Induced cell surface expression of functional alpha 2 beta 1 integrin during megakaryocytic differentiation of K562 leukemic cells

Exp Cell Res. 1992 Sep;202(1):28-35. doi: 10.1016/0014-4827(92)90400-3.


The pluripotential hematopoietic cell line K562 was studied as a model of inducible integrin expression accompanying differentiation. Differentiation along the megakaryocytic pathway was induced with phorbol 12,13-dibutyrate and differentiation along the erythroid pathway with hemin. Induction of megakaryocytic differentiation was associated with changes in cell morphology and with increased cell-cell and cell-substrate adhesion and spreading. Erythroid differentiation was not associated with changes in morphology or adhesion. Cell surface expression of the IIb-IIIa and alpha 2 beta 1 integrins increased markedly with phorbol treatment but decreased with hemin treatment. Phorbol-treated K562 cells, but not control cells or hemin-treated cells, adhered to collagen substrates in a Mg(2+)-dependent manner which was specifically inhibited by a monoclonal antibody directed against the alpha 2 beta 1 integrin. Northern blot analysis revealed that megakaryocytic differentiation of K562 cells was accompanied by de novo expression of the alpha 2 integrin mRNA with no change in the level of mRNA for the beta 1 subunit. K562 cells provide a model of differentiation-dependent, regulated integrin expression in which expression is up- or down-regulated depending upon the differentiation pathway selected.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies
  • Antibodies, Monoclonal
  • Cell Adhesion / drug effects
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology*
  • Cell Line
  • Cell Membrane / metabolism
  • Hemin / pharmacology*
  • Humans
  • Integrins / biosynthesis*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive
  • Megakaryocytes / cytology*
  • Phorbol 12,13-Dibutyrate / pharmacology*


  • Antibodies
  • Antibodies, Monoclonal
  • Integrins
  • Phorbol 12,13-Dibutyrate
  • Hemin