Molecular mechanisms of ginsenoside Rh2-mediated G1 growth arrest and apoptosis in human lung adenocarcinoma A549 cells
Molecular mechanisms of ginsenoside Rh2-mediated G1 growth arrest and apoptosis in human lung adenocarcinoma A549 cells
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DOI：
10.1007/s00280-004-0919-6
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发表时间：
2005-06-01
影响因子：
3
通讯作者：
Hsu, SL
中科院分区：
文献类型：
--
作者：
Cheng, CC;Yang, SM;Hsu, SL
人参皂苷Rh2 （Rh2）是一种纯化的人参皂苷，已被证明对某些类型的癌细胞具有抗增殖作用。然而，Rh2对细胞生长和死亡的分子机制尚未完全阐明。本研究探讨了Rh2对人肺腺癌A549细胞的抗增殖作用。用30 μ g/ml Rh2处理A549细胞，导致g(1)期阻滞，随后进入凋亡。这种rh2介导的G(1)阻滞伴随着cyclin-D1、cyclin-E和Cdk6蛋白水平和激酶活性的下调，以及pRb2/p130的上调。TUNEL实验和DNA片段分析证实了rh2诱导的细胞凋亡。Rh2引起TRAIL-RI （DR4）死亡受体表达水平升高，但未改变其他死亡受体或Bcl-2家族分子的表达水平。DR4:Fc融合蛋白抑制trail -DR4介导的细胞凋亡，显著抑制rh2诱导的细胞凋亡。此外，caspase-2、caspase-3和caspase-8在Rh2处理下被高度激活。caspase-2、caspase-3和caspase-8抑制剂可明显抑制Rh2诱导的细胞死亡。caspase-8抑制剂显著抑制caspase-2、caspase-3和caspase-8的活化。这些观察结果表明，多种与G(1)相关的细胞周期调节蛋白受到Rh2的调控，并有助于Rh2诱导的G(1)生长停滞。DR4死亡受体表达水平的升高可能在rh2触发细胞凋亡的启动中起关键作用，而caspase-8/caspase-3级联的激活则是rh2诱导死亡过程的刽子手。
Ginsenoside Rh2 (Rh2), a purified ginseng saponin, has been shown to have antiproliferative effects in certain cancer cell types. However, the molecular mechanisms of Rh2 on cell growth and death have not been fully clarified. In this study, the antiproliferative effect of Rh2 in human lung adenocarcinoma A549 cells was investigated. Treatment of A549 cells with 30 mu g/ml Rh2 resulted in G(1) phase arrest, followed by progression to apoptosis. This Rh2-mediated G(1) arrest was accompanied by downregulation of the protein levels and kinase activities of cyclin-D1, cyclin-E and Cdk6, and the upregulation of pRb2/p130. In addition, Rh2-induced apoptosis was confirmed by TUNEL assay and DNA fragmentation analysis. Administration of Rh2 caused an increase in the expression levels of TRAIL-RI (DR4) death receptor but did not alter the levels of other death receptors or Bcl-2 family molecules. Furthermore, the Rh2-induced apoptosis was significantly inhibited by DR4:Fc fusion protein, which inhibits TRAIL-DR4-mediated apoptosis. In addition, caspase-2, caspase-3 and caspase-8 were highly activated upon Rh2 treatment. Inhibitors of caspase-2, caspase-3 and caspase-8 markedly prevented the cell death induced by Rh2. Inhibitor of caspase-8 significantly inhibited the activation of caspase-2, caspase-3 and caspase-8. These observations indicate that multiple G(1)-related cell cycle regulatory proteins are regulated by Rh2 and contribute to Rh2-induced G(1) growth arrest. The increase in the expression level of DR4 death receptor may play a critical role in the initiation of Rh2-triggered apoptosis, and the activation of the caspase-8/caspase-3 cascade acts as the executioner of the Rh2-induced death process.