Effects of a conditionally active v-ErbB and an EGF-R inhibitor on transformation of NIH-3T3 cells and abrogation of cytokine dependency of hematopoietic cells
| Autor: | James A. McCubrey, Linda S. Steelman, Martin McMahon, Thazepadath Sreevalsan, John G. Shelton, Richard A. Franklin |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
DNA Replication
Cancer Research MAP Kinase Signaling System Receptor ErbB-2 medicine.medical_treatment Apoptosis Biology medicine.disease_cause 3T3 cells Cell Line Mice ErbB Genetics medicine Animals Humans Enzyme Inhibitors Molecular Biology Protein kinase B Binding Sites 3T3 Cells Genes erbB-1 Tyrphostins Hematopoietic Stem Cells ErbB Receptors Haematopoiesis Cell Transformation Neoplastic medicine.anatomical_structure Cytokine Quinazolines Cancer research Cytokines Signal transduction Carcinogenesis |
| Zdroj: | Oncogene. 23:7810-7820 |
| ISSN: | 1476-5594 0950-9232 |
| Popis: | Epidermal growth factor (EGF) and its cognate receptor (EGF-R) are often dysregulated in human neoplasia. Moreover, EGF-R-transformed cell lines have constitutive EGF-R activity, which makes elucidation of its effects difficult to determine. In the following studies, the effects of a novel conditionally activated form of EGF-R, v-ErbB:ER, on the morphological transformation of NIH-3T3 cells and the abrogation of hematopoietic cell cytokine dependence were investigated. The v-ErbB ES-4 oncogene was fused to the hormone binding domain of the estrogen receptor (ER). This construct, v-ErbB:ER, requires beta-estradiol or 4-OH tamoxifen for activation. v-ErbB:ER conditionally transformed NIH-3T3 cells and abrogated cytokine dependence of hematopoietic cells. Stimulation of v-ErbB:ER activity resulted in the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt and Raf/MEK/ERK kinase cascades. To determine the importance of these signal transduction pathways, the conditionally transformed hematopoietic cells were treated with EGF-R, PI3K and MEK inhibitors. The EGF-R inhibitor AG1478 effectively inhibited MEK, ERK and Akt activation, and induced apoptosis when the cells were grown in response to v-ErbB:ER. Apoptosis was observed at 100- to 1000-fold lower concentrations of AG1478 when the cells were grown in response to v-ErbB:ER as opposed to IL-3. Furthermore, the parental, BCR-ABL- and Raf-transformed cells were only susceptible to the apoptosis-inducing effects of AG1478 at the highest concentrations demonstrating the specificity of these inhibitors. MEK or PI3K inhibitors suppressed ERK or Akt activation, respectively, and induced apoptosis in the v-ErbB:ER-responsive cells. However, MEK and PI3K inhibitors only induced apoptosis at 1000-fold higher concentrations than the EGFR inhibitor. This novel v-ErbB:ER construct and these conditionally transformed cell lines will be useful to further elucidate ErbB-mediated signal transduction and to determine the effectiveness of various inhibitors in targeting different aspects of EGF-R-mediated signal transduction and malignant transformation. |
| Databáze: | OpenAIRE |
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