Changes in expression of the human homologue of the Drosophila discs large tumour suppressor protein in high-grade premalignant cervical neoplasias.
The Drosophila tumour suppressor discs large (Dlg) is a cell-junction localized protein that is required for the maintenance of epithelial cyto-architecture and the negative control of cell proliferation. The mammalian homologue is likely to have a similar mode of action, and therefore functional perturbation of this protein may be linked to the development of epithelial-derived cancers. The finding that several unrelated viral oncoproteins, including the E6 protein of oncogenic human papillomaviruses, bind to the human homologue of Dlg (hDlg) supports this proposition. Employing immunohistochemistry, we show that in uterine cervical squamous epithelia, prominent localization of hDlg at sites of intercellular contact occurs in cells that have left the proliferating basal cell layers and begun maturation. The presence of hDlg at sites of cell:cell contact diminishes, whilst intracellular cytoplasmic levels increase significantly in high-grade, but not low-grade, cervical neoplasias. In invasive squamous cell carcinomas, total cellular hDlg levels are greatly reduced. Our data suggest that loss of hDlg at sites of intercellular contact may be an important step in the development of epithelial cancers.
Watson
Richard A
RA
Cancer Research UK Institute for Cancer Studies, The Medical School, University of Birmingham, UK.
Rollason
Terry P
TP
Reynolds
Gary M
GM
Murray
Paul G
PG
Banks
Lawrence
L
Roberts
Sally
S
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal / Q000276:immunology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D002448:Cell Adhesion; D002451:Cell Compartmentation; D002584:Cervix Uteri / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D000074288:Discs Large Homolog 1 Protein; D004847:Epithelial Cells / Q000737:chemistry; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D008565:Membrane Proteins; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000276:immunology; D002578:Uterine Cervical Dysplasia / Q000378:metabolism / Q000473:pathology / Q000737:chemistry / Q000235:genetics*; D002583:Uterine Cervical Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; C513314:DLG1 protein, human; D000074288:Discs Large Homolog 1 Protein; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D011506:Proteins