Background: Information on the carcinogenic potential of chemicals is only availably for High Production Volume products. There is however, a pressing need for alternative methods allowing for the chronic toxicity of substances, including carcinogenicity, to be detected earlier and more reliably. Here we applied advanced genomics to a cellular transformation assay to identify gene signatures useful for the prediction of risk for carcinogenicity. Methods: Genome wide gene expression analysis and qRT-PCR were applied to untransformed and transformed Balb/c 3T3 cells that exposed to 2, 4-diaminotoluene (DAT), benzo(a)pyrene (BaP), 2-Acetylaminoflourene (AAF) and 3-methycholanthrene (MCA) for 24h and 120h, at different concentrations, respectively. Furthermore, various bioinformatics tools were used to identify gene signatures predicting for the carcinogenic risk. Results: Bioinformatics analysis revealed distinct datasets for the individual chemicals tested while the number of significantly regulated genes increased with ascending treatment concentration of the cell cultures. Filtering of the data revealed a common gene signature that comprised of 13 genes whose regulation in cancer tissue has already been established. Strikingly, this gene signature was already identified prior to cell transformation therefore confirming the predictive power of this gene signature in identifying carcinogenic risks of chemicals. Comparison of fold changes determined by microarray analysis and qRT-PCR were in good agreement. Conclusion: Our data describes selective and commonly regulated carcinogenic pathways observed in an easy to use in vitro carcinogenicity assay. Here we defined a set of genes which can serve as a simply assay to predict the risk for carcinogenicity by use of an alternative in vitro testing strategy.
Toxicogenomics applied to in vitro carcinogenicity testing with Balb/c 3T3 cells revealed a gene signature predictive of chemical carcinogens.
Cell line, Treatment, Time
View SamplesWe recently reported isolation of various cancer progenitor cells of transgenic c-Myc and c-Raf mouse lung tumors [Reamon-Buettner SM and Borlak J, 2008]. As lung tumors can arise following dysregulation of signalling pathways normally activated during lung development we were particularly interested in investigating the genetic heterogeneity of these cancer cell lines. By whole genome expression analysis we identified two cell lines (A2C12, cRAF_cMYC) to be very different from the remaining tumor cells. Specifically the A2C12 and cRAF_cMYC cell lines expressed various stem cell markers, most notably CD34, CD44, Pdpn and Dlg7. Likewise, the A2C12 and cRAF_cMYC expressed the ATP-binding cassette (ABC) transporters Abcc1 and Abcg2 at different level when compared to other established cell lines. Furthermore, a genome wide expression profiling displayed differential gene expression pattern between and within progenitor cell lines. That provided important clues on heterogeneity in the signalling pathways amongst the cancer cell lines. We also knock down CD44 using a retroviral delivery system and observed an increased G1 peak and apoptosis as determined by flow cytometry. Finally, we analyzed promoters of regulated genes and identified overrepresented 18 transcription factor binding sites (TFBS) in common regulated genes, 10 unique TFBS in A2C12 and 9 unique TFBS in cRaf_cMyc. These data indicates that our tumor cell lines are suitable models to study the biology of lung cancer progenitor cell. Most importantly, we show that our tumor cell lines do not represent a homogeneous population of tumor-initiating cells. Understanding heterogeneity in tumors will lead to new diagnostic and therapeutic approaches.
No associated publication
Disease, Disease stage, Cell line
View SamplesBackground The side population (SP) phenotype, a subset of cells that extrude the nucleic acid dye Hoechst 33342, has been reported to be enriched for stem cells in several human normal tissues, cancers and cell lines, and thus may be useful for the identification and isolation of cancer stem cells. Methods We demonstrated the presence of SP fractions in all analyzed tumor cell lines ranging between 7- 20% of cells. To identify gene expression patterns that contribute to SP phenotype, microarray analysis of SP and non-SP cells was performed. We additionally confirmed regulation of some genes by qRT-PCR. Results Surprisingly, only a subset of few genes in SP cells showed altered gene expression. A total of 11 genes in A2C12, 103 genes in cRAF_cMYC and 101 genes in beta5 SP cells were regulated. Most regulated genes are involved in transcription / transcriptional regulation and transport. In addition, we found no enrichment of previously described stem cell marker like CD24a, CD90 or CD133 and also the ABC transporter ABCG2 was only slightly increased in side population fraction of two cell lines. But despite the few differences between SP and non-SP cells, the beta5 tumor cells were highly tumorigenic due to their capacity to form an original murine tumor when injected in NOD/SCID mice. Conclusion These findings stand in contrast to other observations but indicate that there are further factors responsible for the SP phenotype and that SP cells alone are not suitable as a universal stem cell marker.
No associated publication
Specimen part, Disease, Disease stage, Cell line
View SamplesLung cancer is a leading cause of deaths in the world. There is a need to improve an understanding of mechanisms of malignant transformation and to develop genetic markers of disease for better and targeted therapies.
Cancer genomics identifies regulatory gene networks associated with the transition from dysplasia to advanced lung adenocarcinomas induced by c-Raf-1.
No sample metadata fields
View SamplesBackground: Lung cancer is a multistage process with poor prognosis and high morbidity. Importantly, the genetics of dysplasia, a facultative cancer, at the edge of malignant transformation is unknown.
No associated publication
No sample metadata fields
View SamplesPhagocytosis and killing of the opportunistic pathogen Pseudomonas aeruginosa by polymorphonuclear neutrophils (PMNs) is the major antipseudomonal host defense of vertebrates. By screening a transposon library of the clinical P. aeruginosa isolate TBCF10839 that can grow and replicate in PMNs, a mutant was identified that was most strongly sensitized to killing by PMNs. The inactivated gene PA1572 termed nadK1 was found to encode an ATP:NAD kinase. The transcriptomes of the TBCF10839 wild type and nadK1 mutant were investigated in the presence of PMNs or H2O2. Exposure to H2O2 led to diametrical mRNA expression profiles. H2O2-degrading enzymes were upregulated by wild type, but not by nadK1 mutant. This data demonstrates that NadK1 is crucial for the response of P. aeruginosa to reactive oxygen species.
No associated publication
No sample metadata fields
View SamplesWe investigated whether we could identify gene expression profiles in initial core biopsies of breast cancer samples that would permit to a) predict a clinically meaningful response to Epi/Doc in terms of tumor size reduction, b) predict a profound reduction in intratumoral Ki67 protein expression, and c) predict an in vitro response to Epi/Doc in the ATP-TCA.
No associated publication
Specimen part
View SamplesIschemia reperfusion injury (IRI) in organ transplantation remains a significant problem with limited alternative therapeutic options. Organs that undergo significant damage during IRI, particularly those enduring long warm ischemia times, undergo significant delayed graft function (DGF) after reperfusion and tend to have greater complications long term with the onset of chronic rejection. The gas molecule carbon monoxide (CO) has emerged as an agent that can suppress IRI in rodent models of solid organ transplantation. Since the use of CO is a potential therapeutic modality in humans, we tested if CO can prevent DGF in a pig model of kidney transplantation
Intraoperative administration of inhaled carbon monoxide reduces delayed graft function in kidney allografts in Swine.
Specimen part
View SamplesTyrosine kinase inhibitors represent a new generation of targeted drugs for cancer treatment and chemoprevention. The EGF receptor inhibitor erlotinib is under discussion for chemoprevention of hepatocellular carcinoma.
No associated publication
Specimen part, Cell line
View SamplesBackground
Adapted Boolean network models for extracellular matrix formation.
Sex, Age
View Samples