The CRISPR/Cas13 System can specifically recognize and cleave ssRNA complementary. Its capability as a biotechnological tool has been explored, including RNA knockdown and RNA editing. While most studies have been performed using DNA encoding for Cas13 systems, it is widely known that the delivery of RNPs (pre-formed protein-crRNA complexes) is a safe but more challenging possibility. Here, we studied the knockdown efficiency of LwaCas13a and PspCas13b delivered as RNPs into human cells, for the knockdown of GFP as a model target and kRas as an endogenous target. Furthermore, we used Cas13b to target survivin, a protein overexpressed in many types of cancer that plays a role in promoting cell survival and preventing apoptosis. Thus, targeting survivin could have great therapeutic potential in the treatment of cancer.

We have designed and tested different guides that target survivin, evaluating the RNA knockdown in various cancer cell lines that overexpress survivin and the cell viability of the treated cells. The ability to selectively degrade survivin and kRas mRNAs using CRISPR/Cas13 represents a promising new approach for cancer therapy.