title: Wnt signaling is involved in 6-benzylthioinosine-induced AML cell differentiation.
abstract: BACKGROUND
  We previously demonstrated that 6-benzylthioinosine (6-BT) could induce the differentiation of a subset of acute myeloid leukemia (AML) cell lines and primary AML cells regardless of their cytogenetics. In this study we investigated whether Wnt signaling pathways played roles in 6-BT-induced differentiation of AML cells.
  
  
  METHODS
  We induced differentiation of HL-60 leukemic cells and primary AML cells in vitro using 6-BT. Real-time PCR (qPCR), western blot, and luciferase assays were used to examine the molecules' expression and biological activity in canonical and noncanonical Wnt signaling pathways. AML cell differentiation was measured by the Nitroblue tetrozolium (NBT) reduction assay.
  
  
  RESULTS
  6-BT regulated the expression of both canonical and non-canonical Wnt signaling molecules in HL-60 cells. Both 6-BT and all-trans-retinoic-acid (ATRA) reduced canonical Wnt signaling and activated noncanonical Wnt/Ca2+ signaling in HL-60 cells. Pre-treatment of HL-60 cells with an inhibitor of glycogen synthase kinase-3β (GSK-3β), which activated canonical Wnt signaling, partly abolished the differentiation of HL-60 cells induced by 6-BT. Pre-treatment of HL-60 cells with an inhibitor of protein kinase C (PKC), resulting in inactivation of non-canonical Wnt/Ca2+ signaling, abolished 6-BT-induced differentiation of HL-60 cells. Several molecules in the non-canonical Wnt/Ca2+ pathway were detected in bone marrow samples from AML patients, and the expression of FZD4, FZD5, Wnt5a and RHOU were significantly reduced in newly diagnosed AML samples compared with normal controls.
  
  
  CONCLUSIONS
  Both canonical and non-canonical Wnt signaling were involved in 6-BT-induced differentiation of HL-60 cells, and played opposite roles in this process. Wnt signaling could be involved in the pathogenesis of AML not only by regulating self-renewal of hematopoietic stem cells, but also by playing a role in the differentiation of AML cells.
authors.forename: Shaolei
authors.initials: S
authors.lastname: Zang
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.forename: Hongchun
authors.initials: H
authors.lastname: Wang
authors.forename: David N
authors.initials: DN
authors.lastname: Wald
authors.forename: Na
authors.initials: N
authors.lastname: Shao
authors.forename: Jingru
authors.initials: J
authors.lastname: Zhang
authors.forename: Daoxin
authors.initials: D
authors.lastname: Ma
authors.affiliation: Department of Hematology, Qilu Hospital, Shandong University, 107 West Wenhua Road, Jinan, Shandong 250012, P,R, China. jichunyan@sdu.edu.cn.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Ji
authors.forename: William
authors.initials: W
authors.lastname: Tse
mesh_terms: D020013:Calcium Signaling; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D018922:HL-60 Cells; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D013868:Thioinosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology; D060449:Wnt Signaling Pathway / Q000187:drug effects*
chemical_list: C485108:6-benzylthioinosine; D013868:Thioinosine; D014212:Tretinoin