β-Arrestin2 mediates the initiation and progression of myeloid leukemia.
Fereshteh M, Ito T, Kovacs JJ, Zhao C, Kwon HY, Tornini V, Konuma T, Chem M, Lefkowitz RJ, and Reya T. 2012.
Proceedings of the National Academy of Sciences 109(31):12532-7. PubMed | PDF |
β-Arrestins were initially discovered as negative regulators of G protein-coupled receptor signaling. Although β-arrestins have more recently been implicated as scaffold proteins that interact with various mitogenic and developmental signals, the genetic role of β-arrestins in driving oncogenesis is not known. Here we have investigated the role of β-arrestin in hematologic malignancies and have found that although both β-arrestin1 and -2 are expressed in the hematopoietic system, loss of β-arrestin2 preferentially leads to a severe impairment in the establishment and propagation of the chronic and blast crisis phases of chronic myelogenous leukemia (CML). These defects are linked to a reduced frequency, as well as defective self-renewal capacity of the cancer stem-cell population, in mouse models and in human CML patient samples. At a molecular level, the loss of β-arrestin2 leads to a significant inhibition of β-catenin stabilization, and ectopic activation of Wnt signaling reverses the defects observed in the β-arrestin2 mutant cells. These data cumulatively show that β-arrestin2 is essential for CML disease propagation and indicate that β-arrestins and the Wnt/β-catenin pathway lie in a signaling hierarchy in the context of CML cancer stem cell maintenance.