GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com

PMID:22232519

From GONUTS
Jump to: navigation, search
Citation

Gajadhar, AS, Bogdanovic, E, Muñoz, DM and Guha, A (2012) In situ analysis of mutant EGFRs prevalent in glioblastoma multiforme reveals aberrant dimerization, activation, and differential response to anti-EGFR targeted therapy. Mol. Cancer Res. 10:428-40

Abstract

Aberrations in epidermal growth factor receptor (EGFR/ErbB1) are the most common oncogenic alterations in glioblastoma multiforme (GBM), the most common primary brain tumor. Interactions between wild-type (wt) and mutant EGFRs and their subsequent activation are of biologic and potential therapeutic importance in GBMs. We recently showed that in situ proximity ligation assay (PLA) allows for quantitative evaluation of EGFR dimerization and activation in intact cells. Using this in situ platform, we show the aberrant homo-/heterodimeric properties of EGFRvIII and EGFRc958 mutants, the two most common EGFR mutants in GBMs. In addition, dimer phosphoactivation status could be detected by PLA with superior signal-noise ratio (>17-fold) and sensitivity (>16-fold) than immunofluorescence-based phospho-EGFR measurements. Dimer activation analysis indicated quantitative activation differences of mutant dimers. These aberrant features were not overexpression dependent but appeared independent of cellular expression levels, suggesting inherent properties of the mutant receptors. Moreover, we observed in situ detection of EGFRwt-EGFRvIII heterodimerization in GBM specimens, supporting our cell line observations. Notably, currently used anti-EGFR therapeutics, such as cetuximab, matuzumab, and panitumumab, could effectively block EGFRwt dimerization and activation but did not equally impair EGFRvIII homodimers, EGFRwt-EGFRvIII, or EGFRvIII-EGFRc958 heterodimers. EGFRvIII appears to have intrinsic phosphoactivation independent of dimerization as matuzumab blockade of homodimerization had no effect on receptor phosphorylation levels. These data suggest differences in the dimerization-blocking efficacy of EGFR monoclonal antibodies as mutant EGFR dimer configurations prevalent in GBMs can evade blockade by anti-EGFR treatments. Further studies are warranted to evaluate whether this evasion contributes to poor therapeutic response or resistance.

Links

PubMed Online version:10.1158/1541-7786.MCR-11-0531

Keywords

Animals; Antibodies, Neoplasm/immunology; Biological Assay; CHO Cells; Cricetinae; Cricetulus; Enzyme Activation; Epitopes/immunology; Glioblastoma/enzymology; Humans; Immunoblotting; Molecular Targeted Therapy; Mutant Proteins/metabolism; Phosphorylation; Protein Multimerization; Receptor, Epidermal Growth Factor/antagonists & inhibitors; Receptor, Epidermal Growth Factor/immunology; Receptor, Epidermal Growth Factor/metabolism; Signal-To-Noise Ratio

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

HUMAN:EGFR

enables

GO:0042802: identical protein binding

ECO:0000353: physical interaction evidence used in manual assertion

UniProtKB:P00533

F

Seeded From UniProt

complete

HUMAN:EGFR

enables

GO:0042802: identical protein binding

ECO:0000353: physical interaction evidence used in manual assertion

UniProtKB:P00533

F

occurs_in:(GO:0005938)

Seeded From UniProt

complete

Notes

See also

References

See Help:References for how to manage references in GONUTS.