Project description:Wilms tumor (nephroblastoma) is a pediatric kidney tumor that arises from renal progenitor cells. Since the blastemal type is associated with adverse prognosis, we characterized such Wilms tumors by exome and transcriptome analysis. We detected novel, recurrent somatic mutations affecting the SIX1/2 – SALL1 pathway implicated in kidney development, the DROSHA/DGCR8 microprocessor genes as well as alterations in MYCN and TP53, the latter being strongly associated with dismal outcome. The DROSHA mutations impair the RNase III domains, while DGCR8 exhibits stereotypic E518K mutations in the RNA binding domain - both may skew miRNA representation. SIX1 and SIX2 mutations affect a single hotspot (Q177R) in the homeodomain indicative of a dominant effect. In larger cohorts, these mutations cluster in blastemal and chemotherapy-induced regressive tumors that likely derive from blastemal cells and these are characterized by generally higher SIX1/2 expression. These findings broaden the spectrum of human cancer genes and may open new avenues for stratification and therapeutic leads for Wilms tumors. 53 Wilms tumor samples were selected for RNA extraction and hybridization on Affymetrix Affymetrix Human Genome U133 Plus 2.0 Arrays.
Project description:Wilms tumor (nephroblastoma) is a pediatric kidney tumor that arises from renal progenitor cells. Since the blastemal type is associated with adverse prognosis, we characterized such Wilms tumors by exome and transcriptome analysis. We detected novel, recurrent somatic mutations affecting the SIX1/2 – SALL1 pathway implicated in kidney development, the DROSHA/DGCR8 microprocessor genes as well as alterations in MYCN and TP53, the latter being strongly associated with dismal outcome. The DROSHA mutations impair the RNase III domains, while DGCR8 exhibits stereotypic E518K mutations in the RNA binding domain - both may skew miRNA representation. SIX1 and SIX2 mutations affect a single hotspot (Q177R) in the homeodomain indicative of a dominant effect. In larger cohorts, these mutations cluster in blastemal and chemotherapy-induced regressive tumors that likely derive from blastemal cells and these are characterized by generally higher SIX1/2 expression. These findings broaden the spectrum of human cancer genes and may open new avenues for stratification and therapeutic leads for Wilms tumors.
Project description:Wilms tumors are pediatric cancers thought to arise from kidney-specific stem cells. In order to identify transcriptional and epigenetic mechanisms that drive these malignant cells, we compared genomewide chromatin profiles of Wilms tumors to embryonic stem (ES) cells and normal kidney. Data represent examination of genome-wide chromatin modifications in primary Wilms tumors, fetal and mature kidney.
Project description:Wilms tumors are pediatric cancers thought to arise from kidney-specific stem cells. In order to identify transcriptional and epigenetic mechanisms that drive these malignant cells, we compared genomewide chromatin profiles of Wilms tumors to embryonic stem (ES) cells and normal kidney.
Project description:Oncogenic stabilizing mutations in the beta-catenin gene CTNNB1 are common in one class of human Wilms tumors. To model these tumors, we crossed mice carrying an inducible Cre recombinase (Rosa26-CreERT2) with a conditional gain-of-function beta-catenin allele (Ctnnb1Ex3flox). We obtained kidneys at embryonic day 13.5 and placed them in organ culture with tamoxifen. Multiple small tumors formed in the Ctnnb1∆Ex3 kidneys while the control kidneys developed normally. Immunostaining for Sall1, a marker of condensing metanephric mesenchyme, indicated that the tumors arise from this tissue compartment, analogous to the origin of human Wilms tumors. Expression profiling identified a set of induced genes overlapping with those up-regulated in human Wilms tumors with CTNNB1 mutations, including genes encoding feedback inhibitors of Wnt/beta-catenin signaling, the epithelial-mesenchymal transition (EMT) inducers, and the transcription factor E2-2 (ITF2/TCF4). A conditional deletion of E2-2 showed that this gene is important for growth of the nephroblastomas, in part via promoting an epithelial to mesenchymal transition downstream of beta-catenin. Given these cross-species validations, and genetic proof of the oncogenic function of a key downstream target gene, we expect that this rapid and efficient organ culture model will be useful for further studies to dissect and inhibit oncogenic Wnt/beta-catenin signaling.
Project description:The global gene expression pattern of Wilms tumors in comparison with clear cell sarcoma of the kidney (CCSK) and non-neoplastic fetal and adult kidneys.
Project description:Blastemal histology in chemotherapy-treated pediatric Wilms tumors (nephroblastoma) is associated with adverse prognosis. To uncover the underlying tumor biology and find novel therapeutic leads for this subgroup of patients, we analyzed 58 blastemal-type Wilms tumors by exome and transcriptome sequencing and validated our findings in a large independent replication cohort. Recurrent mutations identified either somatically or in the germline included a hotspot mutation (Q177R) in the homeodomain of SIX1 and SIX2 in tumors with high proliferative potential, mutations in microprocessor genes like DROSHA, DGCR8, DICER1 and DIS3L2, and alterations in IGF2, MYCN, and TP53, the latter being strongly associated with dismal outcome. DROSHA and DGCR8 mutations had a strong effect on miRNA expression patterns in tumors, which was functionally validated in cell lines transfected with mutant DROSHA. total samples analyzed are 16, each done as technical replicate
Project description:Purpose: Bulk transcriptomics analysis of Wilms tumor SIX2+CITED1+ cells to compare and identify unique nephron progenitor transcriptome profiling (RNA-seq) signature between unfavorable and favorable Wilms Tumors and against human fetal kidney Methods: Wilms tumor samples were collected and transported on ice at 4°C in RPMI-1640 and a single cell suspensions were prepared following mechanical and enzymatic dissociation as previously publication. Enzymatic dissociation was performed with 125 U/ml collagenase I in RPMI-1640 at 37 °C for 35 min. The digested cells were then passed through a 100-μm cell strainer and a 40-μm cell strainer with washes of 1x PBS. The cell suspension was than centrifuged at 1500 rpm for 5 min and erythrocytes were eliminated using a red blood cell lysis kit. WT SIX2+CITED1+ cells were isolated using SIX2-Cy5 and CITED1-Cy3 Smartflare RNA probes following manufacturer’s instructions and previous publication. Briefly, cells were incubated over night at 37 °C with both RNA probes diluted at 1:20 in PBS and 25ul/ml in RPMI-1640 supplemented with 5% FBS, and 0.2% antimicrobial agent Primocin. After 16-18 h, cells were dissociation using TrypLE 1x for 5 min, cells were centrifuged at 1500 rpm for 5 min and prepared for FACS. RNA extraction was performed immediately after FACS using the RNeasy Micro Kit following manufacturer’s recommendations. After cDNA production and construction of DNA libraries, the samples were run on an Illumina NextSep500 (Illumina). Differential gene expression was analyzed using ERCC ExFold probes with the Remove Unwanted Variation R/Bioconductor software package combined with edgeR Results: Transcriptomics analysis of Wilms Tumor SIX2+CITED1+ cells in comparison to different tumor types and human fetal kidneys confirmed the nephrogenic signature of hFK-SIX2+CITED1+ and WT-SIX2+CITED1+ cells but highlighted differences in expression of pluripotency and self renewal-related genes like OCT4, FOXO1, SALL, NANOG along with a lower expression of β-catenin, TCF, and other growth factors known to promote differentiation (BMPs, FGFs). Hierarchical clustering of gene expression showed shared similarities between Wilms tumor samples against human fetal kidney samples however, with major differences in gene expression between tumor-to-tumor type was also present. Conclusion: Our study represents the first transcriptomic characterization of Wilms Tumor cancer stem cells (SIX2+CITED1+) against human fetal kidney SIX2+CITED1+ cells. Identifying specify gene expression and signaling pathway profiles across different subtypes of Wilms Tumor and against human fetal kidney SIX2+CITED1+ cells.
Project description:Blastemal histology in chemotherapy-treated pediatric Wilms tumors (nephroblastoma) is associated with adverse prognosis. To uncover the underlying tumor biology and find novel therapeutic leads for this subgroup of patients, we analyzed 58 blastemal-type Wilms tumors by exome and transcriptome sequencing and validated our findings in a large independent replication cohort. Recurrent mutations identified either somatically or in the germline included a hotspot mutation (Q177R) in the homeodomain of SIX1 and SIX2 in tumors with high proliferative potential, mutations in microprocessor genes like DROSHA, DGCR8, DICER1 and DIS3L2, and alterations in IGF2, MYCN, and TP53, the latter being strongly associated with dismal outcome. DROSHA and DGCR8 mutations had a strong effect on miRNA expression patterns in tumors, which was functionally validated in cell lines transfected with mutant DROSHA.