Open AccessFBXW7 Mutations in Melanoma and a New Therapeutic Paradigm
Author(s) -
Iraz T. Aydin,
Rachel Melamed,
Sarah J. Adams,
Mireia Castillo-Martin,
Ahu Yorulmaz,
Diana Bryk,
Georg Brunner,
Carlos Cordón-Cardó,
Iman Osman,
Raúl Rabadán,
Jülide Tok Çelebi
Publication year - 2014
Publication title -
journal of the national cancer institute
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.797
H-Index - 356
eISSN - 1460-2105
pISSN - 0027-8874
DOI - 10.1093/jnci/dju107
Subject(s) - melanoma , cancer research , neuroblastoma ras viral oncogene homolog , biology , synthetic lethality , gene silencing , ectopic expression , targeted therapy , mutation , somatic cell , in vivo , gene , germline mutation , mutant , cancer , genetics , kras
Melanoma is a heterogeneous tumor with subgroups requiring distinct therapeutic strategies. Genetic dissection of melanoma subgroups and identification of therapeutic agents are of great interest in the field. These efforts will ultimately lead to treatment strategies, likely combinatorial, based on genetic information.To identify "driver" genes that can be targeted therapeutically, we screened metastatic melanomas for somatic mutations by exome sequencing followed by selecting those with available targeted therapies directed to the gene product or its functional partner. The FBXW7 gene and its substrate NOTCH1 were identified and further examined. Mutation profiling of FBXW7, biological relevance of these mutations and its inactivation, and pharmacological inhibition of NOTCH1 were examined using in vitro and in vivo assays.We found FBXW7 to be mutated in eight (8.1%) melanoma patients in our cohort (n = 103). Protein expression analysis in human tissue samples (n = 96) and melanoma cell lines (n = 20) showed FBXW7 inactivation as a common event in melanoma (40.0% of cell lines). As a result of FBXW7 loss, we observed an accumulation of its substrates, such as NOTCH1. Ectopic expression of mutant forms of FBXW7 (by 2.4-fold), as well as silencing of FBXW7 in immortalized melanocytes, accelerated tumor formation in vivo (by 3.9-fold). Its inactivation led to NOTCH1 activation, upregulation of NOTCH1 target genes (by 2.6-fold), and promotion of tumor angiogenesis and resulted in tumor shrinkage upon NOTCH1 inhibition (by fivefold).Our data provides evidence on FBXW7 as a critical tumor suppressor mutated and inactivated in melanoma that results in sustained NOTCH1 activation and renders NOTCH signaling inhibition as a promising therapeutic strategy in this setting.