title: Disposition and metabolism of the angiogenic moderator O-(chloroacetyl-carbamoyl) fumagillol (TNP-470; AGM-1470) in human hepatocytes and tissue microsomes.
abstract: The biotransformation of O-(chloroacetyl-carbamoyl) fumagillol (TNP-470; AGM 1470), a potent in vitro inhibitor of angiogenesis, was investigated in primary cultured human hepatocytes and microsomal fractions of various human tissues. Exposure of human hepatocytes to 5 microM [3H]TNP-470 led to a rapid metabolism of unchanged drug to six metabolic derivatives within 30 min. The predominant extracellular metabolites were M-II and M-IV, attaining a maximum level of 3.23 +/- 0.34 and 0.88 +/- 0.10 microM, respectively. M-II leveled off, while M-IV rapidly declined to 0.06 +/- 0.05 microM by 3 h. TNP-470 was undetectable after 60 min. M-V and M-VI slowly reached maximal concentrations of 0.26 +/- 0.12 and 0.32 +/- 0.16 microM, respectively. M-I only reached a concentration of 0.18 +/- 0.07 microM at 60 min and leveled at 0.13 +/- 0.06 microM for the remaining time of the experiment. The intracellular profile was different, with M-III and M-V representing the major metabolites detected. Studies using human liver microsomes demonstrated that M-IV formation was associated with an esterase-like enzymatic cleavage of TNP-470 and that this metabolite was then further metabolized by microsomal epoxide hydrolase to M-II, as evidenced by inhibition of this metabolic step by cyclohexene oxide, a microsomal epoxide hydrolase inhibitor. Extrahepatic metabolism of TNP-470 was also demonstrated using different sites of human intestinal, stomach, and kidney microsomes, with metabolite M-IV as the principal derivative detected in these tissues. Hepatic microsomal samples from seven different donors demonstrated large interindividual variations in the formation of both M-II and M-IV. In summary, this study demonstrates a rapid and extensive metabolism of TNP-470 in human tissues. The data emphasize the need to evaluate the in vivo formation and extent of TNP-470 metabolites to adequately assess the pharmacodynamic effects of this novel anticancer drug with a novel mechanism of action.
authors.affiliation: Department of Pharmacology, Center for AIDS Research, University of Alabama at Birmingham 35294, USA.
authors.forename: L
authors.initials: L
authors.lastname: Placidi
authors.forename: E
authors.initials: E
authors.lastname: Cretton-Scott
authors.forename: G
authors.initials: G
authors.lastname: de Sousa
authors.forename: R
authors.initials: R
authors.lastname: Rahmani
authors.forename: M
authors.initials: M
authors.lastname: Placidi
authors.forename: J P
authors.initials: JP
authors.lastname: Sommadossi
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000378:metabolism* / Q000493:pharmacokinetics; D001711:Biotransformation; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003510:Cyclohexanes; D005110:Extracellular Space / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000648:ultrastructure; D007424:Intracellular Fluid / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000648:ultrastructure; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D000077609:O-(Chloroacetylcarbamoyl)fumagillol; D012717:Sesquiterpenes / Q000378:metabolism* / Q000493:pharmacokinetics; D013270:Stomach / Q000648:ultrastructure; D014018:Tissue Distribution; D014316:Tritium
chemical_list: D000903:Antibiotics, Antineoplastic; D003510:Cyclohexanes; D012717:Sesquiterpenes; D014316:Tritium; D000077609:O-(Chloroacetylcarbamoyl)fumagillol