Use of CRISPR-modified human stem cell organoids to study the origin of mutational signatures in cancer
Menée à l'aide de la technologie CRISPR/Cas9 pour supprimer des gènes de réparation de l'ADN dans des organoïdes de cellules souches du côlon, cette étude met notamment en évidence des mécanismes par lesquels des erreurs de réplication de l'ADN induisent des mutations du gène de réparation des mésappariements MLH1
Mutational processes underlie cancer initiation and progression. Signatures of these processes in cancer genomes may explain cancer etiology, and hold diagnostic and prognostic value. Here, we develop a strategy that can be used to explore the origin of cancer-associated mutational signatures. We used CRISPR/Cas9 technology to delete key DNA repair genes in human colon organoids, followed by delayed sub-cloning and whole-genome sequencing. We found that mutation accumulation in organoids deficient in the mismatch repair gene MLH1 is driven by replication errors and accurately models the mutation profiles observed in mismatch repair-deficient colorectal cancers. Application of this strategy to the cancer predisposition gene NTHL1, which encodes a base excision repair protein, revealed a mutational footprint (signature 30) previously observed in a breast cancer cohort. We show that signature 30 can arise from germline NTHL1 mutations.
Science , résumé, 2016