目的 研究猪苓多糖(polyporus polysaccharide,PPS)抑制肺癌A549 细胞增殖的作用及其机制。方法 设对照组和PPS低、中、高剂量组,用MTT 实验、流式细胞术检测PPS 对细胞增殖的影响,用实时荧光定量PCR(qRT-PCR)法检测PPS 对A549 细胞Cyclin D1 mRNA 表达水平及其稳定性的影响,用Western blotting 检测PPS 对A549 细胞Cyclin D1 蛋白、人抗原R(human antigen R,HuR)蛋白表达及对HuR 蛋白胞浆及胞核内分布的影响。结果 与对照组比较,中、高剂量的PPS 作用后,A549 细胞增殖明显受到抑制(P < 0.05),Cyclin D1 mRNA 稳定性降低(P < 0.05),Cyclin D1 mRNA 及蛋白表达减少(P < 0.05),HuR 总蛋白没有明显变化,但胞浆HuR 蛋白表达下降(P < 0.05),胞核HuR 蛋白表达升高(P < 0.05)。结论 PPS 可抑制A549细胞增殖,其作用机制可能与改变HuR 在细胞内定位,从而降低Cyclin D1 mRNA 稳定性及Cyclin D1 蛋白表达有关。

Objective To study the effects of polyporus polysaccharide (PPS) on the proliferation of human lung cancer A549 cells and the corresponding molecular mechanism. Methods The A549 cells in control group were normally treated and the cells in experimental groups were incubated with different doses of PPS. The MTT method and flow cytometry were used to analyze the influence of drugs on cell proliferation. The qRT-PCR was used to detect mRNA levels of A549 cells and Cyclin D1 mRNA stability. The levels of human antigen R (HuR) protein in plasma and nuclei and cyclin D1 protein were detected by Western blotting. Results Compared with the control, the cell growth was obviously inhibited (P < 0.05), the Cyclin D1 mRNA stability and Cyclin D1 mRNA were decreased in the mid- and high-dose PPS groups (P < 0.05), the total protein of HuR was slightly changed, but the cytoplasm protein of HuR was down-regulated (P < 0.05) and the nucleus protein of HuR was up-regulated (P < 0.05). Conclusion PPS can suppress the proliferation of A549 cells, which is possibly affected by down-regulating the cytoplasm protein of HuR, lowering the stability of Cyclin D1 mRNA, and thus decreasing the expression of Cyclin D1 protein.

国家自然科学基金资助项目(81573769);广东省自然科学基金资助项目(2014A030313415);广东省中医药管理局立项课题资助(20151193);广州中医药大学基础医学院院长基金资助