Low concentrations of doxorubicin sensitizes human solid cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor (R) 2-mediated apoptosis by inducing TRAIL-R2 expression

Cancer Sci. 2007 Dec;98(12):1969-76. doi: 10.1111/j.1349-7006.2007.00632.x. Epub 2007 Oct 8.


There is accumulating evidence suggesting that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor (R) 2 is a promising molecular target for cancer therapy. Therefore, we investigated the effect of chemotherapeutic agents on TRAIL-R2-mediated apoptosis and cytotoxicity in various human solid cancer cells. Treatment of the ACHN human renal cell carcinoma (RCC) cell line with agonistic TRAIL-R2 antibody (lexatumumab) in combination with 5-fluorouracil, vinblastine, paclitaxel, or docetaxel did not overcome resistance to these agents. However, treatment with lexatumumab in combination with doxorubicin had a synergistic cytotoxicity. Synergy was also achieved in two other human RCC cell lines, Caki-1 and Caki-2, and in eight primary RCC cell cultures. Sequential treatment with doxorubicin followed by lexatumumab induced significantly more cytotoxicity than reverse treatment or simultaneous treatment. Low concentrations of doxorubicin (0.1 and 1 microg/mL) significantly increased TRAIL-R2 expression at both the mRNA and protein levels. Furthermore, the combination of doxorubicin and lexatumumab significantly enhanced caspase 8 activity, Bid cleavage, Bcl-xL decrease, release of cytochrome c, and caspase 9 and caspase 3 activity, and induced synergistic apoptosis. The activation of caspases and apoptosis induced with lexatumumab and doxorubicin was blocked by the human recombinant DR5:Fc chimeric protein. In addition, synergistic cytotoxicity was also observed in human prostate, bladder, and lung cancer cells, but was inhibited by the DR5:Fc chimeric protein. These findings suggest that doxorubicin sensitizes solid cancer cells to TRAIL-R2-mediated apoptosis by inducing TRAIL-R2 expression, and that the combination treatment with lexatumumab and doxorubicin might be a promising targeted therapy for cancers, including RCC, prostate, bladder, and lung cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibiotics, Antineoplastic / pharmacology
  • Antibodies, Monoclonal / pharmacology*
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Carcinoma, Renal Cell / pathology*
  • Caspases / drug effects
  • Caspases / metabolism
  • Cell Line, Tumor
  • DNA Primers
  • Doxorubicin / pharmacology*
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Kidney Neoplasms / pathology*
  • Polymerase Chain Reaction
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / drug effects
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / genetics*
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / physiology*


  • Antibiotics, Antineoplastic
  • Antibodies, Monoclonal
  • DNA Primers
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Doxorubicin
  • lexatumumab
  • Caspases