title: In vitro and in vivo irinotecan-induced changes in expression profiles of cell cycle and apoptosis-associated genes in acute myeloid leukemia cells.
abstract: OBJECTIVE
  To study irinotecan (CPT-11)-induced changes in expression profiles of genes associated with cell cycle control and apoptosis in myeloid leukemia cells in vitro and in vivo.
  
  
  METHODS
  HL60 cells were exposed to clinically achievable concentrations of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of CPT-11, and blood sampled from patients with acute myeloid leukemia and chronic myeloid leukemia in myeloid blast transformation treated with CPT-11. Gene expression changes were studied by cDNA microarray and correlated with biological responses by studying DNA distributions by flow cytometry.
  
  
  RESULTS
  cDNA microarray analysis showed down-regulation and up-regulation of specific cell cycle-associated genes, consistent with loss of S-phase cells and temporary delay of G(1)-S-phase transition seen by flow cytometry. Flow cytometry showed that cells in S phase during SN-38 exposure underwent apoptosis, whereas cells in G(2)-M and G(1) were delayed in G(1) and entered S phase only 6 to 8 hours after drug removal, consistent with the observed changes in gene expression. Proapoptotic changes in gene transcription included down-regulation of antiapoptotic genes and up-regulation of proapoptotic genes. Many gene expression changes observed following in vitro SN-38 exposure were also seen following in vivo administration of 10 or 15 mg/m(2) CPT-11; notably, proapoptotic changes included reduced transcription of survivin pathway-associated genes and increased transcription of death receptor 5.
  
  
  CONCLUSIONS
  CPT-11-induced changes in gene expression profiles in vitro and in vivo are consistent with temporary delay in G(1)-S transition and enhanced responsiveness to apoptosis, both of which may contribute to the synergistic interactions of this drug with antimetabolites.
authors.affiliation: Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. hans.minderman@roswellpark.org
authors.forename: Hans
authors.initials: H
authors.lastname: Minderman
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Conroy
authors.forename: Kieran L
authors.initials: KL
authors.lastname: O'Loughlin
authors.forename: Devin
authors.initials: D
authors.lastname: McQuaid
authors.forename: Paul
authors.initials: P
authors.lastname: Quinn
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Pendyala
authors.forename: Norma J
authors.initials: NJ
authors.lastname: Nowak
authors.forename: Maria R
authors.initials: MR
authors.lastname: Baer
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics*; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects* / Q000235:genetics; D018922:HL-60 Cells; D006801:Humans; D000077146:Irinotecan; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D015203:Reproducibility of Results; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D000077146:Irinotecan; D002166:Camptothecin