title: Metronomic 5-fluorouracil, oxaliplatin and irinotecan in colorectal cancer.
abstract: Metronomic chemotherapy (the frequent, long term, low dose administration of chemotherapeutic drugs) is a promising therapy because it enhances the anti-endothelial activity of conventional chemotherapeutics, but with lower or no toxic effects compared to maximum tolerated dose administration. The aims of the present study were to compare, in vitro and in vivo, the antiangiogenic and antitumor activities of metronomic irinotecan (CPT-11), oxaliplatin (L-OHP) and 5-fluorouracil (5-FU) in colorectal cancer and to investigate the metronomic combination of these drugs. In vitro cell proliferation, combination studies and vascular endothelial growth factor (VEGF) secretion analyses were performed on endothelial (HMVEC-d) and colorectal cancer (HT-29) cells exposed for 144 h to metronomic concentrations of SN-38, the active metabolite of CPT-11, L-OHP and 5-FU. HT-29 human colorectal cancer xenograft model was used and tumour growth, microvessel density and VEGF quantification were performed in tumours after the administration of metronomic CPT-11, L-OHP, 5-FU and their simultaneous combination. Low concentrations of SN-38, but not 5-FU and L-OHP, preferentially inhibited endothelial cell proliferation. Simultaneous and continuous exposure of HT-29 and HMVEC-d cells to low concentrations SN-38+L-OHP+5-FU for 144 h showed a strong antagonism and an unfavorable dose-reduction index. Moreover, the ternary combination resulted in a significant increase of VEGF secretion in HT-29 cancer cells. In a xenograft model metronomic CPT-11, but not 5-FU and L-OHP, significantly inhibits HT-29 tumor growth and microvessel density in the absence of toxicity. On the contrary, metronomic 5-FU+L-OHP+CPT-11 therapy did not affect the microvascular count. The metronomic concept might not universally apply to every cytotoxic drug in colorectal cancer and metronomic combination regimens should be used with caution.
authors.affiliation: Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa, Via Roma, 55, I-56126 Pisa, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Fioravanti
authors.forename: Bastianina
authors.initials: B
authors.lastname: Canu
authors.forename: Greta
authors.initials: G
authors.lastname: Alì
authors.forename: Paola
authors.initials: P
authors.lastname: Orlandi
authors.forename: Giacomo
authors.initials: G
authors.lastname: Allegrini
authors.forename: Teresa
authors.initials: T
authors.lastname: Di Desidero
authors.forename: Urban
authors.initials: U
authors.lastname: Emmenegger
authors.forename: Gabriella
authors.initials: G
authors.lastname: Fontanini
authors.forename: Romano
authors.initials: R
authors.lastname: Danesi
authors.forename: Mario
authors.initials: M
authors.lastname: Del Tacca
authors.forename: Alfredo
authors.initials: A
authors.lastname: Falcone
authors.forename: Guido
authors.initials: G
authors.lastname: Bocci
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols; D002166:Camptothecin / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000098:blood supply / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D004334:Drug Administration Schedule; D042783:Endothelial Cells / Q000166:cytology; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D000077146:Irinotecan; D008297:Male; D051379:Mice; D055806:Microvessels / Q000187:drug effects / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D009944:Organoplatinum Compounds / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D000077150:Oxaliplatin; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D009944:Organoplatinum Compounds; D042461:Vascular Endothelial Growth Factor A; D000077150:Oxaliplatin; D000077146:Irinotecan; D005472:Fluorouracil; D002166:Camptothecin