人参皂甙 Rh2对人肝癌细胞 SMMC-7721的诱导分化作用

背景与目的:目前寻找低毒高效的分化诱导剂是肿瘤诱导分化治疗的关键.人参具有抗肿瘤、抗衰老、抗辐射等多种生物学活性,其主要的活性有效成分人参皂甙 Rh2( ginsenoside Rh2,G-Rh2)具有较强的抗癌活性,但其抗肿瘤机制还不十分清楚.因此,本研究探讨 G-Rh2对人肝癌细胞株 SMMC-7721的生长抑制作用及抗癌机制.方法:以 MTT法、光镜、电子显微镜观察 G-Rh2对 SMMC-7721细胞增殖、形态、超微结构的影响.用免疫组化染色和 ELISA法检测细胞浆中甲胎蛋白( alpha-fetoprotein, AFP)合成情况,酶促反应试剂盒检测细胞浆中碱性磷酸酶( alkaline phosphatase, ALP)和γ谷氨酰转肽酶(γ-glutamyltranspeptidase,γ-GT)活性,放射免疫法检测细胞 AFP和白蛋白( albumin, Alb)分泌量,并观察 G-Rh2对以上指标的影响.结果: G-Rh2以时间依赖性和浓度依赖性抑制 SMMC-7721细胞增殖, 10 μ g/ml G-Rh2作用 6天抑制率达 50%;而 20 μ g/ml G-Rh2作用 4天抑制率近 50%.经 20 μ g/ml G-Rh2作用 4天,肝癌细胞形态及亚细胞结构向正常肝细胞方向逆转. 10 μ g/ml、 20 μ g/ml G-Rh2作用 SMMC-7721细胞后, AFP合成明显下降( P< 0.05),分泌量从 6.60± 0.30下降到 2.35± 0.06( P< 0.01);γ-GT及耐热型 ALP活性显著降低( P< 0.01); ALP活性及 Alb分泌量显著升高( P< 0.01).结论: G-Rh2具有诱导人肝癌细胞 SMMC-7721向正常细胞分化的作用.

Induction of differentiation by ginsenoside Rh2 in hepatocarcinoma cell SMMC-7721

BACKGROUND & OBJECTIVE: Up to now, searching for non-toxic and natural origin substances that induced the differentiation of cancer cells is a key for anticancer therapy. Ginseng is one of the most widely used natural tonics in oriental countries for thousands of years and has been reported to have various biological effects. Ginsenosides are thought to be the major effective ingredients in ginseng. Among them, ginsenoside Rh2(G-Rh2) has been suggested to have a cell-growth suppressive effect on various cancer cells, but the mechanism is unclear.This study was to investigate the induced differentiative effects of G-Rh2 on SMMC-7721 hepatocarcinoma cells. METHODS: Effects of G-Rh2 on cell viability was analyzed by MTT assay. Cell morphology was examined by a light and electronic microscope. Alpha-fetoprotein (AFP) in plasma was determined qualitatively and quantitatively with immunohistochemistry and ELISA. The specific activities of alkaline phosphatase (ALP) and heat-resistant ALP in plasma were assayed by ALP kit based on Bessey method. The specific activity of gamma-glutamyltranspeptidase (gamma-GT) was measured with gamma-GT kit.The secretory amount of AFP or albumin was detected with radioimmunoassay kit. RESULTS: G-Rh2 inhibited the proliferation of SMMC-7721 cells in dose and time-dependent manners. The inhibition rate was 50.87% after 6-day treatment with 10 microg/ml G-Rh2 while 46.84% after 4-day treatment with 20 microg/ml G-Rh2. Twenty microg/ml G-Rh2 induced the mature and normality of morphology and ultrastructure in SMMC-7721 cells. After treated with 10 microg/ml or 20 microg/ml G-Rh2, the production of AFP was significantly reduced (P< 0.05), and the secretory amount of AFP was reduced from 6.60+/-0.30 to 2.35+/-0.06 (P< 0.01), and the specific activities of gamma-GT and heat-resistant ALP were remarkably declined (P< 0.01); while the secretory amount of albumin and ALP activity were remarkably enhanced (P< 0.01). CONCLUSION: G-Rh2 could induce the SMMC-7721 cell differentiation tending to normal.