Epigenetic Reactivation of <italic>SOCS-3</italic> and Inhibition of ERK1/2 Underlie Thymoquinone-Induced Apoptosis in a Chronic Myeloid Leukemia Xenograft Model.

OBJECTIVE

This research aimed to assess thymoquinone (TQ)'s potential to demethylate and re-express the suppressor of cytokine signaling-3 (SOCS-3) in the chronic myeloid leukemia (CML) mice model.

SUBJECT AND

METHODS

A nude mouse model of CML was established, and the apoptotic influence of TQ was identified. TQ's impact on the target gene expressions was examined using real-time quantitative PCR (RT-qPCR), and SOCS-3 methylation was assessed by pyrosequencing. TQ's effects on the extracellular signal-regulated kinase 1 (ERK1) and ERK2 phosphorylation were assessed using Jess Simple Western analysis. Molecular docking of TQ's interaction with the anti-apoptotic proteins was assessed.

RESULTS

TQ exerted a marked hypomethylating influence on SOCS-3 and reduced ERK1/2 phosphorylation level in K562-xenograft tumors. TQ also significantly upregulated the apoptosis-related cysteine peptidase (Caspase-3), BCL-2-interacting mediator of cell death (Bim), p53-upregulated modulator of apoptosis (PUMA), and other apoptotic genes and downregulated B-cell lymphoma 2 (BCL-2), BCL2-like 2 (BCL-w), survivin, and X-linked inhibitor of apoptosis (XIAP) in K562 cells. TQ also exhibited marked inhibitory properties on BCL-2-related gene expressed in fetal liver (BFL-1), B-cell lymphoma-extra large (BCL-xL), myeloid cell leukemia-1 (MCL-1), and BCL-2 proteins. This led to growth inhibition and apoptosis of the K562-tumour xenograft.

CONCLUSION

These results indicate that TQ enhances CML cells' apoptosis by hypomethylating and re-expressing SOCS-3, inhibiting ERK1/2, and modulating the apoptosis-regulator gene expression and by showing consistent interaction with most of the anti-apoptotic proteins, highlighting its potential as a scaffold for designing novel inhibitors to combat CML cells.