Jaceosidin induces apoptosis in ras-transformed human breast epithelial cells through generation of reactive oxygen species

Extracts of Artemisia plants possess anti-inflammatory and antioxidative activities. Eupatilin (5,7-dihydroxy-3',4',6-tri-methoxynavone), a pharmacologically active flavone derived from Artemisia asiatica, was shown to inhibit phorbol ester-induced cyclooxygenase-2 expression and NF-kappa B activation in mouse skin, and also to induce cell cycle arrest in ras-transformed human mammary epithelial (MCF10A-ras) cells. In this article, we examined the ability of jaceosidin (4',5,7-trihydroxy-3',6-dimethoxyflavone) isolated from Artemisia argyi to inhibit the proliferation of MCF10A-ras cells. Jaceosidin reduced the viability of MCF10A-ras cells to a greater extent than eupatilin. Jaceosidin treatment resulted in increased intracellular accumulation of reactive oxygen species (ROS) in MCF10A-ras cells, which was blocked by the antioxidant N-acetylcysteine (NAC). NAC attenuated jaceosidin-induced cytotoxicity. To better assess the proapoptotic effects of jaceosidin, we analyzed the treated cells by the flow cytometry. MCF10A-ras cells treated with jaceosidin (100 mu M) exhibited the increased proportion of hypodiploid or apoptotic cells (48.72% as composed to 7.78% in control cells). Jaceosidin treatment also increased the ratio of proapoptotic Bax to the antiapoptotic Bcl-2 and induced the cleavage of caspase-3 and poly(ADP-ribose)polymerase (PARP). Moreover, jaceosidin elevated the expression of p53 and p21, while the compound inhibited the activation of ERK1/2 that is an important component of cell survival signaling.