Novel Approach to Target Endogenous KRAS Mutations By the Crispr/Cas9 Technology

CRISPR/Cas9 is an enabling RNA-guided technology for genome targeting and engineering.  Here we demonstrate that the lentiviral-mediated CRISPR/Cas9 technology can be used to specifically target single-nucleotide heterozygous mutations while exerting no aberrant effects on the wild-type alleles. Specifically, we used a novel gRNA-constraint-mediated method to target the heterozygous G13A activating mutation of KRAS in colorectal cancer cells and we show reversal of drug resistance to a MEK small-molecule inhibitor. Our study introduces a new paradigm in genome editing and therapeutic targeting via the use of gRNA to guide Cas9.