Evidence That Sprouty 2 Is Necessary for Sarcoma Formation by H-Ras Oncogene-transformed Human Fibroblasts
| Autor: | Sandra O'Reilly, Piro Lito, J. Justin McCormick, Bryan D. Mets, Veronica M. Maher, Susanne Kleff |
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| Rok vydání: | 2008 |
| Předmět: |
MAPK/ERK pathway
endocrine system Mice Nude Oncogene Protein p21(ras) Biochemistry Receptor tyrosine kinase Small hairpin RNA Mice medicine Animals Humans Proto-Oncogene Proteins c-cbl Epidermal growth factor receptor Fibrosarcoma Molecular Biology Adaptor Proteins Signal Transducing Cell Line Transformed biology Oncogene Intracellular Signaling Peptides and Proteins Membrane Proteins Sarcoma Cell Biology Fibroblasts medicine.disease Molecular biology Cell biology ErbB Receptors Cell Transformation Neoplastic Cell culture SPRY2 biology.protein |
| Zdroj: | Journal of Biological Chemistry. 283:2002-2009 |
| ISSN: | 0021-9258 |
| Popis: | Sprouty 2 (Spry2) acts as an inhibitor of receptor tyrosine kinase signaling in various cellular contexts. Interestingly, Spry2 also prevents the c-Cbl-induced degradation of epidermal growth factor receptor (EGFR). We compared human fibroblasts malignantly transformed by overexpression of H-Ras(V12) oncogene to their nontransformed parental cells and found that the malignant cells express a high level of Spry2. These cells also exhibited an increase in the level of EGFR compared with their precursor cells. We found that intact EGFR was required if H-Ras-transformed cells were to grow in the absence of exogenous growth factors or form large colonies in agarose. When we decreased expression of Spry2, using a Spry2-specific shRNA, the H-Ras(V12)-transformed fibroblasts could no longer form large colonies in agarose, grow in reduced levels of serum, or form tumors in athymic mice. The level of active H-Ras in these cells remained unaltered. A similar, but less pronounced, effect in tumor formation was observed when Spry2 was down-regulated in human patient-derived fibrosarcoma cell lines. In H-Ras-transformed cells Spry2 sustained the level and the downstream signaling activity of EGFR. In the parental, non-H-Ras-transformed fibroblasts, expression of Spry2 resulted in the inhibition of H-Ras and ERK activation, suggesting that the positive effect of Spry2 in tumor formation is specific to H-Ras transformation. Co-immunoprecipitation studies with H-Ras-transformed cells revealed that Spry2 and H-Ras interact and that H-Ras interacts with Spry2-binding partners, c-Cbl and CIN85, in a Spry2-dependent manner. These data show that Spry2 plays a critical role in the ability of H-Ras-transformed cells to form tumors in athymic mice. |
| Databáze: | OpenAIRE |
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