The effect of ginsenoside Rg1 on EPOR pathway in leukemia cell line TF-1 / 肿瘤

ABSTRACT

Objective: To investigate the effects of ginsenoside Rg1 on the apoptosis of acute myeloid leukemia M6-type human erythroleukemia TF-1 cells and the erythropoietin receptor (EPOR) pathway and to explore the possible mechanisms. Methods: After TF-1 cells treated with different concentrations of ginsenoside Rg1, the proliferation activity of TF-1 cells was detected by cell counting kit-8 (CCK-8) assay. The apoptotic change of TF-1 cells after treatment with ginsenoside Rg1 was demonstrated by flow cytometry (FCM) and observed under a transmission electron microscope. The expression level of EPOR on TF-1 cell membrane after treatment with ginsenoside Rg1 was detected by FCM and immunofluoresence staining. The expression levels of EPOR mRNA and EPOR, phospho-EPOR (p-EPOR), Janus tyrosine kinase 2 (JAK2), phospho-JAK2 (p-JAK2), signal transducers and activators of transcription 5 (STAT5), phospho-STAT5 (p-STAT5), Bcl-2, Bax and cleaved caspase-3 proteins and the reactivity to erythropoietin (EPO) in TF-1 cells after treatment with ginsenoside Rg1 were measured by real-time fluorescent quantitative-PCR and Western blotting, respectively. Results: The proliferation activities of TF-1 cells after treatment with ginsenoside Rg1 (12.5, 25, 50, 100 and 200 μmol/L) for 24, 48 and 72 h were inhibited (P < 0.05). The apoptosis rates of TF-1 cells after treatment with ginsenoside Rg1 (12.5, 25 and 50 μmol/L) for 48 h were higher than that of the control cells (without any treatment) (P < 0.05). The apoptotic changes of TF-1 cells after treatment with ginsenoside Rg1 could be found under a transmission electron microscope. As determined by FCM and immunofluoresence staining analyses, the expression level of EPOR on TF-1 cell membrane was decreased. The expression level of EPOR mRNA in TF-1 cells was decreased (P < 0.05). As compared with the control cells, the expression level of total EPOR protein in TF-1 cells after treatment with ginsenoside Rg1 had no change, but the reactivity to EPO was reduced and the expression level of p-EPOR was significantly decreased, the expressions of Bax and cleaved caspase-3 were significantly enhanced, and the expression levels of Bcl-2, JAK2, p-JAK2, STAT5 and p-STAT5 proteins were significantly decreased (all P < 0.05). Conclusion: The ginsenoside Rg1 can significantly inhibite the proliferation of TF-1 cells and promote apoptosis. This mechanism may be related to a decrease in reactivity to EPO, down-regulation of the expressions of EPOR downstream-related proteins and the activation of caspase-3. Copyright © 2014 by TUMOR.