title: The Stat3/5 Signaling Biosignature in Hematopoietic Stem/Progenitor Cells Predicts Response and Outcome in Myelodysplastic Syndrome Patients Treated with Azacitidine.
abstract: OBJECTIVE
  Azacitidine is the mainstay of high-risk myelodysplastic syndromes (MDS) therapy, but molecular predictors of response and the mechanisms of resistance to azacitidine remain largely unidentified. Deregulation of signaling via Stat3 and Stat5 in acute myeloid leukemia (AML) is associated with aggressive disease. Numerous genes involved in cell signaling are aberrantly methylated in MDS, yet the alterations and the effect of azacitidine treatment on Stat3/5 signaling in high-risk MDS have not been explored.
  
  
  METHODS
  We assessed longitudinally constitutive and ligand-induced phospho-Stat3/5 signaling responses by multiparametric flow cytometry in 74 patients with MDS and low blast count AML undergoing azacitidine therapy. Pretreatment Stat3/5 signaling profiles in CD34(+)cells were grouped by unsupervised clustering. The differentiation stage and the molecular properties of the CD34(+)G-CSF-inducible Stat3/5 double-positive subpopulation were performed by flow cytometry and quantitative real-time PCR in isolated MDS progenitors.
  
  
  RESULTS
  The pretreatment Stat3/5 signaling profiles in CD34(+)cells correlated strongly with response and cytogenetics and independently predicted event-free survival. We further identified a CD34(+)G-CSF-inducible Stat3/5 double-positive subpopulation (DP subset) whose pretreatment levels were inversely associated with treatment response and cytogenetics. The kinetics of the DP subset followed the response to azacitidine and the disease course, whereas its molecular characteristics and cellular hierarchy were consistent with a leukemia propagating cell phenotype.
  
  
  CONCLUSIONS
  Our findings provide a novel link among Stat3/5 signaling and MDS pathobiology and suggest that the Stat3/5 signaling biosignature may serve as both a response biomarker and treatment target.
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Miltiades
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Lamprianidou
authors.affiliation: Department of Hematology, Laikon General Hospital, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Theodoros P
authors.initials: TP
authors.lastname: Vassilakopoulos
authors.affiliation: Second Department of Internal Medicine, Hematology Unit, Attikon University General Hospital, Athens, Greece.
authors.forename: Sotirios G
authors.initials: SG
authors.lastname: Papageorgiou
authors.affiliation: Department of Clinical Hematology, G. Gennimatas Hospital, Athens, Greece.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Galanopoulos
authors.affiliation: Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Christos K
authors.initials: CK
authors.lastname: Kontos
authors.affiliation: Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Panagiotis G
authors.initials: PG
authors.lastname: Adamopoulos
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Nakou
authors.affiliation: Second Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Hippokration Hospital, Thessaloniki, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Vakalopoulou
authors.affiliation: Second Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Hippokration Hospital, Thessaloniki, Greece.
authors.forename: Vassilia
authors.initials: V
authors.lastname: Garypidou
authors.affiliation: Department of Haematology, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Papaioannou
authors.affiliation: Department of Hematology, Theageneion Hospital of Thessaloniki, Thessaloniki, Greece.
authors.forename: Evdoxia
authors.initials: E
authors.lastname: Hatjiharissi
authors.affiliation: Department of Hematology, University Hospital of Heraklion, Heraklion, Greece.
authors.forename: Helen A
authors.initials: HA
authors.lastname: Papadaki
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Emmanuil
authors.initials: E
authors.lastname: Spanoudakis
authors.affiliation: Second Department of Internal Medicine, Hematology Unit, Attikon University General Hospital, Athens, Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Pappa
authors.affiliation: Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Scorilas
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Tsatalas
authors.affiliation: Department of Hematology, Democritus University of Thrace, Alexandroupolis, Greece. ikotsian@med.duth.gr.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kotsianidis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001374:Azacitidine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D015415:Biomarkers; D016000:Cluster Analysis; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism* / Q000401:mortality; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism; D010641:Phenotype; D011379:Prognosis; D020543:Proteome; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D000964:Antimetabolites, Antineoplastic; D015415:Biomarkers; D020543:Proteome; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; D016179:Granulocyte Colony-Stimulating Factor; D001374:Azacitidine