title: Synergistic interaction between tirapazamine and cyclophosphamide in human breast cancer xenografts.
abstract: This study examined the efficacy of combining cyclophosphamide and the hypoxic cytotoxin, tirapazamine, in the treatment of human breast cancer xenografts grown in nude mice. A single dose of tirapazamine was followed 2 h later by a single dose of cyclophosphamide. As determined from tumor regrowth delay, the effectiveness of combined therapy was greater than the additive effects of each treatment given alone. Possible mechanisms of this synergistic interaction include enhancement of DNA damage, inhibition of repair of DNA damage, or induction of apoptosis. Apart from some loss in body weight, the only other toxicity of interest in mice treated with tirapazamine was necrosis of the skin on the distal tail, which appeared to be vascular in origin.
authors.affiliation: SRI International, Menlo Park, California 94025.
authors.forename: V K
authors.initials: VK
authors.lastname: Langmuir
authors.forename: J A
authors.initials: JA
authors.lastname: Rooker
authors.forename: M
authors.initials: M
authors.lastname: Osen
authors.forename: H L
authors.initials: HL
authors.lastname: Mendonca
authors.forename: K R
authors.initials: KR
authors.lastname: Laderoute
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy*; D003520:Cyclophosphamide / Q000008:administration & dosage; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D013623:Tail / Q000187:drug effects; D000077704:Tirapazamine; D014183:Transplantation, Heterologous; D014227:Triazines / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D014227:Triazines; D000077704:Tirapazamine; D003520:Cyclophosphamide