Expression of Rb2/p130 in breast and endometrial cancer: correlations with hormone receptor status

Rb2/p130 is a member of the retinoblastoma family of proteins, consisting of Rb, Rb2 and p107, which are important negative regulators of cell cycle progression and differentiation. While Rb2 downregulation was observed in several malignant tumours including endometrial cancer, the role of p130 in breast carcinomas is still unknown. We investigated Rb2 protein expression in tumour tissue from 68 mammary and 41 endometrial carcinomas, 4 mammary cell lines, and normal tissue samples. Therefore, we performed Western blot experiments for Rb2, Rb, and the oestrogen and progesterone receptors (ER, PR-A, PR-B). Weak or absent Rb2 expression was more often found in endometrial (59%) than in mammary carcinomas (24%). We found significant positive correlations of Rb2 expression with Rb, ER, and PR-B in breast cancer samples, and of Rb2 with Rb, PR-A, PR-B, and younger age in endometrial carcinomas. No significant associations with histological grading, stage, nodal involvement, or Ki67 staining were detected. Rb2 mRNA expression was studied by semi-quantitative RT-PCR in 56 endometrial or mammary tissue samples and correlated significantly with Western blot results. Our results indicate that loss of Rb2 expression, mostly by transcriptional down-regulation, may be associated with the development and dedifferentiation of most endometrial and a subset of mammary carcinomas. © 2001 Cancer Research Campaign http://bjcancer.co

Integration of gene expression data with prior knowledge for network analysis and validation

<p>Abstract</p> <p>Background</p> <p>Reconstruction of protein-protein interaction or metabolic networks based on expression data often involves in silico predictions, while on the other hand, there are unspecific networks of in vivo interactions derived from knowledge bases.</p> <p>We analyze networks designed to come as close as possible to data measured in vivo, both with respect to the set of nodes which were taken to be expressed in experiment as well as with respect to the interactions between them which were taken from manually curated databases</p> <p>Results</p> <p>A signaling network derived from the TRANSPATH database and a metabolic network derived from KEGG LIGAND are each filtered onto expression data from breast cancer (SAGE) considering different levels of restrictiveness in edge and vertex selection.</p> <p>We perform several validation steps, in particular we define pathway over-representation tests based on refined null models to recover functional modules. The prominent role of the spindle checkpoint-related pathways in breast cancer is exhibited. High-ranking key nodes cluster in functional groups retrieved from literature. Results are consistent between several functional and topological analyses and between signaling and metabolic aspects.</p> <p>Conclusions</p> <p>This construction involved as a crucial step the passage to a mammalian protein identifier format as well as to a reaction-based semantics of metabolism. This yielded good connectivity but also led to the need to perform benchmark tests to exclude loss of essential information. Such validation, albeit tedious due to limitations of existing methods, turned out to be informative, and in particular provided biological insights as well as information on the degrees of coherence of the networks despite fragmentation of experimental data.</p> <p>Key node analysis exploited the networks for potentially interesting proteins in view of drug target prediction.</p

Novel Methods to Manipulate Autolysis in Sparkling Wine: Effects on Yeast

Sparkling wine made by the traditional method (Méthode Traditionelle) develops a distinct and desirable flavour and aroma profile attributed to proteolytic processes during prolonged ageing on lees. Microwave, ultrasound and addition of β-glucanase enzymes were applied to accelerate the disruption of Saccharomyces cerevisiae, and added to the tirage solution for secondary fermentation in traditional sparkling winemaking. Scanning electron microscopy and flow cytometry analyses were used to observe and describe yeast whole-cell anatomy, and cell integrity and structure via propidium iodide (PI) permeability after 6-, 12- and 18-months post-tirage. Treatments applied produced features on lees that were distinct from that of the untreated control yeast. Whilst control yeast displayed budding cells (growth features) with smooth, cavitated and flat external cell appearances; microwave treated yeast cells exhibited modifications like ‘doughnut’ shapes immediately after treatment (time 0). Similar ‘doughnut’-shaped and ‘pitted/porous’ cell features were observed on progressively older lees from the control. Flow cytometry was used to discriminate yeast populations; features consistent with cell disruption were observed in the microwave, ultrasound and enzyme treatments, as evidenced by up to 4-fold increase in PI signal in the microwave treatment. Forward and side scatter signals reflected changes in size and structure of yeast cells, in all treatments applied. When flow cytometry was interpreted alongside the scanning electron microscopy images, bimodal populations of yeast cells with low and high PI intensities were revealed and distinctive ‘doughnut’-shaped cell features observed in association with the microwave treatment only at tirage, that were not observed until 12 months wine ageing in older lees from the control. This work offers both a rapid approach to visualise alterations to yeast cell surfaces and a better understanding of the mechanisms of yeast lysis. Microwave, ultrasound or β-glucanase enzymes are tools that could potentially initiate the release of yeast cell compounds into wine. Further investigation into the impact of such treatments on the flavour and aroma profiles of the wines through sensory evaluation is warranted

Palladium-mediated organic synthesis using porous polymer monolith formed in situ as a continuous catalyst support structure for application in microfluidic devices

The development and advantages of in situ synthesis of organic polymer monolith supports for metal pre-catalysts in narrow bore fused silica capillary microreactors are described. Catalyst immobilisation involves the covalent attachment of ligand binding sites to the porous polymer monolith, followed by coordination to metal centres. Flow-through microreactors using poly(chloromethylstyrene-co-divinylbenzene) monolith in capillaries of internal diameter 250 micrometers were used successfully for Suzuki– Miyaura and Sonogashira reactions, utilising both 1,10-phenanthroline and imidazole/carbene binding to palladium and with very low palladium leaching, illustrating the potential of flow-through technology at the microscale level using organic monolith support for transition metal catalysed reactions. Polymer monoliths, present as a continuous phase filling capillaries and bonded to the internal surface, are promising new materials for solid supported catalysis in microreactors. The performance of the flow-through microreactors included quantitative yields for the conversion of iodobenzene in the Suzuki–Miyaura reaction, and quantitative yields for Sonagashira coupling of p-iodoacetophenone with phenylacetylene

Development of Martian saline seep models and their implications for planetary protection

While life on Mars has not been found, Earth-based microorganisms may contaminate the Red Planet during rover expeditions and human exploration. Due to the survival advantages conferred by the biofilm morphology to microorganisms, such as resistance to UV and osmotic stress, biofilms are particularly concerning from a planetary protection perspective. Modeling and data from the NASA Phoenix mission indicate that temporary liquid water might exist on Mars in the form of high salinity brines. These brines could provide colonization opportunities for terrestrial microorganisms brought by spacecraft or humans. To begin testing for potential establishment of microbes, results are presented from a simplified laboratory model of a Martian saline seep inoculated with sediment from Hailstone Basin, a terrestrial saline seep in Montana (USA). The seep was modeled as a sand-packed drip flow reactor at room temperature fed media with either 1 M MgSO4 or 1 M NaCl. Biofilms were established within the first sampling point of each experiment. Endpoint 16S rRNA gene community analysis showed significant selection of halophilic microorganisms by the media. Additionally, we detected 16S rRNA gene sequences highly similar to microorganisms previously detected in two spacecraft assembly cleanrooms. These experimental models provide an important foundation for identifying microbes that could hitch-hike on spacecraft and may be able to colonize Martian saline seeps. Future model optimization will be vital to informing cleanroom sterilization procedures