title: Targeting the wee1 kinase for treatment of pediatric Down syndrome acute myeloid leukemia.
abstract: BACKGROUND
  Most Down syndrome children with acute myeloid leukemia (DS-AML) have an overall excellent prognosis, however, patients who suffer an induction failure or relapse, have an extremely poor prognosis. Hence, new therapies need to be developed for this subgroup of DS-AML patients. One new therapeutic approach is preventing cell cycle checkpoint activation by inhibiting the upstream kinase wee1 with the first-in-class inhibitor MK-1775 in combination with the standard genotoxic agent cytarabine (AraC).
  
  
  METHODS
  Using the clinically relevant DS-AML cell lines CMK and CMY, as well as ex vivo primary DS-AML patient samples, the ability of MK-1775 to enhance the cytotoxicity of AraC was investigated with MTT assays. The mechanism by which MK-1775 enhanced AraC cytotoxicity was investigated in the cell lines using Western blots to probe CDK1 and H2AX phosphorylation and flow cytometry to determine apoptosis, cell cycle arrest, DNA damage, and aberrant mitotic entry.
  
  
  RESULTS
  MK-1775 alone had modest single-agent activity, however, MK-1775 was able to synergize with AraC in causing proliferation arrest in both cell lines and primary patient samples, and enhance AraC-induced apoptosis. MK-1775 was able to decrease inhibitory CDK1(Y15) phosphorylation at the relatively low concentration of 100 nM after only 4 hours. Furthermore, it was able to enhance DNA damage induced by AraC and partially abrogate cell cycle arrest. Importantly, the DNA damage enhancement appeared in early S-phase.
  
  
  CONCLUSIONS
  MK-1775 is able to enhance the cytotoxicity of AraC in DS-AML cells and presents a promising new treatment approach for DS-AML.
authors: MD/PhD Program, Wayne State University School of Medicine, Detroit, Michigan; Cancer Biology Graduate Program, Wayne State University School of Medicine, Detroit, Michigan.
authors: J Timothy
authors: JT
authors: Caldwell
authors: Holly
authors: H
authors: Edwards
authors: Steven A
authors: SA
authors: Buck
authors: Yubin
authors: Y
authors: Ge
authors: Jeffrey W
authors: JW
authors: Taub
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002648:Child; D003561:Cytarabine / Q000008:administration & dosage; D004314:Down Syndrome / Q000150:complications*; D004357:Drug Synergism; D005434:Flow Cytometry; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000150:complications / Q000201:enzymology*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011720:Pyrazoles / Q000008:administration & dosage*; D011743:Pyrimidines / Q000008:administration & dosage*; D011744:Pyrimidinones; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D011720:Pyrazoles; D011743:Pyrimidines; D011744:Pyrimidinones; D003561:Cytarabine; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; C549567:adavosertib
keywords: AraC; DNA damage; Down syndrome; MK-1775; wee1