SPT6-driven error-free DNA repair safeguards genomic stability of glioblastoma cancer stem-like cells
Menée in vitro et à l'aide de xénogreffes de glioblastome sur des modèles murins, cette étude met en évidence un mécanisme par lequel le facteur d'élongation transcriptionnel SPT6, en permettant la réparation fidèle de l'ADN via l'augmentation de la transcription du gène BRCA1, favorise la stabilité génomique des cellules souches cancéreuses
Glioblastoma cancer-stem like cells (GSCs) display marked resistance to ionizing radiation (IR), a standard of care for glioblastoma patients. Mechanisms underpinning radio-resistance of GSCs remain largely unknown. Chromatin state and the accessibility of DNA lesions to DNA repair machineries are crucial for the maintenance of genomic stability. Understanding the functional impact of chromatin remodeling on DNA repair in GSCs may lay the foundation for advancing the efficacy of radio-sensitizing therapies. Here, we present the results of a high-content siRNA microscopy screen, revealing the transcriptional elongation factor SPT6 to be critical for the genomic stability and self-renewal of GSCs. Mechanistically, SPT6 transcriptionally up-regulates BRCA1 and thereby drives an error-free DNA repair in GSCs. SPT6 loss impairs the self-renewal, genomic stability and tumor initiating capacity of GSCs. Collectively, our results provide mechanistic insights into how SPT6 regulates DNA repair and identify SPT6 as a putative therapeutic target in glioblastoma.
Nature Communications , article en libre accès, 2020