title: The HPB-AML-I cell line possesses the properties of mesenchymal stem cells.
abstract: BACKGROUND
  In spite of its establishment from the peripheral blood of a case with acute myeloid leukemia (AML)-M1, HPB-AML-I shows plastic adherence with spindle-like morphology. In addition, lipid droplets can be induced in HPB-AML-I cells by methylisobutylxanthine, hydrocortisone, and indomethacin. These findings suggest that HPB-AML-I is similar to mesenchymal stem cells (MSCs) or mesenchymal stromal cells rather than to hematopoietic cells.
  
  
  METHODS
  To examine this possibility, we characterized HPB-AML-I by performing cytochemical, cytogenetic, and phenotypic analyses, induction of differentiation toward mesenchymal lineage cells, and mixed lymphocyte culture analysis.
  
  
  RESULTS
  HPB-AML-I proved to be negative for myeloperoxidase, while surface antigen analysis disclosed that it was positive for MSC-related antigens, such as CD29, CD44, CD55, CD59, and CD73, but not for CD14, CD19, CD34, CD45, CD90, CD105, CD117, and HLA-DR. Karyotypic analysis showed the presence of complicated abnormalities, but no reciprocal translocations typically detected in AML cases. Following the induction of differentiation toward adipocytes, chondrocytes, and osteocytes, HPB-AML-I cells showed, in conjunction with extracellular matrix formation, lipid accumulation, proteoglycan synthesis, and alkaline phosphatase expression. Mixed lymphocyte culture demonstrated that CD3+ T-cell proliferation was suppressed in the presence of HPB-AML-I cells.
  
  
  CONCLUSIONS
  We conclude that HPB-AML-I cells appear to be unique neoplastic cells, which may be derived from MSCs, but are not hematopoietic progenitor cells.
authors.affiliation: Division of Molecular Medicine and Medical Genetics, Department of Pathology, Graduate School of Medicine, Kobe University, Kobe, Japan. bambang.ardianto@gmail.com
authors.forename: Bambang
authors.initials: B
authors.lastname: Ardianto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Seiji
authors.initials: S
authors.lastname: Kawano
authors.forename: Shimpei
authors.initials: S
authors.lastname: Kasagi
authors.forename: Siti N A
authors.initials: SN
authors.lastname: Jauharoh
authors.forename: Chiyo
authors.initials: C
authors.lastname: Kurimoto
authors.forename: Eiji
authors.initials: E
authors.lastname: Tatsumi
authors.forename: Keiko
authors.initials: K
authors.lastname: Morikawa
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kumagai
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D002454:Cell Differentiation / Q000502:physiology; D045744:Cell Line, Tumor / Q000166:cytology* / Q000502:physiology*; D019070:Cell Lineage; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology*; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000502:physiology*