Platelet‐derived growth factor isoforms prevent cell death during starvation of AKR‐2B fibroblasts

Abstract

Confluent AKR‐2B fibroblasts rapidly desintegrate upon removal of serum until a final density of ∼50% of the initial value was reached after 12 h. This density remained unchanged for at least 48 h. Platelet‐derived growth factor (PDGF)‐BB stimulated more than 95% of these cells to divide. PDGF‐AB or ‐BB added immediately after serum removal caused complete survival of the cells, but did not stimulate cell division as demonstrated by two‐dimensional DNA flow cytometry. PDGF‐AA was less effective leading to ∼75% of the initial cell density. This effect could be augmented by the addition of ocadaic acid, a potent phosphatase inhibitor, suggesting that protein phosphorylation plays a role in this process. By using tyrphostin AG807 it was demonstrated that the signaling mechanism for survival requires receptor tyrosine autophosphorylation.