Vibsanol A induces differentiation of acute myeloid leukemia cells via activation of the PKC signaling pathway and induction of ROS

MS4A3 regulates hematopoietic myeloid differentiation through ROS/TGF-β/p38MAPK pathway

The hematopoietic homeostasis relies on the intricate regulation of hematopoietic stem cells during their proliferation and differentiation. Myeloid differentiation disorders can lead to chronic myeloid leukemia and acute myeloid leukemia. Previous studies have shown increased expression of MS4A3 in myeloid cells, suggesting that MS4A3 may play a critical role in hematopoietic myeloid differentiation. However, the underlying mechanism and its role in hematopoietic myeloid differentiation require further elucidation. In this study, using K562 cell lines with MS4A3 over-expression (oeMS4A3) and MS4A3 knockdown (shMS4A3), we demonstrated that the overexpression of MS4A3 resulted in an augmented skewing towards myeloid differentiation and cell cycle arrest at G0/G1. In addition, inhibition of ROS, TGF-β, and p38MAPK in oeMS4A3 K562 cells attenuated the skewing of myeloid differentiation. Furthermore, in vivo experiments revealed a slight myeloid differentiation suppression tendency in MS4A3 knockout mice. Taken together, we show that MS4A3 overexpression promote myeloid differentiation skewing through the activation of the ROS/p38MAPK/TGFβ pathway. This study underscored the role of MS4A3 in the hematopoietic myeloid differentiation.

Inhibition of pyrimidine biosynthesis by strobilurin derivatives induces differentiation of acute myeloid leukemia cells

All-trans retinoic acid-based differentiation therapies have succeeded in the treatment of acute promyelocytic leukemia, which is a rare subtype of acute myeloid leukemia (AML). Their clinical efficacy is negligible, however, for other subtypes of AML. Here, we showed that strobilurin derivatives, a well-established class of inhibitors of mitochondrial electron transport chain (ETC) complex III, possessed differentiation-inducing activity in AML cells. Impairment of mitochondrial ETC activity was involved in the differentiation effects of strobilurin derivatives, where reactive oxygen species generation appeared unnecessary. Conversely, strobilurin derivative-mediated differentiation was triggered by pyrimidine deficiency, which resulted from the inhibition of the mitochondrial-coupled dihydroorotate dehydrogenase enzyme. Moreover, strobilurin derivative-mediated pyrimidine depletion led to the activation of the Akt/mTOR cascade, which was required for the differentiation. Our study provided evidence that strobilurin derivatives may represent a novel class of differentiation-inducing agents for the treatment of AML.

Salt-inducible kinase inhibition sensitizes human acute myeloid leukemia cells to all-trans retinoic acid-induced differentiation

Differentiation therapies with all-trans retinoic acid (ATRA) have been successful in treating acute promyelocytic leukemia, a rare subtype of acute myeloid leukemia (AML). However, their efficacy is limited in the case of other AML subtypes. Here, we show that the combination of ATRA with salt-inducible kinase (SIK) inhibition significantly enhances ATRA-mediated AML differentiation. SIK inhibition augmented the ability of ATRA to induce growth inhibition and G1 cell cycle arrest of AML cells. Moreover, combining ATRA and SIK inhibition synergistically activated the Akt signaling pathway but not the MAPK pathway. Pharmacological blockade of Akt activity suppressed the combination-induced differentiation, indicating an essential role for Akt in the action of the combination treatment. Taken together, our study reveals a novel role for SIK in the regulation of ATRA-mediated AML differentiation, implicating the combination of ATRA and SIK inhibition as a promising approach for future differentiation therapy.