OBJECTIVETo investigate the effects of polysaccharide fraction of Cordyceps sinensis (PSCS) on triptolide (TPL)-induced apoptosis in the HL-60 cells and the involved molecular mechanism.

METHODSThe cultured leukemia HL-60 cells were divided into three groups: control group, TPL group (cells were treated with 5 ng/ml TPL only), and PSCS+TPL cells group (cells treated with 5 ng/ml TPL and 100 microg/ml or 200 microg/ml PSCS for 18 h). Cell viability was tested by MTT assay and apoptotic cells were quantitatively measured by flow cytometry with Annexin V/PI double stain.The expressions of Caspase-3, 6, 7, 9 and NF-kappa B proteins were tested by Western blot.

RESULTMTT assay showed that different concentrations of PSCS inhibited the cell viability. Flow cytometry indicated that TPL markedly increased the apoptosis rate of the HL-60 cells, and PSCS enhanced the apoptosis in a dose-dependent manner. Western blot showed that TPL did not inhibit the expression of the Caspase-3, 6, 7, 9 and NF-kappa B proteins, and when cells were treated with PSCS, the expression of proteins decreased with the PSCS concentration rising.

CONCLUSIONPSCS can enhance TPL-induced apoptosis in HL-60 cells and inhibit the expression of NF-kappa B and Caspase 3,6,7,9,which might be the possible signaling pathway of inducing apoptosis.