| dc.description.abstract | The HPV16 genome encodes two oncoproteins, E6 and E7, which are essential for viral
carcinogenesis. While E7 promotes cell proliferation, E6 abolishes the resulting p53-dependent
apoptotic response. We hypothesized that antibodies targeting the E6 protein will allow for p53
restoration and induce apoptosis of the infected cells. Our lab has previously generated a pool of
20 Camelidae-derived single-domain antibodies (VHHs) against the E6 protein (Togtema et al.
2019). VHHs have several properties making them well-suited for therapeutic purposes including
low immunogenicity, high stability, and capacity to bind epitopes not accessible to any other type
of antibody. In the current project, we used dot blots to evaluate the VHHs binding potential to
various recombinant E6 proteins, identifying several successful VHH candidates. Co-
immunoprecipitation using Affigel resin was used to confirm the VHH’s endogenous E6 binding
capacity in CaSki cells. Therein, two clones, C26 and A37, were identified as efficient E6 binders,
in triplicate. Interestingly, in denaturing Western Blot analyses, C26 was found to react with the
maltose-binding protein (MBP)-containing proteins but not with E6 6C/6S lacking an MBP tag,
supporting the hypothesis that C26 binds MBP or E6 through different parts of the antibody. To
deliver the VHHs to target cells, cationic lipid-based protein transfection proved inadequate,
however mRNA transfection resulted in improved transfection efficiency. Functional assays,
including proliferation assays to assess cell proliferation, and immunodetection of p53 and PARP-
1 cleavage following mRNA transfection, were used to evaluate the VHH’s therapeutic potential.
Our results indicate that further optimization of our molecules will be needed to yield VHHs with
therapeutic potential, however, our methodology may serve as a template for other researchers,
creating a pipeline of analysis for the evaluation of antibodies against the E6 protein. | en_US |
