Background and Aims: Gene expression analysis of colon biopsies using high-density oligonucleotide microarray can contribute to the understanding of local pathophysiological alterations and to functional classification of precancerous adenoma, different stage colorectal carcinomas (CRC) and inflammatory bowel diseases (IBD).
Evaluation of microarray preprocessing algorithms based on concordance with RT-PCR in clinical samples.
No sample metadata fields
View SamplesGene expression profile of cancer cell lines of breast, lung, pancreatic, gasctric, ovarian, hepatocellular, prostate carcinomas and melanomas.
Gene expression profiling of 30 cancer cell lines predicts resistance towards 11 anticancer drugs at clinically achieved concentrations.
No sample metadata fields
View SamplesReliable clinical tests for predicting cancer chemotherapy response are not available and individual markers failed to correctly predict resistance against anticancer agents. We hypothesized that gene expression patterns attributable to chemotherapy-resistant cells can be used as a classification tool for chemoresistance and provide novel candidate genes involved in anthracycline resistance mechanisms. We contrasted the expression profiles of 4 different human tumor cell lines of gastric, pancreatic, colon and breast origin and of their counterparts resistant to the topoisomerase inhibitors daunorubicin or doxorubicin. We also profiled the sensitive parental cells treated with doxorubicin for 24h. We interrogated Affymetrix HGU133A and U95A arrays independently. We applied two independent methods for data normalization and used Prediction Analysis of Microarrays (PAM) for feature selection. In addition, we established data sets related to drug resistance by using a virtual array composed of features represented on both types of oligonucleotide arrays. We identified 71 candidate genes associated with doxorubicine/daunorubicine resistance. To validate the microarray data, we also analyzed the expression of 12 selected genes by quantitative RT-PCR or immunocytochemistry, respectively. While the comparison of drug-sensitive versus drug-resistant cells yields candidates associated with drug resistance, the 24h treatment of sensitive parental cells produced a distinct transcriptional profile related to short-term drug effects.
PSMB7 is associated with anthracycline resistance and is a prognostic biomarker in breast cancer.
No sample metadata fields
View SamplesBy silencing of RALA, a downstream member of the RAS signal transduction pathway, we aimed to determine whether genes downstream of a mutated KRAS (codon 12 or 13) or a mutated BRAF can have significant functions in colorectal cancer carcinogenesis.
Effects of RAL signal transduction in KRAS- and BRAF-mutated cells and prognostic potential of the RAL signature in colorectal cancer.
Specimen part, Cell line, Treatment
View SamplesReliable clinical tests for predicting cancer chemotherapy response are not available and individual markers failed to correctly predict resistance against anticancer agents. We hypothesized that gene expression patterns attributable to chemotherapy-resistant cells can be used as a classification tool for chemoresistance and provide novel candidate genes involved in anthracycline resistance mechanisms. We contrasted the expression profiles of 4 different human tumor cell lines of gastric, pancreatic, colon and breast origin and of their counterparts resistant to the topoisomerase inhibitors daunorubicin or doxorubicin. We also profiled the sensitive parental cells treated with doxorubicin for 24h. We interrogated Affymetrix HGU133A and U95A arrays independently. We applied two independent methods for data normalization and used Prediction Analysis of Microarrays (PAM) for feature selection. In addition, we established data sets related to drug resistance by using a virtual array composed of features represented on both types of oligonucleotide arrays. We identified 71 candidate genes associated with doxorubicine/daunorubicine resistance. To validate the microarray data, we also analyzed the expression of 12 selected genes by quantitative RT-PCR or immunocytochemistry, respectively. While the comparison of drug-sensitive versus drug-resistant cells yields candidates associated with drug resistance, the 24h treatment of sensitive parental cells produced a distinct transcriptional profile related to short-term drug effects.
PSMB7 is associated with anthracycline resistance and is a prognostic biomarker in breast cancer.
No sample metadata fields
View SamplesIn polygenic disorders we do not know exactly, how many genes are involved in the pathomechanism, but the analysis of fetal gene expression can get us closer to the solution. In our study we were searching for the genetic background of the polygenic neural tube defect, which is the second most common birth defect in the world (1 in 1000 live births). Our data revealed novel candidate genes, like SLAP, LST1 and BENE, which can play an important role in the pathogenesis of neural tube defects. We created a data warehouse from the results, suitable for further analysis. This study also demonstrates that a routinely collected amount of amniotic fluid (as small as 6 mL) is enough to successfully hybridize isolated RNA to expression arrays, making the ability to use the technique from normally collected amniotic fluid samples.
Use of routinely collected amniotic fluid for whole-genome expression analysis of polygenic disorders.
Specimen part, Disease, Disease stage
View SamplesReliable clinical tests for predicting cancer chemotherapy response are not available and individual markers failed to correctly predict resistance against anticancer agents. We hypothesized that gene expression patterns attributable to chemotherapy-resistant cells can be used as a classification tool for chemoresistance and provide novel candidate genes involved in anthracycline resistance mechanisms. We contrasted the expression profiles of 4 different human tumor cell lines of gastric, pancreatic, colon and breast origin and of their counterparts resistant to the topoisomerase inhibitors daunorubicin or doxorubicin. We also profiled the sensitive parental cells treated with doxorubicin for 24h. We interrogated Affymetrix HGU133A and U95A arrays independently. We applied two independent methods for data normalization and used Prediction Analysis of Microarrays (PAM) for feature selection. In addition, we established data sets related to drug resistance by using a virtual array composed of features represented on both types of oligonucleotide arrays. We identified 71 candidate genes associated with doxorubicine/daunorubicine resistance. To validate the microarray data, we also analyzed the expression of 12 selected genes by quantitative RT-PCR or immunocytochemistry, respectively. While the comparison of drug-sensitive versus drug-resistant cells yields candidates associated with drug resistance, the 24h treatment of sensitive parental cells produced a distinct transcriptional profile related to short-term drug effects.
PSMB7 is associated with anthracycline resistance and is a prognostic biomarker in breast cancer.
No sample metadata fields
View SamplesEvolution of antibiotic resistance in microbes is frequently achieved by acquisition of spontaneous mutations during antimicrobial therapy. Here we demonstrate that inactivation of a central regulator of iron homeostasis (fur) facilitates laboratory evolution of ciprofloxacin resistance in Escherichia coli. To decipher the underlying molecular mechanisms, we first performed a global transcriptome analysis and demonstrated a substantial reorganization of the Fur regulon in response to antibiotic treatment. We hypothesized that the impact of Fur on evolvability under antibiotic pressure is due to the elevated intracellular concentration of free iron and the consequent enhancement of oxidative damage-induced mutagenesis. In agreement with expectations, over-expression of iron storage proteins, inhibition of iron transport, or anaerobic conditions drastically suppressed the evolution of resistance, while inhibition of the SOS response-mediated mutagenesis had no such effect in fur deficient population. In sum, our work revealed the central role of iron metabolism in de novo evolution of antibiotic resistance, a pattern that could influence the development of novel antimicrobial strategies.
Perturbation of iron homeostasis promotes the evolution of antibiotic resistance.
No sample metadata fields
View SamplesStudies in yeast and animals have revealed that histone deacetylases (HDACs) often act as components of multiprotein complexes, including chromatin remodeling complexes (CRCs). In our group, we found evidence for the interaction between Arabidopsis HD2C deacetylase and a BRM-containing SWI/SNF chromatin remodeling complex. Moreover, we revealed a novel function of HD2C as a regulator of the heat stress response. HD2C transcript levels were strongly induced in plants subjected to heat treatment and the expression of selected heat-responsive genes was up-regulated in heat-stressed hd2c mutant, suggesting that HD2C acts to down-regulate heat-activated genes.
No associated publication
Age
View SamplesThis SuperSeries is composed of the SubSeries listed below.
RDM4 modulates cold stress resistance in Arabidopsis partially through the CBF-mediated pathway.
Specimen part
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