In vitro and in vivo phase II metabolism of combretastatin A-4: evidence for the formation of a sulphate conjugate metabolite.
1. Combretastatin A-4 (CA-4), is a natural compound with a potent tubulin polymerization and cell growth inhibitor properties. For these reasons CA-4 is one of the most potent anti-vascular agents that shows strong cytotoxicity against a variety of human cancer cells, including multi-drug-resistant cancer cell lines. In order to complete the knowledge of metabolic fate of CA-4, the in vitro and in vivo phase II metabolism was investigated. 2. Both in incubation with rat and human liver S9 preparation in the presence of 39-phosphoadenosine-5 -phosphosulfate (PAPS) as a cofactor the formation of a previously no reported sulphate metabolite was demonstrated through liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) data and comparison with a synthetic reference sample. 3. In incubation of CA-4 using rat and human liver microsomes, the formation of CA-4 glucuronide was observed and chromatographic and mass spectral properties of the metabolite were achieved and compared with those of a synthetic reference sample. 4. Incubation of CA-4 with rat and human liver S9 preparation in the presence of uridine-5 -diphosphoglucuronic acid trisodium salt (UDPGA) and an beta-nicotinamide adenine dinucleotide phosphate, reduced form (NADPH)-regenerating system as cofactors resulted in the formation of glucuronides arising from phase I CA-4 metabolites. 5. When CA-4 was administered intraperitoneally to rat at a dose of 30 mg kg(-1), both glucuronide and sulphate metabolites were observed in LC-ESI-MS-MS chromatograms and their mass spectral data were identical to those obtained from synthetic standards.
Aprile
S
S
Universita Piemonte Orientale, DiSCAFF, Novara, Italy.
Del Grosso
E
E
Grosa
G
G
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism*; D002853:Chromatography, Liquid; D020719:Glucuronides / Q000737:chemistry / Q000378:metabolism / Q000652:urine; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D013267:Stilbenes / Q000737:chemistry / Q000378:metabolism* / Q000652:urine; D013431:Sulfates / Q000737:chemistry / Q000378:metabolism* / Q000652:urine; D053719:Tandem Mass Spectrometry; D014556:Urine / Q000737:chemistry
D000972:Antineoplastic Agents, Phytogenic; D020719:Glucuronides; D013267:Stilbenes; D013431:Sulfates; C058728:fosbretabulin