The immune microenvironment plays an important role in leukemia treatment. However, a specific single-cell profiling of the immune alteration in bone marrow of chronic myeloid leukemia (CML) patients is still lacking. We performed multi-level single-cell sequencing to systematically decipher the bone marrow T cell atlas of CML patients. The results exhibited extensive changes of T cells, including the decreased CD4 T cells and increased CD8 T cells in the CML bone marrow. Subpopulation analysis revealed a significant increase of CD8 terminal effector (TE) cells and a significant decrease of CD4 naïve T cells. T cell receptor sequencing showed that the overall diversity of the T cell receptor repertoire was reduced in CML, with the exception of the CD8 TE cell. In addition, CD8 TE cells were the main source of gene expression differences in CD8 T cells. Intercellular communication analysis revealed the altered interaction between CD8 TE and other non-T cells in CML, including neutrophil subtype, indicating the potential regulation of bone marrow microenvironment cells on CD8 TE dynamics. Collectively, our work characterises the alteration of T cell subsets in CML patients at multiple single-cell levels, providing a valuable resource for understanding the immune microenvironment and developing new immune strategies for CML therapy.

Hematopoiesis represents a meticulously regulated and dynamic biological process. Genetic aberrations affecting blood cells, induced by various factors, frequently give rise to hematological tumors. These instances are often accompanied by a multitude of abnormal post-transcriptional regulatory events, including RNA alternative splicing, RNA localization, RNA degradation, and storage. Notably, post-transcriptional regulation plays a pivotal role in preserving hematopoietic homeostasis. The DEAD-Box RNA helicase genes emerge as crucial post-transcriptional regulatory factors, intricately involved in sustaining normal hematopoiesis through diverse mechanisms such as RNA alternative splicing, RNA modification, and ribosome assembly. This review consolidates the existing knowledge on the role of DEAD-box RNA helicases in regulating normal hematopoiesis and underscores the pathogenicity of mutant DEAD-Box RNA helicases in malignant hematopoiesis. Emphasis is placed on elucidating both the positive and negative contributions of DEAD-box RNA helicases within the hematopoietic system.

Therapeutic targeting FOXO3A (a forkhead transcription factor) represents a promising strategy to suppress acute myeloid leukemia (AML). However, the effective inhibitors that target FOXO3A are lacking and the adaptive response signaling weakens the cytotoxic effect of FOXO3A depletion on AML cells. Here, we show that FOXO3A deficiency induces a compensatory response involved in the reactive activation of mTOR that leads to signaling rebound and adaptive resistance. Mitochondrial metabolism acts downstream of mTOR to provoke activation of JNK/c-JUN via reactive oxygen species (ROS). At the molecular level, FOXO3A directly binds to the promoter of G protein gamma subunit 7 (GNG7) and preserves its expression, while GNG7 interacts with mTOR and restricts phosphorylated activation of mTOR. Consequently, combinatorial inhibition of FOXO3A and mTOR show a synergistic cytotoxic effect on AML cells and prolongs survival in a mouse model of AML. Through a structure-based virtual screening, we report one potent small-molecule FOXO3A inhibitor (Gardenoside) that exhibits a strong effect of anti-FOXO3A DNA binding. Gardenoside synergizes with rapamycin to substantially reduce tumor burden and extend survival in AML patient-derived xenograft model. These results demonstrate that mTOR can mediate adaptive resistance to FOXO3A inhibition and validate a combinatorial approach for treating AML.