A possible role for the WNT-1 pathway in oral carcinogenesis.
Reductions in cell-cell adhesion and stromal and vascular invasion are essential steps in the progression from localized malignancy to metastatic disease for all cancers. Proteins involved in intercellular adhesion, such as E-cadherin and catenin, probably play an important role in metastatic processes and cellular differentiation. While E-cadherin and beta-catenin expression has been extensively studied in many forms of human cancers, less is known about the role of the Wingless-Type-1 (WNT-1) pathway in human tumors. A large body of genetic and biochemical evidence has identified beta-catenin as a key downstream component of the WNT signaling pathway, and recent studies of colorectal tumors have shown a functional link among beta-catenin, adenomatous polyposis coli gene product (APC), and other components of the WNT-1 pathway. WNT-1 pathway signaling is thought to be mediated via interactions between beta-catenin and members of the LEF-1/TCF family of transcription factors. The WNT signal stabilizes beta-catenin protein and promotes its accumulation in the cytoplasm and nucleus. In the nucleus, beta-catenin associates with TCF to form a functional transcription factor which mediates the transactivation of target genes involved in the promotion of tumor progression, invasion, and metastasis, such as C-Myc, cyclin D1, c-jun, fra-1, and u-PAR. There is a strong correlation between the ability of the WNT-1 gene to induce beta-catenin accumulation and its transforming potential in vivo, suggesting that the WNT-1 gene activates an intracellular signaling pathway that can induce the morphological transformation of cells. For these reasons, data obtained from the study of the WNT-1 pathway could be important in our understanding of the mechanisms of epithelial tumors, in general, and probably also of oral squamous cell carcinoma, in particular.
Lo Muzio
L
L
Institute of Dental Sciences, University of Ancona, Italy. llomuzio@tin.it
D000818:Animals; D015820:Cadherins / Q000502:physiology; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D002448:Cell Adhesion / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1; D009062:Mouth Neoplasms / Q000235:genetics*; D009363:Neoplasm Proteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D011519:Proto-Oncogenes / Q000502:physiology; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000502:physiology; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D051176:beta Catenin
C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; C497573:LEF1 protein, human; D051821:Lymphoid Enhancer-Binding Factor 1; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C495247:WNT1 protein, human; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; D051176:beta Catenin