Development of effective tools such as oligo-microarrays and next-generation sequencing methods for monitoring gene expression on a large scale has resulted in the discovery of gene signatures with prognostic/predictive value in various malignant neoplastic diseases. However, with the exponential growth of gene expression databases, biologists are faced with the challenge of extracting useful information from these repositories. Here, we present a software package, BioPlat (Biomarkers Platform), which allows biologists to identify novel prognostic and predictive cancer biomarkers based on the data mining of gene expression signatures and gene expression profiling databases. BioPlat has been designed as an easy-to-use and flexible desktop software application, which provides a set of analytical tools related to data extraction, preprocessing, filtering, gene expression signature calculation, in silico validation, feature selection and annotation that leverage the integration and reuse of gene expression signatures in the context of follow-up data.
Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility.
The de novo synthesis of glycerolipids in mammalian cells begins with the acylation of glycerol-3-phosphate, catalyzed by glycerol-3-phosphate acyltransferase (GPAT). GPAT2 is a mitochondrial isoform primarily expressed in testis under physiological conditions. Because it is aberrantly expressed in multiple myeloma, it has been proposed as a novel cancer testis gene. Using a bioinformatics approach, we found that GPAT2 is highly expressed in melanoma, lung, prostate and breast cancer, and we validated GPAT2 expression at the protein level in breast cancer by immunohistochemistry. In this case GPAT2 expression correlated with a higher histological grade. 5-Aza-2' deoxycytidine treatment of human cells lines induced GPAT2 expression suggesting epigenetic regulation of gene expression. In order to evaluate the contribution of GPAT2 to the tumor phenotype, we silenced its expression in MDA-MB-231 cells. GPAT2 knockdown diminished cell proliferation, anchorage independent growth, migration and tumorigenicity, and increased staurosporine-induced apoptosis. In contrast, GPAT2 over-expression increased cell proliferation rate and resistance to staurosporine-induced apoptosis. To understand the functional role of GPAT2, we performed a co-expression analysis in mouse and human testis and found a significant association with semantic terms involved in cell cycle, DNA integrity maintenance, piRNA biogenesis and epigenetic regulation. Overall, these results indicate the GPAT2 would be directly associated with the control of cell proliferation. In conclusion, we confirm GPAT2 as a cancer testis gene and that its expression contributes to the tumor phenotype of MDA-MB-231 cells.
In cancer patients, MUC1 glycoprotein may carry Lewis y which could be involved in immune response. Purposes: 1- to evaluate the presence of Lewis y and MUC1 in circulating immune complexes (Lewis y/CIC and MUC1/CIC, respectively) and their correlation; 2- to analyze the possible presence of Lewis y in carbohydrate chains of tumoral MUC1 glycoprotein and 3- to correlate serum and tissue parameters considered.
Mucins are related to infectious and non-infectious diseases in Veterinary and Human Medicine. MUC1 mucin is a transmembrane glycoprotein expressed on the apical surface of human epithelia while MUC5AC is the predominant secreted mucin expressed in human gastric epithelium and goblet cells of lung and eyes. MUC5AC C-terminus cysteine rich regions and the cytoplasmic tail of MUC1 domains are conserved among several mammalian species. Objective: to compare the expression of MUC1 and MUC5AC mucins in mammalian epithelia. CT33 anti-MUC1 cytoplasmic tail (MUC1CT) polyclonal antibody and 45M1 anti-MUC5AC monoclonal antibody were employed. By immunohistochemistry, MUC1CT was expressed in most tissues while MUC5AC was restricted to gastric surface epithelium and goblet cells from trachea and lung. By western blot, MUC1CT showed a band at approximately 35 kDa in most tissues; MUC5AC revealed bands at >180 kDa in stomach and lung secretions from rat, cat, pig and cow. When rat MUC5AC was immunoprecipitated, a band at about 180 kDa was obtained.
Many pathogens require direct binding to, or penetration of, mucosal cells to cause pathology. Cell surface mucins are critical components of mucosal defense. Mucin 1, named MUC1 in humans and Muc1 in non-human species, is a transmembrane glycoprotein expressed in apical mammalian epithelial tissues. The aim of this study was to determine the Muc1 profile expression in healthy cat epithelial tissues. An extensive analysis of Muc1 expression was performed by immunohistochemistry (IHC), Western blot (WB) and RT-PCR. By IHC, the presence of Muc1 protein was observed in the epithelial cells of the esophagus, stomach, trachea, lung, small and large intestine, liver, pancreas, salivary glands, lactating mammary glands and bladder. The predominantly linear patterns of reaction as well as the ubiquitous expression of feline Muc1 were consistent with normal human tissues. By WB, a band of 35kDa, corresponding to that predicted for the Muc1 cytoplasmic tail, was detected. The RT-PCR analysis showed a fragment of 115bp, consistent with that found in MCF7 and T47D human cell lines. The results showed that the widest distribution of feline Muc1 expression is in the mucosal tissues most at risk of infections such as the gastrointestinal tract, respiratory tract and lactating mammary gland. This study provides a normal model of cat Muc1 pattern expression as a starting point to evaluate and compare the expression of this epithelial mucin in pathological feline tissues. We believe that the CT33 antibody and the universal primers designed could be valuable tools for veterinary pathologists involved in the diagnostic interpretation of alterations in Muc1 expression of infected tissues in cats.
Tristetraprolin (TTP) is a RNA-binding protein that inhibits the expression of pro-inflammatory cytokines and invasiveness-associated genes. TTP levels are decreased in many different cancer types and it has been proposed that this protein could be used as a prognostic factor in breast cancer. Here, using publicly available DNA microarray datasets, "serial analysis of gene expression" libraries and qRT-PCR analysis, we determined that TTP mRNA is present in normal breast cells and its levels are significantly decreased in all breast cancer subtypes. In addition, by immunostaining, we found that TTP expression is higher in normal breast tissue and benign lesions than in infiltrating carcinomas. Among these, lower grade tumors showed increased TTP expression compared to higher grade cancers. Therefore, these data indicate that TTP protein levels would provide a better negative correlation with breast cancer invasiveness than TTP transcript levels. In mice, we found that TTP mRNA and protein expression is also diminished in mammary tumors. Interestingly, a strong positive association of TTP expression and mammary differentiation was identified in normal and tumor cells. In fact, TTP expression is highly increased during lactation, showing good correlation with various mammary differentiation factors. TTP expression was also induced in mammary HC11 cells treated with lactogenic hormones, mainly by prolactin, through Stat5A activation. The effect of this hormone was highly dependent on mammary differentiation status, as prolactin was unable to elicit a similar response in proliferating or neoplastic mammary cells. In summary, these studies show that TTP expression is strongly linked to the mammary differentiation program in human and mice, suggesting that this protein might play specific and relevant roles in the normal physiology of the gland.
In previous studies, we identified rhomboid domain containing 2 (RHBDD2) gene to be markedly overexpressed in breast cancer patients that developed recurrence of the disease. In this study, we evaluated for the first time RHBDD2 gene expression in colorectal cancer (CRC). Five public available DNA microarray studies were compiled in a homogeneous dataset of 906 colorectal samples. The statistical analysis of these data showed a significant increase of RHBDD2 expression in the advanced stages of CRC (p < 0.01). We validated these findings by immunohistochemistry on 130 colorectal tissue samples; RHBDD2 protein overexpression was also observed in the advanced stages of the disease (p < 0.001). In addition, we investigated RHBDD2 expression in response to the chemotherapy agent 5-fluorouracile (5FU). We detected a significant increase of RHBDD2 mRNA and protein after 5FU treatment (20-40 ?M; p < 0.001). Overall, these results showed that RHBDD2 overexpression might play a role in colorectal cancer progression.
De novo glycerolipid synthesis begins with the acylation of glycerol-3 phosphate catalyzed by glycerol-3-phosphate acyltransferase (GPAT). In mammals, at least four GPAT isoforms have been described, differing in their cell and tissue locations and sensitivity to sulfhydryl reagents. In this work we show that mitochondrial GPAT2 overexpression in CHO-K1 cells increased TAG content and both GPAT and AGPAT activities 2-fold with arachidonoyl-CoA as a substrate, indicating specificity for this fatty acid.
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