Evaluation of cytarabine against Ewing sarcoma xenografts by the pediatric preclinical testing program

Pediatr Blood Cancer. 2010 Dec 1;55(6):1224-6. doi: 10.1002/pbc.22355.


Treatment with the nucleoside analog cytarabine has been shown to mimic changes in gene expression associated with downregulation of the EWS-FLI1 oncogene in Ewing sarcoma cell lines, selectively inhibit their growth in vitro, and cause tumor regression in athymic nude mice. For this report cytarabine was studied in vitro against a panel of 23 pediatric cancer cell lines and in vivo against 6 Ewing sarcoma xenografts. Acute lymphoblastic leukemia cell lines were the most sensitive to cytarabine in vitro (median IC(50) 9 nM), while Ewing sarcoma cell lines showed intermediate sensitivity (median IC(50) 232 nM). Cytarabine at a dose of 150 mg/kg administered daily 5× failed to significantly inhibit growth of five xenograft models, but reduced growth rate of the A673 xenograft by 50%. Cytarabine shows no differential in vitro activity against Ewing sarcoma cell lines and is ineffective in vivo against Ewing sarcoma xenografts at the dose and schedule studied.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antimetabolites, Antineoplastic / pharmacology*
  • Bone Neoplasms / drug therapy*
  • Bone Neoplasms / pathology
  • Cell Line, Tumor
  • Child
  • Cytarabine / pharmacology*
  • Female
  • Humans
  • Mice
  • Mice, SCID
  • Neuroblastoma / drug therapy*
  • Neuroblastoma / pathology
  • Oncogene Proteins, Fusion / genetics
  • Proto-Oncogene Protein c-fli-1 / genetics
  • RNA-Binding Protein EWS
  • Rhabdomyosarcoma / drug therapy*
  • Rhabdomyosarcoma / pathology
  • Sarcoma, Ewing / drug therapy*
  • Sarcoma, Ewing / pathology
  • Translocation, Genetic / genetics
  • Xenograft Model Antitumor Assays*


  • Antimetabolites, Antineoplastic
  • EWS-FLI fusion protein
  • Oncogene Proteins, Fusion
  • Proto-Oncogene Protein c-fli-1
  • RNA-Binding Protein EWS
  • Cytarabine