Targeting BRAF mutant pre-mRNA alternative splicing in melanoma

Alternative splicing of BRAF mRNA can provide a resistance mechanism to BRAF and MEK inhibitors that has been described mostly in BRAF-mutant melanoma. The mechanisms underlying the production of a variety of BRAF mRNA isoforms, e.g., the BRAF3-9 (which lacks exons 4 to 8), remain poorly understood....

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Detalles Bibliográficos
Autor: Aya Moreno, Francisco
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2023
País:España
Institución:CBUC, CESCA
Repositorio:TDR. Tesis Doctorales en Red
OAI Identifier:oai:www.tdx.cat:10803/687762
Acceso en línea:http://hdl.handle.net/10803/687762
Access Level:acceso abierto
Palabra clave:Alternative splicing
Melanoma
BRAF
Drug resistance
MAPK
Splicing alternativo
Resistencia a terapias
575
Descripción
Sumario:Alternative splicing of BRAF mRNA can provide a resistance mechanism to BRAF and MEK inhibitors that has been described mostly in BRAF-mutant melanoma. The mechanisms underlying the production of a variety of BRAF mRNA isoforms, e.g., the BRAF3-9 (which lacks exons 4 to 8), remain poorly understood. Analysis of RNA-seq from melanoma samples identified for the first time BRAF mRNA isoforms associated with resistance in wild type BRAF and in treatment-naïve melanoma samples. Using minigene assays and whole-genome sequencing, we have reasonably rule out a contribution of single-nucleotide sequence variants (such as intronic mutations) in the generation of these isoforms. Using a CRISPR-Cas9 knockout screen, we have identified genetic vulnerabilities related to splicing and chromosome dynamics in melanoma cells, but not splicing factors particularly involved in the generation of BRAF3-9. Importantly, we have identified large intragenic deletions as the underlying mechanism for the production of BRAF3-9 and BRAF1-9 isoforms, suggesting that this can be a general mechanism for the production of resistance-associated mRNA variants in melanoma.