Project description:Mutations of β-catenin gene (CTNNB1) are frequent in adrenocortical adenomas (AA) and carcinomas (ACC). However, the target genes of CTNNB1 have not yet been identified in adrenocortical tumors. Our objective was to identify genes de-regulated in adrenocortical tumors harbouring CTNNB1 genetic alterations.
Project description:Mutations of β-catenin gene (CTNNB1) are frequent in adrenocortical adenomas (AA) and carcinomas (ACC). However, the target genes of CTNNB1 have not yet been identified in adrenocortical tumors. Our objective was to identify genes de-regulated in adrenocortical tumors harbouring CTNNB1 genetic alterations. We compared gene expression profiles of AA with (n: 3) and without (n: 4) CTNNB1 mutations using Affymetrix arrays.
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.
Project description:We used the H295R cell line, human adrenocortical cells, harboring a heterozygous CTNNB1 (beta-catenin) gene mutation affecting the GSK3 beta-phosphorylation site (S45P) and leading to constitutive transcriptional activity of beta-catenin-LEF/TCF. Whole-transcript gene expression was analyzed in three stable clones of H295R cells expressing a doxycycline-inducible shRNA targeting CTNNB1 mRNA and in a control clone, without or with doxycycline for 5 days.
Project description:Medulloblastoma is the most frequent malignant pediatric brain tumor. Considerable efforts are dedicated to identify markers that help to refine treatment strategies. The activation of the Wnt/beta-catenin pathway occurs in 10-15% of medulloblastomas and has been recently described as a marker for favorable patient outcome. We report a series of 72 pediatric medulloblastomas evaluated for beta-catenin immunostaining, CTNNB1 mutations, and studied by comparative genomic hybridization. Gene expression profiles were also available in a subset of 40 cases. Immunostaining of beta-catenin showed extensive nuclear staining (>50% of the tumor cells) in 6 cases and focal nuclear staining (<10% of cells) in 3 cases. The other cases exhibited either a signal strictly limited to the cytoplasm (58 cases) or were negative (5 cases). CTNNB1 mutations were detected in all beta-catenin extensively nucleopositive cases. The expression profiles of these cases documented a strong activation of the Wnt/beta-catenin pathway. Remarkably, 5 out of these 6 tumors showed a complete loss of chromosome 6. In contrast, cases with focal nuclear beta-catenin staining, as well as tumors with negative or cytoplasmic staining, never demonstrated CTNNB1 mutation, Wnt/beta-catenin pathway activation or chromosome 6 loss. Patients with extensive nuclear staining were significantly older at diagnosis and were in continuous complete remission after a mean follow-up of 75.7 months (range 27.5-121.2) from diagnosis. All three patients with a focal nuclear staining of beta-catenin died within 36 months from diagnosis. Altogether, these data confirm and extend previous observations that CTNNB1-mutated tumors represent a distinct molecular subgroup of medulloblastomas with favorable outcome, indicating that therapy de-escalation should be considered. Yet, international consensus on the definition criteria of this distinct medulloblastoma subgroup should be achieved. A series of 72 pediatric medulloblastoma tumors has been studied at the genomic level (array-CGH), screened for CTNNB1 mutations and beta-catenin expression (immunohistochemistry). A subset of 40 tumor samples has been analyzed at the RNA expression level (Affymetrix HG U133 Plus 2.0). Correlations between the genomic data, the expression data, the mutational screening, the pathological classification and clinical data is presented in the study. note: aCGH data not submitted to GEO
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. Keywords: single channel
Project description:Background & Aims: Patients with beta-catenin (encoded by CTNNB1)-mutated hepatocellular carcinoma (HCC) have demonstrated limited clinical benefit to first-line immunotherapy (IO). Animal models of HCC expressing mutant-beta-catenin and additional aberrations via hydrodynamic tail vein injection with sleeping beauty transposon/transposase (SB-HDTVI) represent clinically relevant human HCC subsets. Here, we perform transcriptomic analysis on multiple beta-catenin-mutated and non-mutated HCC animal models to identify Mutated beta-catenin Gene Signature (MBGS) for HCC patient stratification for CTNNB1-mutations and IO response. Methods: We co-expressed in mice mutant-NFE2L2 and hMET +- mutant-CTNNB1 via SB-HDTVI and monitored for HCC development. Bulk RNA-sequencing was assessed for transcriptional differences between various beta-catenin-mutated and non-mutated models. MBGS was generated for predictive ability of CTNNB1 mutations and IO resistance in multiple HCC patient cohorts. Results: Co-expression of S45Y-beta-catenin + G31A-NFE2L2 + hMet (beta-N-M) resulted in HCC development by 4.5 weeks while co-expression of G31A-NFE2L2 + hMet (N-M) led to HCC by 14 weeks with tumors being positive for expected targets by immunohistochemistry (IHC). Bulk RNA-sequencing comparing beta-catenin-driven versus non-beta-catenin driven models yielded 95 common upregulated genes. Differential gene expression analysis of the common genes comparing CTNNB1-mutated vs non-mutated TCGA patients narrowed the gene panel to 13-(or 10-) genes. This MBGS predicted CTNNB1-mutation status in TCGA (n=374) and French (n=398) patient cohorts (with ROC AUC of 0.90 and 0.94). High MBGS expression was also associated with no overall and progression-free survival benefit when comparing atezolizumab + bevacizumab versus sorafenib arms in IMbrave150 cohort implying fewer treatment effects. Conclusions: In an era of patient molecular stratification for HCC, MBGS may aid in optimally selecting patients for IO through diagnosis of a molecular subset which lacks optimal response.
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: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: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.