Rhizoma Zedoariae Inhibits G-CSF-Induced MDSCs-like Differentiation of THP-1 Cells

Abstract

Objective: Rhizoma Zedoariae is widely used in the treatment of solid tumors in China, but there has been no deep research on its role in the formation of timmunosuppressive environments mediated by myeloid-derived suppressor cells (MDSCs) in breast cancer. This research aims to investigate the effect of Rhizoma Zedoariae extract and its active compounds curcumin and germacrone on MDSCs-like differentiation by a novel Granulocyte colony-stimulating factor (G-CSF) induced THP-1 cell model. Methods: THP-1 cells were treated with Rhizoma Zedoariae extract and its active compounds (curcumin, germacrone, curcumol, curcumenol, and curdione) at different concentrations (0.01, 0.1, 0.3, 1, 10, 30, 100, and 300 μg/mL), followed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to detect the changes of cell viability in THP-1. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was performed to quantify the mRNA expression levels of transforming growth factor-β (TGF-β), Interleukin-10 (IL-10), Interleukin-6 (IL-6), Janus kinase 1 (JAK1), nuclear factor kappa-B (NF-κB), signal transducer and activator of transcription 3 (STAT3) and arginase-1 (ARG-1), to detected the differentiation of THP-1 into MDSCs-like cells. Results: G-CSF can induce the cell viability and MDSCs-like differentiation of THP-1 cells. Rhizoma Zedoariae extract (0.1, 1, 10, 30, 100, 300 μg/mL), germacrone (0.1, 1, 10, 30, 100, 300 μg/mL) and curcumin (0.01, 0.1, 1, 10, 30, 100 μg/mL) exerted obvious inhibitory effects (>70%) on THP-1 cell viability. G-CSF increased the ARG-1 and IL-10 mRNA levels. Rhizoma Zedoariae extract in 100 μg/mL decreased the ARG-1 and IL-10 mRNA levels. Furthermore, Rhizoma Zedoariae extract in 300 μg/mL also significantly decreased the mRNA expressions of JAK1 and STAT3 (p < 0.001). Conclusion: Rhizoma Zedoariae extract maybe inhibit G-CSF-induced MDSCs-like differentiation of THP-1 through the STAT3 pathway. The active compound that exerts this effect may be germacrone and curcumin.