[Cordyceps sinensis polysaccharide enhances apoptosis of HL-60 cells induced by triptolide].

Objective: To 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.

Methods: The 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.

Result: MTT 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.

Conclusion: PSCS 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.