title: In vitro and in vivo single-agent efficacy of checkpoint kinase inhibition in acute lymphoblastic leukemia.
abstract: BACKGROUND
  Although progress in children, in adults, ALL still carries a dismal outcome. Here, we explored the in vitro and in vivo activity of PF-00477736 (Pfizer), a potent, selective ATP-competitive small-molecule inhibitor of checkpoint kinase 1 (Chk1) and with lower efficacy of checkpoint kinase 2 (Chk2).
  
  
  METHODS
  The effectiveness of PF-00477736 as single agent in B-/T-ALL was evaluated in vitro and in vivo studies as a single agent. The efficacy of the compound in terms of cytotoxicity, induction of apoptosis, and changes in gene and protein expression was assessed using different B-/T-ALL cell lines. Finally, the action of PF-00477736 was assessed in vivo using leukemic mouse generated by a single administration of the tumorigenic agent N-ethyl-N-nitrosourea.
  
  
  RESULTS
  Chk1 and Chk2 are overexpressed concomitant with the presence of genetic damage as suggested by the nuclear labeling for γ-H2A.X (Ser139) in 68 % of ALL patients. In human B- and T-ALL cell lines, inhibition of Chk1/2 as a single treatment strategy efficiently triggered the Chk1-Cdc25-Cdc2 pathway resulting in a dose- and time-dependent cytotoxicity, induction of apoptosis, and increased DNA damage. Moreover, treatment with PF-00477736 showed efficacy ex vivo in primary leukemic blasts separated from 14 adult ALL patients and in vivo in mice transplanted with T-ALL, arguing in favor of its future clinical evaluation in leukemia.
  
  
  CONCLUSIONS
  In vitro, ex vivo, and in vivo results support the inhibition of Chk1 as a new therapeutic strategy in acute lymphoblastic leukemia, and they provide a strong rationale for its future clinical investigation.
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy. ilaria.iacobucci2@unibo.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Iacobucci
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Andrea Ghelli Luserna
authors.initials: AG
authors.lastname: Di Rorà
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
authors.forename: Maria Vittoria Verga
authors.initials: MV
authors.lastname: Falzacappa
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Agostinelli
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Derenzini
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Ferrari
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Papayannidis
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Lonetti
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Righi
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Imbrogno
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Pomella
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Venturi
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Guadagnuolo
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.|Hematology and BMT Unit, University of Brescia, Brescia, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Cattina
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Ottaviani
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Abbenante
authors.affiliation: Division of Hematology, Department of Cellular Biotechnologies and Hematology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Vitale
authors.affiliation: Division of Hematology, Department of Cellular Biotechnologies and Hematology, "Sapienza" University of Rome, Rome, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Elia
authors.affiliation: Hematology and BMT Unit, University of Brescia, Brescia, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Russo
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Zinzani
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pileri
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Pelicci
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology "L. e A. Seragnoli", University of Bologna, Bologna, Italy. giovanni.martinelli2@unibo.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martinelli
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001570:Benzodiazepinones / Q000494:pharmacology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D000071877:Checkpoint Kinase 1; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling / Q000379:methods; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D006801:Humans; D007942:Leukemia, Experimental / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology*; D016019:Survival Analysis
chemical_list: D001570:Benzodiazepinones; C532366:PF 00477736; D047428:Protein Kinase Inhibitors; D011720:Pyrazoles; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse