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Results for “Protein Array Analysis”

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A differential gene expression profile reveals overexpression of RUNX1/AML1 in invasive endometrioid carcinoma.

Endometrial carcinoma is the most common gynecological malignant disease in industrialized countries. Two clinicopathological types of endometrial carcinoma have been described, based on estrogen relation and grade: endometrioid carcinoma (EEC) and non-EEC (NEEC). Some of the molecular events that occur during the development of endometrial carcinoma have been characterized, showing a dualistic genetic model for EEC and NEEC. However, the molecular bases for endometrial tumorigenesis are not clearly elucidated. In the present work, we attempted to identify new genes that could trigger cell transformation in EEC. We analyzed the differential gene expression profile between tumoral and nontumoral endometrial specimens with cDNA array hybridization. Among the 53 genes for which expression was found to be altered in EEC, the acute myeloid leukemia proto-oncogene, RUNX1/AML1, was one of the most highly up-regulated. The gene expression levels of RUNX1/AML1 were quantified by real-time quantitative PCR, and protein levels were characterized by tissue array immunohistochemistry. Real-time quantitative PCR validated RUNX1/AML1 up-regulation in EEC and demonstrated a specific and significantly stronger up-regulation in those tumor stages associated with myometrial invasion. Furthermore, tissue array immunohistochemistry showed that RUNX1/AML1 up-regulation correlates to the process of tumorigenesis, from normal atrophic endometrium to simple and complex hyperplasia and then, on to carcinoma. These results demonstrate for the first time the up-regulation of RUNX1/AML1 in EEC correlating with the initial steps of myometrial infiltration.

Aged↗

Highly parallel dispensing of chemical and biological reagents.

We present a technology for the highly parallel dispensing of a multitude of reagents. It allows one to dispense up to 96 different reagents simultaneously in a fixed array, in a volume range of 100 pL up to several nL. The pitch of the dispensed droplets can be as small as 500 microm. All channels are fired simultaneously, giving an unprecedented throughput. The system was originally developed for the high-throughput fabrication of microarrays, but can easily be adopted for other applications such as highly parallel filling of nanotiterplates. Based on our standard configuration we achieved droplets with 125- micro m in-flight diameter (1.2 nL) with a CV of <1%.

Buffers↗

Linking ligand-induced alterations in androgen receptor structure to differential gene expression: a first step in the rational design of selective androgen receptor modulators.

We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful selective AR modulators. To this end, we used combinatorial peptide phage display coupled with molecular dynamic structure analysis to identify the surfaces on AR that are exposed specifically in the presence of selected AR ligands. Subsequently, we used a DNA microarray analysis to demonstrate that differently conformed receptors facilitate distinct patterns of gene expression in LNCaP cells. Interestingly, we observed a complete overlap in the identity of genes expressed after treatment with mechanistically distinct AR ligands. However, it was differences in the kinetics of gene regulation that distinguished these compounds. Follow-up studies, in cell-based assays of AR action, confirmed the importance of these alterations in gene expression. Together, these studies demonstrate an important link between AR structure, gene expression, and biological outcome. This relationship provides a firm underpinning for mechanism-based screens aimed at identifying SARMs with useful clinical profiles.

Amino Acid Sequence↗

Single molecule techniques for biomedicine and pharmacology.

The present review gives a short summary on techniques useful for single molecule research, describes experiments on in vitro single molecule detection and reactions of single molecules and finally reports on the behavior of single molecules and single virus particles in living cells. One experiment on single molecule enzyme kinetics of lactate dehydrogenase, an enzyme used in the diagnosis of heart attacks and one experiment on restriction analysis of individual DNa molecules are described in some detail. Where it is possible, the relevance to pharmacology and biomedicine is emphasized, often as a perspective or suggestion for experiments, since in this young field of science a not too large variety of experiments have indeed already been devoted directly to drug action.

Animals↗

Recent advances in high-throughput molecular marker identification for superficial and invasive bladder cancers.

Bladder cancer is the fifth most common neoplasm in industrialized countries. Due to frequent recurrences of the superficial form of this disease, bladder cancer ranks as one of the most common cancers. Despite the description of a large number of tumor markers for bladder cancers, none have individually contributed to the management of the disease. However, the development of high-throughput techniques for simultaneous assessment of a large number of markers has allowed classification of tumors into clinically relevant molecular subgroups beyond those possible by pathological classification. Here, we review the recent advances in high-throughput molecular marker identification for superficial and invasive bladder cancers.

Biomarkers, Tumor↗

Changes in gene expression profile by HCV core protein in cultured liver cells: analysis by DNA array assay.

In this study, we established hepatitis C virus (HCV) core-expressing mouse liver cells and investigated changes occurring in the gene expression profile accompanied by expression of the viral core protein using DNA array analysis. Both non-transformed and transformed mouse liver cells constitutively expressing the viral core protein were established by DNA transfection, and subjected to DNA array analysis. For the genes judged positive by DNA array, Northern blot analysis was done for corroboration. DNA array analysis revealed one up-regulated gene and three down-regulated genes by expression of the viral core protein in non-transformed liver cells. For the transformed liver cells, four enhanced and five suppressed genes were observed. The Northern blot corroboration analysis clarified two genes, osteopontin precursor and activating transcription factor 4, as being down-regulated by the viral core protein in both non-transformed and transformed liver cells, and three genes, cathepsin D, matrix metalloproteinase 14 and anti-proliferative B-cell translocation gene 2, as being up-regulated by the viral core protein in only transformed liver cells. In conclusion, a total of five genes were identified as viral core protein-responsive ones in the DNA array analysis. Alterations in the expression levels of these genes may be relevant to the viral core-mediated pathogenesis.

Journal Article↗

Identification of Epstein-Barr virus proteins as putative targets of the immune response in multiple sclerosis.

MS is a chronic inflammatory and demyelinating disease of the CNS with as yet unknown etiology. A hallmark of this disease is the occurrence of oligoclonal IgG antibodies in the cerebrospinal fluid (CSF). To assess the specificity of these antibodies, we screened protein expression arrays containing 37,000 tagged proteins. The 2 most frequent MS-specific reactivities were further mapped to identify the underlying high-affinity epitopes. In both cases, we identified peptide sequences derived from EBV proteins expressed in latently infected cells. Immunoreactivities to these EBV proteins, BRRF2 and EBNA-1, were significantly higher in the serum and CSF of MS patients than in those of control donors. Oligoclonal CSF IgG from MS patients specifically bound both EBV proteins. Also, CD8(+) T cell responses to latent EBV proteins were higher in MS patients than in controls. In summary, these findings demonstrate an increased immune response to EBV in MS patients, which suggests that the virus plays an important role in the pathogenesis of disease.

Antibodies↗

Controlled three-dimensional immobilization of biomolecules on chemically patterned surfaces.

We used electron-beam lithography to fabricate chemical nanostructures, i.e. amino groups in aromatic self-assembled monolayers (SAMs) on gold surfaces. The amino groups are utilized as reactive species for mild covalent attachment of fluorescently labeled proteins. Since non-radiative energy transfer results in strong quenching of fluorescent dyes in the vicinity of the metal surfaces, different labeling strategies were investigated. Spacers of varying length were introduced between the gold surface and the fluorescently labeled proteins. First, streptavidin was directly coupled to the amino groups of the SAMs via a glutaraldehyde linker and fluorescently labeled biotin (X-Biotin) was added, resulting in a distance of approximately 2 nm between the dyes and the surface. Scanning confocal fluorescence images show that efficient energy transfer from the dye to the surface occurs, which is reflected in poor signal-to-background (S/B) ratios of approximately 1. Coupling of a second streptavidin layer increases the S/B-ratio only slightly to approximately 2. The S/B-ratio of the fluorescence signals could be further increased to approximately 4 by coupling of an additional fluorescently labeled antibody layer. Finally, we introduced tetraethylenepentamine as functional spacer molecule to diminish fluorescence quenching by the surface. We demonstrate that the use of this spacer in combination with multiple antibody layers enables the controlled fabrication of highly fluorescent three-dimensional nanostructures with S/B-ratios of >20. The presented technique might be used advantageously for the controlled three-dimensional immobilization of single protein or DNA molecules and the well-defined assembly of protein complexes.

Adsorption↗

Protein microarrays: challenges and promises.

Genomics and proteomics are playing increasingly important roles as discovery tools in basic biological sciences and as diagnostic and rational therapeutic aids in the clinical arena. In recent years, high-density arrays of specified DNA sequences have gained popularity. Protein microarrays are at the forefront of this biochip revolution and promise the parallel examination of large numbers of proteins. These miniaturized arrays are currently being developed to facilitate high analytical resolution, detection sensitivity and sample throughput. Many challenges are presented by proteome scale manipulation of proteins, as there is currently no methodological equivalent to the gene chip for comparative proteomics.

Humans↗

The impact of protein biochips and microarrays on the drug development process.

With the genome sequences of several organisms now in public databases, the scientific community has realized that it is time to prepare for the next step: the understanding of biological systems or systems biology. Whereas genes contain the information for life, the encoded proteins and RNAs fulfill nearly all the functions, from replication to regulation. At present, there is a perceived demand for high-throughput and parallel analytical devices as research tools in systems biology, and, in addition, for new concepts to extract knowledge and value from these data. Protein biochips will play a decisive role in meeting this need in the future.

Drug Evaluation, Preclinical↗

Molecular diagnosis of leishmaniasis.

This review describes the worldwide situation of visceral and tegumentary leishmaniasis with an emphasis on diagnosis, including methods for the detection of antibodies, antigens, parasite DNA and of skin testing. The advantages and problems of each method are discussed and the need for a rapid, sensitive and low-cost diagnostic method for use in field conditions is highlighted. Recent advances in Leishmania genome sequencing, the use of DNA microarrays and protein microarray methodologies and their potential use for leishmaniasis diagnosis are presented.

Animals↗

Head and neck squamous cell carcinoma transcriptome analysis by comprehensive validated differential display.

Head and neck squamous cell carcinoma (HNSCC) is common worldwide and is associated with a poor rate of survival. Identification of new markers and therapeutic targets, and understanding the complex transformation process, will require a comprehensive description of genome expression, that can only be achieved by combining different methodologies. We report here the HNSCC transcriptome that was determined by exhaustive differential display (DD) analysis coupled with validation by different methods on the same patient samples. The resulting 820 nonredundant sequences were analysed by high throughput bioinformatics analysis. Human proteins were identified for 73% (596) of the DD sequences. A large proportion (>50%) of the remaining unassigned sequences match ESTs (expressed sequence tags) from human tumours. For the functionally annotated proteins, there is significant enrichment for relevant biological processes, including cell motility, protein biosynthesis, stress and immune responses, cell death, cell cycle, cell proliferation and/or maintenance and transport. Three of the novel proteins (TMEM16A, PHLDB2 and ARHGAP21) were analysed further to show that they have the potential to be developed as therapeutic targets.

Amino Acid Sequence↗