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cDNA microarray analysis of vestibular schwannomas
D Bradley Welling1, John M Lasak, Elena Akhmametyeva
1Department of Otolaryngology, Ohio State University College of Medicine, Ohio, USA. welling.1@osu.edu
Background:
Vestibular schwannomas are known to harbor mutations in the neurofibromatosis type 2 tumor suppressor gene, but the mechanism of the neurofibromatosis type 2 tumor suppressor gene action is not well understood. Identification of genes differentially expressed in normal and diseased tissues through the use of a large-scale, cDNA microarray approach may lead to increased understanding of pathways that lead to tumor formation.
Objective:
The objectives of this study were to evaluate the gene expression profiles in vestibular schwannomas in comparison with normal vestibular nerve tissues and to identify pathways that may be altered in schwannomas.
Methods:
Total RNA was extracted from one normal vestibular nerve and seven vestibular schwannomas. The normal vestibular nerve was from one of the seven patients with small vestibular schwannomas. Radiolabeled cDNA was synthesized and hybridized to cDNA microarray filters that contained 25,920 known genes or expressed sequence tags. Expression profiles were imaged and analyzed. Selected genes that showed three-fold or greater difference in the intensity between the normal nerve and the schwannomas were further examined by real-time polymerase chain reaction and by immunohistochemical staining.
Results:
Forty-two genes (0.2%) were upregulated 3-fold or more in at least 5 of the 7 tumors when the filter images were compared with a normal adjacent vestibular nerve. Among them, osteonectin, an angiogenesis mediator, and RhoB GTPase, which is important in cell signaling, were significantly upregulated in 5 of 7 tumors. Among genes that were downregulated, an apoptosis-related LUCA-15 gene was highly underexpressed in 6 of 7 schwannomas when compared with the normal nerve. Also, ezrin, a relative of the NF2 protein, was significantly downregulated in 5 of 7 tumors. Real-time PCR and immunohistochemistry data support the cDNA microarray findings.
Conclusion:
Our cDNA microarray analysis of schwannomas suggested several interesting and potentially important tumorigenesis pathways associated with vestibular schwannoma formation. Further in vivo study is necessary to define the roles of these identified genes and their potential relationships with the neurofibromatosis type 2 tumor suppressor gene.
Insights
This study identified key genes and pathways involved in vestibular schwannoma development using cDNA microarray analysis. Findings highlight potential therapeutic targets and a deeper understanding of neurofibromatosis type 2 tumor suppressor gene function.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Vestibular schwannomas are associated with neurofibromatosis type 2 (NF2) gene mutations, but the underlying mechanisms remain unclear.
- Gene expression profiling offers a method to identify molecular pathways involved in tumor formation.
Purpose of the Study:
- To compare gene expression profiles in vestibular schwannomas versus normal vestibular nerve tissue.
- To identify altered molecular pathways implicated in schwannoma tumorigenesis.
Main Methods:
- cDNA microarray analysis of 25,920 genes using RNA from one normal vestibular nerve and seven schwannomas.
- Validation of differentially expressed genes using real-time PCR and immunohistochemistry.
Main Results:
- Forty-two genes were significantly upregulated (≥3-fold) in at least 5 of 7 tumors, including osteonectin and RhoB GTPase.
- Downregulated genes included LUCA-15 (apoptosis-related) and ezrin (NF2 protein relative).
- Real-time PCR and immunohistochemistry confirmed microarray findings.
Conclusions:
- cDNA microarray analysis revealed potential tumorigenesis pathways in vestibular schwannomas.
- Further in vivo research is needed to elucidate the roles of identified genes and their connection to the NF2 tumor suppressor gene.