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In vitro ‐generated stem cell leukaemia showing altered cell cycle progression with distinct signalling of the tyrosine‐phosphorylated rasGAP‐associated p62 dok protein
Author(s) -
Huss Ralf,
Weissinger Eva M.,
Lange Claudia,
Gatsios Petros,
Eissner Günther,
Kolb HansJochem,
Diebold Joachim,
Heinrich Peter C.,
Graeve Lutz
Publication year - 2000
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/1096-9896(2000)9999:9999<::aid-path716>3.0.co;2-n
Subject(s) - biology , microbiology and biotechnology , cell cycle , tyrosine phosphorylation , progenitor cell , stem cell , haematopoiesis , transfection , cell growth , cell culture , cyclin a , cyclin d1 , cancer research , phosphorylation , cell , genetics
In an attempt to gain more insight into the events of leukaemic transformation, a cell line overexpressing MHC class II (DR) was generated by transfecting an early CD34‐negative haematopoietic progenitor stem cell line with the appropriate constructs. The stable transfection with genes for DR antigens leads to cellular transformation. The DR + transformed cell clones express a tyrosine‐phosphorylated DR heterodimer and show a significantly different morphology. DR + clones present the morphology of an immature myeloid neoplasia expressing α‐naphthyl‐acetate‐esterase (ANAE), but neither myeloperoxidase nor CD34. While D064 cells predominately grow adherent as fibroblast‐like cells, the DR + clones display a decrease in adherent growth. Although both cell lines express similar amounts of the interleukin‐6 (IL‐6) signal transducer gp130, the DR‐transfected cells still show activation of STAT factors by IL‐6, whereas D064 cells do not. Although the transformed clones present acceleration of cell‐cycle transition and growth, the G 0 /G 1 progression inhibitor p27 kip‐1 is up‐regulated, while the expression of proteins involved in the S/G 2 phase transition, such as cyclin B and cdc2 (p34), is suppressed. Instead cyclin D3, one of the G 0 /G 1 progression factors, is up‐regulated, as well as tyrosine‐phosphorylated p62 dok , suggesting dysregulation of cell cycle‐controlling proteins. In addition, DR + leukaemia‐like cells also overexpress Bcl‐2, while bax expression is suppressed, compared with the wild‐type (wt) parental haematopoietic stem cell line. Copyright © 2000 John Wiley & Sons, Ltd.