A Comprehensive Study of the Chemosensitizing Effects of AZD‐1775, WEE‐1 Inhibitor in Combination with DNA Damaging Treatments in the Jurkat Leukemia Cell Model
Authors: Rodriguez Gabriel Omar , Carrero Ricardo , Diaz‐Quiñones Adriana , Salgado Iris , Silva Walter , Maldonado Héctor 
Published: June 2021

Current treatment for leukemia focuses on DNA damaging treatments (DNAdt), including chemo (cytarabine, vincristine, doxorubicin, etc.) and/or radiotherapy. However, Acute Lymphoblastic Leukemia (ALL) mechanisms of resistance limit the value of these treatments. Recent studies evaluated the G2‐M gatekeeper Wee1 inhibition as a possible alternative treatment for other types of cancer, such as: breast, prostate, pancreatic, lung, leukemia, glioblastoma, among others. AZD‐1775, a well‐documented Wee1 (G2‐M‐Gatekeeper) inhibitor, has shown chemosensitizing, synergistic effects, and currently is undergoing clinical trials. Therefore, our working hypothesis is that: AZD‐1775 sensitizes Leukemia cell lines to DNA‐damaging drugs, via a mitotic catastrophe process. This study evaluates the cytotoxic and chemo‐sensitization effect of AZD‐1775 on an ALL T‐cell model (Jurkat). Even more, this study innovates the understanding of AZD‐1775 by carefully crafting a panel of drugs with different mechanisms that induce DNA damage. Cell viability assays (resazurin‐based; high throughput 384 well plates) were done to determine the inhibitory effects of AZD‐1775 and a series of DNAdt drugs alone and in combinations. The corresponding IC50 value for all curves obtained were calculated using GraphPAD Prism (Vers.7). The nature of the interactions (synergy, additivity, antagonism) between AZD‐1775 and the different DNAdt drugs was determined with Combenefit and the CompuSyn Software. The Combenefit freeware permitted fitting and analysis of the data to various synergy models (Loewe‐additivity, Bliss‐independence and Highest‐single Agent); while, GraphPad Prism and CompuSyn allowed estimates of drug combination indexes (CI) and dose‐reduction indexes (DRI). The individual agents exhibited the following rank order of inhibitory potencies (IC50±SEM): cytarabine (160nM±6nM SEM) ≥ AZD‐1775 (370nM±9nM SEM) >> etoposide (2μM±60nM SEM) = cisplatin (3μM±127nM SEM) > 5′‐fluorouracil (34μM±2.7μM SEM). The results demonstrate a significant synergistic effect of AZD‐1775 with cytarabine, 5FU, cisplatin and etoposide. Conversely, most of these drugs were also capable of potentiating the effect of AZD‐1775 in a synergistic manner. In all models of synergy analysis, statistically significant synergistic interactions were confined to specific concentration ranges of drug‐combinations. For example, the most significant synergistic interactions were obtained with AZD‐1775 concentrations of 58nM to 270nM, and cytarabine concentrations of 8nM to 125nM, with the Bliss‐independence model. In conclusion, our findings strongly suggest that AZD‐1775 can be used as a chemosensitizing agent in ALL, capable of potentiating the effect and susceptibility to DNAdt; whilst, allowing the patient to require lower doses of these chemotherapies to decrease adverse effects.Support or Funding InformationPartially supported by NIGMS/INBRE award P20GM103475. The content is solely the responsibility of the author and does not necessarily represent the official views of any of the supporting agencies.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.