A chimeric poxvirus with J2R (thymidine kinase) deletion shows safety and anti-tumor activity in lung cancer models

Cancer Gene Ther. 2020 Apr;27(3-4):125-135. doi: 10.1038/s41417-019-0114-x. Epub 2019 Jun 17.

Abstract

Oncolytic viruses have shown excellent safety profiles in preclinical and clinical studies; however, in most cases therapeutic benefits have been modest. We have previously reported the generation of a chimeric poxvirus (CF33), with significantly improved oncolytic characteristics, through chimerization among different poxviruses. Here we report the sequence analysis of CF33 and oncolytic potential of a GFP-encoding CF33 virus (CF33-GFP) with a J2R deletion in lung cancer models. Replication of CF33-GFP and the resulting cytotoxicity were higher in cancer cell lines compared to a normal cell line, in vitro. After infection with virus, cancer cells expressed markers for immunogenic cell death in vitro. Furthermore, CF33-GFP was safe and exerted potent anti-tumor effects at a dose as low as 1000 plaque forming units in both virus-injected and un-injected distant tumors in A549 tumor xenograft model in mice. Likewise, in a syngeneic model of lung cancer in mice, the virus showed significant anti-tumor effect and was found to increase tumor infiltration by CD8+ T cells. Collectively, these data warrant further investigation of this novel chimeric poxvirus for its potential use as a cancer bio-therapeutic.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • A549 Cells
  • Animals
  • CD8-Positive T-Lymphocytes / immunology
  • Chlorocebus aethiops
  • Female
  • Gene Deletion
  • Genes, Reporter / genetics
  • Green Fluorescent Proteins / genetics
  • Humans
  • Lung Neoplasms / immunology
  • Lung Neoplasms / pathology
  • Lung Neoplasms / therapy*
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Mice
  • Oncolytic Virotherapy / methods*
  • Oncolytic Viruses / genetics
  • Oncolytic Viruses / immunology
  • Poxviridae / genetics*
  • Poxviridae / immunology
  • Thymidine Kinase / genetics
  • Viral Proteins / genetics
  • Xenograft Model Antitumor Assays

Substances

  • Viral Proteins
  • Green Fluorescent Proteins
  • Thymidine Kinase