Shikonin Suppresses Human T Lymphocyte Activation through Inhibition of IKKβ Activity and JNK Phosphorylation
Figure 1
Effect of shikonin on suppression of cell proliferation and its cytotoxicity in human T lymphocytes. Chemical structure of shikonin (a). Effect of shikonin on T lymphocytes proliferation stimulated by PMA/ionomycin (b) or OKT-3/CD28 (c). Human T cells (105/well) were pretreated with the indicated concentrations of shikonin for 2 h and then activated with PMA (20 ng/mL)/ionomycin (1 μM) (P/I) or with the coated OKT-3 (5 μg/mL)/CD28 (1 μg/mL) (OKT-3/CD28) for 72 h. BrdU was added to the cells for 14 h incubation before the end of cell culture, and then the amount of BrdU incorporation was measured by using plate reader at 450 nm. Data are expressed as relative folds of BrdU incorporation of the controlled cells and represent the mean ± SEM of three independent experiments. Cytotoxicity of shikonin on human T lymphocytes (d). The cells (105/well) were treated with shikonin at the indicated concentrations for 3 days, and then MTT reagent was added to the cells for 4 h of incubation followed by addition of solubilization buffer. The absorbance was then read at 570 nm. Data are expressed as the percentage of absorbance of controlled cells and represent the mean ± SEM of three independent experiments.
