Different regulation of plasminogen activator inhibitor 2 gene expression by phorbol ester and cAMP in human myeloid leukemia cell line PL-21

Thromb Haemost. 1994 Jul;72(1):92-7.

Abstract

Previous studies have shown that protein kinase C (PKC) activators and dibutyryl cyclic AMP (Bt2cAMP) synergistically increase the antigen level of plasminogen activator inhibitor type-2 (PAI-2) in a human myeloid leukemia cell line PL-21. To clarify the mechanism, PAI-2 gene expression induced by phorbol myristate acetate (PMA), a PKC activator, and Bt2cAMP was investigated by Northern blot hybridization using a PAI-2 cDNA probe cloned from a human placental library. The level of PAI-2 mRNA was markedly increased in response to PMA and reached a maximum 5-9 h after stimulation. Nuclear run-on assay revealed an increase in PAI-2 gene transcription in PMA-treated cells. The induction was inhibited by inhibiting de novo protein synthesis with cycloheximide (CHX). cAMP also increased PAI-2 mRNA level in a dose-dependent manner. The increase began within 2 hours and, contrary to the case of PMA, the mRNA levels were maintained. Moreover, cAMP-induced increase in PAI-2 mRNA was not inhibited by CHX, rather enhanced. PMA and cAMP synergistically induced PAI-2 gene expression, which was completely inhibited by CHX. The cells pretreated with PMA for 24 h did not any more respond to stimulation with PMA but responded to cAMP and PAI-2 mRNA level was increased. The apparent half-life of constitutive level PAI-2 mRNA in PL-21 cells, determined by actinomycin-D-decay experiments, was approximately 2 h. Those induced by PMA and cAMP were approximately 5 h and 2 h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bucladesine / antagonists & inhibitors
  • Bucladesine / pharmacology*
  • Cycloheximide / pharmacology
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Humans
  • Leukemia, Myeloid / genetics*
  • Plasminogen Activator Inhibitor 2 / genetics*
  • RNA, Messenger / biosynthesis
  • Tetradecanoylphorbol Acetate / antagonists & inhibitors
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Transcription, Genetic / drug effects
  • Tumor Cells, Cultured

Substances

  • Plasminogen Activator Inhibitor 2
  • RNA, Messenger
  • Bucladesine
  • Cycloheximide
  • Tetradecanoylphorbol Acetate