ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of sCD40L on biological behavior of leukemia cell line K562 and the possible mechanism.</p><p><b>METHODS</b>The different concentration of sCD40L was used to treat K562 cells, and the optimum concentration of sCD40L was screened by detecting the proliferation inhibition rate of K562 cells. The optimum concentration of sCD40L was used to treat K562 cells, the cell apoptosis rate and expression level of P53 and BCL-2 were detected by flow cytometry and the expression levels of Caspase 8 and Caspase 3 were detected by ELISA.</p><p><b>RESULTS</b>The optimum concentration of sCD40L was 4 µg/ml. After treated with sCD40L, the cell apoptosis rate, the expression of apoptosis-related factor P53 and the expression of Caspase 8 and Caspase 3 were significantly up-regulated in K562 cells,but the expression of BCL-2 was significantly down-regulated.</p><p><b>CONCLUSION</b>4 µg/ml sCD40L can inhibit the cell proliferation and promote the apoptosis of K562 cells, its mechanism may be related with mitochondrial and P53 pathway.</p>