Restricted expression of an adenoviral vector encoding fas ligand (CD95L) enhances safety for cancer gene therapy

Kazunori Aoki, Levent M. Akyürek, Hong San, Kwanyee Leung, Michael S. Parmacek, Elizabeth G. Nabel, Gary J. Nabel

Research output: Contribution to journalArticlepeer-review

Abstract

Gene transfer of Fas ligand (CD95L) using adenoviral vectors has been shown to generate apoptotic responses and potent inflammatory reactions that can be used to induce the regression of malignancies in vivo, but these vectors also cause significant hepatotoxicity that may limit their clinical utility. Here we describe an adenoviral vector encoding CD95L with restricted gene expression that reduces itstoxicity in vivo. Preclinical efficacy and gene expression studies of lineage-restricted CD95L adenoviral vectors were performed. To enhance its cytotoxicity and reduce potential systemic effects, a noncleavable CD95L was made by deleting a segment containing the cleavage site (CD95LΔQP). Higher CD95L expression of this mutant was observed on the tumor cell surface, together with a reduction in the release of soluble CD95L This CD95L cleavage mutant was then expressed under control of a smooth muscle-specific promoter, SM22α, and analyzed for its ability to suppress the growth of tumors of smooth muscle origin in vivo. Growth of human leiomyosarcomas but not gliomas was inhibited after ADV gene transfer into tumor-bearing immunodeficient mice. In contrast to viral promoters, in which mortality was uniformly seen after injection of 1012 particles, no significant hepatic injury or systemic toxicity was observed in mice, and the maximum tolerated dose was increased ≥10-to 100-fold. These findings suggest that restricted specif icity of adenoviral CD95Lgene expression enhances the safety of this approach for cancer gene therapy.

Original languageEnglish (US)
Pages (from-to)555-565
Number of pages11
JournalMolecular Therapy
Volume1
Issue number6
StatePublished - Jun 2000
Externally publishedYes

Keywords

  • Adenoviral vectors
  • Cancer gene therapy
  • CD95L
  • Cleavage mutant
  • Fas ligand
  • Leiomyosarcoma
  • SM22α promoter
  • Smooth muscle cell

ASJC Scopus subject areas

  • Molecular Biology

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