title: Overexpression of SET is a recurrent event associated with poor outcome and contributes to protein phosphatase 2A inhibition in acute myeloid leukemia.
abstract: BACKGROUND
  Protein phosphatase 2A is a novel potential therapeutic target in several types of chronic and acute leukemia, and its inhibition is a common event in acute myeloid leukemia. Upregulation of SET is essential to inhibit protein phosphatase 2A in chronic myeloid leukemia, but its importance in acute myeloid leukemia has not yet been explored.
  
  
  METHODS
  We quantified SET expression by real time reverse transcriptase polymerase chain reaction in 214 acute myeloid leukemia patients at diagnosis. Western blot was performed in acute myeloid leukemia cell lines and in 16 patients' samples. We studied the effect of SET using cell viability assays. Bioinformatics analysis of the SET promoter, chromatin immunoprecipitation, and luciferase assays were performed to evaluate the transcriptional regulation of SET.
  
  
  RESULTS
  SET overexpression was found in 60/214 patients, for a prevalence of 28%. Patients with SET overexpression had worse overall survival (P<0.01) and event-free survival (P<0.01). Deregulation of SET was confirmed by western blot in both cell lines and patients' samples. Functional analysis showed that SET promotes proliferation, and restores cell viability after protein phosphatase 2A overexpression. We identified EVI1 overexpression as a mechanism involved in SET deregulation in acute myeloid leukemia cells.
  
  
  CONCLUSIONS
  These findings suggest that SET overexpression is a key mechanism in the inhibition of PP2A in acute myeloid leukemia, and that EVI1 overexpression contributes to the deregulation of SET. Furthermore, SET overexpression is associated with a poor outcome in acute myeloid leukemia, and it can be used to identify a subgroup of patients who could benefit from future treatments based on PP2A activators.
authors: Division of Oncology, Center for Applied Medical Research (CIMA), University of Navarra, Pio XII-55 31008 Pamplona, Spain.
authors: Ion
authors: I
authors: Cristóbal
authors: Laura
authors: L
authors: Garcia-Orti
authors: Cristina
authors: C
authors: Cirauqui
authors: Xabier
authors: X
authors: Cortes-Lavaud
authors: María A
authors: MA
authors: García-Sánchez
authors: María J
authors: MJ
authors: Calasanz
authors: María D
authors: MD
authors: Odero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics; D004268:DNA-Binding Proteins; D005260:Female; D015870:Gene Expression; D015973:Gene Expression Regulation, Leukemic; D056488:Histone Chaperones / Q000235:genetics*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000235:genetics* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors; D012008:Recurrence; D014157:Transcription Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; D056488:Histone Chaperones; C513473:SET protein, human; D014157:Transcription Factors; D054648:Protein Phosphatase 2