Pb1788: a screening of donated chemical probes to identify novel therapeutic options for acute myeloid leukemia (aml) in childhood

Topic: 3. Acute myeloid leukemia - Biology & Translational Research Background: Despite intensive treatment regimens, the survival rate for children with acute myeloid leukemia (AML) has remained stagnant at around 70%. To improve the chances of survival for children with AML, novel therapeutic agents are urgently needed. Recently, targeted therapies and small molecules have emerged as promising alternative treatment options. The Structural Genomics Consortium (SGC), along with several pharmaceutical companies, has made multiple validated small molecules available for research. These so-called “donated chemical probes” (DCPs) can aid in identifying therapeutic targets and treatment options for various diseases. Aims: The goal of this study was to identify novel therapeutic targets and options for children with AML. We conducted a screening of donated chemical probes (DCPs) in AML cell lines and patient-derived cells from pediatric AML. Methods: In this study, we treated various AML cell lines with 105 small molecules from a donated chemical probe (DCP) library at concentrations ranging from 1nM to 10µM. To assess the effect of each compound on cell viability, we conducted a CellTiter-Glo assay after the treatment period. Analysis of dose-response curves and calculation of the area under the curve (AUC) identified several effective compounds in AML cell lines. We subsequently evaluated the most promising candidates from our initial screening in patient-derived AML-blasts, which identified certain groups of small molecules as potent anti-leukemic compounds. To further elucidate their effects in AML cells, we used various methods, including flow cytometric analysis of surface markers and cell cycle, analysis of cell death, and Western blotting. Results: From the 105 small molecules we tested, we identified inhibitors of Cdc2-like kinases (CLKs), among others, as promising compounds for our study. CLKs play a crucial role in splicing processes, and mutations in splicing factors or changes in their expression levels are linked to both solid and hematological malignancies. Based on our screening results, we investigated the potential of CLK inhibitors in pediatric AML. We found that these inhibitors reduced cell viability and induced apoptotic cell death in AML cells in a dose-dependent manner. Additionally, the tested compounds caused G1-phase arrest in AML cells. These findings suggest that interfering with alternative splicing through inhibition of CLKs could offer a novel therapeutic option for pediatric AML. Summary/Conclusion: Our screening of a donated chemical probe (DCP) library revealed the inhibition of CLKs as a highly promising therapeutic option for childhood AML. Keywords: Alternative splicing, Acute myeloid leukemia