Acute myeloid leukemia (AML) stem cells (AMLSCs) are thought to be responsible for disease initiation, chemoresistance and treatment failure. AMLSCs and residual cytarabine (AraC)-resistant AML cells (constituting minimal residual disease, MRD) were shown to be highly dependent on mitochondrial function for survival and thus are vulnerable to pharmacological blockade of the oxidative phosphorylation (OXPHOS) (Farge et al. Cancer Discov, 2017). Efficacy of OXPHOS inhibitor IACS-010759 was previously reported, demonstrating potent inhibition of mitochondrial complex I, OXPHOS suppression and growth inhibition of AML cells (Molina, et al. Nat Med, 2018). Here we evaluated OXPHOS dependency of AML MRD cells and determined impact of OXPHOS blockade on residual AML cells surviving standard chemotherapy (Doxorubicin/AraC, DA). Our results demonstrated that AML cell lines treated with AraC or DA induced accumulation of reactive oxygen species, mitochondrial superoxides, increased mitochondrial mass and mitochondrial membrane potential. AraC- and DA-based therapies in vitro were significantly potentiated by IACS-010759. OxPhos dependency shown as a significantly increased basal and maximal oxygen consumption rate after AraC and DA treatment, was fully inhibited by OxPhos inhibitor, leading to a total mitochondrial collapse. OxPhos inhibition in combination with DA consolidated reduction of viable cell number, induction of apoptosis and differentiation in cell lines and in AraC-resistant primary patient samples. Next, the efficacy of IACS-010759 together with DA chemotherapy was evaluated in several chemotherapy-sensitive and -resistant animal models in vivo. DA/IACS-010759 combination significantly reduced leukemia burden and significantly extended survival in OCI-AML3/Luc/GFP model and in FLT3-ITD+ AML PDX model. In the latter, IACS-010759 led to reduction of leukemia burden, and delayed leukemia recurrence when administered post completion of DA. At the single-cell level, CyTOF analysis demonstrated that this combination reduced frequency of CD34+CD38lowCD123+AML LSCs and has superior efficacy to facilitate differentiation of immature subpopulations. Furthermore, addition of IACS-010759 to DA extended survival of mice inoculated with chemoresistant PDX AML models. Finally, IACS-010759 administered during consolidation phase significantly extended mice survival compared to standard of care arm, supporting clinical utility of OXPHOS inhibitors in AML. In conclusion, our findings indicate that chemotherapy fosters mitochondrial respiration in AML, which could be abrogated by OXPHOS inhibitor at the LSCs and MRD level, in vitro and in vivo. Our data advocate for combining mitochondrial targeting strategies with chemotherapy as a part of induction and consolidation treatment for improved control of MRD, eradication of AMLSC and extended response duration.
Citation Format: Natalia Baran, Lina Han, Lucille Stuani, Antonio Cavazos, Laurie M. Cooper, Cassandra L. Ramage, Vinitha M. Kuruvilla, Qi Zhang, Marie Sabatier, Emeline Boet, Jason P. Gay, Ningping Feng, Lokesh Battula, Emeline Chu-Van, Florence Castelli, Martin Carrol, Sergej Konoplev, Beenu Thakral, Hagop M. Kantarjian, Naval Daver, Joseph Marszalek, Michael Andreeff, Jean-Emmanuel Sarry, Marina Konopleva. Targeting mitochondrial metabolism following Induction Chemotherapy eradicates Acute Myeloid Leukemia at the level of Minimal Residual Disease [abstract]. In: Proceedings of the AACR Special Conference: Acute Myeloid Leukemia and Myelodysplastic Syndrome; 2023 Jan 23-25; Austin, TX. Philadelphia (PA): AACR; Blood Cancer Discov 2023;4(3_Suppl):Abstract nr A24.