Rapid CRISPR/Cas12a-based dual-crRNA library screening in high fidelity reveals novel genetic interactions during hepatocarcinogenesis [RNA-Seq]

CRISPR/Cas12a-based combinational screening has shown remarkable potential in identifying genetic interactions. Here, we described an innovative method for combinational genetic screen with rapid constructing of dual-crRNA library by gene splicing through overlap extension PCR (SOE PCR) and the adoption of CeCas12a, which was identified previously by us with strict PAM recognition and low off- targeting, to guarantee the fidelity and efficiency. The custom, pooled SOE crRNA array (SOCA) library for double knockout screen could be conveniently constructed in lab for widespread use and CeCas12a mediated high fidelity screen display good performances even under negative selection screen. By designing an SOCA dual-crRNA library which covered the most of kinase and metabolism-associated gene targets of FDA- approved drugs that were implicated in hepatocellular carcinoma (HCC) tumorigenesis, novel cross talks between the two gene sets were negatively selected out to synergistically inhibit HCC cell growth in vitro and in vivo and also validated by virtual double knockdown screening based on TCGA databases. Thus through our rapid, efficient and high fidelity double knockout screening system, it is very promising to systemically dig genetic interactions between multiple gene sets or synergistic combinations of FDA-approved drugs for clinical translational medicine in the future.