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An expression profile of active genes in human colonic mucosa.

An expression profile of genes active in the human colonic mucosa was obtained by collecting 959 partial sequences from a 3'-directed cDNA library. Seven genes were found to produce mRNA each of which comprised more than 1% of total mRNA. Four of these genes are novel, and are likely to be uniquely expressed in the colonic mucosa, and the other three have been identified as genes for fatty acid binding protein, immunoglobulin lambda chain, and carcinoma-associated antigen GA733-2. In the remaining 952 clones, 310 were composed of 118 species occurred recurrently but less than 1%, and 533 clones appeared only once. Because the 3'-directed cDNA library faithfully represents the mRNA population in the source tissue, these numbers represent the relative activities of the gene expression. Altogether 156 gene species were identified in GenBank, and a significant portion of these genes encode proteins found in Golgi apparatus and lysosomes, chromosome-encoded mitochondrial proteins, cell surface proteins, and components in the protein synthesis machinery. The types and proportions of genes identified is consistent with the known major activities of the colonic mucosa such as mucous protein production, energy-dependent water absorption, and rapid cell proliferation and turnover.

Aged↗

Prediction of lymph node metastasis by analysis of gene expression profiles in non-small cell lung cancer.

OBJECTIVE: Non-small cell lung carcinoma (NSCLC) is one of the leading causes of death in the world. Lymph node metastasis is not only an important factor in estimating the extent and the metastatic potential of an NSCLC but also in prognosticating the patient outcome. Preoperative prediction of lymph node metastasis might greatly facilitate the choice of appropriate surgical and medical options in patients with NSCLC. METHODS AND RESULTS: Using a cDNA array, we analyzed the expression profiles of 1,289 genes in 92 cancer tissues of NSCLC (37 squamous cell carcinomas and 55 adenocarcinomas). We divided the patients into two groups (classes) for each of various pathological factors, such as lymph node metastasis and pT-stage. For each pair of classes, we searched for an optimal combination of genes to classify the cases using a sequential forward selection algorithm starting from a gene set that showed significant difference in expression between the classes. We used the leave-one-out error cross-validation on a k-nearest neighbor classifier to sequentially choose the gene. Using the optimized set of genes, it was possible to stratify the patients for lymph node metastasis (pN-stage) and pT-stage at, respectively, 100% (23 genes) and 100% (55 genes) for cases with squamous cell carcinomas and 94% (43 genes) and 92% (35 genes) for those with adenocarcinomas. CONCLUSION: We conclude that expression profiling using feature selection provides a powerful means of stratification (personalization) of NSCLC patients and choice in treatment options, particularly for factors such as lymph node metastasis whose radiological diagnosis is presently incomplete.

Adenocarcinoma↗

Impact of the phytoestrogen content of laboratory animal feed on the gene expression profile of the reproductive system in the immature female rat.

The effect of the dietary background of phytoestrogens on the outcome of rodent bioassays used to identify and assess the reproductive hazard of endocrine-disrupting chemicals is controversial. Phytoestrogens, including genistein, daidzein, and coumestrol, are fairly abundant in soybeans and alfalfa, common ingredients of laboratory animal diets. These compounds are weak agonists for the estrogen receptor (ER) and, when administered at sufficient doses, elicit an estrogenic response in vivo. In this study, we assessed the potential estrogenic effects of dietary phytoestrogens at the gene expression level, together with traditional biologic end points, using estrogen-responsive tissues of the immature female rat. We compared the gene expression profile of the uterus and ovaries, as a pool, obtained using a uterotrophic assay protocol, from intact prepubertal rats fed a casein-based diet (free from soy and alfalfa) or a regular rodent diet (Purina 5001) containing soy and alfalfa. Estrogenic potency of the phytoestrogen-containing diet was determined by analyzing uterine wet weight gain, luminal epithelial cell height, and gene expression profile in the uterus and ovaries. These were compared with the same parameters evaluated in animals exposed to a low dose of a potent ER agonist [0.1 microg/kg/day 17alpha-ethynyl estradiol (EE) for 4 days]. Exposure to dietary phytoestrogens or to a low dose of EE did not advance vaginal opening, increase uterine wet weight, or increase luminal epithelial cell height in animals fed either diet. Although there are genes whose expression differs in animals fed the soy/alfalfa-based diet versus the casein diet, those genes are not associated with estrogenic stimulation. The expression of genes well known to be estrogen regulated, such as progesterone receptor, intestinal calcium-binding protein, and complement component 3, is not affected by consumption of the soy/alfalfa-based diet when assessed by microarray or quantitative reverse transcriptase-polymerase chain reaction analysis. Our results indicate that although diet composition has an impact on gene expression in uterus and ovaries, it does not contribute to the effects of an ER agonist.

Animal Feed↗

Systematic comparison of the fidelity of aRNA, mRNA and T-RNA on gene expression profiling using cDNA microarray.

In cDNA microarray technology, there are three main reverse transcription based RNA labeling methods, using total RNA (T-RNA), mRNA, and amplified antisense RNA (aRNA), respectively. However, despite the common use of the three types of RNAs, limited data are available regarding their differences and concordances. In this report, we compared the three methods through two sets of self-comparison experiments using the same RNA sample in all cases. Within each method, duplicate hybridizations are highly reproducible with low biases, which are randomly produced. When combining different RNAs within a single array, correlation coefficients between the two channels are rather low, while the discrepancies are persistent. Furthermore, the fidelity of aRNA and mRNA microarrays in the expression profile study shows no significant difference with standard T-RNA based labeling methods. These results suggest that some RNA abundance are selectively changed during aRNA amplification/mRNA purification processes, but it will not affect the gene expression ratio of the two samples if the same type RNA are used. Therefore all three types of RNAs can be used in expression profiling analysis as long as the test and reference samples are generated by identical method within single study.

Carcinoma, Hepatocellular↗

Microarray-based gene expression profiling of retransplanted rat cardiac allografts that develop cardiac allograft vasculopathy.

We studied the expression of 9,906 genes in retransplanted rat cardiac allografts that developed cardiac allograft vasculopathy (CAV) with the use of DNA microarray and real-time reverse transcriptase-polymerase chain reaction. Although only a slight difference in the timing of the retransplantation induced the later development of CAV, 1,067 genes were differentially expressed in the allografts 1 day after retransplantation. Thus, the development of CAV was determined by a robust difference in gene expression soon after retransplantation, controlled by a slight difference in retransplantation timing. In contrast, only 26 genes showed significant upregulation in the later phase of CAV development, and the time-course of the induction of 16 genes was associated with CAV progression. Of these genes, 8 were induced in 2 different aortic allograft combinations, and the time-course of the induction was correlated with the development of transplant vasculopathy. Microarray-based gene expression profiling has the potential to elucidate the mechanism of experimental chronic cardiac allograft rejection.

Animals↗

Gene expression profiles of hepatic cell-type specific marker genes in progression of liver fibrosis.

AIM: To determine the gene expression profile data for the whole liver during development of dimethylni-trosamine (DMN)-induced hepatic fibrosis. METHODS: Marker genes were identified for different types of hepatic cells, including hepatic stellate cells (HSCs), Kupffer cells (including other inflammatory cells), and hepatocytes, using independent temporal DNA microarray data obtained from isolated hepatic cells. RESULTS: The cell-type analysis of gene expression gave several key results and led to formation of three hypotheses: (1) changes in the expression of HSC-specific marker genes during fibrosis were similar to gene expression data in in vitro cultured HSCs, suggesting a major role of the self-activating characteristics of HSCs in formation of fibrosis; (2) expression of mast cell-specific marker genes reached a peak during liver fibrosis, suggesting a possible role of mast cells in formation of fibrosis; and (3) abnormal expression of hepatocyte-specific marker genes was found across several metabolic pathways during fibrosis, including sulfur-containing amino acid metabolism, fatty acid metabolism, and drug metabolism, suggesting a mechanistic relationship between these abnormalities and symptoms of liver fibrosis. CONCLUSION: Analysis of marker genes for specific hepatic cell types can identify the key aspects of fibrogenesis. Sequential activation of inflammatory cells and the self-supporting properties of HSCs play an important role in development of fibrosis.

Alanine Transaminase↗

Differential gene expression profile between PC-14 cells treated with free cisplatin and cisplatin-incorporated polymeric micelles.

Cisplatin (CDDP)-incorporated polymeric micelles (CDDP/m) are a macromolecular carrier system possessing a time-modulated decaying property accompanied by sustained release of free drug. The gene expression profiles in nonsmall cell lung cancer PC-14 cells treated with free CDDP and CDDP/m were evaluated by a cDNA expression array for 807 genes. Although the total gene expression profile of the cells treated with CDDP/m approximated that of free CDDP in the hierarchical clustering analysis, a number of genes showed differential expression according to whether the cells had been treated with CDDP or CDDP/m. Ultimately, 50 genes with significant differential expression between cells treated with CDDP and CDDP/m were selected by principal component (PC) analysis and the unpaired t-test. The genes selected, including genes related to cell cycle regulation, apoptosis-related proteins, detoxification, and DNA repair enzymes, were considered to be related to CDDP-induced cytotoxicity. Interestingly, CDDP/m down-regulated the genes encoding integrins and matrix metalloproteinases (MMPs), which play an integral role in tumor invasion, metastasis, and angiogenesis, whereas free CDDP up-regulated them. The results suggest that use of the macromolecular carriers may yield additional therapeutic effects over free drug.

Animals↗

The effects of proinflammatory cytokines on cytokine-chemokine gene expression profiles in the human corneal endothelium.

PURPOSE: To determine the effects of proinflammatory cytokines on differential gene expression profiles in the human corneal endothelium (HCE), by using a cDNA expression array. METHODS: A human cDNA expression array technology was used to study the simultaneous expression of HCE incubated with interleukin (IL)-1alpha and tumor necrosis factor-(TNF)-alpha. Gene-specific semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) were performed to examine the gene and protein expression patterns revealed by the cDNA expression array, in the presence and absence of proinflammatory cytokines. Moreover, the expression of these genes was studied in ex vivo HCE of donor cornea by RT-PCR. RESULTS: IL-1alpha and TNF-alpha upregulated the expression of 46 of 268 genes for cytokines, chemokines, and their receptors in stimulated HCE. The most upregulated genes in the cDNA expression array, those of monocyte chemotactic protein (MCP)-1 (CCL2), IL-8 (CXCL8), IL-6, and growth-related beta (GRObeta, CXCL2), were studied. Semiquantitative RT-PCR and ELISA analyses revealed the proinflammatory cytokine-mediated changes in the respective gene transcription and protein expression levels. The mRNAs were detected in ex vivo HCE of donor cornea stimulated with proinflammatory cytokines. CONCLUSIONS: HCE can abundantly express cytokines and chemokines through the stimulation of proinflammatory cytokines. The detected genes, those of CCL2, CXCL8, IL-6, and CXCL2, in HCE could facilitate understanding of the inflammatory responses, including the production of keratic precipitates and the correlation between CE and an inflamed cornea or aqueous humor.

Cells, Cultured↗

Microarray-based copy number and expression profiling in dedifferentiated and pleomorphic liposarcoma.

Sixteen dedifferentiated and pleomorphic liposarcomas were analyzed by comparative genomic hybridization (CGH) to genomic microarrays (matrix-CGH), cDNA-derived microarrays for expression profiling, and by quantitative PCR. Matrix-CGH revealed copy number gains of numerous oncogenes, i.e., CCND1, MDM2, GLI, CDK4, MYB, ESR1, and AIB1, several of which correlate with a high level of transcripts from the respective gene. In addition, a number of genes were found differentially expressed in dedifferentiated and pleomorphic liposarcomas. Application of dedicated clustering algorithms revealed that both tumor subtypes are clearly separated by the genomic profiles but only with a lesser power by the expression profiles. Using a support vector machine, a subset of five clones was identified as "class discriminators." Thus, for the distinction of these types of liposarcomas, genomic profiling appears to be more advantageous than RNA expression analysis.

Algorithms↗

Gene expression profiling after radiation-induced DNA damage is strongly predictive of BRCA1 mutation carrier status.

PURPOSE: The impact of the presence of a germ-line BRCA1 mutation on gene expression in normal breast fibroblasts after radiation-induced DNA damage has been investigated. EXPERIMENTAL DESIGN: High-density cDNA microarray technology was used to identify differential responses to DNA damage in fibroblasts from nine heterozygous BRCA1 mutation carriers compared with five control samples without personal or family history of any cancer. Fibroblast cultures were irradiated, and their expression profile was compared using intensity ratios of the cDNA microarrays representing 5603 IMAGE clones. RESULTS: Class comparison and class prediction analysis has shown that BRCA1 mutation carriers can be distinguished from controls with high probability (approximately 85%). Significance analysis of microarrays and the support vector machine classifier identified gene sets that discriminate the samples according to their mutation status. These include genes already known to interact with BRCA1 such as CDKN1B, ATR, and RAD51. CONCLUSIONS: The results of this initial study suggest that normal cells from heterozygous BRCA1 mutation carriers display a different gene expression profile from controls in response to DNA damage. Adaptations of this pilot result to other cell types could result in the development of a functional assay for BRCA1 mutation status.

Ataxia Telangiectasia Mutated Proteins↗

Gene expression profiles of cutaneous B cell lymphoma.

We studied gene expression profiles of 17 cutaneous B cell lymphomas that were collected with 4-6 mm skin punch biopsies. We also included tissue from two cases of mycosis fungoides, three normal skin biopsies, and three tonsils to create a framework for further interpretation. A hierarchical cluster algorithm was applied for data analysis. Our results indicate that small amounts of skin tissue can be used successfully to perform microarray analysis and result in distinct gene expression patterns. Duplicate specimens clustered together demonstrating a reproducible technique. Within the cutaneous B cell lymphoma specimens two specific B cell differentiation stage signatures of germinal center B cells and plasma cells could be identified. Primary cutaneous follicular and primary cutaneous diffuse large B cell lymphomas had a germinal center B cell signature, whereas a subset of marginal zone lymphomas demonstrated a plasma cell signature. Primary and secondary follicular B cell lymphoma of the skin were closely related, despite previously reported genetic and phenotypic differences. In contrast primary and secondary cutaneous diffuse large B cell lymphoma were less related to each other. This pilot study allows a first glance into the complex and unique microenvironment of B cell lymphomas of the skin and provides a basis for future studies, which may lead to the identification of potential histologic and prognostic markers as well as therapeutic targets.

Adult↗

Differential protein expression profiles in anterior gills of Eriocheir sinensis during acclimation to cadmium.

Using a proteomic approach, we characterized different protein expression profiles in anterior gills of the Chinese mitten crab, Eriocheir sinensis, after cadmium (Cd) exposure. Two experimental conditions were tested: (i) an acute exposure (i.e. 500 microg Cd l(-1) for 3 days) for which physiological, biochemical and ultrastructural damage have been observed previously; (ii) a chronic exposure (i.e. 50 microg Cd l(-1) for 30 days) resulting in physiological acclimation, i.e. increased resistance to a subsequent acute exposure. Two-dimensional gel electrophoresis (2-DE) revealed six protein spots differentially expressed after acute, and 31 after chronic Cd exposure. From these spots, 15 protein species were identified using MS/MS micro-sequencing and MS BLAST database searches. Alpha tubulin, glutathione S-transferase and crustacean calcium-binding protein 23 were down-regulated after an acute exposure, whereas another glutathione S-transferase isoform was up-regulated. Furthermore, analyses revealed the over-expression of protein disulfide isomerase, thioredoxin peroxidase, glutathione S-transferase, a proteasome subunit and cathepsin D after chronic exposure. Under the same condition, ATP synthase beta, alpha tubulin, arginine kinase, glyceraldehyde-3-phosphate dehydrogenase and malate dehydrogenase were down-regulated. These results demonstrate that acute and chronic exposure to waterborne Cd induced different responses at the protein expression level. Protein identification supports the idea that Cd mainly exerts its toxicity through oxidative stress induction and sulfhydryl-group binding. As a result, analyses showed the up-regulation of several antioxidant enzymes and chaperonins during acclimation process. The gill proteolytic capacity seems also to be increased. On the other hand, the clearly decreased abundance of several enzymes involved in energy transfer suggests that chronic metal exposure induced an important metabolic reshuffling.

Acclimatization↗

Context-specific infinite mixtures for clustering gene expression profiles across diverse microarray dataset.

MOTIVATION: Identifying groups of co-regulated genes by monitoring their expression over various experimental conditions is complicated by the fact that such co-regulation is condition-specific. Ignoring the context-specific nature of co-regulation significantly reduces the ability of clustering procedures to detect co-expressed genes due to additional 'noise' introduced by non-informative measurements. RESULTS: We have developed a novel Bayesian hierarchical model and corresponding computational algorithms for clustering gene expression profiles across diverse experimental conditions and studies that accounts for context-specificity of gene expression patterns. The model is based on the Bayesian infinite mixtures framework and does not require a priori specification of the number of clusters. We demonstrate that explicit modeling of context-specificity results in increased accuracy of the cluster analysis by examining the specificity and sensitivity of clusters in microarray data. We also demonstrate that probabilities of co-expression derived from the posterior distribution of clusterings are valid estimates of statistical significance of created clusters. AVAILABILITY: The open-source package gimm is available at http://eh3.uc.edu/gimm.

Algorithms↗

Gene expression profile of empirically delineated classes of unexplained chronic fatigue.

OBJECTIVES: To identify the underlying gene expression profiles of unexplained chronic fatigue subjects classified into five or six class solutions by principal component (PCA) and latent class analyses (LCA). METHODS: Microarray expression data were available for 15,315 genes and 111 female subjects enrolled from a population-based study on chronic fatigue syndrome. Algorithms were developed to assign gene scores and threshold values that signified the contribution of each gene to discriminate the multiclasses in each LCA solution. Unsupervised dimensionality reduction was first used to remove noise or otherwise uninformative gene combinations, followed by supervised dimensionality reduction to isolate gene combinations that best separate the classes. RESULTS: The authors' gene score and threshold algorithms identified 32 and 26 genes capable of discriminating the five and six multiclass solutions, respectively. Pair-wise comparisons suggested that some genes (zinc finger protein 350 [ZNF350], solute carrier family 1, member 6 [SLC1A6], F-box protein 7 [FBX07] and vacuole 14 protein homolog [VAC14]) distinguished most classes of fatigued subjects from healthy subjects, whereas others (patched homolog 2 [PTCH2] and T-cell leukemia/lymphoma [TCL1A]) differentiated specific fatigue classes. CONCLUSION: A computational approach was developed for general use to identify discriminatory genes in any multiclass problem. Using this approach, differences in gene expression were found to discriminate some classes of unexplained chronic fatigue, particularly one termed interoception.

Algorithms↗

Expression profiling of endocrine-disrupting compounds using a customized Cyprinus carpio cDNA microarray.

Exposure to a variety of anthropogenic compounds has been shown to interfere with normal development, physiology, and reproduction in a wide range of organisms, both in laboratory studies and wildlife. We have developed a Cyprinus carpio cDNA microarray consisting of endocrine-related genes. In the current study, we investigated the applicability of this microarray (1) to study the molecular effects induced by exposure to a variety of endocrine-disrupting compounds (EDCs) in fish and (2) to discriminate the specific transcriptional profiles associated with these compounds. To that purpose, gene expression profiles were generated in livers of juvenile carp exposed to 14 Organization of Economical Cooperation Development (OECD)-recommended reference EDCs (17beta-estradiol, 17alpha-ethinylestradiol, 4-nonylphenol, bisphenol A, tamoxifen, 17alpha-methyltestosterone, 11-ketotestosterone, dibutyl phthalate, flutamide, vinclozolin, hydrocortisone, CuCl(2), propylthiouracil, and a mixture of L-triiodothyronine and L-thyroxine). Our results show that, in addition to some expression similarities between analogous acting substances, each individual compound produced its own unique expression pattern on the array, distinct from the profiles generated by the other compounds. In addition, we were able to identify a minimal subset of genes, which also allowed to discriminate between the different compounds. Overall, our findings suggest that the developed cDNA array has great promise to screen new and existing chemicals on their endocrine-disruptive potential and to identify distinct classes of EDCs.

Animals↗

Different gene expression profiles of AD293 and HEK293 cell lines that show contrasting susceptibility to apoptosis induced by overexpression of Bim L.

Bim is a pro-apoptotic member of the Bcl-2 protein family. Overexpression of Bim proved to be highly cytotoxic for diverse cells. The AD293 cell line is derived directly from the HEK293 cell line but has been transfected with a gene that can improve cell adherence. We found that there was almost no apoptosis seen in Bim L-transfected AD293 cells, but more than half of Bim L-transfected HEK293 cells underwent apoptosis. Suppression subtractive hybridization was used to detect the different gene expression profile between these two cell lines. In 192 sequenced positive clones, there were 30 clones repeating twice or more. Ten genes were selected for identification by semi-quantitative RT-PCR. The transcripts of two adhesion-related genes (actin and parvin) and two apoptosis-related genes (cyclin 2 and protein phosphatase 1G) were up-regulated in AD293 cells. These results suggest that the high expression of cell adhesion-related proteins might be responsible for the different apoptosis status after the transfection of Bim L. Our data provide candidate genes responsible for the different apoptosis sensitivity of these two cell lines. Further investigation on the differential expression profile between AD293 and HEK293 might improve our understanding of cell apoptosis mechanism.

Actins↗

Analysis of gene expression profile in colon cancer using the Cancer Genome Anatomy Project and RNA interference.

OBJECTIVE: To investigate the changes in the gene expression profile in colon cancer to further identify gene markers that may be useful in the management of this disease. METHODS: Data from serial analysis of gene expression (SAGE) collected by the Cancer Genome Anatomy Project (CGAP) were used to detect the difference in gene expression between normal tissue and colon cancer, and were further confirmed in a sample of 20 patients using RT-PCR. To identify the functions of differential genes in regulating the cell growth of colon cancer, RNA interference (RNAi) was used to block one of these genes in the colon cancer cell line HCT-116. RESULTS: Expression changes of greater than twofold in two SAGE libraries of colon cancer compared to two of normal tissue were observed for 216 tags of a total of 195,160 transcript tags (54 up-regulated genes and 136 down-regulated genes). Subsequent analysis of 17 genes by RT-PCR confirmed the reliability of this analysis. RNAi-mediated blockage of one of these genes, transforming growth factor (TGF)beta1, significantly reduced the growth of a colon cancer cell line. CONCLUSIONS: The combination of CGAP analysis and RNAi provides an excellent system to rapidly define the specific genes that are up-regulated in cancer to impact the growth of cancer cells. Further study on these differential overexpressed genes may provide gene markers for the detection and treatment of colon cancer.

Biomarkers, Tumor↗

Systemic analysis of the differential gene expression profile in a colonic adenoma-normal SSH library.

BACKGROUND: The discovery of differentially expressed genes of colonic adenoma minus normal mucosa enables the understanding of early molecular events in colorectal carcinogenesis. In our previous study, we have developed an adenoma minus normal mucosa suppression subtractive hybridization (SSH) library and identified 109 differentially expressed clones. METHODS: An in-house EST pipeline and the Gene Ontology web-based tool () were used to analyze these clones. Realtime quantitative RT-PCR (Q-PCR) was applied to detect the expression of 14-3-3 zeta, REG4 and 6 ribosomal protein genes (RPS2, RPS12, RPS27A, RPL5, RPL7a and RPL10a) in 14 adenomas (8 with concurrent cancers) and 44 colorectal adenocarcinomas with paired normal mucosa. RESULTS: Sixty-two candidate genes were obtained from this library. Bioinformatics analysis indicated that both ribosomal protein genes and immune-related genes were enriched. REG4 was significantly upregulated in colorectal adenomas (medium fold: 1.676, p<0.05, Wilcoxon test) and 14-3-3 zeta in cancers (medium fold: 1.202, p<0.01, Wilcoxon test), as compared with those of paired normal mucosa. However, all ribosomal protein genes were not significantly overexpressed in colorectal adenomas or cancers. CONCLUSIONS: A differential gene expression profile in A-N SSH library may be helpful in understanding the molecular mechanism of colorectal cancer initiation and progression. REG4 and 14-3-3 zeta may be potential biomarkers for early colorectal cancer detection.

Adenoma↗