Lycopene's Effects on Cancer Cell Functions within Monolayer and Spheroid Cultures.

Lycopene, a compound that blocks the action of free radicals and oxygen molecules, is found in tomatoes and tomato-based products and linked to a reduced incidence of cancer. Increasing willingness of patients to maintain a healthy lifestyle by supplemental intake of nutrients and acceptance of alternative therapeutics has boosted research into nutraceuticals. The potential of lycopene to prevent or treat cancer has been investigated, but outcomes are inconsistent and its mode of action is still unknown. Further studies are needed to understand the role of lycopene in cancer prevention and treatment. The impact of lycopene on viability, proliferation, migration, and invasion of five different cancer cell lines was determined using monolayer and spheroid cultures. Cell viability was significantly reduced upon lycopene treatment at physiologically attainable concentrations. Cell proliferation, migration, and invasion did not change upon lycopene treatment. Ovarian cancer spheroids initially showed a decreased proliferation and after 14 days increased cell viability upon lycopene treatment, confirming the potential of lycopene to reduce cancer cell growth in short-term cultures and also indicate enhanced cell viability over prolonged exposure. This study cannot substantiate that lycopene inhibits cell functions associated with tumor growth, even in a 3D cancer model that mimics the natural tumor microenvironment.

The potential role of lycopene for the prevention and therapy of prostate cancer: from molecular mechanisms to clinical evidence.

Lycopene is a phytochemical that belongs to a group of pigments known as carotenoids. It is red, lipophilic and naturally occurring in many fruits and vegetables, with tomatoes and tomato-based products containing the highest concentrations of bioavailable lycopene. Several epidemiological studies have linked increased lycopene consumption with decreased prostate cancer risk. These findings are supported by in vitro and in vivo experiments showing that lycopene not only enhances the antioxidant response of prostate cells, but that it is even able to inhibit proliferation, induce apoptosis and decrease the metastatic capacity of prostate cancer cells. However, there is still no clearly proven clinical evidence supporting the use of lycopene in the prevention or treatment of prostate cancer, due to the only limited number of published randomized clinical trials and the varying quality of existing studies. The scope of this article is to discuss the potential impact of lycopene on prostate cancer by giving an overview about its molecular mechanisms and clinical effects.

Lycopene reduces ovarian tumor growth and intraperitoneal metastatic load.

Mutagens like oxidants cause lesions in the DNA of ovarian and fallopian tube epithelial cells, resulting in neoplastic transformation. Reduced exposure of surface epithelia to oxidative stress may prevent the onset or reduce the growth of ovarian cancer. Lycopene is well-known for its excellent antioxidant properties. In this study, the potential of lycopene in the prevention and treatment of ovarian cancer was investigated using an intraperitoneal animal model. Lycopene prevention significantly reduced the metastatic load of ovarian cancer-bearing mice, whereas treatment of already established ovarian tumors with lycopene significantly diminished the tumor burden. Lycopene treatment synergistically enhanced anti-tumorigenic effects of paclitaxel and carboplatin. Immunostaining of tumor and metastatic tissues for Ki67 revealed that lycopene reduced the number of proliferating cancer cells. Lycopene decreased the expression of the ovarian cancer biomarker, CA125. The anti-metastatic and anti-proliferative effects were accompanied by down-regulated expression of ITGA5, ITGB1, MMP9, FAK, ILK and EMT markers, decreased protein expression of integrin α5 and reduced activation of MAPK. These findings indicate that lycopene interferes with mechanisms involved in the development and progression of ovarian cancer and that its preventive and therapeutic use, combined with chemotherapeutics, reduces the tumor and metastatic burden of ovarian cancer in vivo.

Interfacial characteristics of heterogeneous layers of linear polyvinylamine and branched polyethyleneimine or polyethyleneimine grafted with C12-C22 alkyl chains.

We investigated the characteristics of heterogeneous layers composed of linear hydrolyzed polyvinylamine and branched polyethyleneimine adsorbed at silica/water interfaces. The studies also included heterogeneous layers where branched polyethyleneimine was replaced by polyethyleneimine modified by grafting with C12-C22 alkyl chains. Surface area exclusion chromatography was used to determine the interfacial relaxation and surface affinity of the polymer molecules within homogeneous layers. The relaxation of bare and grafted polyethyleneimine was found to be small and of equal extent but to develop at different rates. Comparatively, the relaxation of hydrolyzed polyvinylamine was faster and of greater extent. Within heterogeneous layers composed of polyvinylamine and bare or grafted polyethyleneimine, the relaxation of the different molecules was strongly increased as compared to that prevailing in homogeneous layers. The chromatographic method was then used to determine the mode of layer establishment. The polymer coating profiles on successive glass fiber filters were found to depend on the sequence of injection of the two polymers, due to the interfacial stability or instability of the initially established layer. It was shown that a previously established extremely thin layer of bare or grafted polyethyleneimine molecules strongly modified the adsorption profile of subsequently adsorbed polyvinylamine molecules.

Relaxation phenomena of polyethyleneimine molecules within saturated homogeneous and heterogeneous layers adsorbed at a silica/water interface.

Surface area exclusion chromatography was used to investigate the adsorption characteristics of the highly branched polyethyleneimine (PEI) molecule and of a related molecule resulting from the grafting of PEI with C12 to C22 alkyl chains. The interfacial relaxation and surface affinity of the two polymers was determined in homogeneous and heterogeneous layers. The presence of hydrophobic moieties within the branched morphology of the grafted PEI molecule was found to modify the adsorption histogram as compared to bare PEI and to lead to greater interfacial stability. The relaxation of the bare and grafted macromolecules proved to be of equal extent but to develop at different rates within homogeneous layers. In heterogeneous layers composed of the two polymers, the slower relaxation of the grafted macromolecules decreased the rate of relaxation of the bare molecules, while the faster relaxation of the bare molecules strongly increased the rate and extent of the relaxation of the grafted macromolecules. The same technique was then used to determine the mode of establishment of the layers. The polymer coating profiles on successive glass fiber filters of the chromatography column were found to depend on the sequence of injection of the two polymers. Simultaneous and sequential adsorption processes were analyzed on the basis of the random sequential adsorption of macromolecules.

Destabilization of polystyrene latex particles induced by adsorption of polyvinylamine: mass, size and structure characteristics of the growing aggregates.

The obviously visible aggregation of suspended colloidal particles resulting from the addition of polyvinylamine to the aqueous dispersion of polystyrene latex particles bearing surface sulfate groups set in with a delay of 24 h. The aggregation mechanisms and the fractal dimension of the aggregates were derived from the variations with time of the weight and number averaged masses of the aggregates as well as of the weight averaged harmonic mean diameter of the size distribution. Since the establishment of starved layers was determined to be relatively fast and to leave the liquid phase free of polymer, the delay for the obvious destabilization was attributed to the reconformation of adsorbed macromolecules that was expected to be extremely slow. This reconformation promoted the emergence of the diffusion-limited aggregation process that accompanies the permanent reaction-limited aggregation process. The fractal dimension of the latex particles/polyvinylamine aggregates was determined to be 2.12.

Relaxation phenomena of hydrolyzed polyvinylamine molecules adsorbed at the silica/water interface II. Saturated heterogeneous polymer layers.

Surface area exclusion chromatography (SAEC) was employed to determine the individual relaxation of polymer molecules within a saturated heterogeneous layer composed of two polymers of different molecular characteristics. The investigations focused on three systems differing in molecular weight and/or hydrolysis grade. The molecular relaxation process was determined to be different within the heterogeneous layer when compared with the behavior of the same polymer in the homogeneous layer. The modifications in the relaxation process of a given polymer were imposed by the interfacial characteristics of the second polymer. Finally, in heterogeneous layers, the relative variation of the interfacial area of the two polymers is expressed in a single relationship.

Relaxation phenomena of hydrolyzed polyvinylamine molecules adsorbed at the silica/water interface III. Interfacial exchange and transfer processes.

Surface area exclusion chromatography (SAEC) was employed to determine the stability characteristics of saturated homogeneous layers when interfacial exchange or transfer of molecules was promoted. In these experiments, the first polymer layer was established by elution of a column composed of stacked glass-fiber filters with one polymer. Then, after displacement of the void by water, the second polymer was subsequently injected under the same elution conditions. The experiments combine polymers of equal or different molecular weight and/or hydrolysis grade. Histograms of SAEC experiments demonstrate the great stability of the initially adsorbed layer. Domains of high and low adsorption values were determined to exist along the chromatography column after injection of the first polymer sample. The polymer injected second slightly modifies the initial adsorption histogram and mainly overadsorbs on the low adsorption domain of the first polymer. The major result relates to the relaxation phenomenon affecting or not the second adsorbed polymer when it adsorbs on filters belonging to the low adsorption domain of the polymer first injected. The relaxation is impeded when the relaxation of the first polymer is of great amplitude, whereas it occurs when the relaxation of the first polymer is small.

Relaxation phenomena of hydrolyzed polyvinylamine molecules adsorbed at the silica/water interface I. Saturated homogeneous polymer layers.

Surface area exclusion chromatography was used to investigate the adsorption and reconformation characteristics of hydrolyzed polyvinylamine molecules at silica/water interfaces employing radiolabeled polymers. The polymer solution was injected at the inlet of the column, whereas the polymer was successively adsorbed on the stacked glass-fiber filters constituting the stationary phase of the column. The filters and effluent samples collected at the outlet were individually analyzed for radioactivity content, which provided the adsorption histogram and the relative affinity of the various polymers. For saturated polymer layers, the relaxation process was demonstrated when the exceedingly adsorbed molecules desorbed. Modifications in the adsorption on the successive filters were thus converted into changes in the interfacial area of adsorbed molecules, taking into account the deviation from the plateau adsorption expected for nonrelaxing systems. Adsorption characteristics of nonrelaxed polymer layers were determined from the adsorption values determined before relaxation occurred. Adsorption and relaxation characteristics were determined to depend strongly on molecular weight and degree of hydrolysis of the polyvinylamine molecules. Half-hydrolyzed polymers had adsorption and relaxation characteristics close to those of the fully hydrolyzed polyvinylamine. Accordingly, adsorption isotherms on the cellulose/water interface were carried out to possibly extend the main conclusions of the study.

Kinetics of adsorption of polyvinylamine on cellulose fibers. II. Adsorption from electrolyte solutions.

Adsorption from electrolyte solutions of fully hydrolyzed polyvinylamine on cellulose fibers was investigated by supplying the polymer to the fibers at controlled rate. This was implemented by employing a reactor only open to the fluid in which the fiber dispersion were confined and homogenized. The adsorbed layers may be defined as diffuse or dense layers. Diffuse layers are characterized by a surface coverage limited to 0.65 mg/g cellulose in salt-free solutions. Addition of NaCl or CaCl(2) to the fiber dispersion and the polymer solution promotes the adsorption rate and increases the amount of adsorption to 1.5 mg/g cellulose. For dense polymer layers, for which the coverage amounts to values close to 10 mg/g cellulose in salt-free systems, addition of electrolyte does not change the kinetic and adsorption characteristics. Insofar as the variation of the molecular areas of the polymer within the diffuse layers as a function of the ionic strength parallels the variation of the molecular characteristics of solute molecules, the formation of diffuse layers is expected to proceed by random deposition of solute molecules which later individually sustain strong reconformation. Adsorption isotherms show a limited influence of the ionic strength. Obviously, the passage from dense layers of high surface coverage to low adsorption values at equilibrium requires extended reconformation of adsorbed macromolecules and desorption of a great part of the molecules already adsorbed.

Kinetics of adsorption of polyvinylamine on cellulose fibers. I. Adsorption from salt-free solutions.

Adsorption of fully hydrolyzed polyvinylamine on cellulose fibers in the short term was investigated by supplying the polymer to the fibers, first instantaneously by pouring the polymer solution into a jar containing the fiber dispersion (jar experiments) and second, at controlled rates (the reactor experiments). In the latter case, the rate of supply of polymer to the fiber dispersion confined in the reactor was monitored by setting the concentration of the solution being injected at a controlled rate. The concentration of the polymer solution exerts a paramount influence on the kinetics of adsorption and on the amount of polymer adsorbed at (or near) fiber surface saturation, while the rate of polymer supply only plays a minor role. The main observation is the emergence of two types of polymer layers corresponding to diffuse and dense layers. The former were characterized by adsorption layers of density smaller than 0.65 mg/g cellulose that are composed of adsorbed polymers having sustained extended flattening in the adsorbed state. The latter reach densities as high as 10 mg/g cellulose when the fiber surface is fully coated, thus indicating that reconformation is limited or even impeded at short terms. The threshold adsorption corresponds more or less to equilibrated layers, since the final coverage determined at adsorption equilibrium did not exceed 0.6 to 0.7 mg/g cellulose.

Reconformation of polyvinylamine adsorbed on glass fibers.

Surface area exclusion chromatography was used to investigate the reconformation of fully hydrolyzed polyvinylamine. The polymer is adsorbed on stacked glass fiber filters constituting the stationary phase while the polymer solution is injected at the inlet of the chromatography column. From numerical simulation and experimental chromatograms of nonreconforming polyelectrolytes, the amount of polymer adsorbed per filter represented as a function of the filter position along the column (the histogram) was determined to be continuously decreasing and not to depend on the rate of elution. For polyvinylamine, the histograms are peaked and the height of the peak was determined to depend greatly on the rate of polymer supply to the column that was controlled by monitoring the polymer concentration and/or the rate of elution (mass-transfer-controlled adsorption). Modifications in the adsorption on the successive filters were converted into changes in the interfacial area of adsorbed molecules taking into account model histograms as well as experimental adsorption histograms of non reconforming systems. Macromolecule concentration in the mobile phase and contact time between solute and adsorbed molecules were determined to be the two parameters controlling the extent of polymer desorption. The unusual shape of the histogram thus was attributed to reconformation of the adsorbed polymer, which was stimulated by interfacial exchange between segments belonging to trains of adsorbed macromolecules and chain segments of solute ones.

Questionnaires from the heart: national agendas and private hopes.

This article reflects on issues in mental health research from the user's perspective. Simon Champ, who is himself a user of mental health services as well as an activist in mental health reform, discusses the frustrations felt by consumers of mental health services in Australia at their lack of involvement in research into mental health. He examines the importance of research to consumers and puts forward an argument for the need for greater partnership between consumers and researchers.

Advanced Tissue Sciences Inc.: learning from the past, a case study for regenerative medicine.

On 31st March 2003 Advanced Tissue Sciences (ATS) was liquidated, with the effect that in excess of US$300 million of stakeholder financing was destroyed. Although successful in the development of breakthrough technologies in the regenerative medicine arena and the building of a substantial portfolio of patents, the company never made a profit. In this case study, ATS’ business strategy, market and competitive environment will be discussed in the context of the company’s historical development. A number of important lessons from this case are discussed. From a management perspective the most critical lesson is the importance of effective financial planning and management of costs, and in particular R&D costs, including the significant costs associated with clinical trials. In addition, a clear strategic focus is extremely important due to the significant resources required in the development of a new therapy. From an investor’s perspective the lessons to be gathered from the ATS case are related to the risk involved in investing in the field of regenerative medicine. This case indicates that both professional and private investors did not fully question the validity of ATS’ business strategy and financial forecasts. A clear and focused strategy based on long-term investor commitment is essential for the successful commercialization of regenerative medicine.

Colloidal complexes from poly(vinyl amine) and carboxymethyl cellulose mixtures.

The phase behaviors of polyelectrolyte complexes formed from dilute solutions of poly(vinyl amine) (PVAm) and carboxymethyl cellulose (CMC) were determined as a function of overall composition and pH. The phase diagram included regions with soluble complexes, colloidal complexes, and macroscopic precipitates. Colloidal complexes were stable when either polymer was in sufficient excess to give electrosteric stabilization. The polymer mixing ratios giving complexes with an isoelectric point of 7 could be predicted from a simple model using the degree of ionization vs pH data for PVAm and CMC. The model failed at extreme pH values because not all added polymer was incorporated into the complexes. At pH 7, essentially all the added polymer was incorporated into the colloidal complex or precipitate, as long as the mixing ratio was within +/-10% of charge stoichiometry. The interaction of PVAm and CMC at pH 7 was endothermic, supporting the generally accepted viewpoint that the interaction of oppositely charged polyelectrolytes is entropy-driven. Although the colloidal complexes had a broad particle size distribution, the average particle size was rather insensitive to mixing ratio. By contrast, complex size was sensitive to electrolyte concentration with no complex formation when the NaCl concentration was > or =2 M.