Effect of artesunate on inhibiting proliferation and inducing apoptosis of SP2/0 myeloma cells through affecting NFκB p65

The initial treatment of multiple myeloma (MM) experienced a paradigm shift, in the past decade, with the introduction of novel agents such as thalidomide, lenalidomide and bortezomib, leading to improved outcomes. High dose therapy and autologous stem cell transplantation remain an important therapeutic option for patients with MM eligible for the procedure. However, most of these treatment regimens are too expensive for Chinese patients. Therefore, we investigated the effects of artesunate, which is commonly used in the treatment of severe malaria, on inhibition of proliferation and induction of apoptosis of a mouse myeloma cell line SP2/0. The growth inhibition of SP2/0 cell proliferation induced by artesunate (ART) treatment was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and the rate of apoptosis and cell cycle changes induced by ART were analyzed by flow cytometry. ART-induced morphology changes of apoptosis in SP2/0 cells, as observed by light and transmission electron microscopy. Additionally, DNA laddering, which is a hallmark of apoptosis, was observed by agarose gel electrophoresis of DNA harvested from SP2/0 cells treated with ART. The levels of nuclear factor kappa B p65 (NF kappa B p65) protein in nucleus and the inhibitor of NF kappa B (I kappa B alpha) in the cytoplasm were measured by western blot analysis and ELISA to evaluate NF kappa B p65 transcription activity indirectly. The results show that artesunate inhibited the proliferation and induced apoptosis of SP2/0 cells in a dose- and time-dependent manner. Artesunate also increased the proportion of SP2/0 cells in G(0)/G(1) phase, while decreased the proportion of cells in G2/M or S phase. Additionally, artesunate treatment decreased the level of NF kappa B p65 protein in the nucleus, while increased the level of I kappa B alpha protein in the cytoplasm. The present result is the first report to show that artesunate may be useful in the treatment of MM.