Abstract 5201: Elucidating distinct roles for NF1 in melanomagenesis.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC BRAF mutations play a well-established role in melanomagenesis; however, without additional genetic alterations tumor development is restricted by oncogene-induced senescence (OIS). Here we show that mutations in the NF1 tumor suppressor gene cooperate with BRAF mutations in melanomagenesis by preventing OIS. In a genetically engineered mouse model, Nf1 mutations suppress Braf-induced senescence, promote melanocyte hyperproliferation, and enhance melanoma development. Nf1 mutations function by deregulating both PI3K and ERK pathways. As such, Nf1/Braf mutant tumors are resistant to BRAF inhibitors but are sensitive to combined MEK/mTOR inhibition. Importantly, NF1 is mutated or suppressed in human melanomas that harbor concurrent BRAF mutations, NF1 ablation decreases the sensitivity of melanoma cell lines to BRAF inhibitors, and NF1 is lost in tumors from patients following treatment with these agents. Collectively, these studies provide mechanistic insight into how NF1 cooperates with BRAF mutations in melanoma and demonstrate that NF1-inactivation may impact responses to targeted therapies. Citation Format: Ophelia Maertens, Bryan Johnson, Pablo Hollstein, Dennie Frederick, Zachary Cooper, Ludwine Messiaen, Roderick Bronson, Martin McMahon, Scott Granter, Keith Flaherty, Jennifer Wargo, Richard Marais, Karen Cichowski. Elucidating distinct roles for NF1 in melanomagenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5201. doi:10.1158/1538-7445.AM2013-5201