Differential expression of the human homologue of Drosophila Discs large oncosuppressor in histological samples from HPV-associated lesions as a marker for progression to malignancy

CAVATORTA, ANA LAURA; FUMERO, GASTÓN; CHOUHY, DIEGO; AGUIRRE, ROXANA; NOCITO, ANA LIA; GIRI, ADRIANA A.; BANKS, LAWRENCE; GARDIOL, DANIELA

INTERNATIONAL JOURNAL OF CANCER. JOURNAL INTERNATIONAL DU CANCER.

Wiley Interscience

Año: 2004 vol. 111 p. 373 - 380

0020-7136

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 histological samples by Dlg immunohistochemistry. HPV association was ascertained by a PCR-colorimetric method. Although Dlg was certainly expressed in the intraepithelial cervical, vulvar and laryngeal HPV associated lesions, its cellular and tissue distribution pattern was altered compared with normal tissue. However, a 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 tumours 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.