Abstract 7224: Investigation of the efficacy of duocarmycin SA in combination with FDA approved drugs in acute myeloid leukemia cells in vitro

Abstract Acute myeloid leukemia (AML) is a hematological malignancy that is characterized by the arrest of hematopoietic stem cell differentiation, clonal expansion of myeloid hematopoietic precursors and poor patient survival outcomes. Despite therapeutic advancements, the prognosis of AML patients remains poor and improving patient survival outcomes continues to be a challenge. Therefore, the objective of this study was to investigate the efficacy of Duocarmycin SA (DSA- an antitumor antibiotic that induces DNA alkylation) in combination with FDA approved drugs currently used in the treatment of AML. In this study, DSA was evaluated in combination with doxorubicin (an anthracycline that disrupts topoisomerase II mediated DNA repair) or etoposide (a topoisomerase II inhibitor used to treat relapsed/refractory AML) in human AML cells in vitro. We hypothesized that DSA in combination with doxorubicin or etoposide would exhibit synergistic effects by improving the efficacy of both doxorubicin and etoposide in AML cells. The human AML cell lines (Molm-14 and HL60) were used for all studies. The phenotype of the cells was confirmed by flow cytometry and the IC50 of the drugs were determined using the MTT assay. Our results showed that the AML cells were CD45+, CD33+, CD13+ and CD4+. The IC50 of DSA alone for Molm-14 cells and HL60 cells were 11.12 pM and 114.8 pM, respectively. DSA alone induced DNA double-stranded breaks, significantly decreased the production of colonies and significantly increased apoptosis in AML cells in a dose-dependent manner. The IC50 of doxorubicin alone and etoposide alone was 68.6 nM and 129.7 nM, respectively. DSA in combination with the FDA approved AML drugs showed increased cytotoxic efficacy by observable decreases in AML cell viability. In summary, 1) picomolar concentrations of DSA alone was sufficient to significantly reduce AML cell viability; 2) DSA in combination with doxorubicin or etoposide significantly reduced AML cell viability and reduced the IC50 concentration of doxorubicin and etoposide. Thus, highlighting the therapeutic potential of using DSA in combination with doxorubicin or etoposide as a drug combination strategy to improve AML patient survival outcomes by decreasing the concentration of drugs necessary to treat patients and reducing off-target toxicity. Citation Format: William A. Chen, Diego Aguilar, Leena So, Yasmeen Jawhar, Nhi Nguyen, Natalie Drew, Terry G. Williams, Carlos A. Casiano, Sinisa Dovat, Kristopher Boyle, Olivia L. Francis-Boyle. Investigation of the efficacy of duocarmycin SA in combination with FDA approved drugs in acute myeloid leukemia cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7224.