红花多糖对肝癌细胞增殖阻滞的机制探讨

目的： 通过研究红花多糖（safflower polysaccharide，SPS）对人肝癌SMMC-7721细胞增殖的影响，探讨SPS抗肿瘤作用的分子机制。 方法： 体外培养人肝癌SMMC-7721细胞，加入含不同质量浓度SPS（0，0.02，0.04，0.08，0.16，0.32，0.64，1.28 g·L^-1）的培养液，分别培养24，48 h，用四甲基偶氮唑盐比色法（MTT法）检测SPS对细胞增殖的影响；用免疫组化法检测0.16，0.32，0.64 g·L^-1SPS作用肝癌细胞48 h，细胞的细胞周期素B₁（cyclin B₁）蛋白表达；采用实时荧光定量PCR技术（realtime PCR，RT-PCR）和蛋白免疫印迹（Western blot）法检测细胞分裂周期25B（Cdc25B）基因的表达。 结果： 肝癌细胞的生存率随SPS浓度和作用时间的增加而降低，而1.28 g·L^-1SPS组除外。SPS作用48 h后SMMC-7721细胞的cyclin B₁蛋白、Cdc25B蛋白和mRNA表达降低，并具有剂量依赖性。 结论： SPS可能通过抑制细胞周期相关基因的表达，诱导肝癌细胞增殖阻滞，进而起到抗肿瘤作用。

Mechanism Investigation of Cell Cycle Arrest in Hepatic Cancer Cell Induced by Safflower Polysaccharide

Objective: To detect how safflower polysaccharide (SPS) affects cell proliferation of human hepatic cancer cell line SMMC-7721. Method: SMMC-7721 cells were treated with different concentrations(0, 0.02, 0.04, 0.08, 0.16, 0.32, 0.64, 1.28 g·L^-1) of SPS for 24, 48 hours. The cell proliferation was assessed by methyl thiazolyl tetrazolium (MTT) assay. The proteins of cyclin B₁ were compared by IHC. The expression of mRNA and protein of Cdc25B was compared by RT-PCR and Western blot. Result: The cell survival rate of SMMC-7721 cells was significantly inhibited by SPS in a dose-dependent and time-dependent manner, except 1.28 g·L^-1 SPS group. The protein expression of cyclin B₁ and Cdc25B was down-regulated compared with the control group at 48 hour. The mRNA of Cdc25B also decreased and had good dose-dependent. Conclusion: SPS can inhibit proliferation of SMMC-7721 cell by affecting expression of cycle regulation genes.