Abstract 1116: Sleeping Beauty mutagenesis identifies genes and pathways that cooperate with BrafV600E in melanoma initiation and progression.

Abstract

Abstract Malignant melanoma is a devastating disease the prevalence of which is on the rise. In humans, somatic mutation of BRAF, to encode the BRAFV600E oncoprotein, is an early predisposing event in melanoma initiation, but is insufficient to drive malignant melanomagenesis in the absence of additional cooperating events. We describe a genome-wide, forward genetic screen in mice restricted to pigment producing melanocytes as an unbiased approach to identify new candidate melanoma progression genes. By combining Sleeping Beauty (SB) with a Cre-activated BRafCA allele we observed frank melanomas with average latency of 36 weeks. By contrast, melanocyte specific expression of BRAFV600E elicited benign melanocytic nevi that failed to progress to malignant melanoma by one year of age. These findings confirm that SB mobilization altered genes that cooperate with BRAFV600E to promote melanoma progression. A discovery set of 1,200 statistically-defined candidate melanoma genes was identified from 70 SB|BRAFV600E tumors. Importantly, our screen identified seven SB mutated genes with human orthologs that are well established human melanoma drivers including: Cdkn2a, Pten, Gnaq, Mitf, Nf1, Rac1 and Ppp6c. Many biological signaling pathways and cellular processes were enriched for candidate melanoma genes altered in SB|BRAFV600E melanomas, including Wnt/Beta-catenin, TGFβ, PI3’-kinase and MAPK signaling pathways and biological processes regulating ubiquitin mediated proteolysis, tight junctions, cell cycle and axonal guidance. Integrated comparative oncogenomic analysis with human melanoma data sets provided a data-driven method to filter and prioritize candidate melanoma genes. The genes identified using the SB|BRAFV600E model may represent new human melanoma candidate cancer genes with potential clinical relevance to the progression and maintenance of human BRAF mutated melanoma. Citation Format: Michael B. Mann, Michael A. Black, Jerrold M. Ward, Marcus W. Bosenberg, Martin McMahon, Cristin G. Print, David J. Adams, Neal G. Copeland, Nancy A. Jenkins. Sleeping Beauty mutagenesis identifies genes and pathways that cooperate with BrafV600E in melanoma initiation and progression. [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 1116. doi:10.1158/1538-7445.AM2013-1116