Recombinant adenovirus encoding H-ras ribozyme induces apoptosis in laryngeal cancer cells through caspase- and mitochondria-dependent pathways

Biochem Biophys Res Commun. 2002 Nov 15;298(5):805-14. doi: 10.1016/s0006-291x(02)02574-3.


Previously, we designed a ribozyme that targets the H-ras oncogene at the 12th codon mutation site (Chang et al., 1997). Ribozymes have antisense molecule and site-specific ribonuclease potential. In this study, an adenoviral vector was used to transduce the H-ras ribozyme into laryngeal cancer cells (HEp-2). This served to downregulate the H-ras gene expression in which this ribozyme performed antisense activity due to HEp-2 cells containing wild-type alleles in the 12th H-ras codon. Together, our data demonstrated that the recombinant adenovirus encoding H-ras ribozyme can be broadly regarded as a cytotoxic gene therapy in laryngeal cancer cells regardless of containing wild-type or mutant ras gene. In addition, the mechanism through which the H-ras ribozyme inhibited tumor growth was apoptosis and involved both caspase- and mitochondria-mediated pathways. The activators caspase-8 and -9 as well as the effector caspase-3 in the induction phase of apoptosis and the substrate PARP of caspase-3 in the execution phase were activated 48h following the H-ras ribozyme treatment. Mitochondrial events characterized by the production of superoxide anion and the release of cytochrome c started at 24h. Mitochondrial transmembrane potential loss occurred 48h after the ribozyme treatment. However, Bcl-2 delayed cytochrome c release to the cytosol, but it could not protect the apoptosis effect, suggesting that cytochrome c release from mitochondria may not play a role in H-ras ribozyme-induced apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenoviridae / genetics
  • Apoptosis / genetics*
  • Apoptosis / physiology
  • Caspases / metabolism
  • Cell Division
  • Cytochrome c Group / metabolism
  • Enzyme Activation
  • Genes, bcl-2
  • Genes, ras*
  • Genetic Therapy
  • Humans
  • Laryngeal Neoplasms / enzymology
  • Laryngeal Neoplasms / pathology
  • Laryngeal Neoplasms / therapy
  • Mitochondria / metabolism
  • RNA, Catalytic / genetics*
  • Tumor Cells, Cultured


  • Cytochrome c Group
  • RNA, Catalytic
  • Caspases