Concanavalin A-induced granulocyte-macrophage colony-stimulating factor production in a murine T-cell line is posttranscriptionally controlled

Exp Hematol. 1992 Feb;20(2):271-5.

Abstract

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor (HGF) that regulates the proliferation and differentiation of cells of the myeloid lineage. It can be produced by a variety of cells. One of the major sources of GM-CSF is activated T cells, which transiently produce this HGF. We used the EL-4 thymoma cell line as a model system to address the molecular basis for GM-CSF regulation in T cells. Both concanavalin A (ConA) and the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) induce GM-CSF expression in EL-4 cells. However, the biological activity of GM-CSF in the supernatants of the TPA-stimulated cells was higher than that of ConA-stimulated cells. To elucidate this difference in biological activity levels, we examined how ConA regulates GM-CSF gene expression in EL-4 cells and compared it to the better-characterized regulation by TPA. Peak mRNA levels of GM-CSF occur 6 h after stimulation with either of these two agents. GM-CSF mRNA levels after ConA treatment are lower and decrease significantly after 10 h compared to TPA treatment, which causes much higher levels that persist for at least 24 h. Neither agent alters GM-CSF gene transcription. Actinomycin D chase experiments show that ConA increases the GM-CSF mRNA half-life from less than 30 to 90 min, whereas TPA prolongs it to greater than 3 h. These results indicate that GM-CSF mRNA induction by ConA (in common with TPA) is regulated predominantly via RNA stabilization and that the difference in prolongation of the mRNA half-life provides the primary explanation for the lower levels of GM-CSF mRNA induced by ConA compared to TPA.

MeSH terms

  • Animals
  • Concanavalin A / pharmacology*
  • Dactinomycin
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation, Neoplastic / drug effects
  • Granulocyte-Macrophage Colony-Stimulating Factor / genetics
  • Granulocyte-Macrophage Colony-Stimulating Factor / metabolism*
  • Half-Life
  • Mice
  • RNA Processing, Post-Transcriptional / drug effects*
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • RNA, Neoplasm / analysis
  • RNA, Neoplasm / genetics
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / pathology*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thymoma / metabolism
  • Thymoma / pathology
  • Thymus Neoplasms / metabolism
  • Thymus Neoplasms / pathology
  • Transcription, Genetic / drug effects
  • Tumor Cells, Cultured / metabolism
  • Tumor Cells, Cultured / pathology

Substances

  • RNA, Messenger
  • RNA, Neoplasm
  • Concanavalin A
  • Dactinomycin
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • Tetradecanoylphorbol Acetate