An atempt of gene therapy for oral squamous cell carcinoma

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ElAF and Bax activation was investigated since ElAF was shown to activate promoter activity of p21waf1/cip1, a cell cycle inhibitory molecule.CAT (Chloramphenicol acetyl transferase) assay was carried out to determine the promoter activity of bax by transfectipn with bax reporter plasmid, ElAF, wild type (wt) or mutant (mt) p53 expression plasmids into a p53 diffident cell line. CAT activity increased with ElAF in a dose-dependent manner and synergistical increase of the promoter activity was observed with wt p53 and ElAF. Protein expression of Bax was confirmed in ElAF transfected cells by Western blotting. Growth suppression assay was performed and decreased colony formation was observed in ElAF transfected p53 diffident cells. These results suggest that ElAF associates with p53 to induce apoptosis through activating bax.E4orf6 is a newly identified viral oncoprotein of the adenovirus. E4orf6 markedly enhances the ability of transformed rat BRK and human 293 cells to form tumors in nude mice. The E4orf6 protein has been shown to interact with p53 and p73 gene products and to block the induction of apoptosis which is mediated by these antioncogenes. We investigated whether or not E4orf6 can influence molecules that induce apoptosis other than the p53 family, because p53-independent apoptosis pathways have also been proposed. We demonstrate that the adenovirus E4orf6 protein suppresses the apoptotic activity of BNIP3, a member of a group of an apoptosis initiators of the Bcl-2 family. Expression of E4orf6 inhibits BNIP3-mediated apoptosis and its mitochondrial translocation. E4orl6 interacts with BNIP3. In addition, the nuclear export signal of E4orf6 is important for these functions of E4orf6. Our data suggest that the pro-apoptotic protein of the Bcl-2 family is a target of the E4orf6 protein in transformed cells.