Effective downregulation of BCR-ABL tumorigenicity by RNA targeted CRISPR-Cas13a

CML is a clonal myeloproliferative disorder of pluripotent stem cells driven by a reciprocal translocation between chromosome 9 and 22, forming a BCR-ABL fusion gene. Tyrosine kinase inhibitor drugs like imatinib are mainstay of treatment and cases resistant to these drugs have a poor prognosis in absence of a compatible stem-cell donor. However, with rapid advancements in the gene editing technologies, most studies are now focusing on developing a translational model targeting single gene disorders with prospective permanent cure.

The present study explores the potential application of the RNA targeting CRISPR Cas13a system for effective knockdown of BCR-ABL fusion transcript in K562 cell line.

The CRISPR system was successfully able to lower the expression of downstream genes (pCRKL and pCRK) dependent on the activated BCR-ABL kinase signal by up-to 4.3 folds. The time dependent kinetics also highlighted the significant in vitro suppressive activity to last up to 8 weeks (p-value: 0.025). As per the cDNA sequencing data from Oxford MinION next generation sequencer, the CRISPR activity was 57.45% resulting in 42.55% wild type, 19.15% stop-gain, 10.64% frameshift and 27.66% base substitution transcripts.

These preliminary results highlight an excellent potential application of RNA targeting CRISPRs in Hematological neoplasms like CML and should pave way for further research in this direction.