SCHWANNOMA-DERIVED GROWTH-FACTOR PROMOTES THE NEURONAL DIFFERENTIATION AND SURVIVAL OF PC12 CELLS

Schwannoma-derived growth factor (SDGF) was initially isolated from schwannoma cells as a mitogen for glial cells and fibroblasts. The present data show that SDGF causes the morphological and molecular differentiation of rat PC12 cells in a manner similar to, but distinguishable from nerve growth factor (NGF). It also promotes PC12 survival in serum-free conditions. SDGF induced changes include neurite outgrowth and the induction of the mRNAs for GAP-43 and transin, proteins which are highly expressed in axons. In addition, both SDGF and NGF induce the transcription factor, NGFI-A. The time course of the response to SDGF is similar to that for NGF. Gap-43 mRNA induction by both SDGF and NGF is inhibited by dexamethasone, but dexamethasone has no effect on NGFI-A mRNA synthesis. These observations show that SDGF has a differentiation and survival promoting effect on PC12 cells in addition to its mitogenic activity on glial cells and fibroblasts.