Retinoic acid-induced apoptosis of the CHP134 neuroblastoma cell line is associated with nuclear accumulation of p53 and is rescued by the GDNF/Ret signal.
BACKGROUND
Neuroblastoma (NBL) is one of the most common solid malignancies in childhood and is derived from the sympathetic precursor cells. Although p53, a tumor suppressor, has been reported to be rarely mutated in NBLs, it is sequestered abnormally in the cytoplasm of the NBL cell. The mechanism and functional role of the abnormal intracellular localization of p53 remain unclear.


METHODS
Here, we established an in vitro system of apoptosis model using a NBL cell line CHP134 which also showed a cytoplasmic sequestration of p53. The treatment of the cells with 1 or 5 microM all-trans retinoic acid (RA) induced moderate neurite outgrowth followed by massive death of CHP134 cells by days 5 to 6.


RESULTS
TUNEL staining showed that the cell death was due to apoptosis. Immunofluorescent stain demonstrated that p53 was strongly positive in the nucleus on day 5, which was accompanied with induction of p21WAF1. In addition, expression of caspase-3 was also increased during the cell death. Intriguingly, the RA treatment induced expression of Ret tyrosine kinase receptor in CHP134 cells.


CONCLUSIONS
The addition of ligands, glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN), inhibited apoptosis as well as nuclear accumulation of p53 in the cell. The present results suggest that the RA-induced apoptosis of NBL cells is associated with activation of both the caspase cascade and the p53-mediated pathway with its nuclear translocation. The neurotrophic signal through the GDNF-Ret system may prevent the neuronal cell death.
Takada
N
N
Division of Biochemistry, Chiba Cancer Center Research Institute, Japan.
Isogai
E
E
Kawamoto
T
T
Nakanishi
H
H
Todo
S
S
Nakagawara
A
A
D021581:Active Transport, Cell Nucleus; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics; D029721:Drosophila Proteins; D004790:Enzyme Induction / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006801:Humans; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology* / Q000502:physiology; D016501:Neurites / Q000187:drug effects; D009447:Neuroblastoma / Q000473:pathology*; D051101:Neurturin; D011518:Proto-Oncogene Proteins / Q000187:drug effects* / Q000502:physiology; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects* / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D029721:Drosophila Proteins; C495039:GDNF protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; C495053:NRTN protein, human; D009363:Neoplasm Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D051101:Neurturin; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D014212:Tretinoin; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases