['To identify whether Pulsatilla saponin A (PsA), an active molecule extracted from Pulsatilla chinensis regel, can induce acute myeloid leukemia (AML) cells differentiate.', 'PsA was isolated from P. chinensis, and its effects of differentiation induction on both AML cell lines and the primary leukemia cells were investigated.', 'Compared with the untreated control, PsA induced the differentiation of U937 cells, K562 cells and HL-60 cells, represented as the increased CD15+ cells in a dose- and time-dependent manner in all the three AML cell lines, after PsA treatment. As the same time, the cell morphology of these AML cells was changed correspondingly; the cytoplasm/nuclei ratio was increased, basophilic cytoplasm was decreased, and eccentric nucleus and granules were also observed. Also, the same effects of differentiation induction by PSA were confirmed in the primary leukemia cells. However, the specific MEK/ERK inhibitor U0126 effectively abrogated the differentiation induced by PsA in vitro.'] Does pulsatilla saponin A induce differentiation in acute myeloid leukemia in vitro?