Apoptosis induction after 48 h treatment with fucoidan in 4T1 cells.

<p>A) Morphology of 4T1 cells observed under fluorescence microscope (Hoechst33258×400). DNA fragment and chromatin condensation were observed in fucoidan-treated cells, but few in untreated cells. The 50,100,200 µg/ml fucoidan treated 4T1 cells that underwent apoptosis were calculated at 18.9±1.17%, 42.3±4.38% and 67±7.52% respectively, while there were7.4±0.29% of the apoptotic cells in the control cells (<i>P</i><0.01). B) The apoptosis cells determined by FCM. 4T1 cells were stained with annexin V-FITC and propidium iodide (PI). The lower right quadrant (annexin V+/PI−) represents early apoptosis, and the upper right quadrant (annexin V+/PI+) represents late apoptosis and necrosis. The early apoptotic rates of 4T1 cells treated with fucoidan were 24±1.34%, 41±3.75% and 59±5.27% respectively and significantly higher than that in control cells(11±0.89%) (<i>P</i><0.05). Data are a representative of three independent experiments showing similar results. 1: control; 2: fucoidan 50 µg/ml; 3: fucoidan 100 µg/ml; 4: fucoidan 200 µg/ml.</p>