1,1,3 tricyano-2-amino-1-propene (Triap): a small molecule which mimics or potentiates nerve growth factor

1,1,3 Tricyano-2-amino-1-propene (Triap) is a small molecular weight compound which increases the rate of nerve and tissue regeneration in several experimental systems. Early experiments with this compound showed that, like nerve growth factor (NGF), Triap induced neurite formation in chick spinal ganglia. To assess the similarity between NGF and Triap, we compared the effects of Triap and NGF on a rat pheochromocytoma cell line (PC12) and on cell survival in a primary chick neuronal culture. In the latter, Triap at less than 0.01 nM preserved neurons and caused them to extend neurites as did 1 nM NGF. Triap induced neurite outgrowth in the PC12 cell line giving a maximal response (40-50% of the maximal response of NGF) at a concentration of 20 micrograms/ml (151 microM). Triap's morphological effects were not inhibited by antibodies directed against NGF or the NGF receptor. Low concentrations of Triap also potentiated the morphological effects of NGF. Triap induced an increase in cell-substratum adhesion and cellular hypertrophy in PC12 cells and also potentiated the adhesive actions of NGF. Triap had no effect on ornithine decarboxylase activity even though it potentiated NGF's effects on this enzyme. These data indicate that Triap induces neurotrophic effects and does not seem to act through the same mechanisms as NGF but can potentiate many of NGF's morphological and biochemical actions.