The novel lipophilic camptothecin analogue gimatecan is very active in vitro in human neuroblastoma: A comparative study with SN38 and topotecan

Angela Maria Di Francesco, Anna Shirley Riccardi, Giuseppe Barone, Sergio Rutella, Daniela Meco, Roberta Frapolli, Massimo Zucchetti, Maurizio D'Incalci, Claudio Pisano, Paolo Carminati, Riccardo Riccardi

Research output: Contribution to journalArticle

Abstract

Neuroblastoma is one of the most common extracranial solid tumours in childhood with a poor prognosis in its advanced stage. Treatment failure is often associated to the occurrence of drug resistance. To date, treatment of paediatric neuroblastoma is still dismal, and therefore novel effective drugs are awaited. In recent years, an increasing interest has concentrated on camptothecin analogues. Topotecan and irinotecan, the only two clinically relevant camptothecin derivatives to date, have entered clinical trials in neuroblastoma but so far the results have been disappointing. Gimatecan (ST1481, LBQ707; 7-t-butoxyiminomethylcamptothecin), is a novel lipophilic camptothecin derivative that was selected from a series of lipophilic analogues rationally designed and synthesized in order to overcome some of the main drawbacks of conventional camptothecins, limiting their clinical efficacy. Gimatecan is endowed with potent antitumour activity, strong topoisomerase I inhibition, stable drug-target interactions and a better pharmacological profile. The present study deals with the comparative evaluation of cellular pharmacology features of gimatecan, topotecan and SN38 in neuroblastoma cell lines. We show that, despite the lowest intracellular accumulation, gimatecan was the most active among the camptothecin analogues studied. Our findings suggest that the high activity of gimatecan in neuroblastoma is related to the ability of this novel analogue to cause a very high number of DNA breaks as assessed by the Comet assay in both cellular or sub-cellular systems. We propose that DNA strand breaks efficiency as measured by the Comet assay might provide important information about the stability of the ternary complexes induced by camptothecin compounds.

Original languageEnglish
Pages (from-to)1125-1136
Number of pages12
JournalBiochemical Pharmacology
Volume70
Issue number8
DOIs
Publication statusPublished - Oct 15 2005

Keywords

  • Alkaline comet assay
  • Camptothecins
  • DNA strand breaks
  • Gimatecan
  • Neuroblastoma
  • Topoisomerase I inhibitors

ASJC Scopus subject areas

  • Pharmacology

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