Artesunate induces apoptosis through caspase-dependent and -independent mitochondrial pathways in human myelodysplastic syndrome SKM-1 cells

Abstract

Artesunate (ART) is a semi-synthetic derivative of artemisinin extracted from Artemisia annua (sweet wormwood) that is conventionally used in anti-malarial drugs and more recently in medications that induce tumor cell apoptosis. Here, we investigated the effects and mechanistic pathways of ART in human myelodysplastic syndrome (MDS), a condition that commonly progresses to acute myeloid leukemia (AML). Human MDS SKM-1 cells, primary bone marrow (PBM) mononuclear cells from patients with refractory anemia with excess blasts (RAEB) or MDS–AML (MDS cell group), and PBM stromal cells from three patients without hematological diseases (non-MDS cell group) were cultured for 24, 48, or 72h with or without various ART concentrations. CCK-8, western blot, JC-1 fluorescence, and Annexin-V/Propidium iodide (PI) labeling were used to assess cell proliferation, protein levels, mitochondrial membrane potentials (MMPs) and apoptosis, respectively. ART administration dose- and time-dependently inhibited SKM-1 proliferation. At 24, 48, and 72h, ART IC50 values were 89.92, 4.24, and 1.28μmol/L, respectively. ART only significantly inhibited proliferation in the MDS cell group, but it has little impact on proliferation of non-MDS cells. ART decreased MMPs, and dose-dependently induced SKM-1 cell apoptosis, peaking at 82.9% when treated with 200μmol/L ART for 24h. Caspase-3 and -9 activation, poly(ADP-ribose) polymerase cleavage, decreased Bcl-2/Bax ratio and apoptosis inducing factor nuclear localization were implicated in apoptosis. Our results indicate that ART effectively induces apoptosis in SKM-1 cells through both caspase-dependent and -independent mitochondrial pathways.