Inhibitory effect of astragalus polysaccharide on the proliferation of human erythroleukemia K562 cells and its mechanisms / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the inhibitory effect of astragalus polysaccharide (APS) on the proliferation of human erythroleukemia K562 cells and its mechanisms.Methods After K562 cells (purchased from Shanghai cell bank of chinese academy of science) were treated with different concentrations (0 mg/L,100 mg/L,200 mg/L and 400 mg/L) of APS.The influences of APS on the growth rate,doubling time and cell cycle distribution of K562 cells were observed by methyl thiazolyl tetra-zolium assay (MTF) and flow cytometry,respectively.Furthermore,the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assay were used to detect the expressions of Cyclin A,Cyclin B,Cyclin E and p21 gene at the mRNA and protein levels,respectively.Results MTT assay findings showed that,compared to the control group (0 mg/L APS),growth rates of K562 cells treated with 100 mg/L,200 mg/L and 400 mg/L APS decreased significantly (all P ＜ 0.01),and the doubling times lengthened significantly (all P ＜ 0.01).Flow cytometry findings revealed that,compared to the control group,the G1 phase cells in K562 cells of APS group increased significantly (P ＜0.01),while the S and G2/M phase cells decreased significantly (all P ＜ 0.01).RT-PCR and Western blotting results indicated that Cyclin B and Cyclin E expression of K562 cells at the mRNA and protein levels in the APS group were significantly lower than those of the control group(all P ＜ 0.01),whereas p21 expression was significantly enhanced at mRNA and protein levels (P ＜ 0.01),and Cyclin A expression was not significantly different at mRNA and protein levels between the 2 groups (all P ＞ 0.05).Conclusions APS could inhibit the proliferation of human erythroleukemia K562 cells.APS could inhibit the proliferation of K562 cells by down-regulating the expression of Cyclin B and Cyclin E and up-regulating the expression of p21.