Institute of Vascular Medicine, Medical Research Center, Peking University Third Hospital, Beijing, China.
Acta Pharmacol Sin. 2012 Jan;33(1):101-8. doi: 10.1038/aps.2011.164.
To investigate the molecular mechanisms underlying the antitumor activity of cepharanthine (CEP), an alkaloid extracted from Stephania cepharantha Hayata.
Human osteosarcoma cell line SaOS2 was used. MTT assay, Hoechst 33342 nuclear staining, flow cytometry, Western blotting and nude mouse xenografts of SaOS2 cells were applied to examine the antitumor activity of CEP in vitro and in vivo. The expression levels of STAT3 and its downstream signaling molecules were measured with Western blotting and immunochemistry analysis. The activity of STAT3 was detected based on the phosphorylation level of STAT3, luciferase gene reporter assay and translocation of STAT3 to the nucleus.
Treatment of SaOS2 cells with CEP (2.5-20 μmol/L) inhibited the cell growth in a concentration- and time-dependent manner. CEP (10 μmol/L) caused cell cycle arrest at G(1) phase and induced apoptosis of SaOS2 cells. CEP (10 and 15 μmol/L) significantly decreased the expression of STAT3 in SaOS2 cells. Furthermore, CEP (5 and 10 μmol/L) significantly inhibited the expression of target genes of STAT3, including the anti-apoptotic gene Bcl-xL and the cell cycle regulators c-Myc and cyclin D1. In nude mouse xenografts of SaOS2 cells, CEP (20 mg·kg(-1)·d(-1), ip for 19 d) significantly reduced the volume and weight of the tumor.
Our findings suggest that inhibition of STAT3 signaling pathway is involved in the anti-tumor activity of CEP.
研究从Stephania cepharantha Hayata 中提取的生物碱石蒜裂碱（CEP）的抗肿瘤活性的分子机制。
使用人骨肉瘤细胞系 SaOS2。MTT 测定法、Hoechst 33342 核染色、流式细胞术、Western 印迹和 SaOS2 细胞的裸鼠异种移植用于体外和体内研究 CEP 的抗肿瘤活性。Western 印迹和免疫组织化学分析测量 STAT3 及其下游信号分子的表达水平。基于 STAT3 的磷酸化水平、荧光素酶基因报告基因测定和 STAT3 向核内易位来检测 STAT3 的活性。
CEP（2.5-20 μmol/L）处理 SaOS2 细胞以浓度和时间依赖的方式抑制细胞生长。CEP（10 μmol/L）导致 SaOS2 细胞周期停滞在 G1 期并诱导细胞凋亡。CEP（10 和 15 μmol/L）显著降低了 SaOS2 细胞中 STAT3 的表达。此外，CEP（5 和 10 μmol/L）显著抑制了 STAT3 的靶基因的表达，包括抗凋亡基因 Bcl-xL 和细胞周期调节剂 c-Myc 和细胞周期蛋白 D1。在 SaOS2 细胞的裸鼠异种移植中，CEP（20 mg·kg(-1)·d(-1)，腹腔注射 19 d）显著减少了肿瘤的体积和重量。
我们的研究结果表明，抑制 STAT3 信号通路参与了 CEP 的抗肿瘤活性。
