Abstract | HYPOTHESIS: BACKGROUND: METHODS: Immunohistochemical staining was used to investigate the expression of PDGFR and c-Kit in archived acoustic neuroma tissue. Clinical data including size of tumors, age, sex, and symptoms were correlated with kinase expression, whereas Western blot analysis and immunofluorescence were performed to demonstrate the expression and localization of PDGFR and c-Kit in HEI193, an immortalized VS cell line. Clonogenic survival assays were performed to assess proliferation inhibition by Gleevec. Gleevec's effect on the cell cycle profile also was investigated via flow cytometry analysis. RESULTS: Expression of PDGFR in the formalin-fixed VS tumor tissue was observed in 23 (67.5%) of the 34 samples. C-kit was expressed in 18 (52.9%) of the 34 samples. Western blot analysis demonstrates positive expression of c-Kit and PDGFR-Q in HEI193 and a primary VS culture. Western blot analysis showed downregulation of phospho-c-kit and phospho-PDGFR-Q with 5 and 10 uM Gleevec. Immunofluorescent staining of this cell line also reveals that PDGFR-β is localized primarily in the cytoplasm, whereas c-Kit is both nuclear and cytoplasmic. Cell cycle analysis of HEI193 96 hours after incubation with Gleevec indicates a dose-dependent increase in G1 from 61.6% to 70.7% and 74% at 5 and 10 uM of Gleevec, respectively. Colony formation assays demonstrate dose-dependent growth inhibition by Gleevec, in the HEI193 cell line as well as in a VS cell culture derived from a fresh tumor. CONCLUSION: The expression of PDGFR-Q and c-Kit in VS tissue may indicate novel molecular targets involved in the development of this tumor. Direct inhibition of these molecules by Gleevec may have relevant therapeutic applications.
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Authors | Xabier Altuna, Jay Patrick Lopez, Michael Andrew Yu, Maria Jesus Arandazi, Jeffrey P Harris, Jessica Wang-Rodriguez, Yi An, Robert Dobrow, Joni K Doherty, Weg M Ongkeko |
Journal | Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology
(Otol Neurotol)
Vol. 32
Issue 1
Pg. 163-70
(Jan 2011)
ISSN: 1537-4505 [Electronic] United States |
PMID | 21157293
(Publication Type: Journal Article)
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Chemical References |
- Antineoplastic Agents
- Benzamides
- Piperazines
- Pyrimidines
- Imatinib Mesylate
- Proto-Oncogene Proteins c-kit
- Receptor, Platelet-Derived Growth Factor beta
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Topics |
- Adult
- Aged
- Antineoplastic Agents
(pharmacology, therapeutic use)
- Benzamides
- Blotting, Western
- Cell Cycle
(drug effects)
- Cell Death
(drug effects)
- Cell Line, Tumor
- Cell Proliferation
(drug effects)
- Dose-Response Relationship, Drug
- Female
- Flow Cytometry
- Humans
- Imatinib Mesylate
- Immunohistochemistry
- Male
- Middle Aged
- Neuroma, Acoustic
(drug therapy, metabolism)
- Phosphorylation
(drug effects)
- Piperazines
(pharmacology, therapeutic use)
- Proto-Oncogene Proteins c-kit
(metabolism)
- Pyrimidines
(pharmacology, therapeutic use)
- Receptor, Platelet-Derived Growth Factor beta
(metabolism)
- Tumor Cells, Cultured
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