and ΔH app was dependent on Ca-content. Mixtures of the proteins were studied at pH 4.0, 5.0 and 6.6. In general, when mixed, the proteins seemed to denaturate independently of each other.

Importance of casein micelle size and milk composition for milk gelation.

The economic output of the dairy industry is to a great extent dependent on the processing of milk into other milk-based products such as cheese. The yield and quality of cheese are dependent on both the composition and technological properties of milk. The objective of this study was to evaluate the importance and effects of casein (CN) micelle size and milk composition on milk gelation characteristics in order to evaluate the possibilities for enhancing gelation properties through breeding. Milk was collected on 4 sampling occasions at the farm level in winter and summer from dairy cows with high genetic merit, classified as elite dairy cows, of the Swedish Red and Swedish Holstein breeds. Comparisons were made with milk from a Swedish Red herd, a Swedish Holstein herd, and a Swedish dairy processor. Properties of CN micelles, such as their native and rennet-induced CN micelle size and their zeta-potential, were analyzed by photon correlation spectroscopy, and rennet-induced gelation characteristics, including gel strength, gelation time, and frequency sweeps, were determined. Milk parameters of the protein, lipid, and carbohydrate profiles as well as minerals were used to obtain correlations with native CN micelle size and gelation characteristics. Milk pH and protein, CN, and lactose contents were found to affect milk gelation. Smaller native CN micelles were shown to form stronger gels when poorly coagulating milk was excluded from the correlation analysis. In addition, milk pH correlated positively, whereas Mg and K correlated negatively with native CN micellar size. The milk from the elite dairy cows was shown to have good gelation characteristics. Furthermore, genetic progress in relation to CN micelle size was found for these cows as a correlated response to selection for the Swedish breeding objective if optimizing for milk gelation characteristics. The results indicate that selection for smaller native CN micelles and lower milk pH through breeding would enhance gelation properties and may thus improve the initial step in the processing of cheese.

Lactoferrin and cancer disease prevention

Lactoferrin (LF) is an iron-binding glycoprotein that is composed of the transferrin family and is predominantly found in the products of the exocrine glands located in the gateways of the digestive, respiratory, and reproductive systems, suggesting a role in the non-specific defence against invading pathogens. Additionally, several physiological roles have been attributed to LF, namely regulation of iron homeostasis, host defence against infection and inflammation, regulation of cellular growth, and differentiation and protection against cancer development and metastasis. These findings have suggested LFs great potential therapeutic use in cancer disease prevention and/or treatment, namely as a chemopreventive agent. This review looks at the recent advances in understanding the mechanisms underlying the multifunctional roles of LF and future perspectives on its potential therapeutic applications.

Binding of Sodium Dodecyl Sulphate and Dodecyl Trimethyl Ammonium Chloride to β-Lactoglobulin: A Calorimetric Study

Abstract Thermally induced unfolding of β -lactoglobulin in the presence of surfactants was studied by differential scanning calorimetry (DSC). Anionic surfactants, sodium dodecyl sulphate (SDS), and cationics, dodecyl trimethyl ammonium chloride (DOTAC), were used. In a solution containing a 1:1 molar ratio of SDS and β -lactoglobulin, the protein was stabilised as evidenced by a substantial increase in the unfolding temperature. Further increase of the SDS concentration causes unfolding of the protein. As opposed to these effects of the anionic surfactant, a slight decrease in the unfolding temperature was observed in the presence of DOTAC under similar conditions. An increase of the DOTAC/ β -lactoglobulin molar ratios above 1:1 causes precipitation of the protein. The cationic surfactant could be fairly easily removed from a mixed β -lactoglobulin/DOTAC solution by dialysis. The anionic surfactant appeared to interact more strongly with the protein and the 1:1 molar interaction with SDS was impossible to separate by dialysis. The experimental findings are discussed in terms of possible binding sites for the surfactant and connected to micelle formation of the surfactants which is related in a predictable scheme to temperature and ionic strength effects.

Heat induced aggregation of b-lactoglobulin studied by dynamic light scattering

The in situ heat-induced aggregation of commercial β-lactoglobulin as such, or after further purification, was followed to a z-average hydrodynamic diameter of 15–20 nm at 59–63 °C by dynamic light scattering. In this temperature range, measurable increase of hydrodynamic diameter occurred after an apparent lag period, which was strongly dependent on heating temperature, pH and initial protein concentration. The changes in time scale of the aggregation process agreed with changes in amount of unfolded β-lactoglobulin, assuming a two-state model of the denaturation. The pH dependence reflected the midpoint unfolding temperature and not the sulphydryl group reactivity, suggesting that this reactivity was not rate limiting in the aggregation. The aggregation process was modelled numerically with FuchsSmoluchowski kinetics.

Interactions between endothelium-derived relaxing factors in the rat hepatic artery: focus on regulation of EDHF.

In rat isolated hepatic arteries contracted with phenylephrine, acetylcholine and the calcium ionophore A23187 each elicit endothelium‐dependent relaxations, which involve both nitric oxide (NO) and endothelium‐derived hyperpolarizing factor (EDHF). However, the contribution of prostanoids to these responses, and the potential interaction between EDHF and other endothelium‐derived relaxing factors have not been examined. In the presence of the NO synthase inhibitor NG‐nitro‐L‐arginine (L‐NOARG, 0.3 mM) and a mixture of charybdotoxin (0.3 μM) and apamin (0.3 μM), inhibitors of the target potassium (K) channel(s) for EDHF, acetylcholine and A23187 each induced a concentration‐dependent and almost complete relaxation, which was abolished in the additional presence of indomethacin (10 μM). Thus, in addition to EDHF and NO, a relaxing factor(s) generated by cyclo‐oxygenase (COX) contributes to endothelium‐dependent relaxation in the rat hepatic artery. The resting membrane potentials of endothelium‐intact and endothelium‐denuded vascular segments were −57 mV and −52 mV, respectively (P>0.05). In intact arteries, the resting membrane potential was not affected by L‐NOARG plus indomethacin, but reduced to −47 mV in the presence of charybdotoxin plus apamin. Acetylcholine and A23187 (10 μM each) elicited a hyperpolarization of 13 mV and 15 mV, respectively. The hyperpolarization induced by these agents was not affected by L‐NOARG plus indomethacin (12 mV and 14 mV, respectively), but reduced in the presence of charybdotoxin plus apamin (7 mV and 10 mV, respectively), and abolished in the combined presence of charybdotoxin, apamin and indomethacin. The NO donor 3‐morpholino‐sydnonimine (SIN‐1) induced a concentration‐dependent relaxation, which was unaffected by charybdotoxin plus apamin, but abolished by the selective soluble guanylate cyclase inhibitor 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxaline‐1‐one (ODQ, 10 μM). SIN‐1 (10 μM) did not alter the resting membrane potential in endothelium‐denuded vascular segments. The COX‐dependent relaxation induced by acetylcholine was abolished following exposure to 30 mM KCl, but unaffected by glibenclamide (10 μM). The prostacyclin analogue iloprost induced a concentration‐dependent relaxation, which was also abolished in 30 mM KCl and unaffected by the combined treatment with glibenclamide, charybdotoxin and apamin. Iloprost (10 μM) induced a glibenclamide‐resistant hyperpolarization (8 mV with and 9 mV without glibenclamide) in endothelium‐denuded vascular segments. Exposure to SIN‐1 or iloprost did not affect the EDHF‐mediated relaxation induced by acetylcholine (i.e. in the presence of L‐NOARG and indomethacin). Replacement of L‐NOARG with the NO scavenger oxyhaemoglobin (10 μM) or the soluble guanylate cyclase inhibitor ODQ (10 μM) or methylene blue (10 μM), which all significantly inhibited responses to endothelium‐derived NO, did not affect the acetylcholine‐induced relaxation in the presence of indomethacin, indicating that endogenous NO also does not suppress EDHF‐mediated responses. These results show that, in addition to EDHF and NO, an endothelium‐derived hyperpolarizing factor(s) generated by COX contributes significantly to endothelium‐dependent relaxation in the rat heptic artery. Neither this factor nor NO seems to regulate EDHF‐mediated responses. Thus, EDHF does not serve simply as a ‘back‐up’ system for NO and prostacyclin in this artery. However, whether EDHF modulates the NO and COX pathways remains to be determined.

The occurrence of noncoagulating milk and the association of bovine milk coagulation properties with genetic variants of the caseins in 3 Scandinavian dairy breeds

Substantial variation in milk coagulation properties has been observed among dairy cows. Consequently, raw milk from individual cows and breeds exhibits distinct coagulation capacities that potentially affect the technological properties and milk processing into cheese. This variation is largely influenced by protein composition, which is in turn affected by underlying genetic polymorphisms in the major milk proteins. In this study, we conducted a large screening on 3 major Scandinavian breeds to resolve the variation in milk coagulation traits and the frequency of milk with impaired coagulation properties (noncoagulation). In total, individual coagulation properties were measured on morning milk collected from 1,299 Danish Holstein (DH), Danish Jersey (DJ), and Swedish Red (SR) cows. The 3 breeds demonstrated notable interbreed differences in coagulation properties, with DJ cows exhibiting superior coagulation compared with the other 2 breeds. In addition, milk samples from 2% of DH and 16% of SR cows were classified as noncoagulating. Furthermore, the cows were genotyped for major genetic variants in the αS1- (CSN1S1), β- (CSN2), and κ-casein (CSN3) genes, revealing distinct differences in variant frequencies among breeds. Allele I of CSN2, which had not formerly been screened in such a high number of cows in these Scandinavian breeds, showed a frequency around 7% in DH and DJ, but was not detected in SR. Genetic polymorphisms were significantly associated with curd firming rate and rennet coagulation time. Thus, CSN1S1 C, CSN2 B, and CSN3 B positively affected milk coagulation, whereas CSN2 A(2), in particular, had a negative effect. In addition to the influence of individual casein genes, the effects of CSN1S1-CSN2-CSN3 composite genotypes were also examined, and revealed strong associations in all breeds, which more or less reflected the single gene results. Overall, milk coagulation is under the influence of additive genetic variation. Optimal milk for future cheese production can be ensured by monitoring the frequency of unfavorable variants and thus preventing an increase in the number of cows producing milk with impaired coagulation. Selective breeding for variants associated with superior milk coagulation can potentially increase raw milk quality and cheese yield in all 3 Scandinavian breeds.

Characterization of a cold-gelling whey protein concentrate

Abstract Cold-gelling whey protein concentrates, produced by heat pre-treatment during manufacture, gelled without heating when dissolved at sufficient protein concentration and under suitable conditions of pH and ionic strength. A cold-gelling whey protein concentrate was dissolved at low concentrations in water or NaCl solutions of varying ionic strength, pH and with the addition of a reducing agent, dithiothreitol (DTT) for studies by rheology, light microscopy and atomic force microscopy. The cold-gelling whey protein powder was found to consist of large, micron-sized, drying-induced, weak aggregates consisting of primary disulfidebridged aggregates of 20–30 nm in diameter. In dilute solutions under conditions of large repulsive forces (low ionic strength and pH far from the isoelectric point) the large aggregates dissolved slowly over many hours. In less good solvents, larger aggregates remained or were formed.