Comparing gene expression in human colon tumor vs paired normal colon mucosa
Ontology highlight
ABSTRACT: 24 colon normal and tumor pairs using Illumina BeadChip Human Ref8-v2. Genetic and epigenetic defects in Wnt/ß-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/ß-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. The clinical information for the colon tumor is not available. Keywords: human colon tumor
Project description:Genetic and epigenetic defects in Wnt/ß-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/ß-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. Keywords: Colon cancer cell line
Project description:Genetic and epigenetic defects in Wnt/?-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/ß-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly de-repressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/?-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/ß-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/ß-catenin signaling in colorectal cancer. This SuperSeries is composed of the SubSeries listed below.
Project description:In colorectal cancer, p53 is commonly inactivated, associated with chemo-resistance, and marks the transition from non-invasive to invasive disease. Cancers, including colorectal cancer, are thought to be diseases of aberrant stem cell populations, as stem cells are able to self-renew, making them long-lived enough to acquire mutations necessary to manifest the disease. We have shown that extracts from sweet sorghum stalk components eliminate colon cancer stem cells (CCSC) in a partial p53-dependent fashion. However, the underlying mechanisms are unknown. In the present study, CCSC were transfected with short hairpin-RNA against p53 (CCSC p53 shRNA) and treated with sweet sorghum phenolics extracted from different plant components (dermal layer, leaf, seed head and whole plant). While all components demonstrated anti-proliferative and pro-apoptotic effects in CCSC, phenolics extracted from the dermal layer and seed head were more potent in eliminating CCSC by elevating caspases 3/7 activity, PARP cleavage, and DNA fragmentation in a p53-dependent and p53-independent fashion, respectively. Further investigations revealed that the anti-proliferative and pro-apoptotic effects were associated with decreases in beta-catenin protein levels, and beta-catenin targets cyclin D1, cMyc, and survivin. These results suggest that the anti-proliferative and pro-apoptotic effects of sweet sorghum extracts against human colon cancer stem cells are via suppression of Wnt/beta-catenin pro-survival signaling in a p53-dependent (dermal layer) and partial p53-independent (seed head) fashion. LCMS used to identify phenolic compounds associated with extract activity
Project description:Wnt signalling maintains the undifferentiated state of intestinal crypt/progenitor cells through the TCF4/ß-catenin activating transcriptional complex. In colorectal cancer, activating mutations in Wnt pathway components lead to inappropriate activation of the TCF4/ß-catenin transcriptional program and tumourigenesis in the gut epithelium. The mechanisms by which TCF4/ß-catenin activate key target genes are not well understood. Using a proteomics approach, we identified Tnik, a member of the Germinal centre kinase family, as a Tcf4 interactor in the proliferative crypts of mouse small intestine. Tnik is recruited to promoters of Wnt target genes in mouse crypts and in Ls174T colorectal cancer cells in a ß-catenin dependent manner. Depletion of TNIK and expression of TNIK kinase mutants abrogated TCF-LEF transcription, highlighting the essential role of the kinase activity in Wnt target gene activation. siRNA depletion of TNIK followed by expression array analysis demonstrated that TNIK is an essential and exclusive activator of Wnt induced transcriptional program. As an essential component in the TCF4/ß-catenin activator complex, the kinase TNIK may present an attractive candidate for drug targeting in colorectal cancer.
Project description:Mitogen-activated protein kinases (MEK 1/2) are central components of the RAS signaling pathway and attractive targets for cancer therapy. However, PIK3CA mutation, which commonly co-occurs with KRAS mutation, offered resistance to MEK inhibitor through activation of PI3K-AKT signaling. We identified a gene that cooperates with MEK inhibitors to forcefully treat PIK3CA mutant colon cancer cells. -catenin, a key molecule of the WNT pathway, emerged as a candidate by protein/Ab Chip array. MEK inhibitor treatment led to a decrease in -catenin in PIK3CA wild-type colon cancer cells but not in PIK3CA mutant colon cancer cells. Tumor regression was promoted by a combination of MEK inhibitor and NVP-TNS656, which targets the WNT pathway. Furthermore, combined inhibition of MEK and -catenin by NVP-TNS656 promoted tumor regression in colon cancer patient-derived xenograft (PDX) models expressing mutant PIK3CA. Taken together, we propose that inhibition of the WNT pathway, particularly -catenin, may bypass resistance to MEK inhibitor in human PIK3CA mutant colon cancer. Additionally, -catenin is a potential PD marker of MEK inhibitor resistance. In the study, we identified and evaluated biomarker for response to MEK inhibitor on colon cancer cells.
Project description:The recent classification of colon cancer into molecular subtypes revealed that patients with the poorest prognosis harbor tumors with the lowest levels of Wnt signaling. This is contrary to the long-standing understanding that overactive Wnt signaling promotes tumor progression from early initiation stages through to the later stages including invasion and metastasis. Here, we lower the levels of Wnt signaling in SW480 and SW620 colon cancer cell lines via interference with two different steps in Wnt signaling that lie upstream or downstream of the effector protein ß-catenin. We find that these Wnt-reduced lines exhibit a more aggressive disease phenotype, including increased mobility in vitro and localized invasion in an orthotopic mouse model. RNA sequencing reveals that interference with Wnt signaling leads to an upregulation of gene programs that favor cell migration and invasion. We identify a set of upregulated genes common among the Wnt perturbations, and find that elevated expression of these genes is strongly predictive of poor patient outcomes in early-invasive colon cancer. These genes may have clinical applications as either patient biomarkers or new drug targets to be used in concert with existing therapies.
Project description:Strong activation of the oncogenic Wnt/beta-catenin pathway is a main mechanism of resistance to FOXO3a-induced apoptosis promoted by PI3K and AKT inhibitors in colorectal cancer (CRC). Reducing Wnt/beta-catenin activity would sensitize colorectal tumors to these inhibitors. However, no Wnt/beta-catenin signaling inhibitor has proven clinical potential yet. Recently, inhibitors that block tankyrases were shown to reduce colon cancer cell proliferation by decreasing nuclear beta-catenin. We aim to identify determinants of response to these novel Wnt-inhibitors. Therefore, we treated in vivo three different patient-derived xenograft models (PDX; P2, P5 and P30) growing subcutaneously in NOD SCID mice with the novel tankyrase inhibitor NVP-TNKS656.
Project description:Mitogen-activated protein kinases (MEK 1/2) are central components of the RAS signaling pathway and attractive targets for cancer therapy. However, PIK3CA mutation, which commonly co-occurs with KRAS mutation, offered resistance to MEK inhibitor through activation of PI3K-AKT signaling. We identified a gene that cooperates with MEK inhibitors to forcefully treat PIK3CA mutant colon cancer cells. -catenin, a key molecule of the WNT pathway, emerged as a candidate by protein/Ab Chip array. MEK inhibitor treatment led to a decrease in -catenin in PIK3CA wild-type colon cancer cells but not in PIK3CA mutant colon cancer cells. Tumor regression was promoted by a combination of MEK inhibitor and NVP-TNS656, which targets the WNT pathway. Furthermore, combined inhibition of MEK and -catenin by NVP-TNS656 promoted tumor regression in colon cancer patient-derived xenograft (PDX) models expressing mutant PIK3CA. Taken together, we propose that inhibition of the WNT pathway, particularly -catenin, may bypass resistance to MEK inhibitor in human PIK3CA mutant colon cancer. Additionally, -catenin is a potential PD marker of MEK inhibitor resistance.
Project description:The Wnt/β-catenin signaling pathway plays crucial roles in nearly all parts of embryonic development and adult stem cell homeostasis. Its aberrant activation has been linked to many diseases such as developmental irregularities and various severe forms of cancer, with colorectal cancer (CRC) as a prime example. While much work has been dedicated to uncovering effective therapeutics to block oncogenic Wnt signaling, such interventions have not proven trivial because of the broad activity of Wnt throughout the adult body and the difficulty in finding suitable molecular targets. We have previously identified the developmental transcription factor TBX3 as a participant of the Wnt-mediated transcriptional regulation. Here, we performed Cap-Analysis Gene Expression sequencing (CAGE-seq) to assess the genome-wide transcriptional consequences upon TBX3 overexpression in the human colorectal cancer cell line HCT116.