Quantity-quality trade-off in the acquisition of token preference by capuchin monkeys (Sapajus spp.)

Money represents a cornerstone of human modern economies and how money emerged as a medium of exchange is a crucial question for social sciences. Although non-human primates have not developed monetary systems, they can estimate, combine and exchange tokens. Here, we evaluated quantity-quality trade-offs in token choices in tufted capuchin monkeys as a first step in the investigation of the generalizability of tokens as reinforcers, which is a potentially relevant factor underlying the emergence of money in humans. We measured capuchins' exchange preferences when they were repeatedly provided with 10 units of three token types yielding food combinations varying in quantity and quality. Overall, capuchins maximized their quantitative payoff, preferring tokens associated with a higher food amount, rather than showing violations of rationality. However, some individuals did not maximize their qualitative payoff, possibly because of conditional valuation effects or owing to the choice overload phenomenon, according to which too many options reduce the accuracy of choice. Our study supports the importance of comparative research to finely analyse the multiple components shaping the economic behaviours of other species, possibly to achieve a more comprehensive, evolutionary- and ecologically based understanding of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

B-cell-activating factor in rituximab-treated patients with anti-MAG polyneuropathy

BACKGROUND

Antimyelin-associated glycoprotein (MAG) polyneuropathy is a slowly progressive distal form of mixed motor-sensory polyneuropathy that is scarcely responsive to conventional immunosuppressive therapy. Rituximab, a B-cell depleting antibody, is a promising therapeutic choice for anti-MAG polyneuropathy, and the evaluation of factors, such as B-cell-activating factor (BAFF), that control B-cell homeostasis is important to understand how this drug works.

METHODS

Using an ELISA method, the authors measured serum BAFF concentrations in 23 patients with anti-MAG polyneuropathy, before and after rituximab therapy, in 20 neurological controls and in 14 healthy subjects. The patients were followed up over a mean period of 38±12 months and categorised as responders/non-responders, and, between the responders, as relapsing/non-relapsing.

RESULTS

Pretherapy serum BAFF concentrations in non-responders were higher than in responders (cut-off 1665 pg/ml; sensitivity 71.4%; specificity 93.7%; likelihood ratio 11.4), with the highest post-therapy increases in responders. In the responders who relapsed, relapses occurred when serum BAFF concentrations returned to baseline values, 1-2 years after blood B-cell reappearance.

CONCLUSIONS

Before and during therapy, measurements of serum BAFF in rituximab-treated patients with anti-MAG polyneuropathy may help predict the response to the therapy. The findings in this study also provide information about rituximab-induced modifications on B-cell homeostatic regulation.

A preclinical algorithm of soluble surrogate biomarkers that correlate with therapeutic inhibition of the MET oncogene in gastric tumors

The MET oncogene is amplified in a fraction of human gastric carcinoma cell lines, with consequent overexpression and constitutive activation of the corresponding protein product, the Met tyrosine kinase receptor. This genetically driven hyperactivation of Met is necessary for cancer cell growth and survival, so that Met pharmacological blockade results in cell-cycle arrest or apoptosis (oncogene addiction). MET gene amplification also occurs in vivo in a number of human gastric carcinomas, and clinical trials are now ongoing to assess the therapeutic efficacy of Met inhibitors in this type of malignancy. The aim of our study was to identify a preclinical algorithm of soluble surrogate biomarkers indicative of response to Met inhibition in gastric tumors, as a potential tool to integrate imaging criteria during patient follow-up. We started from a survey of candidate molecules based on antibody proteomics and gene expression profiling; after ELISA validation and analytical quantification, four biomarkers were identified that appeared to be strongly and consistently modulated by Met inhibition in a panel of Met-addicted gastric carcinoma cell lines, but not in Met-independent cell lines. Pharmacologic blockade of Met using specific small-molecule inhibitors led to reduced secretion of IL-8, GROα and the soluble form of uPAR and to increased production of IL-6 both in vitro (in culture supernatants) and in vivo (in the plasma of xenografted mice). If confirmed in patients, this information might prove useful to monitor clinical response to Met-targeted therapies in MET-amplified gastric carcinomas.

Genetic and expression analysis of MET, MACC1, and HGF in metastatic colorectal cancer: response to met inhibition in patient xenografts and pathologic correlations

PURPOSE

We determined the gene copy numbers for MET, for its transcriptional activator MACC1 and for its ligand hepatocyte growth factor (HGF) in liver metastases from colorectal carcinoma (mCRC). We correlated copy numbers with mRNA levels and explored whether gain and/or overexpression of MET and MACC1 predict response to anti-Met therapies. Finally, we assessed whether their genomic or transcriptional deregulation correlates with pathologic and molecular parameters of aggressive disease.

EXPERIMENTAL DESIGN

One hundred three mCRCs were analyzed. Copy numbers and mRNA were determined by quantitative PCR (qPCR). Thirty nine samples were implanted and expanded in NOD (nonobese diabetic)/SCID (severe combined immunodeficient) mice to generate cohorts that were treated with the Met inhibitor JNJ-38877605. In silico analysis of MACC1 targets relied on genome-wide mapping of promoter regions and on expression data from two CRC datasets.

RESULTS

No focal, high-grade amplifications of MET, MACC1, or HGF were detected. Chromosome 7 polysomy and gain of the p-arm were observed in 21% and 8% of cases, respectively, and significantly correlated with higher expression of both Met and MACC1. Met inhibition in patient-derived xenografts did not modify tumor growth. Copy number gain and overexpression of MACC1 correlated with unfavorable pathologic features better than overexpression of Met. Bioinformatic analysis of putative MACC1 targets identified elements besides Met, whose overexpression cosegregated with aggressive forms of colorectal cancer.

CONCLUSIONS

Experiments in patient-derived xenografts suggest that mCRCs do not rely on Met genomic gain and/or overexpression for growth. On the basis of pathologic correlations and bioinformatic analysis, MACC1 could contribute to CRC progression through mechanisms other than or additional to Met transcriptional upregulation.

Only a subset of Met-activated pathways are required to sustain oncogene addiction

Tumor onset and progression require the accumulation of many genetic and epigenetic lesions. In some cases, however, cancer cells rely on only one of these lesions to maintain their malignant properties, and this dependence results in tumor regression upon oncogene inactivation ("oncogene addiction"). Determining which nodes of the many networks operative in the transformed phenotype specifically mediate this response to oncogene neutralization is crucial to identifying the vulnerabilities of cancer. Using the Met receptor as the major model system, we combined multiplex phosphoproteomics, genome-wide expression profiling, and functional assays in various cancer cells addicted to oncogenic receptor tyrosine kinases. We found that Met blockade affected a limited subset of Met downstream signals: Little or no effect was observed for several pathways downstream of Met; instead, only a restricted and pathway-specific signature of transducers and transcriptional effectors downstream of Ras or phosphoinositide 3-kinase (PI3K) was inactivated. An analogous signature was also generated by inhibition of epidermal growth factor receptor in a different cellular context, suggesting a stereotyped response that likely is independent of receptor type or tissue origin. Biologically, Met inhibition led to cell-cycle arrest. Inhibition of Ras-dependent signals and PI3K-dependent signals also resulted in cell-cycle arrest, whereas cells in which Met was inhibited proliferated when Ras or PI3K signaling was active. These findings uncover "dominant" and "recessive" nodes among the numerous oncogenic networks regulated by receptor tyrosine kinases and active in cancer, with the Ras and PI3K pathways as determinants of therapeutic response.

Alkylphenol oxidation with a laccase from a white-rot fungus: effects of culture induction and of ABTS used as a mediator

We investigated the potential of the laccase from the white-rot fungus Marasmius quercophilus to transform certain alkylphenols (p-nonylphenol, p-octylphenol and p-t-octylphenol). We tested the reactivity of this enzyme under different conditions: in liquid cultures and using the partially purified laccase with and without 2,2'-azino-bis-3-ehtylbenzothiazoline-6-sulfonicacid (ABTS) as a mediator. The percentage of p-t-octylphenol disappearance in liquid cultures was 69.0 ± 1.5% and 81 ± 5% after a 8-d or 15-d incubation, respectively, with p-nonylphenol, these percentages were 62 ± 4% and 91 ± 6% and with p-octylphenol 37 ± 3% and 65 ± 1% after a 15-d and a 21-d incubations, respectively. Induced pre-cultures were also used to inoculate the liquid cultures to enhance p-octylphenol transformation: the percentages of disappearance were 91.0 ± 0.5% and 97 ± 1% after a 8-d and a 15-d incubation, respectively. Mass spectrometry analysis showed that the products of oxidation of p-octylphenol were dimers with a mass of 411 m/z. Furthermore, we identified a purple compound (m/z 476) formed when ABTS was added to the reaction medium with the purified laccase. This result confirms that, in complex environments such as soils or litters where many molecules can interact with the enzyme substrate or the product of oxidation, laccase activities and those of other phenoloxidases should not be measured with ABTS.

The Met oncogene and basal-like breast cancer: another culprit to watch out for?

Recent findings suggest the involvement of the MET oncogene, encoding the tyrosine kinase receptor for hepatocyte growth factor, in the onset and progression of basal-like breast carcinoma. The expression profiles of basal-like tumors - but not those of other breast cancer subtypes - are enriched for gene sets that are coordinately over-represented in transcriptional signatures regulated by Met. Consistently, tissue microarray analyses have revealed that Met immunoreactivity is much higher in basal-like cases of human breast cancer than in other tumor types. Finally, mouse models expressing mutationally activated forms of Met develop a high incidence of mammary tumors, some of which exhibit basal characteristics. The present review summarizes current knowledge on the role and activity of Met in basal-like breast cancer, with a special emphasis on the correlation between this tumor subtype and the cellular hierarchy of the normal mammary gland.

Inhibition of Src impairs the growth of met-addicted gastric tumors

PURPOSE

We examined whether inhibition of Src tyrosine kinase, a downstream effector of the MET oncogene, can hinder the malignant properties of gastric tumors dependent on Met for growth and survival.

EXPERIMENTAL DESIGN

Sensitivity to Src inhibition was determined in vitro by measuring clonogenic survival (anchorage-independent growth) and in vivo by establishing xenograft models. Four "Met-addicted" gastric carcinoma cell lines (GTL16, MKN45, HS746T, and SNU5) and three Met-independent gastric carcinoma cell lines (KATO III, AGS, and NCI-N87) were treated with the Src inhibitor saracatinib (AZD0530). In GTL16 and KATO III, Src neutralization was also achieved by dasatinib and RNA interference. The biochemical and transcriptional consequences of Src inhibition were explored using anti-phosphoprotein antibodies and oligonucleotide microarrays.

RESULTS

Inhibition of Src in Met-addicted gastric carcinoma cell lines (a) decreased the phosphorylation/activation levels of signaling intermediates involved in cell proliferation and protection from apoptosis and down-modulated the expression of several cell cycle regulators; (b) reduced anchorage-independent growth; (c) enhanced impairment of cell viability produced by Met inhibition; and (d) delayed tumorigenesis in xenotransplantation models. Immunohistochemical analysis of tumor xenograft tissues following systemic treatment with saracatinib showed a reduction of tumor cell proliferation index, increased apoptosis, and diminished phospho-focal adhesion kinase and phospho-paxillin staining. Tumor stroma parameters such as angiogenesis or inflammatory infiltration were unaffected. In clonogenic survival assays, gastric carcinoma cells without addiction to Met were less sensitive than Met-addicted cells to Src inhibition.

CONCLUSIONS

Src is as a key downstream transducer of Met-driven tumor growth. Targeting Src might provide therapeutic benefit in Met-addicted tumors.

Hemopexin prevents endothelial damage and liver congestion in a mouse model of heme overload

Intravascular hemolysis results in the release of massive amounts of hemoglobin and heme into plasma, where they are rapidly bound by haptoglobin and hemopexin, respectively. Data from haptoglobin and hemopexin knockout mice have shown that both proteins protect from renal damage after phenylhydrazine-induced hemolysis, whereas double-mutant mice were especially prone to liver damage. However, the specific role of hemopexin remains elusive because of the difficulty in discriminating between hemoglobin and heme recovery. To study the specific role of hemopexin in intravascular hemolysis, we established a mouse model of heme overload. Under these conditions, both endothelial activation and vascular permeability were significantly higher in hemopexin-null mice compared with wild-type controls. Vascular permeability was particularly altered in the liver, where congestion in the centrolobular area was believed to be associated with oxidative stress and inflammation. Liver damage in hemopexin- null mice may be prevented by induction of heme oxygenase-1 before heme overload. Furthermore, heme-treated hemopexin-null mice exhibited hyperbilirubinemia, prolonged heme oxygenase-1 expression, excessive heme metabolism, and lack of H-ferritin induction in the liver compared with heme-treated wild-type controls. Moreover, these mutant mice metabolize an excess of heme in the kidney. These studies highlight the importance of hemopexin in heme detoxification, thus suggesting that drugs mimicking hemopexin activity might be useful to prevent endothelial damage in patients suffering from hemolytic disorders.

Decrease of Serotonin Transporters in Blood Platelets after Epileptic Seizures

Serotonin transporter (SERT) was studied by [3H]-paroxetine binding in blood platelets from controls and epileptic patients with generalized convulsive seizures. The average KD and BMax were not different in the two cases. However, a significant decrease was found in the serotonin transporter density in the platelet membranes from patients having undergone an epileptic seizure less than 4 days before. This circumstance may indicate a homeostatic reaction to the epileptic attack.

[Evaluation of various hemorheological parameters in nonagenarians: evidence of an increase of fibrinogen]

Cardiovascular disease is the most frequent cause of mortality in the elderly. A reduced microvascular blood flow associated with an increase in atherosclerosis might contribute to age related increases in the incidence of ischemic vascular disease. In order to evaluate the effect of age on some haemorheological parameters, blood and plasma viscosity and fibrinogen have been measured in 10 healthy elderly subjects, aged between 88 and 96 years, compared with 15 healthy young subjects (mean age 37 years). Elderly subjects showed a significant increase in plasma fibrinogen (p less than 0.0005) and a trend to an increase in plasma viscosity, whereas no difference was present in blood viscosity. These data confirm that aging is associated with a greater deal of thrombotic risk factors, the most important of which seems to be fibrinogen.

Bis-substituted hydroxy-anthracenediones: DNA binding and biological activity

Three new hydroxy-9,10-anthracenedione derivatives (compounds 1-3 in Figure 1), bearing two charged or polar side chains at positions 2 and 4/5 of the tricyclic system, have been investigated for their DNA binding, cytotoxic and genotoxic activity. The interaction mode with nucleic acids is intercalative for compounds 1 and 2, while external and intercalative binding probably coexist for compound 3. Complexation of the nucleic acid occurs in all cases in a cooperative manner, so that drug binding favours further binding to double helical DNA. The scale of the intrinsic binding constant is discussed in terms of the nature and position of the side chain. Cell growth and DNA synthesis inhibition data match quite well with DNA affinity. Alkaline elution experiments show a correlation between drug cytotoxicity and DNA damage. Our results indicate that the position and number of OH groups, as well as of charged side chains, play an important role in modulating drug affinity for DNA and the consequent biological effects.

Genotoxic activity of some water-soluble derivatives of 5-methoxypsoralen and 8-methoxypsoralen

This paper shows some results obtained by assaying the genotoxic activity on procaryotic and eucaryotic cells of some water-soluble psoralen derivatives. In particular, six newly synthesized derivatives of 5-methoxypsoralen (5-MOP) and of 8-methoxypsoralen (8-MOP) were tested; in previous studies they showed a strong anti-proliferative activity and a slight phototoxic effect; moreover, in view of a clinical use in the therapy of hyperproliferative skin diseases, these drugs should be less toxic than their parent compounds because of their good water solubility which could lead to a more efficient absorption and excretion. All the compounds tested here have shown genotoxic activity on both procaryotic and eucaryotic systems: however, on the procaryotic cells the water-soluble derivatives were less genotoxic than their respective parent compounds 5-MOP and 8-MOP. Quite different results were obtained on V79 Chinese hamster cells, showing that, in general, the 8-methoxy-derivatives are more mutagenic than the methoxy-ones, although the 5-MOP itself was shown to be highly genotoxic in this system. This fact confirms that a conclusive estimate of the genotoxic risk related to the use of new drugs cannot be drawn from the results obtained on a single biological system.

New anthracenedione derivatives: interaction with DNA and biological effects

Two anthracenedione derivatives [1 - (omega - diethylaminopropylamido) - 4 - hydroxy - 9,10 - anthracenedione hydrochloride (I) and 1 - (omega - diethylaminopropylamido) - 2 - methoxy - 4 - hydroxy - 9, 10 - anthracenedione hydrochloride (II)], having an electron-rich planar chromophore and an amino-substituted side chain, have been synthesized. Their binding ability to DNA was investigated by means of spectroscopic, equilibrium dialysis and fluorescence measurements. Their inhibition efficiency on nucleic acid synthesis was also evaluated both in mouse and human cells. Our results indicate that, in comparison with adriamycin, compound I shows a slightly weaker complexation ability to DNA, while compound II interacts with DNA at a substantially lower level. These data match quite well with the biological response on the inhibition of DNA and RNA synthesis exhibited by the above mentioned compounds; in fact compound I is slightly less efficient than adriamycin and about ten times more efficient than compound II. The close relationship between the results of physicochemical and biological studies is discussed.