title: AKT-mediated regulation of polarization in differentiated human neutrophil-like HL-60 cells.
abstract: OBJECTIVE
  Neutrophil polarization is critical for the inflammatory response. AKT is a serine/threonine protein kinase and has been implicated in cell migration. However, it is not completely clear whether AKT affects neutrophil polarization. In this study, we tested the hypothesis that AKT regulates the polarization of neutrophil-like differentiated HL-60 cells (dHL-60) in response to fMLP.
  
  
  METHODS
  HL-60 cells were differentiated into dHL-60 by incubation in medium containing 1.3 % DMSO for up to 6 days. Polarization of dHL-60 cells and primary human neutrophils were measured by Zigmond chamber. Phospho-Akt was analyzed by immunofluorescence and Western blot analysis. F-actin polymerization was detected by Rhodamine-Phalloidine staining. Rac2 activation was evaluated using GST Pull-down assay.
  
  
  RESULTS
  We found that changes in the rate of cell polarization were consistent with the changes in AKT phosphorylation levels during HL-60 cell differentiation in response to fMLP. Moreover, cell polarization and AKT phosphorylation were reduced in fMLP-stimulated dHL-60 cells pretreated with the PI3 kinase inhibitors or the AKT inhibitors, which was confirmed in the primary human neutrophils. The AKT inhibitors altered fMLP-induced F-actin polymerization. Rac2 GTPases was also decreased by the AKT inhibitors in fMLP-stimulated dHL-60 cells.
  
  
  CONCLUSIONS
  This study demonstrates that AKT activation plays a crucial role in dHL-60 cell polarization.
authors.affiliation: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Zou
authors.forename: Xinwei
authors.initials: X
authors.lastname: Chu
authors.forename: Chunqing
authors.initials: C
authors.lastname: Cai
authors.forename: Mengchen
authors.initials: M
authors.lastname: Zou
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Meng
authors.forename: Haiyang
authors.initials: H
authors.lastname: Chen
authors.forename: Fei
authors.initials: F
authors.lastname: Zou
mesh_terms: D000199:Actins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002633:Chemotaxis; D018922:HL-60 Cells; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D000097766:RAC2 GTP-Binding Protein
chemical_list: D000199:Actins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D051057:Proto-Oncogene Proteins c-akt; D020744:rac GTP-Binding Proteins; D000097766:RAC2 GTP-Binding Protein