Early diagnosis and treatment of pre-leukemia

Early diagnosis and treatment of pre-leukemia

Currently, there is no reliable method to identify which patients with age-related clonal hematopoiesis (ARCH) will develop acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Based on preliminary data, the investigators propose to identify and treat high-risk individuals with ARCH, before they have developed the disease.

Lay Abstract

Acute myeloid leukemia (AML) has a long latent period of years before its aggressive and deadly clinical presentation. This latent period is characterized by the clonal expansion of preleukemic hematopoietic stem and progenitor cells (preL-HSPCs) carrying recurrent leukemia related somatic mutations. Spliceosome machinery mutations (SMMs) occur many years before AML, and accurately predict the progression to AML. As such, they are considered promising targets for preventive interventions. 
Our aim was to reveal an Achilles heel of cells that harbor the SRSF2 mutation, as well as the mechanistic role of this weak point. For this, we established 5 cell lines (MARIMO, K562, OCI-AML2, OCI-AML3 and MOLM14) in which we inserted the SRSF2 mutation using CRISPR that have served as platform for our overarching research goal.  Using these lines, we conducted a drug screen that resulted in the discovery of 39 potential molecules which demonstrated selectivity against the SRSF2 mutation. These hits included ROCK pathway inhibitors (ROCKi). The top performing ROCKi molecule was RKI-1447 with an IC50 value of roughly 100nM in the SRSF2 mut lines. Therefore, we chose RKI-1447 for the final validation step and screened its selectivity against five different biological replicates from each of the cell lines. We discovered that both OCI-AML2 and MOLM14 cell lines carrying SRSF2 mutations were significantly more sensitive to ROCKi compared to the WT isogenic line and specifically to RKI-1447. We then stained MOLM14 carrying SRSF2 mutation and  WT for Actin and Tubulin. Results demonstrated a unique phenotype observed in the SRSF2 mutant cell lines, which was aggravated by the addition of ROCK inhibitors. Cells carrying the SRSF2 mutant had a significantly more indented and lobulated nuclei. While we have established that ROCKi are effective against SRSF2 mutant cells, it remains crucial to understand why they are active.