Eradication of therapy-resistant human prostate tumors using a cancer terminator virus

Cancer Res. 2007 Jun 1;67(11):5434-42. doi: 10.1158/0008-5472.CAN-07-0195.

Abstract

Terminal prostate cancer is refractory to conventional anticancer treatments because of frequent overexpression of antiapoptotic proteins Bcl-2 and/or Bcl-x(L). Adenovirus-mediated delivery of melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24), a secreted cytokine having cancer-selective apoptosis-inducing properties, profoundly inhibits prostate cancer cell growth. However, forced overexpression of Bcl-2 or Bcl-x(L) renders prostate cancer cells resistant to Ad.mda-7. We constructed a conditionally replication-competent adenovirus in which expression of the adenoviral E1A gene, necessary for replication, is driven by the cancer-specific promoter of progression elevated gene-3 (PEG-3) and which simultaneously expresses mda-7/IL-24 in the E3 region of the adenovirus (Ad.PEG-E1A-mda-7), a cancer terminator virus (CTV). This CTV generates large quantities of MDA-7/IL-24 as a function of adenovirus replication uniquely in cancer cells. Infection of Ad.PEG-E1A-mda-7 (CTV) in normal prostate epithelial cells and parental and Bcl-2- or Bcl-x(L)-overexpressing prostate cancer cells confirmed cancer cell-selective adenoviral replication, mda-7/IL-24 expression, growth inhibition, and apoptosis induction. Injecting Ad.PEG-E1A-mda-7 (CTV) into xenografts derived from DU-145-Bcl-x(L) cells in athymic nude mice completely eradicated not only primary tumors but also distant tumors (established in the opposite flank), thereby implementing a cure. These provocative findings advocate potential therapeutic applications of this novel virus for advanced prostate cancer patients with metastatic disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Adenovirus E1A Proteins / biosynthesis
  • Adenovirus E1A Proteins / genetics
  • Animals
  • Antigens, Differentiation / genetics
  • Cell Line, Tumor
  • Genetic Therapy / methods*
  • Humans
  • Interleukins / biosynthesis
  • Interleukins / genetics*
  • Male
  • Mice
  • Mice, Nude
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / therapy
  • Neovascularization, Pathologic / virology
  • Oncolytic Virotherapy / methods
  • Promoter Regions, Genetic
  • Prostatic Neoplasms / blood supply
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / therapy*
  • Prostatic Neoplasms / virology
  • Proto-Oncogene Proteins / genetics
  • Xenograft Model Antitumor Assays
  • bcl-X Protein / biosynthesis
  • bcl-X Protein / genetics

Substances

  • Adenovirus E1A Proteins
  • Antigens, Differentiation
  • Interleukins
  • Ppp1r15a protein, rat
  • Proto-Oncogene Proteins
  • bcl-X Protein
  • interleukin-24