Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aberrant activation of the Wnt/beta-catenin signaling pathway is a hallmark of colon cancer. We show that the Wnt antagonist DICKKOPF-4 (DKK-4) gene is repressed by 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) in human colon cancer cells. This effect correlated with the inhibition of the DKK-4 promoter. Chromatin immunoprecipitation assays revealed that 1,25(OH)2D3 induces early and transient binding of the vitamin D receptor (VDR) and the SMRT corepressor to the region adjacent to the transcription start site of DKK-4. Additionally, we demonstrate that the DKK-4 gene is a new downstream target of TCF/beta-catenin. Remarkably, expression of DKK-4 messenger RNA (mRNA) was not detected in a series of 29 human normal (N) colon biopsies but expression was upregulated in all the matched tumour (T) tissues. An inverse correlation existed between the expression of DKK-4 and VDR RNA in the Ts. Ectopic DKK-4 expression increased the migration and invasion properties of colon cancer cells and conditioned media (CM) from DKK-4-expressing cells enhanced the capacity to migrate and form capillary-like tubules of human primary microvascular endothelial cells. In conclusion, DKK-4 is upregulated in colon cancer and is associated with the acquisition of malignant properties by neoplastic cells. DKK-4 downregulation is a novel effect of 1,25(OH)2D3 that may contribute to its anticancer action.
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PMID:DICKKOPF-4 is induced by TCF/beta-catenin and upregulated in human colon cancer, promotes tumour cell invasion and angiogenesis and is repressed by 1alpha,25-dihydroxyvitamin D3. 1840 52

Intrinsically disordered proteins are emerging as substantial functional constituents of mammalian proteomes. Although the abundance of these proteins has been established by bioinformatics approaches, the vast majority have not been characterized structurally or functionally. The C/EBP homologous protein (CHOP) is a proto-oncogene, traditionally shown as a dominant-negative inhibitor of C/EBPs and a transcriptional activator of activating protein-1. We report here the in vitro characterization of CHOP, where our computational analyses and experimental evidences show for the first time that CHOP is an intrinsically disordered protein. Intrinsic fluorescence, NMR spectroscopy, and analytical size-exclusion chromatography studies indicate that CHOP contains extensive disordered regions and self-associate in solution. Interestingly, the disordered N-terminal region has a key role in the oligomerization of CHOP and is vital for its biological activity. We report a novel mechanistic role of CHOP in the inhibition of Wnt/TCF signaling and stimulation of c-Jun and sucrase-isomaltase reporter activity in intestinal colon cancer cells. These findings are discussed in the context of oligomerization of intrinsically disordered proteins as one of the mechanisms through which they exert their biological function.
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PMID:Intrinsically disordered human C/EBP homologous protein regulates biological activity of colon cancer cells during calcium stress. 1853 16

Fibroblast growth factors (FGF) play important roles in development, angiogenesis, and cancer. FGF19 uniquely binds to FGF receptor 4 (FGFR4). Our previous study has shown that FGF19 transgenic tumors have an activated Wnt-pathway phenotype. Wnt signaling is implicated in initiating or promoting FGF signaling in various cell types and organs. In this study, we examined whether FGF19 or inhibition of FGF19 affects the beta-catenin signaling pathway using human colon cancer cell lines (HCT116, Colo201). Our results show that FGF19 increases tyrosine phosphorylation of beta-catenin and causes loss of beta-catenin-E-cadherin binding. FGF19 increases p-GSK3beta and active beta-catenin levels and anti-FGF19 antibody (1A6) treatment abrogates this effect of FGF19. Anti-FGF19 antibody treatment increases S33/S37/T41 phosphorylation and ubiquitination of beta-catenin. Ion-trap mass spectrometric analysis confirmed that 1A6 increases phosphorylation of beta-catenin in the NH(2) terminus. Using HCT116-paired beta-catenin knockout cells, we show that FGF19 induces TCF/LEF reporter activity in parental (WT/Delta45) and in WT/--but not in mutant (-/Delta45) cells, and that inhibition of endogenous FGF19 reduces this reporter activity, indicating that wild-type beta-catenin is accessible for modulation. FGFR4 knockdown using inducible short hairpin RNA significantly reduces the colony-forming ability in vitro and tumor growth in vivo. Although cleaved caspase-3 immunoreactivity remains unchanged, the number of ki67-positive nuclei is reduced in FGFR4 knockdown tumor xenograft tissues. Consistent with the reduced beta-catenin activation, Taqman analyses show that FGF19/FGFR4 inhibition reduced beta-catenin target gene (cyclin D1, CD44, c-jun, Cox-2, UPAR) expression. These findings highlight that FGF19/FGFR4 cross-talk with beta-catenin and that pathway intervention reduces tumor growth.
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PMID:Inhibition of fibroblast growth factor 19 reduces tumor growth by modulating beta-catenin signaling. 1859 7

Side chain fluorination is often used to make analogs of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] resistant to degradation by 24-hydroxylase. The fluorinated nonsteroidal analogs CD578, WU515, and WY1113 have an increased prodifferentiating action on SW480-ADH colon cancer cells, which correlated with stronger induction of vitamin D receptor (VDR)-coactivator interactions and stronger repression of beta-catenin/TCF activity. Cocrystallization of analog CD578 with the zebrafish (z)VDR and an SRC-1 coactivator peptide showed that the fluorine atoms of CD578 make additional contacts with Val444 and Phe448 of activation helix 12 (H12) of the zVDR and with Leu440 of the H11-H12 loop. Consequently, the SRC-1 peptide makes more contacts with the VDR-CD578 complex than with the VDR-1,25(OH)2D3 complex. These data show that fluorination not only affects degradation of an analog but can also have direct effects on H12 stabilization.
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PMID:Superagonistic fluorinated vitamin D3 analogs stabilize helix 12 of the vitamin D receptor. 1894 Jun 64

Aberrant Wnt/beta-catenin signaling has recently been implicated in tumorigenesis. On the basis of our screening program targeting inhibition of TCF/beta-catenin transcriptional activity, a plant extract of Eleutherine palmifolia was selected as a hit sample. Activity-guided fractionations led to the isolation of 15 naphthalene derivatives (1-15), including 4 new glucosides, eleutherinosides B-E (1-4), and 10 of the 15 compounds showed strong activities with high viability among 293T cells. Our data showed that 2 and 9 inhibited the transcription of TCF/beta-catenin in SW480 colon cancer cells in a dose-dependent manner. These two compounds also showed selective cytotoxicity against three colorectal cancer cell lines. In addition, treatment with 9 led to a significant decrease in the level of nuclear beta-catenin protein, suggesting this reduction to have resulted in the inhibitory effect of 9 on the transcription of TCF/beta-catenin.
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PMID:New Wnt/beta-catenin signaling inhibitors isolated from Eleutherine palmifolia. 1906 97

Although peroxisome proliferator-activated receptor gamma (PPARgamma) is strongly expressed in the intestinal epithelium, the role of PPARgamma in intestinal tumorigenesis has not yet been elucidated. To address this issue, we investigated the effect of PPARgamma inhibition and its mechanism on intestinal tumorigenesis using a selective antagonist, T0070907. We treated Apc(Min/+) mice and carcinogen-induced colon cancer model C57BL/6 mice with T0070907 and counted the number of spontaneous polyps and aberrant crypt foci and observed cell proliferation and beta-catenin protein in the colon epithelium. To investigate its mechanism, the changes of beta-catenin/TCF (T cell factor) transcriptional activity and location of beta-catenin induced by T0070907 were investigated in the colon cancer cell lines. T0070907 promoted polyp formation in the small intestine of Apc(Min/+) mice and aberrant crypt foci in the colon of C57BL/6 mice. PPARgamma inhibition promoted cell proliferation and increased expressions of the c-myc and cyclin D1 genes and the beta-catenin protein in the colon epithelium. In vitro, cell proliferation was promoted, but it was inhibited by the transfection of dominant-negative Tcf4. T0070907 increased beta-catenin/TCF transcriptional activity and beta-catenin protein in the cytsol and nucleus, but relatively decreased it on the cell membrane. PPARgamma antagonist promotes tumorigenesis in the small intestine and colon through stimulation of epithelial cell proliferation. beta-Catenin contributes to the promotion of tumorigenesis by PPARgamma antagonist due to activation of TCF/LEF (lymphoid enhancer factor) transcriptional factor.
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PMID:Inhibition of peroxisome proliferator-activated receptor gamma promotes tumorigenesis through activation of the beta-catenin / T cell factor (TCF) pathway in the mouse intestine. 1907 13

A key step in human colon cancer development includes the hyperactivation of Wnt/beta-catenin signaling and the induction of beta-catenin-TCF target genes that participate in colon cancer progression. Recent studies identified members of the immunoglobulin-like cell adhesion molecules (IgCAM) of the L1CAM family (L1 and Nr-CAM) as targets of beta-catenin-TCF signaling in colon cancer cells. L1 was detected at the invasive front of colon cancer tissue and confers metastasis when overexpressed in cells. In contrast to L1, we did not detect in colon cancer cells significant levels of another IgCAM family of molecules, the nectin-like (Necl) receptors Necl1 and Necl4, while Necl4 was previously found in the normal small intestine and colon tissues. We studied the properties of colon cancer cells in which Necl4 and Necl1 were expressed either alone, or in combination, and found that such cells display a wide range of properties associated with tumor suppression. Expression of both Necl1 and Necl4 was the most efficient in suppressing the tumorigenicity of colon cancer cells. This was associated with enhanced rates of apoptosis and change in several apoptosis-related markers. In contrast to its capacity to suppress tumorigenesis, Necl4 was unable to affect the highly malignant and metastatic capacities of colon cancer cells in which L1 was overexpressed. Our results suggest that various IgCAM receptor families play different roles in affecting the tumorigenic function of the same cells, and that Necl1 and Necl4 can fulfill a tumor suppressive role.
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PMID:The cell adhesion nectin-like molecules (Necl) 1 and 4 suppress the growth and tumorigenic ability of colon cancer cells. 1956 70

Constitutive activation of the Wnt/beta-catenin pathway has been implicated as the primary cause of colon cancer. However, the major transducers of Wnt signaling in the intestine, T-cell factor 1 (TCF-1) and TCF-4, have opposing functions. Knockout of TCF-4 suppresses growth and maintenance of crypt stem cells, whereas knockout of TCF-1 leads to adenomas. These phenotypes suggest that TCF-4 is Wnt-promoting, whereas TCF-1 acts like a tumor suppressor. Our study of TCF expression in human colon crypts reveals a mechanistic basis for this paradox. In normal colon cells, a dominant-negative isoform of TCF-1 (dnTCF-1) is expressed that is equally distributed between nuclear and cytoplasmic compartments. In colon cancer cells, TCF-1 is predominantly cytoplasmic. Localization is because of active nuclear export and is directed by an autocrine-acting Wnt ligand that requires Ca2+/calmodulin-dependent kinase II (CaMKII) activity for secretion and a downstream step in the export pathway. TCF-4 remains nuclear; its unopposed activity is accompanied by downregulation of dnTCF-1 and increased expression of full-length isoforms. Thus, the dnTCF-1 and TCF-4 balance is corrupted in cancer by two mechanisms, a Wnt/CaMKII kinase signal for nuclear export and decreased dnTCF-1 expression. We propose that dnTCF-1 provides homeostatic regulation of Wnt signaling and growth in normal colon, and the alterations in nuclear export and promoter usage contribute to aberrant Wnt activity in colon cancer.
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PMID:A Wnt kinase network alters nuclear localization of TCF-1 in colon cancer. 1974 92

Non-steroidal analogs of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] represent a most particular class of analogs because they are either not directly derived from the core 1,25(OH)2D3-structure or they have modifications in the core structure that are so drastic that the steroidal structure is lost. Non-steroidal CD-ring analogs of 1,25(OH)2D3 have been developed to study the role of the central rigid CD-ring system in the biological activity of 1,25(OH)2D3. Here we review the different classes of CD-ring analogs and highlight some representative analogs such as the fluorinated D-ring analogs CD578, WU515 and WY1113 which show markedly increased differentiating activity on human SW480-ADH colon cancer cells, characterized by a stronger induction of the invasion suppressor E-cadherin and a stronger repression of the beta-catenin/TCF target oncogene c-Myc. Correspondingly, CD578, WU515 and WY1113 are more potent inhibitors of beta-catenin/TCF signaling than 1,25(OH)2D3 and induce stronger VDR-coactivator interactions. Underlying the increased biological potency of analog CD578 are additional contacts between the side chain fluorine atoms of the analog with specific residues of helix 12 (H12) of the Vitamin D Receptor (VDR) and subsequent stronger VDR-coactivator interactions.
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PMID:CD-ring modified vitamin D3 analogs and their superagonistic action. 2013 86

Fibroblast growth factor 18 (FGF18) is one of the genes downstream of Wnt, one of the most important signaling pathways activated in colon cancer. An FGF18 promoter containing a single T-cell factor/lymphocyte enhancing factor 1 (TCF/LEF1) binding site was inserted upstream of a thymidine kinase (TK) suicide gene module, while a bacterial beta-Gal (LacZ) element served as the reporter gene. Following transient transfection with pUCFGF18LacZ, beta-Gal staining showed that 5% of SW480, 10% of HCT116, 0% of human umbilical vein endothelial cells (HUVECs) and 0% of normal colon cells (NCCs) had expressed LacZ. beta-Gal enzyme-linked immunosorbent assay revealed that the ratio of pUCFGF18LacZ activity to that of positive control was 0.09 and 0.25 in SW480 and HCT116, respectively (significantly higher than mock plasmid), while there were no significant changes in the beta-Gal expression in HUVEC and NCC cells transfected with pUCFGF18LacZ or mock plasmid. Following transfection with pUCFGF18TK and pUCCMVTK (positive control), cytotoxicity analysis of transfected cells showed that treatment with ganciclovir (GCV) significantly decreased SW480 and HCT116 cell survival at GCV concentrations above 20 microg/mL. An inverse correlation between GCV concentration and cell viability was evident in both colon cancer cell lines following transfection with these suicide plasmids. pUCFGF18TK and pUCCMVTK induced apoptosis after the administration of GCV in HCT116, but not in SW480, as demonstrated by M30 cytodeath antibody. This discrepancy may stem from differences in the mechanisms of TK/GCV-induced apoptosis in p53-proficient (HCT116) and -deficient (SW480) cells. The specific activity of the FGF18 promoter in HCT116 and SW480 may reflect the advantage of this promoter over artificial promoters containing artificial TCF/LEF binding sites.
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PMID:Selective suicide gene therapy of colon cancer cell lines exploiting fibroblast growth factor 18 promoter. 2018 3


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