Eradication of established tumors by vaccination with Venezuelan equine encephalitis virus replicon particles delivering human papillomavirus 16 E7 RNA

Cancer Res. 2001 Nov 1;61(21):7861-7.

Abstract

The etiological role of human papillomaviruses (HPV) in cervical and other cancers suggests that therapeutic vaccines directed against requisite viral antigens may eradicate tumors or their precursors. A Venezuelan equine encephalitis (VEE) alphavirus vector delivering the HPV16 E7 RNA was evaluated for antitumor efficacy using a murine E7+ tumor model. Vaccination with VEE replicon particles expressing E7 (E7-VRP) induced class I-restricted CD8+ T-cell responses as determined by IFN-gamma enzyme-linked immunospot (ELISPOT), tetramer, and cytotoxicity assays. E7-VRP vaccination prevented tumor development in all of the mice and effectively eliminated 7-day established tumors in 67% of tumor-bearing mice. The induction of protective T-cell responses was dependent on CD8+, but not CD4+ T cells. Long-lasting T-cell memory responses developed in E7-VRP-vaccinated mice as determined by complete protection from tumor challenge 3 months after the final vaccination. These promising results highlight the potent CD8+ T-cell-mediated antitumor effects elicited by VEE replicon-based vectors and support their further development toward clinical testing against cervical intraepithelial neoplasia or carcinoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cancer Vaccines / genetics*
  • Cancer Vaccines / immunology*
  • Encephalitis Virus, Venezuelan Equine / genetics*
  • Encephalitis Virus, Venezuelan Equine / immunology
  • Female
  • Genetic Therapy / methods
  • Genetic Vectors / genetics
  • Immunologic Memory / immunology
  • Interferon-gamma / biosynthesis
  • Interferon-gamma / immunology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neoplasms, Experimental / genetics
  • Neoplasms, Experimental / immunology
  • Neoplasms, Experimental / therapy*
  • Oncogene Proteins, Viral / genetics*
  • Oncogene Proteins, Viral / immunology*
  • Papillomavirus E7 Proteins
  • RNA, Viral / administration & dosage
  • RNA, Viral / genetics*
  • Replicon / genetics*
  • Replicon / immunology
  • T-Lymphocyte Subsets / immunology
  • Vaccines, Synthetic / genetics
  • Vaccines, Synthetic / immunology

Substances

  • Cancer Vaccines
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • RNA, Viral
  • Vaccines, Synthetic
  • oncogene protein E7, Human papillomavirus type 16
  • Interferon-gamma