Related Experiment Videos
Insulin-like growth factor-II expression is down-regulated in TrkA-transfected SK-N-AS neuroblastoma cells
1Department of Pathology, Seoul National University College of Medicine, Korea. cjkim@snu.ac.kr
Abstract:
Expression level of trkA tyrosine kinase receptor for nerve growth factor is a major prognostic determinant of neuroblastoma, suggesting that defective trkA-mediated signaling is responsible for the tumorigenesis of this childhood malignancy. We investigated the biologic effect of trkA, with special reference to its effect on insulin-like growth factor-II (IGF-II) expression, in SK-N-AS human neuroblastoma cells transfected with human trkA cDNA. Nerve growth factor treatment of trkA-transfected cells promoted growth and changed the morphologic phenotype into a substrate-adherent, flatter phenotype (S-type), and down-regulated the mRNA expression of IGF-II. The effects on both growth and the morphologic differentiation of SK-N-AS cells differed significantly from those of previous studies, and implied that trkA effects can be diverse, depending on the phenotype of the individual neuroblastoma cells. Immunohistochemical screening of trkA and IGF-II expression in adrenal neuroblastomas (n = 25) also favored the nonoverlapping pattern of trkA and IGF-II expression (p < 0.05). Because IGF-II is believed to play a significant role in the tumorigenesis of neuroblastoma, the inverse relationship between trkA and IGF-II strongly suggests that a low level of trkA can be a feature of the pathogenetic mechanism of IGF-II expressing adrenal neuroblastomas.
Insights
Neuroblastoma growth is linked to trkA tyrosine kinase receptor signaling. Low trkA receptor levels correlate with increased insulin-like growth factor-II (IGF-II) expression, suggesting a role in tumor development.
Area of Science:
- Oncology
- Molecular Biology
- Neuroscience
Background:
- The trkA tyrosine kinase receptor for nerve growth factor (NGF) is crucial in neuroblastoma prognosis.
- Defective trkA signaling is implicated in neuroblastoma tumorigenesis.
- Insulin-like growth factor-II (IGF-II) is a key factor in neuroblastoma development.
Purpose of the Study:
- To investigate the biological effects of trkA, specifically its influence on IGF-II expression.
- To analyze trkA and IGF-II expression patterns in human neuroblastoma cells and tissues.
Main Methods:
- Transfection of SK-N-AS human neuroblastoma cells with human trkA cDNA.
- Treatment of transfected cells with NGF and analysis of growth and morphology.
- Quantitative analysis of IGF-II mRNA expression.
- Immunohistochemical screening of trkA and IGF-II in adrenal neuroblastomas.
Main Results:
- NGF treatment of trkA-transfected cells promoted growth and induced an S-type morphologic phenotype.
- IGF-II mRNA expression was down-regulated by NGF treatment in trkA-transfected cells.
- A non-overlapping expression pattern of trkA and IGF-II was observed in adrenal neuroblastomas (p < 0.05).
Conclusions:
- The effects of trkA signaling on neuroblastoma cells can be diverse, depending on cellular phenotype.
- The inverse relationship between trkA and IGF-II suggests that low trkA levels may contribute to IGF-II-driven neuroblastoma pathogenesis.
- Targeting trkA signaling or modulating IGF-II expression could offer therapeutic strategies for neuroblastoma.