Morin inhibits the growth of human leukemia HL-60 cells via cell cycle arrest and induction of apoptosis through mitochondria dependent pathway

The effects of morin (3,5,7,20,40-pentahydroxyflavone) on human leukemia HL-60 cells in vitro were investigated and the molecular mechanisms of morin-induced G2/M arrest and Apoptosis in HL-60 cells were examined. Morin induced morphological changes and decreased the percentage of viable cells via induction of G2/M-phase arrest and Apoptosis. Morin-induced G2/M-phase arrest was accompanied by the promotion of p21 and Wee1, and decreased levels of Cdc25c and cyclins A and B1 complex. Morin-induced Apoptosis in HL-60 cells was also confirmed by flow cytometric assay, DNA gel electrophoresis for DNA fragmentation and DAPI staining. Morin induced Apoptosis in time- and dose-dependent manners. Morin-induced Apoptosis was associated with elevated intracellular Reactive Oxygen Species (ROS) increased and Ca2+ production; decreased the levels of mitochondria membrane potential (deltapsi(m)) and increased Caspase-3 activation. Collectively, these results suggest that the morin-induced Apoptosis in HL-60 cells may result from the activation of Caspase-3 and intracellular Ca2+ release, as well as the mitochondria membrane potential pathway.