Enhancement of Ad-CRT/E7-mediated antitumor effect by preimmunization with L. lactis expressing HPV-16 E7

Viral Immunol. 2014 Nov;27(9):463-7. doi: 10.1089/vim.2014.0055. Epub 2014 Sep 12.

Abstract

Although current polyvalent vaccines can prevent development of cervical cancer, they cannot be used to treat patients who already have the disease. Adenovirus expressing calreticulin-E7 (Ad-CRT-E7) has shown promising results in the cervical cancer murine model. We also demonstrated that immunization with Lactococcus lactis encoding HPV-16 E7 (Ll-E7) anchored to its surface induces significant HPV-16 E7-specific immune response. Here, we assessed the combination of both approaches in the treatment of a cervical cancer animal model. Intranasal preimmunization of Ll-E7, followed by a single Ad-CRT/E7 application, induced ∼80% of tumor suppression in comparison with controls. Mice treated with a combination of Ll-E7 and Ad-CRT/E7 resulted in a 70% survival rate 300 days post-treatment, whereas 100% of the mice in the control groups died by 50 days. Significant CD8+ cytotoxic T-lymphocytes infiltration was detected in the tumors of mice treated with Ll-E7+Ad-CRT/E7. Tumors with regression showed a greater number of positive cells for in situ TUNEL staining than controls. Our results suggest that preimmunization with Ll-E7 enhances the Ad-CRT/E7-mediated antitumor effect. This treatment provides an enormous advantage over repeated applications of Ad-CRT/E7 by maintaining the effectiveness of the three-dose application of Ad-CRT/E7, but avoiding the high systemic toxicities associated with such repeat treatments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Antineoplastic Agents / administration & dosage*
  • CD8-Positive T-Lymphocytes / immunology
  • Calreticulin / administration & dosage
  • Cell Surface Display Techniques / methods
  • Disease Models, Animal
  • Drug Carriers / administration & dosage
  • Female
  • Genetic Vectors
  • Immunotherapy / methods*
  • Lactococcus lactis / genetics
  • Mice, Inbred C57BL
  • Papillomavirus E7 Proteins / administration & dosage*
  • Papillomavirus E7 Proteins / genetics
  • Papillomavirus E7 Proteins / immunology*
  • Papillomavirus Vaccines / administration & dosage
  • Papillomavirus Vaccines / genetics
  • Papillomavirus Vaccines / immunology*
  • Recombinant Fusion Proteins / administration & dosage
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Survival Analysis
  • Treatment Outcome
  • Uterine Cervical Neoplasms / pathology
  • Uterine Cervical Neoplasms / therapy*
  • Vaccines, Synthetic / administration & dosage
  • Vaccines, Synthetic / genetics
  • Vaccines, Synthetic / immunology*

Substances

  • Antineoplastic Agents
  • Calreticulin
  • Drug Carriers
  • Papillomavirus E7 Proteins
  • Papillomavirus Vaccines
  • Recombinant Fusion Proteins
  • Recombinant Proteins
  • Vaccines, Synthetic
  • oncogene protein E7, Human papillomavirus type 16