Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aberrant activation of the Wnt signaling pathway has been reported in different human tumor types, including malignant melanomas. We investigated 37 malignant melanomas (15 primary tumors and 22 metastases) for alterations of 4 genes encoding members of this pathway, i.e., CTNNB1 (beta-catenin gene, 3p22.1), APC (adenomatous polyposis coli gene, 5q22.2), BTRC (beta-transducin repeat-containing protein gene, 10q24.3) and ICAT (inhibitor of beta-catenin and Tcf-4, 1p36.2). Mutational analysis of CTNNB1 identified somatic mutations in 1 primary melanoma and 1 melanoma metastasis from 2 different patients (5%). Both mutations affected the N-terminal degradation box of beta-catenin, which is important for the regulation of beta-catenin homeostasis. Another primary melanoma carried a somatic APC missense mutation within the known mutation cluster region in exon 15. Fourteen tumors (40%) showed LOH at microsatellite markers on 1p36. None of the tumors had lost both copies of the ICAT gene, but 1 melanoma metastasis carried a somatic point mutation altering the translation start codon of ICAT. Real-time RT-PCR showed markedly reduced ICAT transcript levels (<or=20% relative to normal skin and benign melanocytic nevi) in 28/36 malignant melanomas (78%), including 13/14 tumors with LOH on 1p36. Allelic loss on 10q was detected in 15 tumors (44%). We found neither mutations nor complete loss of expression of the BTRC gene in our melanoma series. Taken together, our results indicate that the Wnt pathway may be altered in malignant melanomas by different mechanisms, including rare somatic mutations in CTNNB1, APC or ICAT, as well as low or absent expression of ICAT transcripts.
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PMID:Molecular genetic analysis of malignant melanomas for aberrations of the WNT signaling pathway genes CTNNB1, APC, ICAT and BTRC. 1212 4

Cadherins are a large family of single-pass transmembrane proteins principally involved in Ca2+-dependent homotypic cell adhesion. The cadherin molecules comprise three domains, the intracellular domain, the transmembrane domain and the extracellular domain, and form large complexes with a vast array of binding partners (including cadherin molecules of the same type in homophilic interactions and cellular protein catenins), orchestrating biologically essential extracellular and intracellular signalling processes. While current, contrasting models for classic cadherin homophilic interaction involve varying numbers of specific repeats found in the extracellular domain, the structure of the domain itself clearly remains the main determinant of cell stability and binding specificity. Through intracellular interactions, cadherin enhances its adhesive properties binding the cytoskeleton via cytoplasmic associated factors alpha- catenin, beta-catenin and p120ctn. Recent structural studies on classic cadherins and these catenin molecules have provided new insight into the essential mechanisms underlying cadherin-mediated cell interaction and catenin-mediated cellular signalling. Remarkable structural diversity has been observed in beta-catenin recognition of other cellular factors including APC, Tcf and ICAT, proteins that contribute to or compete with cadherin/catenin functioning.
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PMID:The cadherin-catenin complex as a focal point of cell adhesion and signalling: new insights from three-dimensional structures. 1511 30

The Wnt/beta-catenin pathway is involved in various cellular activities--including determination, proliferation, migration and differentiation--in embryonic development and adult homeostasis. The deregulation or constitutive activation of the Wnt/beta-catenin pathway may lead to cancer formation. This review focuses on the role of the Wnt/beta-catenin canonical signaling pathway in the melanocyte lineage, and more specifically, in melanoma. Several components of the Wnt/beta-catenin pathway, such as APC, ICAT, LEF1 and beta-catenin are modified in melanoma tumors and cell lines, leading to activation of this signaling. A hallmark of the activation of this pathway is the presence of beta-catenin in the nucleus. Indeed, beta-catenin is found in about 30% of human melanoma nuclei, indicating a potentially specific role for this signaling pathway in this aggressive type of cancer. Beta-catenin can induce ubiquitous genes such as myc or cyclinD1, cell lineage-restricted genes such as Brn2 and melanocyte-specific genes such as Mitf-M and Dct. The Mitf-M and Brn-2 genes encode transcription factors. Mitf plays a critical role in melanocyte survival, proliferation and differentiation. Brn-2 is involved in melanoma proliferation. Determining how the Wnt/beta-catenin signaling pathway, alone or with other pathways, orchestrates the induction of target genes involved in a diverse range of activities represents a major challenge in research into melanoma formation and tumor progression.
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PMID:The WNT/Beta-catenin pathway in melanoma. 1614 65

The Wnt/beta-catenin pathway plays critical roles in cell physiology, including determination, proliferation, migration and differentiation in embryonic development and adult homeostasis. Several components of the Wnt/beta-catenin pathway, such as SFRPs, WIF-1, DKK-1, APC, AXIN2, ICAT, LEF1 and beta-catenin, are the target of mutations or epigenetic inactivation leading to the deregulation or constitutive activation of the Wnt/beta-catenin pathway. Aberrant activation of the Wnt signalling pathway abrogates controlled growth and impairs cell differentiation. Alterations of the Wnt signalling pathway have been found in cancer, osteoporosis, ischemic neuronal death and other human diseases. Here we review the alterations of the Wnt/beta-catenin signalling cascade and discuss the biological significance and relationship between mutation and/or epigenetic silencing within the same pathway.
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PMID:Epigenetic alterations of the Wnt/beta-catenin pathway in human disease. 1734