TRAIL enhances efficacy of radiotherapy in a p53 mutant, Bcl-2 overexpressing lymphoid malignancy

Radiother Oncol. 2006 Aug;80(2):214-22. doi: 10.1016/j.radonc.2006.07.030. Epub 2006 Aug 17.


Background and purpose: Resistance to apoptosis is a contributing factor in the response to radiotherapy. Aim of this study was to evaluate whether TRAIL--in a soluble isoleucine zippered form--enhances the cytotoxic effect of irradiation on tumour cells with a blockade in the mitochondrial apoptosis route and/or a dysfunctional p53 pathway.

Materials and methods: The p53 mutant human T acute lymphoblastic leukemia line Jurkat transduced with the Bcl-2 gene was used as model system in vitro and in a subcutaneous transplant setting in immunodeficient mice. Sensitivity to single and combined treatment was read out by apoptosis hallmarks and clonogenic survival in vitro, and by bioluminescence and palpation in vivo.

Results: Jurkat cells overexpressing Bcl-2 did not undergo apoptosis after irradiation, but the combination with TRAIL synergistically induced apoptosis without breaking mitochondrial resistance. TRAIL also reduced clonogenic survival after irradiation. In vivo, radiotherapy or TRAIL alone delayed tumour outgrowth, but combination treatment had the most profound effect.

Conclusions: Isoleucine zippered TRAIL can strongly enhance the efficacy of tumour therapy with ionising radiation in an unfavourable setting of p53 mutation and Bcl-2 overexpression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / radiation effects
  • Combined Modality Therapy
  • Female
  • Humans
  • Isoleucine / genetics
  • Jurkat Cells
  • Leukemia-Lymphoma, Adult T-Cell / drug therapy*
  • Leukemia-Lymphoma, Adult T-Cell / genetics
  • Leukemia-Lymphoma, Adult T-Cell / metabolism
  • Leukemia-Lymphoma, Adult T-Cell / radiotherapy*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Transgenic
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Recombinant Proteins / adverse effects
  • Recombinant Proteins / genetics
  • Recombinant Proteins / pharmacology
  • TNF-Related Apoptosis-Inducing Ligand / adverse effects
  • TNF-Related Apoptosis-Inducing Ligand / genetics
  • TNF-Related Apoptosis-Inducing Ligand / pharmacology*
  • Tumor Suppressor Protein p53 / biosynthesis
  • Tumor Suppressor Protein p53 / genetics*
  • Xenograft Model Antitumor Assays


  • Proto-Oncogene Proteins c-bcl-2
  • Recombinant Proteins
  • TNF-Related Apoptosis-Inducing Ligand
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Isoleucine