The curative efficacy of namitecan (ST1968) in preclinical models of pediatric sarcoma is associated with antiangiogenic effects

Riccardo Riccardi, Giuliana Cassinelli, Valentina Zuco, Giovanna Petrangolini, Michelandrea De Cesare, Monica Tortoreto, Cinzia Lanzi, Denis Cominetti, Nadia Zaffaroni, Augusto Orlandi, Daniela Passeri, Federica Bucci, Claudio Pisano, Franco Zunino

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Namitecan (ST1968), a novel hydrophilic camptothecin analog of the 7-oxyiminomethyl series, was selected for clinical development on the basis of its promising preclinical efficacy. Since there is clinical evidence of efficacy of camptothecins against pediatric tumors, this study was performed to explore the antitumor and antiangiogenic activity of the camptothecin derivative in pediatric sarcoma models. With the exception of an undifferentiated rhabdomyosarcoma (A204), namitecan exhibited curative efficacy even at well-tolerated suboptimal doses in a panel of five models. The good therapeutic index of namitecan likely reflected a high and persistent drug accumulation at tumor site. The four responsive tumors were characterized by high topoisomerase I expression. In the RD/TE-671 rhabdomyosarcoma model the drug activity was associated with a marked antiangiogenic effect, which was consistent with the downregulation of proangiogenic factors, including VEGF, bFGF and the multifunctional chemokines CCL-2 and CXCL16. In agreement with this modulation, the combination of low doses of namitecan with other antiangiogenic agents, such as bevacizumab (a humanized anti-VEGF antibody) and sunitinib (a multitarget tyrosine kinase inhibitor effective against receptors implicated in the angiogenesis process), enhanced the antitumor effects. In conclusion, this preclinical study provides evidence of curative efficacy of namitecan at well-tolerated doses against pediatric sarcoma models, likely reflecting a contribution of antiangiogenic effects. Based on the promising therapeutic profile, namitecan is a good candidate for clinical evaluation in pediatric sarcomas.
Original languageEnglish
Pages (from-to)163-171
Number of pages9
JournalBiochemical Pharmacology
Volume84
DOIs
Publication statusPublished - 2012

Keywords

  • ST1968
  • antiangiogenic effects
  • namitecan
  • pediatric sarcoma

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