114 research outputs found

    Candidate pathways and genes for prostate cancer: a meta-analysis of gene expression data

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    <p>Abstract</p> <p>Backgound</p> <p>The genetic mechanisms of prostate tumorigenesis remain poorly understood, but with the advent of gene expression array capabilities, we can now produce a large amount of data that can be used to explore the molecular and genetic mechanisms of prostate tumorigenesis.</p> <p>Methods</p> <p>We conducted a meta-analysis of gene expression data from 18 gene array datasets targeting transition from normal to localized prostate cancer and from localized to metastatic prostate cancer. We functionally annotated the top 500 differentially expressed genes and identified several candidate pathways associated with prostate tumorigeneses.</p> <p>Results</p> <p>We found the top differentially expressed genes to be clustered in pathways involving integrin-based cell adhesion: integrin signaling, the actin cytoskeleton, cell death, and cell motility pathways. We also found integrins themselves to be downregulated in the transition from normal prostate tissue to primary localized prostate cancer. Based on the results of this study, we developed a collagen hypothesis of prostate tumorigenesis. According to this hypothesis, the initiating event in prostate tumorigenesis is the age-related decrease in the expression of collagen genes and other genes encoding integrin ligands. This concomitant depletion of integrin ligands leads to the accumulation of ligandless integrin and activation of integrin-associated cell death. To escape integrin-associated death, cells suppress the expression of integrins, which in turn alters the actin cytoskeleton, elevates cell motility and proliferation, and disorganizes prostate histology, contributing to the histologic progression of prostate cancer and its increased metastasizing potential.</p> <p>Conclusion</p> <p>The results of this study suggest that prostate tumor progression is associated with the suppression of integrin-based cell adhesion. Suppression of integrin expression driven by integrin-mediated cell death leads to increased cell proliferation and motility and increased tumor malignancy.</p

    A transcriptomic analysis of Echinococcus granulosus larval stages:implications for parasite biology and host adaptation

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    The cestode Echinococcus granulosus--the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide--is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages.We generated ~10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H(+)-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development.This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths

    Cancer Biomarker Discovery: The Entropic Hallmark

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    Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

    Prebiotic, probiotic and symbiotic as alternative to Antibiotics on the Performance and Immune Response of Broiler Chickens

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    This study aimed to evaluate diets supplemented with prebiotic, probiotic and symbiotic as an alternative to antibiotics on the performance and immune response against the virus of Newcastle disease in broiler chickens. 1,400 one-day old male Cobb 500 chicks were raised until 42 days old in a completely randomized design with 2x2+1 factorial scheme with seven replications. The treatments were: diet without supplementation (base diet - BD), BD + prebiotic, BD + probiotic, BD + symbiotic (prebiotic + probiotic), and BD + antibiotic. The parameters evaluated were performance and antibody serum titers against Newcastle disease. No antibiotic effect was observed on performance. The symbiotic provided better results for weight gain and feed:gain ratio until 21 days old than isolated additives. At 28 days old, the broilers fed diets with prebiotic presented better feed: gain ratio. In the same period (28 d-old), there was an antibody production increase against the Newcastle disease virus in the group supplemented with prebiotic. It can be concluded that the utilization of symbiotic in broiler chickens' diets can substitute performance enhancing antibiotics. The inclusion of prebiotic in the diet improves feed: gain ratio at 1-28 days old. The chickens' immune response increases at 28 days against the Newcastle disease virus in the group supplemented with prebiotic

    Effect of holder pasteurisation on human milk glycosaminoglycans

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    OBJECTIVES: The benefits of human milk for preterm infants are mainly the result of its nutritional characteristics and the presence of biologically active compounds. Among these compounds, glycosaminoglycans (GAGs) play an emerging leading role. When mother's milk is unavailable or in short supply, pasteurised donor milk represents an important nutritional alternative. The aim of this study was to evaluate the effect of Holder pasteurisation on the concentration of different GAGs in preterm human milk. METHODS: Milk samples collected from 9 mothers having delivered preterm were divided into 2 parts. One part of each sample was immediately frozen (-80\ub0C), whereas the other part was pasteurised with the Holder method before being frozen at -80\ub0C. Specific analytical procedures were applied to evaluate the amount, composition, and structure of main human milk GAGs. RESULTS: No significative differences were measured between not-treated and pasteurised samples for total GAGs content, relative percentages of chondroitin sulfate and heparan sulfate, and main parameters related to galactosaminoglycans structure, even if a slight decrease of total GAGs content of 3c18% was observed in treated samples. CONCLUSIONS: Our results indicate that the Holder pasteurisation does not significatively affect the concentration of the main human milk GAGs
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