15-Deoxy-Δ12,14 Prostaglandin J2 Up-Regulates Krüppel-Like Factor 4 Expression Independently of Peroxisome Proliferator-Activated Receptor γ by Activating the Mitogen-Activated Protein Kinase Kinase/Extracellular Signal-Regulated Kinase Signal Transduction Pathway in HT-29 Colon Cancer Cells

2005 ◽  
Vol 68 (5) ◽  
pp. 1203-1213 ◽  
Author(s):  
Zhi Yi Chen ◽  
Chi-Chuan Tseng
Blood ◽  
2007 ◽  
Vol 110 (5) ◽  
pp. 1420-1428 ◽  
Author(s):  
Chia-Lin Hsu ◽  
Kazu Kikuchi ◽  
Motonari Kondo

Abstract Common lymphoid progenitors (CLPs) are lymphoid-lineage-committed progenitor cells. However, they maintain a latent myeloid differentiation potential that can be initiated by stimulation with interleukin-2 (IL-2) via ectopically expressed IL-2 receptors. Although CLPs express IL-7 receptors, which share the common γ chain with IL-2 receptors, IL-7 cannot initiate lineage conversion in CLPs. In this study, we demonstrate that the critical signals for initiating lineage conversion in CLPs are delivered via IL-2 receptor β (IL-2Rβ) intracellular domains. Fusion of the A region of the IL-2Rβ cytoplasmic tail to IL-7Rα enables IL-7 to initiate myeloid differentiation in CLPs. We found that Shc, which associates with the A region, mediates lineage conversion signals through the mitogen activated protein kinase (MAPK) pathway. Because mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitors completely blocked IL-2-mediated lineage conversion, MAPK activation, specifically via the MEK/ERK pathway, is critically involved in the initiation of this event. Furthermore, formation of granulocyte/macrophage (GM) colonies by hematopoietic stem cells, but not by common myeloid progenitors (CMPs), was severely reduced in the presence of MEK/ERK inhibitors. These results demonstrate that activation of MEK/ERK plays an important role in GM lineage commitment.


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