Project description:The Wilms' tumor suppressor gene (WT1) encodes a zinc finger transcription factor that plays important roles during development of several organs including metanephric kidneys. A number of WT1 target genes have been identified, but the detailed mechanisms by which WT1 orchestrates renal development remain elusive. To identify WT1 target genes relevant to development, genome-wide expression profiling was performed using oligonucleotide microarrays representing 39,000 human transcripts Experiment Overall Design: Sample_source_name: UB27 cells, U2OS cells with Tetracycline-repressible WT1(-KTS) expression Experiment Overall Design: Sample_characteristics: U2OS cell line (osteosarcoma; female), Tetracycline-repressible WT1(-KTS) expression, time-course induction Experiment Overall Design: of WT1(-KTS) expression Experiment Overall Design: Sample_description: WT1(-KTS) expression was induced for 4, 8 or 12 Experiment Overall Design: hrs and the expression profile of each time-points was compared to the Experiment Overall Design: uninduced sample (0 hr).
Project description:The Wilms' tumor suppressor gene (WT1) encodes a zinc finger transcription factor that plays important roles during development of several organs including metanephric kidneys. A number of WT1 target genes have been identified, but the detailed mechanisms by which WT1 orchestrates renal development remain elusive. To identify WT1 target genes relevant to development, genome-wide expression profiling was performed using oligonucleotide microarrays representing 39,000 human transcripts Keywords: Wilms' tumor 1 (WT1) gene, -KTS isoform; time course
Project description:Here we identify -KTS, a major alternatively spliced isoform of the Wilms’ tumor suppressor WT1, as a key determinant of female sex determination.
Project description:Patients with Wilms tumors are efficiently treated by chemotherapy; however, tumors with mutant WT1 genes show a poor volume response. Here we used an unbiased gene expression profiling approach and identified a novel mechanism of conventional chemotherapy that explains how the cure of these patients is brought about. Transcription profiling of an untreated WT1 mutant Wilms tumor (Wilms10) and a corresponding lung metastasis that was detected after long-term chemotherapy, revealed the induction of a myogenic transcriptional network with concomitant down-regulation of cell cycle genes. Cell culture experiments showed convincingly that the Wilms10 tumor cells from this lung metastasis had lost their growth potential due to an induction of terminal skeletal muscle differentiation by chemotherapy. These results were confirmed using a set of Wilms tumors with mutant WT1 genes that were treated by preoperative chemotherapy. We conclude here that chemotherapy-induced terminal skeletal muscle differentiation of Wilms tumors with concomitant loss of growth potential enables the cure of Wilms tumor patients with WT1 mutations in the clinical setting. We have shown before that cell lines derived from Wilms tumors with WT1 mutations have characteristic features of mesenchymal stem cells and it will be of great interest to evaluate whether other tumor types with stem cell features show a differentiation reponse to chemotherapy.
Project description:We report the microRNA profiles of the mouse embryonic stem cell (E14IV), which have been deleted for tumour suppressor Wilms' Tumour 1 (WT1), and induced with retinoic acid. Additionally, cells that had an inducibe WT1 expression where also used to compare the microRNA profile during different time points of WT1 induction.
Project description:The Wilms tumor 1 (WT1) gene encodes a zinc finger transcription factor important for normal kidney development. WT1 is a suppressor for Wilms tumor development and an oncogene for diverse malignant tumors. We recently established cell lines from primary Wilms tumors and identified the corresponding WT1 mutations (see GSE18058). To investigate the function of mutant WT1 proteins we performed WT1 knockdown experiments in primary Wilms tumor cell lines with a frameshift/extension (p.V432fsX87 = Wilms3) and a stop mutation (p.P362X = Wilms2) of WT1, followed by genome wide gene expression analysis. A detailed analysis of these gene expression data using MetaCore enabled us to classify the WT1 mutations as gain of function mutations. The mutant WT1Wilms2 and WT1Wilms3 proteins acquired an ability to modulate the expression of a highly significant number of genes from the G2/M phase of the cell cycle, and WT1 knockdown experiments showed that they are required for Wilms tumor cell proliferation. Data from the literature show that p53 negatively regulates the activity of a large number of these genes which are also part of a core proliferation cluster in diverse human cancers. Our data strongly suggest that mutant WT1 proteins facilitate expression of these cell cycle genes by antagonizing transcriptional repression mediated by p53. In light of this it is important to note that mutant WT1 has an ability to physically interact with the tumor suppressor p53. Together the findings show for the first time, that mutant WT1 proteins have a gain of function and act as oncogenes for Wilms tumor development by regulating Wilms tumor cell proliferation.
Project description:The Wilms tumor 1 (WT1) gene encodes a zinc finger transcription factor important for normal kidney development. WT1 is a suppressor for Wilms tumor development and an oncogene for diverse malignant tumors. We recently established cell lines from primary Wilms tumors and identified the corresponding WT1 mutations (see GSE18058). To investigate the function of mutant WT1 proteins we performed WT1 knockdown experiments in primary Wilms tumor cell lines with a frameshift/extension (p.V432fsX87 = Wilms3) and a stop mutation (p.P362X = Wilms2) of WT1, followed by genome wide gene expression analysis. A detailed analysis of these gene expression data using MetaCore enabled us to classify the WT1 mutations as gain of function mutations. The mutant WT1Wilms2 and WT1Wilms3 proteins acquired an ability to modulate the expression of a highly significant number of genes from the G2/M phase of the cell cycle, and WT1 knockdown experiments showed that they are required for Wilms tumor cell proliferation. Data from the literature show that p53 negatively regulates the activity of a large number of these genes which are also part of a core proliferation cluster in diverse human cancers. Our data strongly suggest that mutant WT1 proteins facilitate expression of these cell cycle genes by antagonizing transcriptional repression mediated by p53. In light of this it is important to note that mutant WT1 has an ability to physically interact with the tumor suppressor p53. Together the findings show for the first time, that mutant WT1 proteins have a gain of function and act as oncogenes for Wilms tumor development by regulating Wilms tumor cell proliferation. siWT1 mediated knockdown in two Wilms tumor cell lines one and two days after transfection versus non-silencing controls
Project description:In order to get a better insight into the timing of WT1 mutant Wilms tumor development, we compared the gene expression profiles of nine established WT1 mutant Wilms tumor cell lines with published data from different kidney cell types during development. Publications describing genes expressed in nephrogenic precursor cells, ureteric bud cells, more mature nephrogenic epithelial cells and interstitial cell types were used. These studies uncovered that the WT1 mutant Wilms tumor cells lines express genes from the earliest nephrogenic progenitor cells, as well as from more differentiated nephron cells with the highest expression from the stromal/interstitial compartment. The expression of genes from all cell compartments points to an early developmental origin of the tumor in a common stem cell. Although variability of the expression of specific genes was evident between the cell lines the overall expression pattern was very similar. This is likely dependent on their different genetic backgrounds with distinct WT1 mutations and the absence/presence of mutant CTNNB1.
Project description:Gain-of-function mutations in exon 3 of beta-catenin (CTNNB1) are specific for Wilms' tumors that have lost WT1, but 50% of WT1-mutant cases lack such "hot spot" mutations. To ask whether stabilization of beta-catenin might be essential after WT1 loss, and to identify downstream target genes, we compared expression profiles in WT1-mutant versus WT1 wild-type Wilms' tumors. Supervised and nonsupervised hierarchical clustering of the expression data separated these two classes of Wilms' tumor. The WT1-mutant tumors overexpressed genes encoding myogenic and other transcription factors (MOX2, LBX1, SIM2), signaling molecules (TGFB2, FST, BMP2A), extracellular Wnt inhibitors (WIF1, SFRP4), and known beta-catenin/TCF targets (FST, CSPG2, CMYC). Beta-Catenin/TCF target genes were overexpressed in the WT1-mutant tumors even in the absence of CTNNB1 exon 3 mutations, and complete sequencing revealed gain-of-function mutations elsewhere in the CTNNB1 gene in some of these tumors, increasing the overall mutation frequency to 75%. Lastly, we identified and validated a novel direct beta-catenin target gene, GAD1, among the WT1-mutant signature genes. These data highlight two molecular classes of Wilms' tumor, and indicate strong selection for stabilization of beta-catenin in the WT1-mutant class. Beta-Catenin stabilization can initiate tumorigenesis in other systems, and this mechanism is likely critical in tumor formation after loss of WT1. Experiment Overall Design: Identification of WNT/Beta-Catenin or WT1 target genes. 39 individual samples.