Differential expression of the human homologue of drosophila discs large oncosuppressor in histologic samples from human papillomavirus-associated lesions as a marker for progression to malignancy.
High-risk HPVs play a causal role in the development of cervical cancer, and their E6 oncoproteins target h-Dlg for ubiquitin-mediated proteolysis. The h-Dlg oncosuppressor is associated with cell-cell interactions, and deregulation of these structures leads to defective cell adhesion, loss of cell polarity and unregulated proliferation. We evaluated the contribution of this E6 activity in the progression to malignancy in HPV infections by analyzing h-Dlg expression in HPV-associated lesions. We analyzed h-Dlg in cervical, laryngeal, vulvar, colon and kidney histologic samples by Dlg immunohistochemistry. HPV association was ascertained by a PCR-colorimetric method. Although Dlg was certainly expressed in intraepithelial cervical, vulvar and laryngeal HPV-associated lesions, its cellular and tissue distribution patterns were altered compared to normal tissue. However, marked reduction in Dlg levels was observed in HPV-positive invasive cervical carcinomas. To elucidate whether the loss of Dlg was significant for carcinogenesis in general, we investigated Dlg expression in tumors not associated with HPV. In colon and kidney carcinomas, Dlg was expressed, albeit with a different pattern of distribution with respect to the normal tissue. The loss of Dlg may be considered a late-stage marker in cervical carcinogenesis, but alterations in its expression and localization take place during the different dysplastic stages. Dlg downregulation and/or alterations in its localization may contribute to transformation and may explain some of the characteristics of the malignant cells, such as loss of polarity and high migration ability.
Cavatorta
Ana Laura
AL
Departamento de Microbiología, Facultad de Ciencias Bioquímicas, Instituto de Biología Molecular y Celular de Rosario, Rosario, Argentina.
Fumero
Gastón
G
Chouhy
Diego
D
Aguirre
Roxana
R
Nocito
Ana Lía
AL
Giri
Adriana A
AA
Banks
Lawrence
L
Gardiol
Daniela
D
D048868:Adaptor Proteins, Signal Transducing; D002584:Cervix Uteri / Q000473:pathology / Q000821:virology; D000074288:Discs Large Homolog 1 Protein; D018450:Disease Progression; D004847:Epithelial Cells / Q000473:pathology / Q000821:virology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins; D009361:Neoplasm Invasiveness; D027383:Papillomaviridae / Q000145:classification / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000235:genetics / Q000473:pathology* / Q000821:virology; D011506:Proteins / Q000235:genetics*; D014412:Tumor Virus Infections / Q000235:genetics / Q000473:pathology* / Q000821:virology; D002583:Uterine Cervical Neoplasms / Q000473:pathology* / Q000821:virology
D048868:Adaptor Proteins, Signal Transducing; C513314:DLG1 protein, human; D000074288:Discs Large Homolog 1 Protein; D008565:Membrane Proteins; D011506:Proteins