Adenovirus mediated gene therapy in cell lines derived from canine oral melanoma

The study of cancer in dogs can provide valuable insights into the basic biology and the development of novel cancer treatments as veterinary cases develop spontaneously, exhibit heterogeneity and closely match the biology of human cancers. Here we have isolated and characterized cell lines derived from spontaneous oral melanomas from companion dogs and subjected these cells to adenovirus-mediated gene transfer both in vitro and in vivo. Two newly established cell lines, BAN and TIG, were confirmed to be oncogenically transformed, as they bypassed G1 arrest under serum starvation and were tumorigenic in nude mice. These cell lines harbor wild-type p53, which, in response to treatment with doxorubicin or Nutlin-3, promoted the expression of well-known p53 target genes (CDKN1A, MDM2). The established cell lines are permissive to transduction with RGD-modified non-replicating adenoviral vectors and allowed reporter gene activity from p53-responsive promoter vectors controlled. Treatment with adenoviral vectors encoding canine p14^ARF and interferon-β (IFNβ) resulted in cell death with liberation of immunogenic cell death markers in vitro and reduction of tumor progression when subcutaneous tumors in nude mice were treated with in situ gene therapy. These results indicate that adenovirus-mediated delivery of p14ARF and IFNβ is effective in a canine model of oral melanoma, supporting the feasibility of applying comparative oncology approaches to the development of this gene therapy strategy.