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Expression of the cholecystokinin gene in pediatric tumors
J M Friedman1, M Vitale, J Maimon
1Howard Hughes Medical Institute, Rockefeller University, New York, NY 10021.
Abstract:
We have examined a wide range of cultured human tumor cell lines and found that a specific subset of tumors expresses the cholecystokinin (CCK) gene. All neuroepitheliomas (eight) and Ewing sarcoma (eight) cell lines that were tested express CCK RNA. In addition, two of six rhabdomyosarcoma cell lines also express the CCK gene, suggesting that rhabdomyosarcomas are probably heterogenous and that a subset may be similar to Ewing sarcoma and neuroepithelioma. Very few of the positive tumors express completely processed immunoreactive CCK. However, we have used a radioimmunoassay that detects the CCK precursor to demonstrate synthesis of CCK precursor-like peptides by all of the Ewing sarcoma and neuroepithelioma lines that were tested and by the rhabdomyosarcoma cell line that expresses CCK mRNA. These data demonstrate a consistent association of CCK gene expression with a specific group of human neoplasms. The data also add credence to the theory that Ewing sarcoma and neuroepithelioma are derived from the same transformed cell type. Finally, our results suggest that CCK gene expression may serve as a marker to distinguish these tumors, which are considered to be small-round-cell tumors of childhood, from other pediatric tumors.
Insights
Cholecystokinin (CCK) gene expression is consistently found in neuroepitheliomas and Ewing sarcoma. This CCK marker may help differentiate these pediatric small-round-cell tumors from others.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Neuroepitheliomas and Ewing sarcoma are rare pediatric cancers.
- The cholecystokinin (CCK) gene's role in these tumors is not well understood.
Purpose of the Study:
- To investigate the expression of the cholecystokinin (CCK) gene in various human tumor cell lines.
- To determine if CCK gene expression can serve as a diagnostic marker for specific pediatric tumors.
Main Methods:
- Analysis of CCK gene expression in cultured human tumor cell lines.
- Detection of CCK RNA and precursor-like peptides using radioimmunoassay.
Main Results:
- CCK gene expression was detected in all tested neuroepithelioma and Ewing sarcoma cell lines.
- A subset of rhabdomyosarcoma cell lines also expressed CCK, indicating tumor heterogeneity.
- CCK precursor-like peptides were synthesized by tumors expressing CCK mRNA.
Conclusions:
- Consistent association between CCK gene expression and specific neoplasms like Ewing sarcoma and neuroepithelioma.
- Suggests a common cellular origin for Ewing sarcoma and neuroepithelioma.
- CCK gene expression may be a valuable marker for distinguishing small-round-cell tumors of childhood.