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Gene expression profiles of drug-metabolizing enzymes (DMEs) in rat liver during pregnancy and lactation.

A cDNA microarray analysis was conducted to examine hepatic gene expression profiles in pregnant and lactating F344 rats compared to a virgin control group using an Affymetrix GeneChip system. Of the approximately 16000 gene transcripts interrogated, more than 1000 were significantly modified in their expression when detected either in late pregnancy (19 days of gestation, GD 19, 513 genes upregulated and 579 downregulated) or on the day of delivery (postpartum 0 day, PPD 0, 497 upregulated and 733 downregulated). Particular interest was paid to the gene expression of drug-metabolizing enzymes (DMEs) and nuclear receptors (NRs). Though the expression of a few genes, those for CYP7A1, CYP51 and Sultx3, increased, the expression of a number of genes encoding DMEs (Phase I and Phase II) and NRs decreased during pregnancy and lactation. Changes in the expression of 9 genes encoding DMEs and NRs were confirmed by quantitative real-time PCR. For all 9 genes tested, overall, the results of the microarray and real-time PCR analyses were in agreement. This is the first application of a microarray analysis to the expression profiling of genes encoding DMEs and NRs in the liver of pregnant and lactating rats. When combined with other studies, the present study may provide a basis for investigating the mechanism of toxicity of environmental or other nonphysiologic chemicals to the fetus and mother and drug safety during pregnancy and lactation.

Animals↗

Differential display analysis of breast carcinoma cells enriched by immunomagnetic target cell selection: gene expression profiles in bone marrow target cells.

The red bone marrow (BM) is an important indicator organ of hematogenous micrometastatic spread of carcinomas. Characterization of biological properties specific for BM micrometastatic cells, however, is technically challenging due to the limited number of target cells usually available for the purpose. This report provides referrals to qualitative gene expression profiling of BM micrometastatic cells enriched by immunomagnetic selection. First, an experimental strategy was used to study regulatory mechanisms involved when BM micrometastatic cells colonize distant organs. The MA-11 cells, originating from BM micrometastases in a breast cancer patient clinically devoid of overt metastatic disease, were injected into immunodeficient rats. Metastatic MA-11 cells were subsequently immunoselected from the resulting in vivo lesions. The selected cell populations were compared to the injected cells by differential display analysis, and several genes possibly involved in tumor cell invasion and proliferation were confirmed as differentially expressed among the various MA-11 cell populations. A direct approach to qualitative gene expression profiling of BM micrometastatic cells was also explored. Carcinoma cells were immunoselected from BM and axillary lymph nodes obtained from breast cancer patients, and the isolated cell populations were compared by differential display analysis. Two candidate genes, identified as factors involved in cellular growth control, appeared as differentially expressed by the target cells from BM. Our study provides detailed information on how to combine an immunomagnetic selection procedure and differential display analysis to reveal gene expression profiles that may characterize BM micrometastatic cells.

Animals↗

Choice of normal ovarian control influences determination of differentially expressed genes in ovarian cancer expression profiling studies.

PURPOSE: As with many cancers thought to be of epithelial origin, expression profiling studies of ovarian cancer have relied on a variety of sources of normal cells for comparison with tumors, including whole ovary samples (WO), ovarian surface epithelium (OSE) exposed to short-term culture, and immortalized OSE cell lines (IOSE). Our purpose was to assess the impact of the use of different types of normal controls on the determination of gene expression alterations in ovarian cancer studies. EXPERIMENTAL DESIGN: We compared the gene expression profiles generated on an 11,000-element cDNA microarray of OSE brushings, whole ovary samples, short-term cultures of normal OSE, SV40 large T antigen-immortalized OSE cell lines, and telomerase-immortalized OSE cell lines. The function of the groups as normal controls was then assessed by separate comparisons of each group to a set of 24 serous ovarian carcinoma samples. RESULTS: The normal groups formed robust, distinct clusters in hierarchical clustering and multidimensional scaling. The Pearson correlation coefficient for all combinations of any two of the groups ranged from 0.04 to 0.54, emphasizing the disparity of the groups. In the gene lists produced by comparing each normal group with the ovarian cancer samples, the majority of genes were unique to that normal-cancer comparison, with no gene appearing on all five lists. CONCLUSIONS: These results suggest that the selection of a normal control to compare with epithelial ovarian cancer samples in microarray studies strongly influences the genes that are identified as differentially expressed and complicates comparison with studies using a different normal control.

Blotting, Northern↗

The m-xylene biodegradation capacity of Pseudomonas putida mt-2 is submitted to adaptation to abiotic stresses: evidence from expression profiling of xyl genes.

The effect of archetypal environmental stresses on expression of the catabolic xyl genes of the TOL plasmid pWW0 of the m-xylene degrading strain Pseudomonas putida mt-2 has been investigated. To this end, a subgenomic DNA chip was employed which included structural and regulatory DNA sequences of the TOL pathway along with selected descriptors of specific physiological conditions. Cells were separately exposed to m-xylene under various oxygen tensions, temperatures and nitrogen sources as well as situations of DNA damage, oxidative stress, carbon and iron starvation, respiratory chain damage, and contact with arsenic, but at doses which did not cause a gross effect on growth or cell viability. The incidence of each stress class was categorized through the corresponding descriptors in the chip in respect to the relative output of xyl transcripts. While most of the stresses downregulated the m-xylene biodegradation-related genes, some uncouplers of the respiratory chain (azide) and small doses of arsenate appeared to stimulate their expression. The replacement of NH4+ by NO3- as N source augmented expression of the TOL cistrons also. We subsequently subjected P. putida mt-2 cells to the multiple abiotic stress brought about by exposure to crude tar from the 2002 oil spill of the Prestige tanker, which embraces a complex mixture of hydrocarbons. The resulting expression profile of xyl genes and stress-responding markers over time suggested that adaptation to external insults precedes any significant expression of the catabolic genes. The consequences of this hierarchy of responses for microbial biodegradation in situ are discussed.

Adaptation, Physiological↗

Gene expression profiling in embryonic mouse lenses.

PURPOSE: In this study, we used laser capture microdissection (LCM) and microarray hybridization technology to compare the gene expression profiles of mouse embryonic days 10 and 12 lenses (E10 and E12). METHODS: Lens cells of C57/BL6 mouse embryos at E10 and E12 were harvested using the PixCell II LCM System. Total RNA was extracted, amplified, labeled, and hybridized to the 430 2.0 mouse chip (Affymetrix) according to the manufacturer's instructions. Data extracted from the images were analyzed using different software programs. Regulated expression of selected genes was confirmed by real-time PCR (RT-PCR). RESULTS: Analysis of the microarray data from E10 and E12 lenses identified 1,573 genes that showed a two fold or greater change in expression level. Among these 1,573 genes, 956 genes were downregulated and 617 were upregulated in E12 lenses. In addition to the upregulated expression of beta- and gamma-crystallin genes, genes that regulate the cell cycle showed significant changes of gene expression during the E10 (lens pit) to E12 (primary fiber cell induction) time period. Genes involved in insulin-like growth factor (IGF) signaling and Wnt (a family of secreted glycoproteins related to the Drosophila segment polarity gene, wingless, and to the proto-oncogene, int-1) signaling were also differentially regulated. In particular, positive regulators of Wnt signaling were downregulated and negative regulators were upregulated, indicating that modulation of Wnt signaling is important for normal lens morphogenesis. CONCLUSIONS: Our results provide new information about differential regulation of gene expression during early lens development. Analysis of global gene expression profiles in embryonic mouse lenses has allowed us to identify several molecular pathways that are differentially regulated during early lens development.

Animals↗

Specific gene expression profiles distinguish among functional allelic variants of the mouse Pthlh gene in transfected human cancer cells.

The mouse parathyroid hormone-like hormone (Pthlh) gene encodes three allelic variants characterized by amino acid substitutions that are associated with susceptibility (Pthlh(Pro)) or resistance (Pthlh(Thr) and Pthlh(SerAspTyr)) to two-stage skin carcinogenesis and to modulation of cell migration in vitro in transfected human cancer cells. cDNA microarray hybridization analysis of 8473 transcript clones revealed a similar gene expression profile for the Pthlh(Thr) and Pthlh(SerAspTyr) alleles but a distinct pattern for the Pthlh(Pro) allele, suggesting an association between a specific gene expression profile and biological function of the Pthlh alleles. Some of the genes modulated by the Pthlh alleles, e.g., ANXA1, CCL2, FN1 and TFF3, play a role in cell migration and may represent candidate targets for this Pthlh function. Our study demonstrates the potential usefulness of gene expression profiling of genetic variants for the functional characterization of candidate cancer modifier genes.

Alleles↗

Modeling T-cell activation using gene expression profiling and state-space models.

MOTIVATION: We have used state-space models to reverse engineer transcriptional networks from highly replicated gene expression profiling time series data obtained from a well-established model of T-cell activation. State space models are a class of dynamic Bayesian networks that assume that the observed measurements depend on some hidden state variables that evolve according to Markovian dynamics. These hidden variables can capture effects that cannot be measured in a gene expression profiling experiment, e.g. genes that have not been included in the microarray, levels of regulatory proteins, the effects of messenger RNA and protein degradation, etc. RESULTS: Bootstrap confidence intervals are developed for parameters representing 'gene-gene' interactions over time. Our models represent the dynamics of T-cell activation and provide a methodology for the development of rational and experimentally testable hypotheses. AVAILABILITY: Supplementary data and Matlab computer source code will be made available on the web at the URL given below. SUPPLEMENTARY INFORMATION: http://public.kgi.edu/~wild/LDS/index.htm

Computer Simulation↗

In vitro and in vivo irinotecan-induced changes in expression profiles of cell cycle and apoptosis-associated genes in acute myeloid leukemia cells.

OBJECTIVE: To study irinotecan (CPT-11)-induced changes in expression profiles of genes associated with cell cycle control and apoptosis in myeloid leukemia cells in vitro and in vivo. METHODS: HL60 cells were exposed to clinically achievable concentrations of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of CPT-11, and blood sampled from patients with acute myeloid leukemia and chronic myeloid leukemia in myeloid blast transformation treated with CPT-11. Gene expression changes were studied by cDNA microarray and correlated with biological responses by studying DNA distributions by flow cytometry. RESULTS: cDNA microarray analysis showed down-regulation and up-regulation of specific cell cycle-associated genes, consistent with loss of S-phase cells and temporary delay of G(1)-S-phase transition seen by flow cytometry. Flow cytometry showed that cells in S phase during SN-38 exposure underwent apoptosis, whereas cells in G(2)-M and G(1) were delayed in G(1) and entered S phase only 6 to 8 hours after drug removal, consistent with the observed changes in gene expression. Proapoptotic changes in gene transcription included down-regulation of antiapoptotic genes and up-regulation of proapoptotic genes. Many gene expression changes observed following in vitro SN-38 exposure were also seen following in vivo administration of 10 or 15 mg/m(2) CPT-11; notably, proapoptotic changes included reduced transcription of survivin pathway-associated genes and increased transcription of death receptor 5. CONCLUSION: CPT-11-induced changes in gene expression profiles in vitro and in vivo are consistent with temporary delay in G(1)-S transition and enhanced responsiveness to apoptosis, both of which may contribute to the synergistic interactions of this drug with antimetabolites.

Apoptosis↗

Expression profile of epidermal differentiation complex genes in normal and anal cancer cells.

Anal cancer originates from a peculiar histological region and provides a useful model for investigating alterations in proliferation and/or differentiation of neoplastic keratinocytes. Epidermal differentiation complex (EDC) genes, which form one of the major gene clusters in the human genome, are involved in the terminal differentiation of epithelial cells and in many instances have been implicated in epithelial tumours. We constructed a DNA macroarray capable of characterising the expression profiles of the entire EDC gene complex in normal mucosa and anal cancer biopsies of seven unrelated patients. Brain tissue and cultured keratinocytes were used as controls. All anal cancer samples showed expression profiles in which none of the EDC genes was silent, as evaluated by phosphor-imager analysis. Variance analysis showed significantly lower expression of SPRR2 with respect to SPRR1 or SPRR3, and significantly higher expression of S100A8 than of other S100A subfamily members. At hierarchical clustering analysis, the four basaloid anal cancer cases conglomerated in the top five positions. The macroarray method used by us provides the first demonstration of the expression profile of the EDC gene family in anal cancer, and is capable of producing significant information on the subgrouping of epithelial tumours such as anal cancer.

Adult↗

Analysis of gene expression profile during 3T3-L1 preadipocyte differentiation.

Cellular differentiation is a process in which a group of differentiation specific genes is programmatically induced. This gene expression program leads to changes in both cellular morphological and physiological phenotypes. Using an 18,376-member cDNA/EST microarray, we analyzed the difference in gene expression profiles between differentiated 3T3-L1 adipocyte and non-differentiated 3T3-L1 preadipocyte. From our study a large number of genes and ESTs were identified as differentially induced or suppressed. In this paper we describe the changes of gene expression profile during 3T3-L1 cell differentiation.

3T3 Cells↗

Gene expression profiling of aging using DNA microarrays.

We have previously employed high density oligonucleotide arrays representing thousands of genes to determine the gene expression profile of the aging process in skeletal muscle (gastrocnemius) and brain (cerebellum and neocortex) of male C57BL/6 mice. Specific gene expression profiles are associated with the aging process of individual organs, and caloric restriction can prevent or retard the establishment of these gene expression alterations. The use of DNA microarrays may provide a new tool to measure biological age on a tissue-specific basis and to evaluate at the molecular level the efficacy of interventions designed to retard the aging process.

Aging↗

Expression profiling of the estrogen responsive genes in response to phytoestrogens using a customized DNA microarray.

Here, we examined phytoestrogens, isoflavones (genistein, daidzein, glycitein, biochanin A and ipriflavone), flavones (chrysin, luteolin and apigenin), flavonols (kaempferol and quercetin), and a coumestan, a flavanone and a chalcone (coumestrol, naringenin and phloretin, respectively) by means of a DNA microarray assay. A total of 172 estrogen responsive genes were monitored with a customized DNA microarray and their expression profiles for the above phytoestrogens were compared with that for 17beta-estradiol (E2) using correlation coefficients, or R values, after a correlation analysis by linear regression. While R values indicate the similarity of the response by the genes, we also examined the genes by cluster analysis and by their specificity to phytoestrogens (specific to genistein, daidzein or glycitein) or gene functions. Several genes were selected from p53-related genes (CDKN1A, TP53I11 and CDC14), Akt2-related genes (PRKCD, BRCA1, TRIB3 and APPL), mitogen-activated protein kinase-related genes (RSK and SH3BP5), Ras superfamily genes (RAP1GA1, RHOC and ARHGDIA) and AP-1 family and related genes (RIP140, FOS, ATF3, JUN and FRA2). We further examined the extracts from two local crops of soy beans (Kuro-daizu or Mochi-daizu) by comparing the gene expression profiles with those of E2 or phytoestrogens as a first step in utilizing the expression profiles for various applications.

Cell Line, Tumor↗

Expression profiling of synovial sarcoma by cDNA microarrays: association of ERBB2, IGFBP2, and ELF3 with epithelial differentiation.

Synovial sarcoma is an aggressive spindle cell sarcoma with two major histological subtypes, biphasic and monophasic, defined respectively by the presence or absence of areas of glandular epithelial differentiation. It is characterized by a specific chromosomal translocation, t(X;18)(p11.2;q11.2), which juxtaposes the SYT gene on chromosome 18 to either the SSX1 or the SSX2 gene on chromosome X. The chimeric SYT-SSX products are thought to function as transcriptional proteins that deregulate gene expression, thereby providing a putative oncogenic stimulus. We investigated the pattern of gene expression in synovial sarcoma using cDNA microarrays containing 6548 sequence-verified human cDNAs. A tissue microarray containing 37 synovial sarcoma samples verified to bear the SYT-SSX fusion was constructed for complementary analyses. Gene expression analyses were performed on individual tumor samples; 14 synovial sarcomas, 4 malignant fibrous histiocytomas, and 1 fibrosarcoma. Statistical analysis showed a distinct expression profile for the group of synovial sarcomas as compared to the other soft tissue sarcomas, which included variably high expression of ERBB2, IGFBP2, and IGF2 in the synovial sarcomas. Immunohistochemical analysis of protein expression in tissue microarrays of 37 synovial sarcomas demonstrated strong expression of ERBB2 and IGFBP2 in the glandular epithelial component of biphasic tumors and in solid epithelioid areas of some monophasic tumors. Fluorescence in situ hybridization analysis indicated that the ERBB2 overexpression was not because of gene amplification. Differentially expressed genes were also found in a comparison of the expression profiles of the biphasic and monophasic histological subgroups of synovial sarcoma, notably several keratin genes, and ELF3, an epithelial-specific transcription factor gene. Finally, we also noted differential overexpression of several neural- or neuroectodermal-associated genes in synovial sarcomas relative to the comparison sarcoma group, including OLFM1, TLE2, CNTNAP1, and DRPLA. Our high-throughput studies of gene expression patterns, complemented by tissue microarray studies, confirm the distinctive expression profile of synovial sarcoma, provide leads for the study of glandular morphogenesis in this tumor, and identify a new potential therapeutic target, ERBB2, in a subset of cases.

Cell Differentiation↗

Gene expression profiles characterize early graft response in living donor small bowel transplantation: a case report.

BACKGROUND: The cellular and histological events that occur during the regeneration process in invertebrates have been studied in the field of visceral regeneration. We would like to explore the molecular aspects of the regeneration process in the small intestine. The aim of this study was to characterize the gene expression profiles of the intestinal graft to identify which genes may have a role in regeneration of graft tissue posttransplant. METHODS: In a patient undergoing living related small bowel transplantation (LRSBTx) in our institution, mucosal biopsies were obtained from the recipient intestine and donor graft at the time of transplant and at weeks 1, 2, 3, and 6 posttransplant. Total RNA was isolated from sample biopsies followed by gene expression profiles determined from the replicate samples (n = 3) for each biopsy using the Affymetrix U133 Plus 2.0 Human GeneChip set. RESULTS: Two profiles were obtained from the data. One profile showed rapid increase of 45 genes immediately after transplant by week 1 with significant changes (P < .05) greater than threefold including the chemokine CXC9 and glutathione-related stress factors, GPX2 and GSTA4. The second profile identified 133 genes that were significantly decreased by threefold or greater immediately after transplant week 1, including UCC1, the human homolog of the Ependymin gene. CONCLUSION: We have identified two gene expression profiles representing early graft responses to small bowel transplantation. These profiles will serve to identify and study those genes whose products may play a role in accelerating tissue regeneration following segmental LRSBTx.

Biopsy↗

Effect of controlled ovarian hyperstimulation in IVF on endometrial gene expression profiles.

Controlled ovarian hyperstimulation (COH) used in IVF produces lower implantation rates per embryo transferred compared to natural cycles utilized in ovum donation, suggesting a suboptimal endometrial development. Endometrial receptivity has recently been investigated in natural menstrual cycles with the aid of microarray technology. The aim of this study is to investigate the impact of COH using urinary gonadotrophins with a long protocol with GnRH agonists without progesterone supplementation (similar to the natural cycle) on endometrial gene expression profiles during the window of implantation by comparing the profiles at day hCG + 7 of COH versus LH + 7 of a previous natural cycle in the same women. For this purpose we have used microarray technology by Affymetrix (GeneChip HG_U133A), which allows more than 22,000 genes to be tested simultaneously. Results were validated by semi-quantitative PCR and quantitative PCR experiments. We found that more than 200 genes showed a differential expression of more than 3-fold when COH and normal cycles were compared at hCG + 7 versus LH + 7. We simultaneously re-analysed the LH + 2 versus LH + 7 endometrial gene expression profiles in previous natural cycles in the same subject using this specific GeneChip, the results obtained were consistent with our own published results. This is the first time that gene expression profiles of the endometrium during COH are reported. The large degree of gene expression disturbance is surprising and highlights the need for further efforts to optimize COH protocols.

Embryo Implantation↗

Large-scale gene expression profiling of discrete brain regions: potential, limitations, and application in genetics of aggressive behavior.

Many behavioral geneticists are interested in unraveling the molecular mechanisms underlying aggressive behavior. So far, most scientists have based their search for aggression-related genes on a preliminary functional hypothesis. Large-scale gene expression profiling techniques, such as serial analysis of gene expression (SAGE) and DNA microarrays, now enable the screening of expression levels of thousands of genes simultaneously, allowing the identification of new candidate aggression-related genes expressed in brain and thus the generation of new hypotheses. However, expression profiling in the brain is challenging, as brain is a complex heterogeneous tissue where large numbers of genes are expressed and relatively small changes in gene expression occur. In this special issue, we focus on the principles of SAGE and DNA microarrays, as well as their advantages and disadvantages and application to analysis in brain tissue in order to identify aggression-related genes.

Aggression↗

Early embryonic death-associated changes in genome-wide gene expression profiles in the fetal placenta of the cow carrying somatic nuclear-derived cloned embryo.

Successful somatic nuclear transfer-derived cloning has been reported in cattle; however, the cloned embryo is highly susceptible to death around day 60 of gestation leading to early embryonic loss. The early embryonic death is postulated to possibly arise in part from an atypical placentation. We have performed cDNA macroarray analysis using 3,353 of the previously cataloged 4,165 genes, in order to characterize the early embryonic death-associated changes in genome-wide gene expression profiles in the fetal placenta of the cow carrying somatic nuclear transfer-derived cloned embryo. A more marked difference in the expression profiles was observed between the fetal placentas of the cows with the cloned immotile embryo (CD) and with the cloned motile embryo (CL) or artificial insemination-derived motile embryo (AI), as compared to between the CL and AI placentas, suggesting an aberration of the expression profile in the CD placenta among the three placentas. Further, 291 and 77 genes showed more than twofold elevation and less than 50% reduction, respectively, in either or both of two CD (CD1 and CD2) placentas in comparison with the CL placenta, but no differential expression between the CL and AI placentas. The expression patterns of six genes in the AI, CL, and CD placentas were confirmed in an experiment with an additional sample for each of the three placentas. Among the placental genes showing the early embryonic death-associated changes of expression in the cow with the cloned embryo, IGF2 (elevated gene), and HBA1, HBA2, SPTB, and SPTBN1 genes (reduced gene) are intriguing in that the changes of expression in these genes were observed in an additional sample of CD placenta as well as the CD1 and CD2 placentas, and in that overexpression (for IGF2) and dysfunction or deficiency (for HBA1, HBA2, SPTB, and SPTBN1) result in embryonic lethality.

Animals↗

Microarray-based compendium of hepatic gene expression profiles for prototypical ADME gene-inducing compounds in rats and mice in vivo.

To examine species-specific aspects of the induction of absorption, distribution, metabolism and excretion (ADME)-related genes, we used 25 000 gene oligonucleotide microarrays to construct a rodent gene-response compendium that compared hepatic gene expression profiles and developed consensus aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR) and pregnane X-receptor (PXR) ligand signatures relevant to drug clearance. Twenty-six inducer compounds were chosen from the literature. Rats and mice received one of six dose levels (log2 dose escalation, 32-fold dose range) of each compound daily for 3 days. Animals were necropsied 6-9 h after the last dose, and tissues were collected for RNA analysis. Hepatic gene expression profiles were obtained using Rosetta Resolver expression analysis system, and ADME-related genes were extracted. Cross-talk among nuclear receptors or hepatoxicity at high dose levels resulted in large signatures (usually >1000 genes at p < 0.01) for most compounds. After ADME gene transcript enrichment, agglomerative clustering separated AhR ligands from CAR/PXR ligands, but it was difficult to distinguish CAR from PXR ligands. Consensus signatures were derived from groups of AhR, CAR and PXR ligands; and cross-talk among responding genes was determined. Many compounds had distinct log dose-response profiles, and relative potencies for ligands were established. Robust responses by CYP1A1, CYP2B10 (CAR responsive in mice) and CYP2B15 (CAR responsive in rats) and CYP3A1 (PXR responsive in rats) were used to benchmark the relative potency of different ligands and to determine the relative selectivity for AhR, CAR or PXR. By using a compendium of gene expression profiles, we defined species-specific induction patterns across the ADME transcriptome.

Animals↗