Urokinase inhibits HL-60 cell proliferation in vitro

A. L. Howell*, J. A. Hunt, T. W. James, A. Mazar, J. Henkin, L. R. Zacharski

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The binding of urokinase-type plasminogen activator (u-PA) to its receptor (u-PA-R) is required for morphological and functional maturation during monocyte differentiation of the promyelocytic leukaemia line HL-60. This paper reports that monocyte differentiation of HL-60 cells induced by 1,25 dihydroxyvitamin D2 (vitamin D2) results in a marked increase in expression of u-PA and u-PA-R. This increase in u-PA expression is of greater magnitude than is observed after culture with interferon-gamma (IFNγ), another potent inducer of monocytic differentiation. Dimethyl sulphoxide (DMSO), an agent that induces granulocytic differentiation, also increased expression of u-PA. However, culture with the granulocyte-inducing all-trans retinoic acid (RA) did not induce an increase in surface expression of u-PA or u-PA-R. The vitamin D2-induced increase in cell-surface u-PA was not coincident with an increase in steady-state levels of u-PA mRNA, suggesting that intracellular stores of this protein, translational or post-translational mechanisms of regulation, or some other regulatory mechanism may be responsible for the increase in u-PA during differentiation. To ascertain an association between the increased expression of cell-surface u-PA and reduced proliferation that accompanies differentiation, the effect of u-PA on cellular proliferation of HL-60 cells was measured. Both pro-u-PA (whole molecule) and fragments of u-PA that retained receptor-binding capability caused a marked inhibition of HL-60 proliferation in the absence of vitamin D2. A modified form of u-PA that retains receptor binding capability but lacks a fucose in the receptor binding domain (defucosylated u-PA) did not diminish HL-60 cell proliferation. These findings suggest that u-PA may regulate myeloid cell proliferation, a finding that may be relevant to the design of experimental treatment protocols for patients with myeloid leukaemia.

Original languageEnglish (US)
Pages (from-to)445-453
Number of pages9
JournalBlood Coagulation and Fibrinolysis
Volume5
Issue number4
StatePublished - Jan 1 1994

Keywords

  • myeloid leukaemia
  • proliferation
  • urokinase
  • urokinase receptor
  • vitamin D2

ASJC Scopus subject areas

  • Hematology

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  • Cite this

    Howell, A. L., Hunt, J. A., James, T. W., Mazar, A., Henkin, J., & Zacharski, L. R. (1994). Urokinase inhibits HL-60 cell proliferation in vitro. Blood Coagulation and Fibrinolysis, 5(4), 445-453.