Development of new therapies targeting human papillomavirus molecules

Abstract

High-risk HPV E6 and E7 oncogenes are an ideal targeting gene for treatment of cervical cancer. In this paper, we introduce researches on cancer-immunotherapy targeting HPV E7 through mucosal immunity and E6/E7-targeting siRNA therapy using PEGylated polymeric micelles. Therapeutic HPV vaccine has also attracted attention as a cancer immunotherapy agent. We have found homing of Integrin β7-positive intestinal mucosal lymphocyte on the cervical mucosa. In this study, we generated a novel therapeutic vaccine; an HPV E7-expressing Lactobacillus casei (LacE7) to induce anti-HPV cellular immunity directly to intestinal mucosa. Cervical lymphocytes (CxLs) and peripheral blood mononuclear cells (PBMCs) were counted E7 specific INFγ-producing cells (E7 cell-mediated immune responses: E7-CMI) by ELISPOT assay. We confirmed induction of anti-E7 IFNγ-producing cells in the cervix lymphocytes obtained from these patients. E6/E7 siRNA therapy requires a delivery system for its systemic intravenous administration. We here demonstrated that intravenous injection of HPV16 or 18 E6/E7 siRNA polymeric micelles suppressed excellently an increase in size of subcutaneous tumor formed by SiHa or HeLa cell, respectively. Our drug-delivery technology using polymeric micelles enabled the successful systemic administration of siRNA to exhibit anti-tumor effect.