Search

T‐cell acute lymphoblastic leukemia (T‐ALL) is an aggressive malignant blood disorder with a high rate of relapse. Patients relapse as a result of minimal residual disease (MRD), which originates from residual T‐ALL cells in the bone marrow microenvironment (BMM). In the present study, it is observed that adipocytes increase dramatically in the BMM of T‐ALL patients after exposure to chemotherapeutic drugs. Then, it is proved that adipocytes attract T‐ALL cells by releasing CXCL13 and support leukemia cell survival by activating the Notch1 signaling pathway via DLL1 and Notch1 binding. Furthermore, it is verified that dexamethasone (DEX) induces adipogenic differentiation by enhancing the expression of SREBF1 in bone marrow mesenchymal stromal cells (BMSCs), and an SREBF1 inhibitor significantly decreases the adipogenic potential of BMSCs and the subsequent ability of adipocytes to support T‐ALL cells in vitro and in vivo. These findings confirm that the differentiation of BMSCs to adipocytes induced by DEX contributes to MRD in T‐ALL and provides an auxiliary clinical treatment to reduce the recurrence rate. [ABSTRACT FROM AUTHOR]

T‐cell acute lymphoblastic leukemia (T‐ALL) is an aggressive hematological malignancy with a poor prognosis, urging for novel therapeutic targets and treatment strategies. N6‐methyladenosine (m6A) is a crucial methylation modification that affects the pathogenesis of leukemia by regulating the mRNA of key genes. Interferon regulatory factor 8 (IRF8) is a crucial transcription factor for hematological lineage commitment, but its role in T‐ALL is unclear. Here, IRF8 is shown to suppress T‐ALL. The expression of IRF8 is abnormally silenced in patients with T‐ALL. Knockout of Irf8 significantly hastens the progression of Notch1‐induced T‐ALL in vivo. Overexpression of IRF8 suppresses the proliferation and invasion of T‐ALL cells by inhibiting the phosphatidylinositol 3‐kinase/AKT signaling pathway. The fat mass‐ and obesity‐associated protein (FTO), an m6A demethylase, is responsible for directly binding to m6A sites in 3′ untranslated region of IRF8 messenger RNA (mRNA) and inducing mRNA degradation via m6A modification. Targeting the FTO‐IRF8 axis is used as a proof of concept therapy; inhibition of FTO's demethylase activity drastically alleviates the proliferation of leukemic cells and prolongs the survival of T‐ALL mice by restoring IRF8 expression. This study elucidates the pathogenesis of T‐ALL from the perspective of epitranscriptomics and provides new insight into the genetic mechanisms and targeted therapy of T‐ALL. [ABSTRACT FROM AUTHOR]

DEX-Induced SREBF1 Promotes BMSCs Differentiation into Adipocytes to Attract and Protect Residual T-Cell Acute Lymphoblastic Leukemia Cells After Chemotherapy (Adv. Sci. 19/2023) Last, an SREBF1 inhibitor demonstrates superior improvement on therapeutic effect of dexamethason by reducing adipogenesis and provides a feasible strategy to solve the dilemma of recurrence. B T-Cell Acute Lym-phoblastic Leukemia b In article number 2205854, Jingjing Ye, Min Ji, Chunyan Ji, and co-workers observed aberrant adipogenesis in the bone marrow of chemotherapy-treated T-cell acute lymphoblastic leukemia (T-ALL) patients, and the differentiated-adipocytes attract and support residual T-ALL cells. [Extracted from the article]