Tetramethylpyrazine Inhibits The Proliferation Of Acute Lymphocytic Leukemia Cell Lines Via Decrease In GSK-3β

Objective:To evaluate the effect of tetramethylpyrazine (TMP) against Jurkat and SUP-B15 ALL cell lines and the expression of GSK-3β and its downstream transcription factors, NF-κB (p65) and c-myc, and investigate the possible detailed mechanism of action of TMP.Methods:Jurkat and SUP-B15 cells were treated with different concentrations of TMP (0-320 ug/ml) for different hours(24h,48h and 72h). The cell proliferation was examed by a Cell Counting Kit-8 (CCK-8) assay. Flow cytometric analysis was conducted to detect the cell cycle distribution and apoptotic rate. The expression of total glycogen synthase kinase-30 (GSK-3β), cox-2, survivin, bcl-2 and p27 RNA and protein levels was detected by quantitative real-time PCR and western blot assay, respectively. Additionally, western blot analysis was used to determine the whole-cell and nuclear protein levels of GSK-3β downstream transcription factors, NF-κB (p65) and c-myc.Results:TMP inhibited the proliferation of Jurkat and SUP-B15 cells in a dose-and time-dependent manner by CCK-8 assay, with IC50 values of 120 and 200 μg/ml, respectively at 48h. TMP induced the apoptosis of Jurkat and SUP-B15 cells and synergistically blocked cell cycle progression at the G0/G1 phase. Cells treated with TMP exhibited significantly attenuated GSK-3β and its downstream transcription factors NF-kB (p65) and c-myc expression, followed by downregulation of cox-2, bcl-2 and survivin and an upregulation of p27.Conclusion:The study showed that TMP induced apoptosis and caused cell cycle arrest in Jurkat and SUP-B15 cells through the downregulation of GSK-3β, which may have further prevented the induced translocation of NF-kB and c-myc from the cytoplasm to the nucleus, thereby exerting its anti-tumor activity.