The p16/Cdkn2a/Ink4a gene is frequently deleted in nitrosourea-induced rat glial tumors
J Schlegel1, G Piontek, M Kersting
1Molecular Neuropathology Laboratory, Department of Neuropathology, University Medical Center, Marburg, Germany. juergen.schlegel@lrz.tu-muenchen.de
Abstract:
The present study investigates nitrosourea-induced rat (Rattus norvegicus) glioma cell lines for the functional status of the p16/Cdkn2a/Ink4a gene, which encodes the p16 cdk4 inhibitor and the alternative reading frame protein, p19ARF. We detected homozygous deletions of the p16/Cdkn2a/Ink4a gene locus in 4 of 5 glioma cell lines (C6, F98, RG2, and RGL.3), but not in the 9L gliosarcoma cell line or in a rat primary fibroblast cell line. RT-PCR demonstrated expression of the p16 and p19ARF mRNAs only in 9L cells and in rat fibroblasts. Comparative genomic in situ hybridization showed that the copy number of rat chromosome RNO5 was not altered in any of the glioma cell lines investigated, indicating that the deletions result from a discrete loss in the region of the p16/Cdkn2a/Ink4a locus. This is the first report of p16/Cdkn2a/Ink4a deletions present in nitrosourea-induced rat glioma cell lines. Since this genetic alteration is also commonly observed in human malignant glial tumors, our results validate the use of chemically induced rat glioma cell lines as an experimental model in the development of gene therapy strategies.
Insights
Researchers found deletions in the p16/Cdkn2a/Ink4a gene in most nitrosourea-induced rat glioma cell lines. This genetic alteration is common in human brain tumors, validating rat glioma models for gene therapy research.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Malignant gliomas are aggressive brain tumors with limited treatment options.
- The p16/Cdkn2a/Ink4a gene plays a crucial role in cell cycle regulation and is frequently altered in human cancers.
- Nitrosourea-induced rat glioma cell lines are utilized as preclinical models for studying glioma development and therapy.
Purpose of the Study:
- To investigate the functional status of the p16/Cdkn2a/Ink4a gene in nitrosourea-induced rat glioma cell lines.
- To determine if deletions in the p16/Cdkn2a/Ink4a locus are present in these rat glioma models.
- To assess the utility of these rat models for gene therapy strategies targeting glioma.
Main Methods:
- Analysis of p16/Cdkn2a/Ink4a gene status in five rat glioma cell lines and one rat fibroblast cell line.
- Detection of homozygous deletions using comparative genomic in situ hybridization (CGH).
- Assessment of p16 and p19ARF mRNA expression using RT-PCR.
Main Results:
- Homozygous deletions of the p16/Cdkn2a/Ink4a gene locus were identified in 4 out of 5 rat glioma cell lines (C6, F98, RG2, RGL.3).
- No deletions were observed in the 9L gliosarcoma cell line or in rat primary fibroblasts.
- Expression of p16 and p19ARF mRNAs was detected only in 9L cells and rat fibroblasts, correlating with the absence of gene deletions.
- Comparative genomic in situ hybridization confirmed that deletions were locus-specific and not due to larger chromosomal alterations.
Conclusions:
- This study reports for the first time the presence of p16/Cdkn2a/Ink4a deletions in nitrosourea-induced rat glioma cell lines.
- The observed genetic alteration mirrors a common event in human malignant gliomas.
- These findings validate the use of chemically induced rat glioma cell lines as relevant experimental models for developing gene therapy strategies against brain tumors.
