title: Long-term culture of primary human lymphoblastic leukemia cells in the absence of serum or hematopoietic growth factors.
abstract: OBJECTIVE
  B-lineage acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia in lymphatic blastic phase in adults have poor prognoses despite intensive chemotherapy. Novel targeted treatment modalities emerge, but their evaluation requires relevant in vitro models of lymphoblastic leukemia. Presently available cell lines do not fully represent this heterogeneous disease. Available in vitro culturing protocols do not support long-term proliferation of primary cells. We therefore aimed to develop a culture system that allows long-term proliferation of primary human B-lineage lymphoblastic leukemia.
  
  
  METHODS
  Primary lymphoblastic leukemia cells were cultured in a defined serum-free medium, in the absence or presence of human hematopoietic growth factors or serum.
  
  
  RESULTS
  In the defined serum-free medium, cells from 12 of 34 cases immediately proliferated in vitro. In the absence of hematopoietic growth factors and serum these cases proliferated for more than 1 year without signs of exhaustion. The culturing system supported different subtypes of lymphoblastic leukemia. Two chronic myeloid leukemia in lymphatic blastic phase, four bcr/abl-positive ALL, one etv6/abl-positive ALL, 2 e2a-pbx1-positive ALL, and one t(9;11)-positive ALL could be long-term expanded, as well as two ALL that displayed nontypical cytogenetics. Not all bcr/abl- or e2a-pbx1-positive ALL proliferated in vitro, demonstrating heterogeneity within these subtypes. The proliferating bcr/abl- and etv6/abl-positive cells displayed sensitivity to imatinib, demonstrating that their proliferation depended on the activity of these oncoproteins.
  
  
  CONCLUSIONS
  The serum-free culturing system may be a valuable instrument in the study of ALL cell biology, as well as in the evaluation of novel targeted therapeutics.
authors.affiliation: Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands. b.a.nijmeijer@lumc.nl
authors.forename: Bart A
authors.initials: BA
authors.lastname: Nijmeijer
authors.forename: Karoly
authors.initials: K
authors.lastname: Szuhai
authors.forename: Henriëtte M
authors.initials: HM
authors.lastname: Goselink
authors.forename: Marianke L J
authors.initials: ML
authors.lastname: van Schie
authors.forename: Marja
authors.initials: M
authors.lastname: van der Burg
authors.forename: Danielle
authors.initials: D
authors.lastname: de Jong
authors.forename: Erik W
authors.initials: EW
authors.lastname: Marijt
authors.forename: Oliver G
authors.initials: OG
authors.lastname: Ottmann
authors.forename: Roel
authors.initials: R
authors.lastname: Willemze
authors.forename: J H Frederik
authors.initials: JH
authors.lastname: Falkenburg
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D016895:Culture Media, Serum-Free; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D015448:Leukemia, B-Cell / Q000473:pathology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology*; D013997:Time Factors
chemical_list: D016895:Culture Media, Serum-Free; D036341:Intercellular Signaling Peptides and Proteins