EIF4A inhibition targets bioenergetic homeostasis in AML MOLM-14 cells in vitro and in vivo and synergizes with cytarabine and venetoclax

Abstract

Background Acute myeloid leukemia (AML) is an aggressive hematological cancer resulting from uncontrolled proliferation of differentiation-blocked myeloid cells. Seventy percent of AML patients are currently not cured with available treatments, highlighting the need of novel therapeutic strategies. A promising target in AML is the mammalian target of rapamycin complex 1 (mTORC1). Clinical inhibition of mTORC1 is limited by its reactivation through compensatory and regulatory feedback loops. Here, we explored a strategy to curtail these drawbacks through inhibition of an important effector of the mTORC1signaling pathway, the eukaryotic initiation factor 4A (eIF4A). Methods We tested the anti-leukemic effect of a potent and specific eIF4A inhibitor (eIF4Ai), CR-1-31-B, in combination with cytosine arabinoside (araC) or the BCL2 inhibitor venetoclax. We utilized the MOLM-14 human AML cell line to model chemoresistant disease both in vitro and in vivo. In eIF4Ai-treated cells, we assessed for changes in survival, apoptotic priming, de novo protein synthesis, targeted intracellular metabolite content, bioenergetic profile, mitochondrial reactive oxygen species (mtROS) and mitochondrial membrane potential (MMP). Results eIF4Ai exhibits anti-leukemia activity in vivo while sparing non-malignant myeloid cells. In vitro, eIF4Ai synergizes with two therapeutic agents in AML, araC and venetoclax. EIF4Ai reduces mitochondrial membrane potential (MMP) and the rate of ATP synthesis from mitochondrial respiration and glycolysis. Furthermore, eIF4i enhanced apoptotic priming while reducing the expression levels of the antiapoptotic factors BCL2, BCL-XL and MCL1. Concomitantly, eIF4Ai decreases intracellular levels of specific metabolic intermediates of the tricarboxylic acid cycle (TCA cycle) and glucose metabolism, while enhancing mtROS. In vitro redox stress contributes to eIF4Ai cytotoxicity, as treatment with a ROS scavenger partially rescued the viability of eIF4A inhibition. Conclusions We discovered that chemoresistant MOLM-14 cells rely on eIF4A-dependent cap translation for survival in vitro and in vivo. EIF4A drives an intrinsic metabolic program sustaining bioenergetic and redox homeostasis and regulates the expression of anti-apoptotic proteins. Overall, our work suggests that eIF4A-dependent cap translation contributes to adaptive processes involved in resistance to relevant therapeutic agents in AML.

The synergistic effect of 2-deoxy-D-glucose and Cytarabine on mitochondria of Stem-like cells derived from KG1-a

“…In contrast to our study, investigations on AML cells obtained from patients illustrated related MMP resistance to oxidative phosphorylation instead of stemness of leukemia cells [35]. Mercier et al, showed that Ara-c did not affect the MMP of AML cells, which could be due to cell source, cell type, and Ara-C dosage [37].…”

“…Results illustrated that the combination of a high dose of Ara-C with ½ EC 50 dose of 2-DG resulted in a signi cant boost in ROS compared to each drug alone. Many reports indicated that a combination of drugs could increase the effectiveness for example; the combinations of myeloperoxidase inhibitor and Cytarabine in leukemia cells [26], EIF4A inhibitor and Ara-c in MOLM-14 cell line [37], 2-DG with arsenic trioxide in AML derived cell line [40] and 2-DG and with l,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in glioblastoma cells [41]. However, there are some controversies to this for example combining Exotimer with 2-DG on HL-60 cells did not increase ROS [31].…”

A second-generation eIF4A RNA helicase inhibitor exploits translational reprogramming as a vulnerability in triple-negative breast cancer

“…In summary, we report on the development of MG-002, an orally available rocaglate capable of reducing primary tumor growth, blocking metastatic seeding, and potentiating the effects of DXR on suppression of metastatic growth. Finally, MG-002 is likely to exert cytotoxic effects in other malignancies given promising pre-clinical studies showing that other eIF4A inhibitors elicit strong anti-neoplastic effects in models of leukemia and pancreatic cancer ( 72 , 73 ).…”

Cytoplasmic TP53INP2 acts as an apoptosis partner in TRAIL treatment: the synergistic effect of TRAIL with venetoclax in TP53INP2-positive acute myeloid leukemia

“…Recently, VEN-based therapies were approved by the Food and Drug Administration (FDA) for the treatment of AML patients who cannot receive intensive chemotherapy or who are older than 75 years of age [ 46 , 47 ]. Numerous studies have shown that the antileukemic activity of VEN is limited to combination therapies [ 48 , 49 ]. In this work, the combinatorial activity of TRAIL and VEN was assessed in AML cell lines and patient samples with high levels of TP53INP2, and this activity was validated in a PDX mouse model.…”