Efficient gene transfer to human squamous cell carcinomas by the herpes simplex virus type 1 amplicon vector

Background: This study evaluates the efficiency of herpes simplex virus (HSV) mediated gene transfer in human squamous cell carcinoma (SCC) cell lines in vitro and in vivo when delivered by selective intra-arterial perfusion. Methods: Human head and neck SCC were exposed to HSV-LacZ and HSV–interleukin-2 (IL-2) and gene transfer and expression assessed by X-gal staining and enzyme-linked immunosorbent assay, respectively. Hamster cheek pouch tumors were perfused with HSV-LacZ or HSV–IL-2, by microcannulating the external carotid artery, and gene transfer determined. Results: A ratio of 5 viral particles per tumor cell achieved gene transfer rates exceeding 50%. Interleukin-2 levels of 287 ± 17 to 424 ± 8.4 ng per million cells were achieved at a ratio of 2 viral particles per tumor cell. Selective intra-arterial perfusion of the HSV–IL-2 vector yielded IL-2 levels of 45.8 ± 17.0 pg per g tumor. Conclusions: HSV amplicon vectors are efficient vehicles for gene transfer in vitro in human head and neck SCC cell lines and in vivo when introduced by selective intra-arterial perfusion.