title: Antiangiogenic effect of gemcitabine following metronomic administration in a pancreas cancer model.
abstract: Gemcitabine shows a marked antitumor effect as a result of its cytotoxic action toward proliferative cells. In this article, we aim to investigate the potential antitumor and antiangiogenic effect of gemcitabine following a metronomic schedule that involves the regular administration of cytotoxic drugs at doses lower than standard treatment. In vitro results showed that human endothelial cells are more sensitive to gemcitabine (IC(50) 3 nmol/L) than pancreatic tumor cells (IC(50) 20 nmol/L). For in vivo studies, we used an orthotopic implantation model of human pancreatic carcinoma in nude mice. Gemcitabine was administered i.p. following a low-dose schedule (1 mg/kg/d for a month) and compared with the conventional schedule (100 mg/kg days 0, 3, 6, and 9 postimplantation). Metronomic treatment effect on established tumor was equivalent to standard administration. The measure of CD31 endothelial marked area allowed us to show an in vivo antiangiogenic effect of this drug that was further enhanced by using metronomic administration. This effect correlated with an induction of thrombospondin-1, a natural inhibitor of angiogenesis. Our results allow us to hypothesize that, in addition to a direct antiproliferative or cytotoxic antiendothelial cell effect, a secondary effect involving thrombospondin-1 induction might provide an explanation for the specificity of the effects of metronomic gemcitabine treatment.
authors.affiliation: Laboratori de Recerca Translacional, Institut Català d'Oncologia-IDIBELL, Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: Laquente
authors.forename: Cristina
authors.initials: C
authors.lastname: Lacasa
authors.forename: Mireia M
authors.initials: MM
authors.lastname: Ginestà
authors.forename: Oriol
authors.initials: O
authors.lastname: Casanovas
authors.forename: Agnès
authors.initials: A
authors.lastname: Figueras
authors.forename: Maica
authors.initials: M
authors.lastname: Galán
authors.forename: Ignacio García
authors.initials: IG
authors.lastname: Ribas
authors.forename: Josep Ramon
authors.initials: JR
authors.lastname: Germà
authors.forename: Gabriel
authors.initials: G
authors.lastname: Capellà
authors.forename: Francesc
authors.initials: F
authors.lastname: Viñals
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004195:Disease Models, Animal; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000098:blood supply*; D000093542:Gemcitabine
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D003841:Deoxycytidine; D000093542:Gemcitabine