Activation of Forkhead Box O Transcription Factors by Oncogenic BRAF Promotes p21(cip1)-Dependent Senescence

作者：de Keizer Peter L J; Packer Leisl M; Szypowska Anna A; Riedl Polderman Paulien E; van den Broek Niels J F; de Bruin Alain; Dansen Tobias B; Marais Richard; Brenkman Arjan B; Burgering Boudewijn M T^*

来源：Cancer Research, 2010, 70(21): 8526-8536.

DOI：10.1158/0008-5472.CAN-10-1563

Oncogene-induced senescence (OIS) is a potent tumor-suppressive mechanism that is thought to come at the cost of aging. The Forkhead box O (FOXO) transcription factors are regulators of life span and tumor suppression. However, whether and how FOXOs function in OIS have been unclear. Here, we show a role for FOXO4 in mediating senescence by the human BRAF(V600E) oncogene, which arises commonly in melanoma. BRAF(V600E) signaling through mitogen-activated protein kinase/extracellular signal-regulated kinase kinase resulted in increased reactive oxygen species levels and c-Jun NH2 terminal kinase-mediated activation of FOXO4 via its phosphorylation on Thr(223), Ser(226), Thr(447), and Thr(451). BRAF(V600E)-induced FOXO4 phosphorylation resulted in p21(cip1)-mediated cell senescence independent of p16(ink4a) or p27(kip1). Importantly, melanocyte-specific activation of BRAFV600E in vivo resulted in the formation of skin nevi expressing Thr(223)/Ser(226)-phosphorylated FOXO4 and elevated p21(cip1). Together, these findings support a model in which FOXOs mediate a trade-off between cancer and aging. Cancer Res; 70(21); 8526-36.

• 出版日期2010-11-1