Increased erythroid potentiating activity/tissue inhibitor of metalloproteinases and jun/fos transcription factor complex characterize tumor promoter-induced megakaryoblastic differentiation of K562 leukemia cells

Blood. 1990 May 15;75(10):1974-82.


Molecular cloning has revealed that erythroid potentiating activity (EPA) and tissue inhibitor of metalloproteinases (TIMP) represent two distinct activities of a single protein. We have studied the expression of the EPA/TIMP gene at the mRNA and protein levels during 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced megakaryoblastic differentiation of K562 human chronic myeloid leukemia cells. Northern hybridization analysis showed that the EPA/TIMP mRNA was increased within 3 hours of TPA-induction and reached maximal levels (about 50-fold induction) during the first day of treatment. The expression of mRNAs for two major metalloproteinases, collagenase-I and stromelysin, were activated in parallel in the differentiation-induced K562 cells. The increase of EPA/TIMP mRNA correlated with increased EPA/TIMP protein biosynthesis and secretion: the TPA-induced cells secreted substantially enhanced amounts of metabolically labeled proteins, of which EPA/TIMP represented up to 50% after the first day of treatment (over 100-fold induction). The induction of EPA/TIMP mRNA was associated with its increased transcription. EPA/TIMP induction required continuous protein synthesis, being completely inhibited by addition of the protein synthesis inhibitor cycloheximide simultaneously with TPA, but only partially inhibited in a time-dependent manner if cycloheximide was added after TPA. Unlike in other cells tested, the jun and c-fos transcription factor mRNAs showed a prolonged biphasic induction response in K562 cells during TPA treatment. This response was associated with enhanced activity of a transfected recombinant reporter plasmid containing binding sites for the jun/fos transcription factor complex (AP-1) similar to the TPA-responsive element (TRE) sequence we found in the EPA/TIMP gene promoter. We suggest that the induction of EPA/TIMP and several other genes specific for the differentiating K562 cells may be a consequence of the sustained activation of immediate early genes encoding transcription factors, such as jun and c-fos.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Transformation, Neoplastic / drug effects*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression / drug effects
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Humans
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / metabolism
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology*
  • Lymphokines / genetics
  • Lymphokines / metabolism*
  • Microbial Collagenase / antagonists & inhibitors*
  • Protein Biosynthesis
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • RNA, Messenger / genetics
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Tissue Inhibitor of Metalloproteinases
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • DNA-Binding Proteins
  • Glycoproteins
  • Lymphokines
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • RNA, Messenger
  • Tissue Inhibitor of Metalloproteinases
  • Transcription Factors
  • Microbial Collagenase
  • Tetradecanoylphorbol Acetate