The staurosporine-like compound L-753,000 (NB-506) potentiates the neurotrophic effects of neurotrophin-3 by acting selectively at the TrkA receptor.
K-252b, a member of the staurosporine family of protein kinase inhibitors, selectively potentiates the activation of the nerve growth factor receptor, TrkA, by a nonpreferred ligand, neurotrophin-3 (NT-3), in a variety of cell types. At higher (micromolar) concentrations of K-252b, an inhibitory effect occurs because of the inhibitory action of K-252b on the Trk kinase. By examining analogs of K-252b, we identified the compound L-753,000 (NB-506), which potentiates the action of NT-3 on TrkA but is devoid of the inhibitory action of K-252b. L-753,000 was effective at nanomolar concentrations in a Chinese hamster ovary cell line that expressed TrkA but was devoid of p75, the low-affinity neurotrophin receptor. L-753,000 also potentiated the activation of mitogen-activating protein kinase signaling (downstream from Trk activation) by NT-3 in this cell line. Although L-753,000, like K-252b, had a negligible effect in the absence of NT-3, the compound was found to potentiate NT-3-induced survival in both rat and chick primary cultures of dissociated dorsal root ganglia (DRG) and on neurite outgrowth of chick DRG explants. Unlike K-252b, which at micromolar concentrations inhibits the survival response of NT-3 in dissociated rat DRG, L-753,000 continued to potentiate the actions of NT-3 up to a concentration of 10 microM. Furthermore, the compound, unlike K-252b, did not inhibit an unrelated protein kinase, protein kinase C, at concentrations up to 10 microM. Because L-753, 000 selectively potentiates the NT-3-induced stimulation of TrkA without inhibiting Trks and other protein kinases, it represents a novel class of selective modifiers of neurotrophin actions.
Pollack
S
S
Department of Biochemistry, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, United Kingdom. scott_pollack@merck.com
Young
L
L
Bilsland
J
J
Wilkie
N
N
Ellis
S
S
Hefti
F
F
Broughton
H
H
Harper
S
S
D000704:Analysis of Variance; D000818:Animals; D016466:CHO Cells; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002227:Carbazoles / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D006224:Cricetinae; D004357:Drug Synergism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005960:Glucosides / Q000737:chemistry / Q000494:pharmacology*; D026121:Indole Alkaloids; D009414:Nerve Growth Factors / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D020933:Neurotrophin 3; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D020917:Receptor, trkA; D017475:Receptors, Nerve Growth Factor / Q000187:drug effects / Q000378:metabolism*; D019311:Staurosporine / Q000737:chemistry
D002227:Carbazoles; D004791:Enzyme Inhibitors; D005960:Glucosides; D026121:Indole Alkaloids; C092476:NB 506; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D011518:Proto-Oncogene Proteins; D017475:Receptors, Nerve Growth Factor; C049985:staurosporine aglycone; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019311:Staurosporine