The carcinoma-specific epithelial glycoprotein-2 promoter controls efficient and selective gene expression in an adenoviral context

Cancer Gene Ther. 2006 Feb;13(2):150-8. doi: 10.1038/sj.cgt.7700882.


Adenoviral vectors are widely used in cancer gene therapy. After systemic administration however, the majority of the virus homes to the liver and the expressed transgene may cause hepatotoxicity. To restrict transgene expression to tumor cells, tumor- or tissue-specific promoters are utilized. The tumor antigen epithelial glycoprotein-2 (EGP-2), also known as Ep-CAM, is expressed in many cancers from different epithelial origins. In this study, the EGP-2 promoter was shown to restrict the expression of luciferase and thymidine kinase in an adenoviral context in different cell lines. In vivo, the EGP-2 promoter mediated efficient expression of luciferase in tumors but showed a 3-log lower activity in liver tissue when compared with the cytomegalovirus (CMV) promoter. Similarly, the EGP-2 promoter mediated specific cell killing after ganciclovir treatment in EGP-2-positive cells. Moreover, in vivo, this treatment regiment did not cause any rise in the liver enzymes aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT), demonstrating absence of liver toxicity. In contrast, CMV-mediated expression of thymidine kinase in combination with ganciclovir treatment resulted in high ASAT and ALAT values. This study demonstrates the value of the EGP-2 promoter to restrict transgene expression to a broad range of tumor types, thereby preventing liver toxicity.

Publication types

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

MeSH terms

  • Adenoviridae
  • Alanine Transaminase / metabolism
  • Animals
  • Antigens, Neoplasm / genetics*
  • Aspartate Aminotransferases / metabolism
  • Cell Adhesion Molecules / genetics*
  • Cell Line, Tumor
  • DNA Primers
  • Epithelial Cell Adhesion Molecule
  • Ganciclovir / toxicity
  • Gene Expression Regulation, Neoplastic*
  • Genetic Therapy / methods*
  • Genetic Vectors / genetics
  • Humans
  • Luciferases / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Neoplasms / therapy*
  • Promoter Regions, Genetic / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Thymidine Kinase / metabolism
  • Thymidine Kinase / toxicity
  • Toxicity Tests
  • Transgenes / genetics


  • Antigens, Neoplasm
  • Cell Adhesion Molecules
  • DNA Primers
  • EPCAM protein, human
  • Epithelial Cell Adhesion Molecule
  • Luciferases
  • Aspartate Aminotransferases
  • Alanine Transaminase
  • Thymidine Kinase
  • Ganciclovir