title: Gene expression and thioguanine nucleotide disposition in acute lymphoblastic leukemia after in vivo mercaptopurine treatment.
abstract: To elucidate interpatient variability in thioguanine nucleotide (TGN) concentrations in acute lymphoblastic leukemia (ALL) cells, we determined the TGN concentrations in leukemic blasts from 82 children with newly diagnosed ALL after intravenous administration of mercaptopurine (MP). Patients treated with MP alone achieved higher TGN concentrations than those treated with the combination of methotrexate plus mercaptopurine (MTX + MP). Analysis of the expression of approximately 9600 genes in ALL cells obtained at diagnosis identified 60 gene probes significantly associated with TGN accumulation in patients treated with MP alone and 75 gene probes in patients treated with MTX + MP, with no overlap between the 2 sets of genes. Genes significantly associated with intracellular TGN accumulation after MP alone included those encoding MP metabolic enzymes and transporters (eg, SLC29A1). Inhibition of SLC29A1 by nitrobenzylmercaptopurine ribonucleoside (NBMPR) caused a 33% to 45% reduction of TGN in ALL cells in vitro (P < .006), consistent with the gene expression findings. Genes associated with TGN concentration after combination therapy included those involved in protein and adenosine triphosphate (ATP)-biosynthesis. Together, these in vivo and in vitro data provide new insight into the genomic basis of interpatient differences in intracellular TGN accumulation and reveal significant differences between treatment with MP alone and treatment with MP and MTX.
authors.affiliation: St. Jude Children's Research Hospital, 332 N Lauderdale St, Memphis, TN 38105, USA.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Zaza
authors.forename: Meyling
authors.initials: M
authors.lastname: Cheok
authors.forename: Wenjian
authors.initials: W
authors.lastname: Yang
authors.forename: John C
authors.initials: JC
authors.lastname: Panetta
authors.forename: Ching-Hon
authors.initials: CH
authors.lastname: Pui
authors.forename: Mary V
authors.initials: MV
authors.lastname: Relling
authors.forename: William E
authors.initials: WE
authors.lastname: Evans
mesh_terms: D000293:Adolescent; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D005838:Genotype; D006150:Guanine Nucleotides / Q000378:metabolism*; D006801:Humans; D015122:Mercaptopurine / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010641:Phenotype; D010802:Phylogeny; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000235:genetics*; D013873:Thionucleotides / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D006150:Guanine Nucleotides; D013873:Thionucleotides; C003964:6-thioguanylic acid; D015122:Mercaptopurine