Matrine-induced apoptosis in leukemia U937 cells: involvement of caspases activation and MAPK-independent pathways.

It is reported that matrine, one of the major effective compounds isolated from the root of Sophora flavescens Ait., has anti-leukemia activity. In this study, we find that the treatment of leukemia U937 cells with matrine results in induction of apoptosis. Analysis of the mechanism underling this apoptotic event showed activation of caspases-9, -3, and -7, and release of cytochrome C from mitochondria to cytosol, and cleavage of poly(ADP-ribose) polymerase. Matrine did not alter the level of bcl-2 and bcl-xL as well as bax. In addition, no correlation was found between matrine administration and activation of the three major MAPK subfamilies (Erk1/2, p38, JNK/SAPK). The results indicate that matrine induces apoptosis in U937 cells via a cytochrome C-triggered caspase activation pathway.