Project description:We find that, in contrast to most cancer types, beta-catenin activation in preB-ALL cells supresses proliferation and leads to cell death. Proteomic analyses indicate that unlike in solid tumors beta-catenin interacts with Ikaros factors (IKZF1 and IKZF3) in pre-B cells. We performed RNA-seq in order to examine changes in expression upon beta-catenin activation in the presence and absence of Ikaros factors.
Project description:Constitutive activation of the anti-apoptotic NF-κB signaling pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphomas (DLBCL) that is characterized by adverse survival. Recurrent oncogenic mutations are found in the scaffold protein CARMA1 (CARD11) that connects B-cell receptor (BCR) signaling to the canonical NF-κB pathway. We asked how far additional downstream processes are activated and contribute to the oncogenic potential of DLBCL-derived CARMA1 mutants. To this end, we expressed oncogenic CARMA1 mutants in the NF-κB negative DLBCL lymphoma cell line BJAB. By a proteomic approach we identified recruitment of β-Catenin and its destruction complex consisting of APC, AXIN1, CK1α and GSK3β to oncogenic CARMA1. Recruitment of the β-Catenin destruction complex was independent of CARMA1-BCL10-MALT1 (CBM) complex formation or constitutive NF-κB activation and promoted the stabilization of β-Catenin. Elevated β-Catenin expression was detected in cell lines and biopsies from ABC DLBCL that rely on chronic BCR signaling. Increased β-Catenin amounts alone were not sufficient to induce classical WNT target gene signatures, but could augment TCF/LEF dependent transcriptional activation in response to WNT signaling. In conjunction with NF-κB, β-Catenin enhanced expression of immune suppressive IL-10 and repressed anti-tumoral CCL3, indicating that β-Catenin may induce a favorable tumor microenvironment. Thus, parallel activation of NF-κB and β-Catenin signaling by gain-of-function mutations in CARMA1 can augment WNT stimulation and is required for maintaining high expression of distinct NF-κB target genes and can thereby trigger cell intrinsic and extrinsic processes that promote DLBCL lymphomagenesis.
Project description:We find that, in contrast to most cancer types, beta-catenin activation in preB-ALL cells supresses proliferation and leads to cell death. Proteomic analyses indicate that unlike in solid tumors beta-catenin interacts with Ikaros factors (IKZF1 and IKZF3) in pre-B cells. In order to examine the interaction between IKZF1/IKZF3 and beta-catenin we performed ChIPseq to assay chromatin state and TF binding in CTNNB1-GOF and IKZF1/3-LOF conditions.
Project description:β-catenin signaling can be both a physiological and an oncogenic pathway in the liver. It controls compartmentalized gene expression, allowing the liver to ensure its essential metabolic function. It is activated by mutations in 20 to 40% of hepatocellular carcinomas with specific metabolic features. We decipher the molecular determinants of β-catenin-dependent zonal transcription using mice with β-catenin-activated or -inactivated hepatocytes, characterizing in vivo their chromatin occupancy by Tcf4 and β-catenin, their transcriptome and their metabolome. We find that Tcf4 DNA-bindings depend on β-catenin. Tcf4/β-catenin binds Wnt-responsive elements preferentially around β-catenin-induced genes. In contrast, genes repressed by β-catenin bind Tcf4 on Hnf4-responsive elements. β-catenin, Tcf4 and Hnf4α interact, dictating β-catenin transcription which is antagonistic to that elicited by Hnf4α. Finally, we find the drug/bile metabolism pathway to be the one most heavily targeted by β-catenin, partly through xenobiotic nuclear receptors. We conclude that β-catenin patterns the zonal liver together with Tcf4, Hnf4α and xenobiotic nuclear receptors. This network represses lipid metabolism, and exacerbates glutamine, drug and bile metabolism, mirroring hepatocellular carcinomas with β-catenin mutational activation. In vivo liver samples in 4 conditions: Betacat activated (WCE, Tcf4 chipseq, Betacat chipseq, mRNAseq with 2 replicates), Betacat null (WCE, Tcf4 chipseq, mRNAseq with 2 replicates), Betacat control (mRNAseq with 2 replicates), Wild type (mRNAseq with 2 replicates)
Project description:Although mutations in Kras are present in 21% of lung tumors, there is a high level of heterogeneity in phenotype and outcomes amongst lung cancer patients suggesting the importance of other pathways. Wnt/β-catenin signaling is a known oncogenic pathway that plays a well defined role in colon and skin cancer but its role in lung cancer remains unclear. We show that activation of Wnt/β-catenin in the bronchiolar epithelium of the adult lung does not promote tumor development by itself. However, activation of Wnt/β- catenin signaling leads to a dramatic increase in tumor formation both in overall tumor number and size compared to KrasG12D alone. We show that activation of Wnt/β- catenin signaling significantly alters the KrasG12D tumor phenotype resulting in a phenotypic switch from bronchiolar epithelium to the highly proliferative distal progenitors found in the embryonic lung. This is associated with a decrease in E- cadherin expression at the cell surface which may increase metastasis in Wnt/β-catenin signaling positive tumors. Together, these data suggest that activation of Wnt/β-catenin signaling in combination with other oncogenic pathways in lung epithelium may lead to a more aggressive phenotype due to the imposition of an embryonic distal progenitor phenotype accompanied by decreased E-cadherin expression. We performed microarray analysis of control murine lung, CC10-cre:KrasG12D, and CC10-cre:Ctnnb1ex3flox:LSL-KrasG12D double mutant micro-dissected murine lung tumors to determine their transcriptional phenotype. Lungs of five-month-old mice were PBS inflated and all the tumors in each lobe were dissected. The total number of tumors obtained from three out of the 5 pulmonar lobes of each animal was called a sample the other two lobes were saved in case there were problems and the array needed to be repeated. Trizol was used to isolate RNA for microarray analysis. Samples & Genotypes: control murine lung n=2 animals, CC10-cre:KrasG12D n=2 animals, and CC10-cre:Ctnnb1ex3flox:LSL-KrasG12D n=2 animals.
Project description:e used interaction and expression proteomic techniques in conjunction with RNA-Seq transcriptomic analysis to analyse how a β-catenin stabilizing mutation alters molecular networks in colorectal cancer cells. Integrated computational analyses of allowed us to identify significantly altered sub-networks linked to β-catenin oncogenesis.
Project description:We used interaction and expression proteomic techniques in conjunction with RNA-Seq transcriptomic analysis to analyse how a β-catenin stabilizing mutation alters molecular networks in colorectal cancer cells. Integrated computational analyses of allowed us to identify significantly altered sub-networks linked to β-catenin oncogenesis.
Project description:Aberrant activation of the Wnt/β-catenin signaling pathway is a hallmark of colorectal cancer (CRC). Here, we identify the deubiquitinating enzyme USP17 as a critical regulator of β-catenin stability in CRC. We demonstrate that USP17 directly interacts with and deubiquitinates β-catenin, preventing its degradation and enhancing its stability. CRISPR/Cas9-mediated knockout of USP17 in CRC-derived cell lines significantly reduced β-catenin levels and suppressed epithelial-mesenchymal transition (EMT), as evidenced by distinct morphological changes and altered expression of classical EMT markers. USP17 depletion reduced the proliferation of CRC cell lines and impaired CRC tumor growth in vivo. Conversely, USP17 overexpression in immortalized rat enterocytes elevated β-catenin levels and enhanced KRAS-induced cell proliferation. RNA sequencing and quantitative proteomic analysis of USP17-depleted CRC cells revealed significant suppression of the transcriptional coactivator function of β-catenin, impacting key oncogenic-related pathways. Our findings establish USP17 as a key regulator of β-catenin signaling and highlight its potential as a candidate therapeutic target in CRC.