Cell polarity disruption during carcinogenic processes: analysis of cellular and viral contributions

MARINA BUGNON VALDANO; A.L. CAVATORTA; F. MARZIALI; F. FACCIUTO; E. BOCCARDO; D. GARDIOL.

Rosario

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB).; 2014

SAIB

We are interested in the expression of polarity proteins during malignant progressions, and particularly, those associated to Human papillomavirus (HPV) infections. We are focused on the DLG1 and PAR3 PDZ polarity proteins, which expression is altered in tumors. By luciferase assays, we found that DLG1 promoter activity is increased in the presence of the HPV E6 and/or E7 proteins. In raft organotypic cultures, expressing HPV E6 and E7, DLG1 and PAR3 were found to be up-regulated and misdistributed, as ascertained by Western Blot and Immunohistochemistry (IHC). These data suggest that the viral proteins could contribute to the changes in the cell proteins expression observed in biopsies. Also, to study if epigenetic regulation mechanisms could contribute to DLG1 regulation in malignant processes in general, we analyzed the methylation pattern of DLG1 promoter in cultured cell lines, by treatment of DNA with sodium bisulfite and subsequent PCR amplification and sequencing. We designed primers suitable for amplification of bisulfite treated DNA and we found a demethylated state of the promoter in transformed cells. Also, we evaluated the methylation status using biopsies, and we found a difference between normal and tumoral colon samples, which could be related with the DLG1 expression, as we tested by IHC. Though, this mechanism could also be involved in regulating DLG1 abundance.