Antitumor effect of adenoviruses expressing mutant non-oncogenic E7 versions from HPV-16 fused to calreticulin

Purpose: To compare the antitumor effect of adenoviruses that express mutant variants of the protein E7 from HPV-16 fused to calreticulin. Methods: Recombinant adenoviruses were generated to express calreticulin fused to mutant versions of E7 (CRT/E7m and CRT/E7dm). Western blot and immunofluorescence assays were made to demonstrate protein expression. Antitumor assays were performed in C57BL6 mice injected with TC-1 cell line. Results: When HEK293 cells were infected with these adenoviruses, we detected that all the recombinant proteins were expressed at endoplasmic reticulum, as expected. Next, the antitumor effect was tested on a murine tumor model established by inoculation of TC-1 cell line. We detected that both Ad CRT/E7m and Ad CRT/E7dm were capable of reducing the antitumor volume when compared to Ad LacZ, which was used as negative control. No significant difference was observed when compared to Ad CRT/E7, a positive control. Conclusions: Here we demonstrated that the mutant versions of E7 HPV-16 fused to calreticulin generate similar antitumor effect than the wild type version.