Regulation of Apoptosis in Interleukin-3-Dependent Myeloid Progenitor Cells

Apoptosis plays an important role in the regulation of hematopoiesis by deleting growth factor-dependent progenitors following physiologic reductions in hemopoietins.1,2 To examine signalling pathways which may influence apoptosis in hematopoietic progenitors we have utilized the Interleukin-3 (IL-3) dependent 32Dcl3 murine myeloid cell line. 32D cells are absolutely dependent upon IL-3 for proliferation and survival,3,4 and have no propensity for developing factor-independent growth. In the absence of IL-3, 32D cells rapidly arrest in the Gl phase of the cell cycle and eventually undergo apoptosis.5