DEVELOPING THERAPIES TO INHIBIT T CELL ACUTE LYMPHOCYTIC LEUKEMIA FROM ENTERING THE BRAIN USING THE CRISPR/CAS9 SYSTEM
Daniel Bassuk, Charlotte Vines.
University of Texas at El Paso, El Paso, TX.
Thirty percent of children who develop T cell acute lymphocytic leukemia (T-ALL) will relapse within two years of chemotherapy treatment and die. Relapse has shown to be attributed to the migration of the leukemic T cells past the blood brain barrier (BBB) and into the central nervous system (CNS) where the leukemic cells can evade the effects of chemotherapies. It has previously been shown that C-C chemokine receptor 7 (CCR7) aids in the leukemic cells invasion past the BBB in response to its ligand CL19. We have preliminary data that shows CCR7-positive T-cells enter the brain, and we are investigating the distribution of CCL19 to determine the site of entry. We propose that blocking expression of CCR7 will inhibit the movement of leukemia into the brain. We are developing a panel of RNA-guided, DNA-cleaving nucleases that use the endonuclease Cas9 to delete genomic CCR7 in human T-ALL. This system uses the type II clustered, regularly interspaced, short palindromic repeats (CRISPR)-associated Cas9 pathway taken from the prokaryote Neisseria meningitides. In this system, Cas9 is guided by short RNA molecules that are homologous to a specific target of DNA to cleave this region of interest. The panel of CRISPR/Cas9 enzymes we are creating use RNA specific to the CCR7 gene to guide Cas9. We anticipate the CRISPR/Cas9 system will lead to a potential therapy that can inhibit T-ALL from entering the brain.