EFFECTS OF NERVE GROWTH-FACTOR, INSULIN, AND EXTRACELLULAR-MATRIX PROTEINS ON THE NEURITE OUTGROWTH OF SK-N-BE(2) HUMAN NEUROBLASTOMA-CELLS

Neurite outgrowth was measured in SK-N-BE(2) [BE(2)] cells treated wit h nerve growth factor (NGF), insulin, or extracellular matrix (ECM) pr oteins to examine neuronal differentiation of this cell line, No morph ological change or neurite formation were observed in the cells treate d with either NGF or insulin, while cells cultured on the either lamin in- or collagen-coated plate formed neurites, Immunoblotting and immun oprecipitation experiments indicate that BE(2) cells have a focal adhe sion kinase (FAK), which is activated by either collagen or laminin, T o figure out why BE(2) cells did not respond to NGF or insulin, tyrosi ne-phosphorylated components were analyzed in the anti-Ras immunopreci pitates from NGF or insulin-treated cells, Tyrosine phosphorylation wa s increased slightly in a few proteins in the anti-Ras immunoprecipita tes from either NGF or insulin treated BE(2) cells, while more tyrosin e phosphorylated proteins and increased phosphorylation of each compon ent was observed in the anti-Ras immunopreipitates from insulin-treate d PC12 cells, However, the existence of insulin receptor in BE(2) cell s was confirmed using anti-insulin receptor immunoblotting. These resu lts indicate that BE(2) cells have a signaling system for NGF and insu lin is abnormal between receptors and Ras.