Abstract 4040: Asciminib activates erythroid differentiation in K562 cell line
Authors: Hassan Hammad , Yousuf Sarah , Ahmed Syed Muhammad , Ruknuddin Karim , Raees Hadiqa , Habib Sadia , Iftikhar Fizza , Mian Afsar Ali , Lalani Elnasir 
Published: April 2023

Abstract
Background: Asciminib an allosteric tyrosine kinase inhibitor (TKI) was recently approved by the FDA for managing Philadelphia positive chronic myeloid leukemia (CML) patients in chronic phase who had failed to respond to previous TKIs. In this study, we used human erythroleukemic K562 cell line to investigate the role of asciminib as an inducer of erythroid differentiation. Additionally, imatinib, which has previously been reported as a potential inducer of erythroid differentiation, was also tested on these cells, both independently as well as in combination, in order to investigate the degree of erythroid differentiation in a K562 cell line.
Methodology: In this study, we investigated the effect of asciminib (5-20nM) with and without imatinib (50-200nM) in differentiating the erythroleukemic cell line K562 towards erythroid lineage. K562 cells were cultured over a 12-day period in basic (IMDM) media and an EPO-based differentiation media to select optimal medium conditions. In addition, an in-vitro drug cytotoxicity experiment (XTT) was used to determine the preliminary toxicity of asciminib with IMDM media and EPO-based differentiation media
CD235a and CD71 surface marker expressions were analyzed by flow cytometry at all time-points to determine the degree of differentiation achieved by each of the conditions
Moreover, to analyze and identify hemoglobin producing cells ensuing differentiation, benzidine staining was performed at indicated time points.
Results: Our results suggest that asciminib, imatinib or a combination of both drugs in EPO-based differentiation media results in efficient erythroid differentiation with high levels of GPA expression (approx. 90%) and significant upregulation of globin genes (p value = 0.0001). These results were further confirmed by benzidine staining, where drug addition and dose escalation significantly increased benzidine-positive cells. Our results also demonstrated that asciminib was able to achieve maximum differentiation at a much earlier time point as compared to imatinib. Moreover, asciminib, when combined with another TKI such as imatinib, can also aid in lowering the drug concentrations being used, hence resulting in lessening the toxicity of the drug when used alone required at high doses.
Conclusion: The results from this study highlighted the novel role of asciminib in erythroid differentiation using an in-vitro K562 model that can give high-levels of surface markers and globin expression. Potential clinical application of asciminib in hematological diseases that are associated specifically with a failure in the expression of globin genes should be evaluated.
Keywords:K562, erythroid differentiation, asciminib, imatinib, glycophorin A, transferrin receptor, hemoglobin
Citation Format: Hammad Hassan, Sarah Yousuf, Syed Muhammad Ahmed, Karim Ruknuddin, Hadiqa Raees, Sadia Habib, Fizza Iftikhar, Afsar Ali Mian, Elnasir Lalani. Asciminib activates erythroid differentiation in K562 cell line. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4040.