title: Topotecan is anti-angiogenic in experimental hepatoblastoma.
abstract: BACKGROUND
  Advanced hepatoblastoma often is lethal despite current therapies, yet development of novel approaches has been hampered by the lack of biologically relevant models. One new strategy selectively targets endothelium rather than tumor cells using frequently administered, low-dose ("metronome") chemotherapy. Metronome topotecan has antiangiogenic activity in some experimental tumors. The authors developed a xenograft model of human hepatoblastoma to test the effect of metronome topotecan in this system.
  
  
  METHODS
  Xenografts resulted from intrarenal injection of cultured human hepatoblastoma cells in athymic mice. Topotecan (0.36 mg/kg/dose) or vehicle was injected intraperitoneally 5 times per week. At week 6, 10 control/treated mice were killed, and remaining animals were maintained without treatment until week 8. Tumor weights were compared by Kruskal-Wallis analysis, and vascular alterations were ascertained by specific immunostaining.
  
  
  RESULTS
  Metronome topotecan affected tumor weights in a delayed fashion: weights were diminished significantly only at 8 weeks (treated v control: 6 weeks, 0.59 g v 82 g, P value, not significant; 8 weeks, 1.13 g v 3.82; P <.02). Decreased vascularity and increased endothelial cell apoptosis were observed in treated xenografts.
  
  
  CONCLUSIONS
  Metronome topotecan inhibits growth and neovascularization in experimental hepatoblastoma. The durability of this effect is novel and has not been observed in other xenograft tumor models. Cytotoxic targeting of endothelial cells may hold particular promise for therapy of children with advanced hepatoblastoma. .
authors.affiliation: Division of Pediatric Surgery, Children's Hospital of New York, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: Kimberly W
authors.initials: KW
authors.lastname: McCrudden
authors.forename: Akiko
authors.initials: A
authors.lastname: Yokoi
authors.forename: Amit
authors.initials: A
authors.lastname: Thosani
authors.forename: Samuel Z
authors.initials: SZ
authors.lastname: Soffer
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Kim
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Huang
authors.forename: Christina
authors.initials: C
authors.lastname: Manley
authors.forename: Kathleen
authors.initials: K
authors.lastname: O'toole
authors.forename: Darrell J
authors.initials: DJ
authors.lastname: Yamashiro
authors.forename: Jessica J
authors.initials: JJ
authors.lastname: Kandel
authors.forename: William
authors.initials: W
authors.lastname: Middlesworth
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D005260:Female; D018197:Hepatoblastoma / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D008175:Lung Neoplasms / Q000556:secondary; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000473:pathology; D019772:Topotecan / Q000494:pharmacology*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D020533:Angiogenesis Inhibitors; D019772:Topotecan