Apoptosis induction of oroxylin A in human chronic myelogenous leukemia cell line K562

To investigate the apoptotic effect of oroxylin A on human chronic myelogenous leukemia cell line K562 and its potential mechanism. K562 cells were treated with oroxylin A. MTT assay was performed to assess growth inhibition effect of oroxylin A on K562 cells. The morphological change of cells were observed under electronic microscope. DAPI staining and flow cytometry were employed to observe the apoptosis rate of K562 cells. Changes in the expression of caspase 9, survivin and ERK1/2 were analyzed by Western blotting. Results showed that oroxylin A inhibited the growth of K562 in a time and dose-dependent manner. Oroxylin A induced cell apoptosis was characterized by appearance of numerous engorged vacuoles, reduction of microvilli on cell surface, condensation of chromatin and emergence of apoptotic body. Besides, oroxylin A dose-dependently induced K562 cell apoptosis, up-regulated the expression of cleaved-caspase 9 and down-regulated expression of survivin, pro-caspase 9 and p-ERK1/2 proteins. In conclusion, all these results showed that oroxylin A can induce apoptosis of K562 cells, which might be related to the down-regulation of survivin expression, activation of caspase 9 and inhibition of ERK signaling pathway.