Adenoviral natural born killer gene therapy for malignant glioma

Hum Gene Ther. 2003 Sep 1;14(13):1235-46. doi: 10.1089/104303403767740777.


Glioblastoma is a lethal neoplasm resistant to conventional radiotherapy and chemotherapy. Natural born killer (NBK), also known as Bcl-2-interacting killer (BIK), is a death-promoting Bcl-2 family protein sharing with Bcl-2 only the Bcl homology 3 (BH3) domain. We here report that an adenoviral vector encoding NBK (Ad-NBK) uniformly induces cell death in 12 human malignant glioma cell lines. Ad-NBK-induced cell death involves neither quantitative mitochondrial cytochrome c release nor caspase 8, 9, 7, or 3 processing and is unaffected by the viral caspase inhibitor, cytokine response modifier A (CRM-A), or selective caspase 8 or 9 inhibitors. In contrast, Ad-NBK-induced cell death is inhibited by the broad-range caspase inhibitor, zVAD-fmk, or by adenoviral gene transfer of the X-linked inhibitor of apoptosis protein (XIAP). Further, Ad-NBK-induced cell death is inhibited by Bcl-2 or Bcl-xL gene transfer. Interestingly, Bcl-2- and Bcl-xL-transfected glioma cells, which are partially protected from Ad-NBK-induced cell death, accumulate much higher levels of NBK than are ever observed in control-infected cells. This indicates that complex formation with Bcl-2 or Bcl-xL sequesters NBK in an inactive form and that free NBK, rather than an NBK-mediated depletion of free antiapoptotic Bcl-2 family proteins, is the proximate mediator of Ad-NBK-induced cell death. Conversely, proteasome inhibition-mediated accumulation of NBK strongly enhances Ad-NBK-induced cell death. Finally, Ad-NBK-infected LN-229 glioma cells are not tumorigenic in nude mice. Thus Ad-NBK triggers an XIAP- and zVAD-fmk-sensitive cell death pathway in glioma cells with potential therapeutic value, provided that NBK expression can be selectively targeted to cancer cells.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Adenoviridae / metabolism
  • Amino Acid Chloromethyl Ketones / pharmacology
  • Animals
  • Apoptosis / drug effects*
  • Apoptosis / genetics
  • Apoptosis Regulatory Proteins
  • Blotting, Northern
  • Caspase Inhibitors
  • Cell Line, Tumor
  • Fluorometry
  • Gene Expression
  • Genes, bcl-2
  • Genetic Therapy / methods*
  • Genetic Vectors
  • Glioblastoma / genetics
  • Glioblastoma / therapy*
  • Humans
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Nude
  • Mitochondrial Proteins
  • Precipitin Tests
  • Proteins / pharmacology
  • X-Linked Inhibitor of Apoptosis Protein


  • Amino Acid Chloromethyl Ketones
  • Apoptosis Regulatory Proteins
  • BIK protein, human
  • Caspase Inhibitors
  • Membrane Proteins
  • Mitochondrial Proteins
  • Proteins
  • X-Linked Inhibitor of Apoptosis Protein
  • XIAP protein, human
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone