Daniel Bogush, Stephanie Buczkowski, Rabab Husain, Sameer Ahmed Bhat, Yen Teng Tai, Avinash Kundadka Kudva, Sinisa Dovat
Penn State College of Medicine, Hershey, PA
摘要 Abstract
Survival for pediatric pre-B cell acute lymphoblastic leukemia (B-ALL) has improved substantially, yet high-risk (HR) subgroups continue to experience significant morbidity and mortality. One molecular feature common in HR ALL is deletion of IKZF1, which reduces the tumor-suppressive activity of the transcription factor IKAROS. Casein kinase 2 (CK2), frequently upregulated in ALL, phosphorylates IKAROS and diminishes its DNA-binding capacity, impairing transcriptional regulation. Prior studies show that pharmacologic CK2 inhibition with CX-4945 can restore IKAROS function. Among IKAROS-regulated targets is the receptor tyrosine kinase c-KIT, which is often overexpressed in cancer. These observations suggest that restoring IKAROS-mediated repression of c-KIT may enhance the activity of c-KIT-targeted therapies such as imatinib. This study evaluated whether CX-4945 synergizes with imatinib in B-ALL cells. Nalm6 cells were treated with imatinib for 72 hours to establish the half-maximal inhibitory concentration (IC50), which was then used to guide concentration ranges for combination testing with CX-4945 in a 72-hour cytotoxicity synergy analysis. Cell viability was assessed using a WST-1 assay, and synergy was defined as a combination index <0.85 using Calcusyn. Experiments were repeated with multiple drug concentrations to refine the synergy window. The IC50 of imatinib as a single agent was 25 μM, while CX-4945 showed an IC50 of 4 μM. When CX-4945 was fixed at 4 μM and imatinib was applied across varying doses, multiple combinations demonstrated synergistic cytotoxicity. These results indicate that CK2 inhibition with CX-4945 enhances the therapeutic efficacy of the c-KIT inhibitor imatinib in B-ALL cells, supporting a cooperative mechanism involving restoration of IKAROS function. Given that imatinib is clinically used for Philadelphia chromosome-positive (Ph+) ALL, future work will assess CX-4945/imatinib synergy in Ph+ B-ALL, where an even more potent effect is anticipated. This combination approach may offer a promising therapeutic avenue for HR ALL subtypes characterized by IKZF1 alteration and chemotherapy resistance.
利益披露 Disclosure
D. Bogush, None..
S. Buczkowski, None..
R. Husain, None..
S. Bhat, None..
Y. Tai, None..
A. Kudva, None..
S. Dovat, None.