Neuronal differentiation in human neuroblastoma cells by nerve growth factor following TrkA up-regulation by interferon-gamma.
BACKGROUND
TrkA mRNA expression has been reported to be related to favorable outcome of neuroblastoma (NB). Previously, we found that interferon-gamma (IFN-gamma) can enhance TrkA mRNA expression in NB cell lines. In the present study, we examined the effect of nerve growth factor (NGF) on IFN-gamma-induced TrkA protein to clarify the relationship between TrkA and cell differentiation of NB.


METHODS
The effect of IFN-gamma on the TrkA mRNA expression was screened in six human NB cell lines and a freshly prepared sample, SK-rib, from a stage IV patient. Using two of them, we examined their morphological change during simultaneous loading of NGF and IFN-gamma. Tyrosine phosphorylation pattern after 5 min of NGF stimulation was also examined in immunoblot analysis with anti-gp140(trkA) antibody and antiphospho tyrosine antibody.


RESULTS
After a 4-day treatment with 500 IU/ml IFN-gamma, TrkA mRNA increased in five cell lines and SK-rib cells in association with growth inhibition. Although the degree of morphological differentiation did not increase in proportion to the TrkA expression induced by IFN-gamma, continuous loading of both IFN-gamma and NGF caused marked morphological differentiation in a cultured KP-N-RT cell line and SK-rib cells during 10 days. Moreover, 5 min of NGF stimulation after IFN-gamma treatment caused the phosphorylation of TrkA protein and downstream proteins.


CONCLUSIONS
IFN-gamma could induce the functional NGF receptor even in the aggressive phenotype of NB.
Shikata
A
A
Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan. ashikata@mailcity.com
Shikata
T
T
Sotozono
Y
Y
Hosoi
H
H
Matsumura
T
T
Sugimoto
T
T
Sawada
T
T
D000970:Antineoplastic Agents / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D007371:Interferon-gamma / Q000494:pharmacology*; D020932:Nerve Growth Factor / Q000378:metabolism*; D009447:Neuroblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D011233:Precipitin Tests; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis; D012333:RNA, Messenger / Q000187:drug effects; D012334:RNA, Neoplasm / Q000187:drug effects; D020917:Receptor, trkA / Q000096:biosynthesis* / Q000187:drug effects* / Q000235:genetics; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
D000970:Antineoplastic Agents; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D014443:Tyrosine; D007371:Interferon-gamma; D020932:Nerve Growth Factor; D020917:Receptor, trkA