遠藤 仁司

ABSTRACT While venetoclax‐based combinations have shown promising results in acute myeloid leukemia (AML), the remission duration is generally short, warranting strategies to further improve efficacy and overcome resistance. Here, we show that the natural quassinoid brusatol induces cell‐cycle arrest and apoptosis in multiple AML cell lines while enhancing venetoclax efficacy irrespective of inherent or acquired resistance. Mechanistically, brusatol increased p53 protein expression, leading to upregulation of its target genes/proteins, including CDKN1A (p21) and BBC3 (PUMA). Genetic deletion of TP53 attenuated brusatol‐induced apoptosis and its synergy with venetoclax, supporting p53 activation as a central mechanism underlying the anti‐leukemia response. Furthermore, the combination synergistically decreased mitochondrial membrane potential and respiratory activity, causing accumulation of reactive oxygen species in AML cells. Although brusatol and venetoclax exhibited limited effects individually, their combination markedly reduced leukemia burden and significantly prolonged survival in three independent cell line‐derived xenograft models, including venetoclax‐resistant and ‐refractory models. Notably, brusatol increased normal leukocyte and platelet counts while reducing leukemic infiltration in both bone marrow and extramedullary sites. These findings provide mechanistic insight into the synergistic effects of the brusatol‐venetoclax combination, supporting further evaluation of this therapeutic strategy in myeloid leukemias.

UNLABELLED: Krüppel-like factor 5 (KLF5) is an intrinsically disordered transcription factor involved in cardiac remodeling, cancer, and metabolic diseases. Targeting KLF5 has been a persistent challenge in drug development due to its structural inaccessibility. We investigated cardioprotective effects of NC114, a rationally designed small molecule that mimics a short, hydrophobic α-helical motif in KLF5, thereby disrupting its protein–protein interactions. Adult C57BL/6J male mice underwent transverse aortic constriction (TAC) or sham surgery, followed by administration of NC114 or vehicle. NC114-treated TAC mice exhibited preserved cardiac function, reduced heart weight-to-body weight ratio, and markedly attenuated interstitial fibrosis. Gene expression analysis demonstrated decreased cardiac expression of Klf5, Nppb, Tgfb1, PAI-1, Col1a1, and Fn1. NC114 also suppressed oxidative stress and reduced phosphorylation of PKCδ and expression of HIF-1α during the early phase post-TAC. Metabolomic profiling revealed that NC114 treatment reversed TAC-induced accumulation of organic and amino acids. NC114, a novel peptidomimetic molecule, targets the undruggable transcription factor KLF5 to attenuate cardiac hypertrophy, fibrosis, and metabolic dysregulation in pressure overload-induced heart failure. This study highlights the potential of KLF5 inhibition as a therapeutic strategy in cardiovascular disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-32155-y.

Abstract Leukemia cells are consistently subjected to higher oxidative stress than normal cells. To mitigate reactive oxygen species (ROS) overload, which can trigger various forms of cell death, leukemia cells employ a robust antioxidant defense system and maintain redox homeostasis. Recent evidence suggests that dimethyl fumarate (DMF), a derivative of fumarate, inactivates the antioxidant glutathione (GSH), thereby inducing oxidative stress and metabolic dysfunction, eventually leading to cell death in cancer cells. In this study, we observed that DMF decreases the GSH/oxidated GSH ratio and increases intracellular ROS levels, the extent of which is closely correlated with cell death, in acute myeloid leukemia (AML) cell lines. DMF reduced the mitochondrial membrane potential and oxidative phosphorylation (OXPHOS), effects that were almost fully restored by the antioxidant N-acetylcysteine, suggesting that these responses are ROS-dependent. Electron microscopy and inhibition assays revealed that apoptosis, rather than necroptosis or ferroptosis, is the predominant form of cell death of AML cells following DMF treatment. Notably, the combination of DMF and the BCL-2 selective BH3-mimetic venetoclax induced marked cell death in AML cells, including venetoclax-refractory BCL-2 low expressing U937 and acquired venetoclax-resistant MOLM-14 cells. This combination also caused greater mitochondrial depolarization and a more profound reduction in OXPHOS activity than either agent alone. Collectively, our findings indicate that DMF exerts potent anti-leukemia activity in AML cells and sensitizes cells to venetoclax treatment by synergistically disrupting mitochondrial integrity through ROS accumulation.