Knocking out genes in cancer genomes with the CRISPR–Cas9 technique decreases the ability of cancer cells to multiply.
William Hahn at the Dana Farber Cancer Institute in Boston, Aviad Tsherniak at the Broad Institute of Harvard and MIT in Cambridge — both in Massachusetts — and their colleagues silenced certain genes in 33 cancer-cell lines using CRISPR–Cas9, which can be programmed to snip DNA at specific locations. They found that in parts of the genome with multiple copies of a gene, the number of DNA breaks made by the CRISPR system was linked to a drop in cell proliferation, an outcome not seen with another gene-silencing tool called RNA interference. This effect could be the result of how CRISPR-made DNA cuts are repaired.
The results suggest that cancer cells are sensitive to site-specific DNA damage, and have implications for how experiments using CRISPR should be interpreted. Targeting genomic regions that have many repeated sequences could be a new therapeutic strategy, the authors suggest.
Cancer Discov. http://doi.org/bjzn (2016)