Tumor Necrosis Factor α‐Gene Therapy for an Established Murine Melanoma Using RGB (Arg‐Gly‐Asp) Fiber‐mutant Adenovirus Vectors

Although adenovirus vectors (Ad) provide high‐level transduction efficacy to many cell types, extremely high doses of Ad are required for sufficient gene transduction into several tumors, including melanoma. Here, we demonstrated that the expression of coxsackie‐adenovirus receptor, a primitive Ad‐receptor, was very low in murine and human melanoma cells. We also found that fiber‐mutant Ad containing the Arg‐Gly‐Asp (RGD) sequence in the fiber knob remarkably augmented gene transduction efficacy in melanoma cells by targeting α(v)‐integrins. In addition, intratumoral injection of RGD fiber‐mutant Ad containing the tumor necrosis factor α gene (AdRGD‐TNFα) revealed dramatic anti‐tumor efficacy through hemolytic necrosis in an established murine B16 BL6 melanoma model. Ad‐RGD‐TNFα required one‐tenth the dosage of Ad‐TNFα to induce an equal therapeutic effect. These results suggest that α(v)‐integrin‐targeted Ad will be a very powerful tool for the advancement of melanoma gene therapy.