1. ¹Gittlen Cancer Research Institute, Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
2. ²Department of Pathology, Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
3. ³Department of Biochemistry & Molecular Biology, Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
4. ⁴Department of Dermatology, Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA
5. ⁵Department of Microbiology & Immunology, Hershey Medical Center, Pennsylvania State University, Hershey, PA, USA

Correspondence: Dr GA Clawson, Gittlen Cancer Research Institute, H059, Hershey Medical Center, The Pennsylvania State University, 500 University Drive, Hershey, PA 17033, USA

⁶Current address: Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO, USA

Received 2 October 2003; Accepted 12 April 2004; Published online 1 July 2004.

Abstract

Human papillomaviruses (HPVs) are recognized as important human pathogens, causing a spectrum of hyperproliferative lesions from benign warts to cervical dysplasias/carcinomas. HPV-associated lesions require continued production of the oncogenic E6/E7 proteins, which are encoded by either bicistronic or overlapping mRNAs. Here we targeted the E6/E7 mRNA of HPV11, a type implicated in causation of genital warts, using molecular reagents. Accessible sites in the HPV11_E6/E7 RNA were identified using library selection protocols, and nucleic acids (DNAzymes, antisense oligonucleotides) targeted to these sites were constructed, and tested in cell culture and on human foreskin grafts. While DNAzymes were at least equally effective in cell culture, antisense oligonucleotides targeted to the region surrounding one of the library-selected sites (ASO₄₀₇) proved most effective in blocking progression of HPV11-induced papillomas in human foreskin grafts on immunodeficient mice. In total, 11 papillomas were treated with ASO₄₀₇. Of these, four of seven small papillomas treated with ASO₄₀₇ showed loss of detectable virus by in situ hybridization (ISH), and in all four of these, papillomas were no longer evident grossly or histologically after treatment. When larger papillomas were treated, one of four showed loss of virus by ISH, associated with a minor decrease in papilloma size. Considering all 11 papillomas treated with ASO₄₀₇, loss of viral staining by ISH was significantly different from that observed in controls (P<0.016), as was true for the seven small treated papillomas (P<0.012). DNAzymes targeted to the same site (or other library selected sites) did not produce statistically significant differences in ISH staining (P<0.15). Our results with ASO₄₀₇ appear to represent the first specific molecular therapy against a bona fide HPV infection, and provide a rational proof-of-principle strategy for development of molecular therapeutics targeting other HPV-associated lesions.