Abstract IA09: Allelic specificity: The key to NRAS-mutant melanoma initiation?

Abstract

Abstract The reason why different NRAS mutants are enriched in each tumor type is unclear. We made a suite of conditional, Nras knock-in models (LSL-Q61R, -K, -L, -H, -P, -Q; G12D and G13D, -R) to test whether melanocyte transformation is dependent upon functions specific to the NRAS mutants found in human melanoma (Q61R and K). Spontaneous melanomas were rare in mice expressing Nras mutants infrequently observed in human melanoma (G12D, G13D, G13R, Q61H, or Q61P). However, melanocyte-specific Nras Q61R or Q61K expression induced rapid melanoma onset with high penetrance. Cohorts of mice carrying one LSL-Nras Q61R and one LSL-Nras Q61K, -L, -H, -P, or -Q allele were used to evaluate potential interactions between Nras mutants. These combinations initiated tumors with kinetics intermediate to those of mice homozygous for either allele (Nras Q61R or 61X) except in the case of Nras Q61Q/Q61R mice, which rarely developed tumors. Genomic and in vitro analyses revealed that the melanoma-initiating potential of each NRAS mutant directly correlated with enhanced MAPK signaling. Together, these data establish that functions specific to the most common NRAS mutants in human melanoma are needed to initiate the disease. Citation Format: Christin E. Burd. Allelic specificity: The key to NRAS-mutant melanoma initiation? [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr IA09.