Fucoidan inhibits proliferation of the SKM-1 acute myeloid leukaemia cell line via the activation of apoptotic pathways and production of reactive oxygen species

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukaemia (AML). Fucoidan, a complex sulphated polysaccharide isolated from the cell wall of brown seaweeds, has recently attracted attention for its multiple biological activities and its potential as a novel candidate for cancer therapy. In the present study, the anti-cancer activity of fucoidan was investigated in the MDS/AML cell line SKM-1. Fucoidan inhibited proliferation, induced apoptosis and caused G1-phase arrest of the cell cycle in SKM-1 cells as determined by a cell counting kit 8 assay and flow cytometry. Furthermore, reverse transcription quantitative polymerase chain reaction and western blot analyses indicated that treatment with fucoidan (100 µg/ml for 48 h) activated Fas and caspase-8 in SKM-1 cells, which are critical for the extrinsic apoptotic pathway; furthermore, caspase-9 was activated via decreases in phosphoinositide-3 kinase/Akt signaling as indicated by reduced levels of phosphorylated Akt, suggesting the involvement of the intrinsic apoptotic pathway. In addition, fucoidan treatment of SKM-1 cells resulted in the generation of reactive oxygen species (ROS) as determined by staining with dichloro-dihydro-fluorescein diacetate. These results suggested that the mechanisms of the anti-cancer effects of fucoidan in SKM-1 are closely associated with cell cycle arrest and apoptotic cell death, which partly attributed to the activation of apoptotic pathways and accumulation of intracellular ROS. Our results demonstrated that Fucoidan inhibits proliferation and induces the apoptosis of SKM-1 cells, which provides substantial therapeutic potential for MDS treatment.