title: Properties of recombinant human N1-acetylpolyamine oxidase (hPAO): potential role in determining drug sensitivity.
abstract: The recent cloning of the mammalian gene coding for N(1)-acetylpolyamine oxidase (PAO) provides the opportunity to directly examine the role of human PAO (hPAO) in polyamine homeostasis as well as its potential role in determining cellular response to antitumor polyamine analogues. To facilitate the study of this enzyme, the production, purification, and characterization of the recombinant hPAO is reported. hPAO oxidizes N(1)-acetylspermidine (K(m)=2.1 microM, K(cat)=15.0 s(-1)) and has very high affinity for N(1)-acetylspermine (K(m)=0.85 microM, K(cat)=31.7 s(-1)). The recombinant hPAO does not efficiently oxidize spermine, thereby demonstrating a significant difference in substrate specificity from the previously described human spermine oxidase PAOh1/SMO. Importantly, hPAO demonstrates the ability to oxidize a subset of antitumor polyamine analogues, suggesting that this oxidase activity could have a significant effect on determining tumor sensitivity to these or similar agents. Transfection of A549 human lung cancer cells with an hPAO-expressing plasmid leads to a profound decrease in sensitivity to those analogues which act as substrates, confirming its potential to alter drug response. One similarity that hPAO shares with human PAOh1/SMO, is that certain oligoamine analogues are potent inhibitors of its oxidase activity. The results of these studies demonstrate how changes in polyamine catabolism may affect drug response.
authors.affiliation: The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Wang
authors.forename: Amy
authors.initials: A
authors.lastname: Hacker
authors.forename: Tracy
authors.initials: T
authors.lastname: Murray-Stewart
authors.forename: Benjamin
authors.initials: B
authors.lastname: Frydman
authors.forename: Aldonia
authors.initials: A
authors.lastname: Valasinas
authors.forename: Alison V
authors.initials: AV
authors.lastname: Fraser
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Woster
authors.forename: Robert A
authors.initials: RA
authors.lastname: Casero
mesh_terms: D019008:Drug Resistance, Neoplasm; D006706:Homeostasis; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics* / Q000494:pharmacology*; D011073:Polyamines / Q000378:metabolism*; D011994:Recombinant Proteins; D013096:Spermine / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D000097667:Polyamine Oxidase
chemical_list: D000587:Oxidoreductases Acting on CH-NH Group Donors; D011073:Polyamines; D011994:Recombinant Proteins; D013096:Spermine; D000097667:Polyamine Oxidase; C501650:N(1)-acetylpolyamine oxidase, human