A Potential Mechanism for the Antioxidant Compound Kushen Injection Targeting the ROS Signaling Pathway in Acute Myeloid Leukemia

Abstract

It is a challenge for treatment of acute myeloid leukemia (AML) in clinic. The increase in the levels of reactive oxygen species (ROS) in AML patients has been previously described; thus, it is important to regulate ROS levels in AML.

In this study, we found that intracellular ROS levels in AML cells were decreased, the total antioxidant capacity (T-AOC) and glutathione (GSH) contents were increased and xanthine oxidase (XOD) vitality was decreased when treated with the compound kushen injection (CKI). This shows that CKI inhibited the proliferation of AML cell lines and patient cells and enhanced the cytotoxicity of AML cells, which has few toxic effects on haematopoietic stem cells (HSCs) and T cells. At the single-cell level, individual AML cells died gradually by CKI treatment on optofluidic chips. CKI could promote apoptosis and arrest cell cycle at G1/G0 phase in U937 cells.

Furthermore, higher peroxiredoxin-3 (Prdx3) expression levels were found in CKI-treated U937 cells through quantitative proteomics detection. Mechanically, the expression of Prdx3 and peroxiredoxin-2 (Prdx2) was up-regulated in CKI-treated AML cells, while thioredoxin 1 (Trx1) was reduced. Laser confocal microscopy showed that the Prdx2 and Trx1 proteins could be co-localized by CKI treatment.

In vivo, in the CKI-treated group, survival was longer in an AML patient-derived xenograft model in B-NSG mice. The disease was partially alleviated by decreased CD45+ immunophenotyping in peripheral blood and bone marrow smear analysis. After CKI injection, the T-AOC vitality, GSH content and CAT activity increased and the concentration of H₂O₂decreased in mouse plasma. A bone marrow biopsy and immunohistochemistry analysis showed that Prdx3 and Prdx2 expression was increased, while Trx1 expression was decreased.

In a conclusion, we provided a model for the anti-leukaemic effects of CKI. CKI decreased intracellular ROS levels by up-regulating the expression of Prdx2 in the cytoplasm and Prdx3 in the mitochondria and down-regulating Trx1 expression, which maintained the intracellular REDOX and further inhibited AML cell proliferation.

Therefore, antioxidant CKI is a promising drug for the treatment of AML in the clinic. We aimed to explore the therapeutic efficacy of low toxicity natural antioxidants against AML by targeting ROS pathways and providing new strategies to improve survival in AML patients.