v-raf suppresses apoptosis and promotes growth of interleukin-3-dependent myeloid cells

Oncogene. 1994 Aug;9(8):2217-26.

Abstract

Interleukin-3 (IL-3) is required for the proliferation, survival and differentiation of myeloid progenitors. In the absence of IL-3, murine myeloid 32D.3 cells accumulate in the G1 phase of the cell cycle and subsequently undergo programmed cell death, or apoptosis. Here we demonstrate that enforced expression of the v-raf oncogene suppresses apoptosis of myeloid 32D.3 cells following the withdrawal of IL-3. Surprisingly, steady state levels of Bcl-2, an oncogene known to suppress apoptosis, were not dependent upon IL-3 in 32D.3 cells and its levels were not augmented in v-raf clones. This suggests that ability of v-raf to suppress apoptosis in the absence of ligand is either Bcl-2 independent or that v-raf kinase promotes Bcl-2 function. v-raf also promoted growth of these cells in the presence of IL-3. v-raf clones proliferated at an increased rate due to a shortened G1 phase and had decreased requirements for IL-3 for growth. Therefore, transformation of myeloid cells by v-raf involves signaling pathways which promote both cell cycle progression and cell survival.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis*
  • Bone Marrow Cells*
  • Cell Division
  • Cells, Cultured
  • Genes, myc
  • Interleukin-3 / physiology*
  • Mice
  • Oncogene Proteins v-raf
  • Proto-Oncogene Proteins / physiology
  • Proto-Oncogene Proteins c-bcl-2
  • Retroviridae Proteins, Oncogenic / genetics
  • Retroviridae Proteins, Oncogenic / physiology*
  • Signal Transduction

Substances

  • Interleukin-3
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Retroviridae Proteins, Oncogenic
  • Oncogene Proteins v-raf