State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Cell Res. 2011 May;21(5):730-40. doi: 10.1038/cr.2011.30. Epub 2011 Feb 15.
The Wnt/β-catenin signaling pathway is a highly conserved pathway in organism evolution and regulates many biological processes. Aberrant activation of the Wnt/β-catenin signaling pathway is closely related to tumorigenesis. In order to identify potent small molecules to treat the over-activated Wnt signaling-mediated cancer, such as colon cancer, we established a mammalian cell line-based reporter gene screening system. The screen revealed a diterpenoid derivative, 15-oxospiramilactone (NC043) that inhibits Wnt3a or LiCl-stimulated Top-flash reporter activity in HEK293T cells and growth of colon cancer cells, SW480 and Caco-2. Treatment of SW480 cells with NC043 led to decreases in the mRNA and/or protein expression of Wnt target genes Axin2, Cyclin D1 and Survivin , as well as decreases in the protein levels of Cdc25c and Cdc2. NC043 did not affect the cytosol-nuclear distribution and protein level of soluble β-catenin, but decreased β-catenin/TCF4 association in SW480 cells. Moreover, NC043 inhibited anchorage-independent growth and xenograft tumorigenesis of SW480 cells. Collectively these results demonstrate that NC043 is a novel small molecule that inhibits canonical Wnt signaling downstream of β-catenin stability and may be a potential compound for treating colorectal cancer.
Wnt/β-连环蛋白信号通路是生物进化中高度保守的通路，调节着许多生物学过程。Wnt/β-连环蛋白信号通路的异常激活与肿瘤发生密切相关。为了鉴定能够有效治疗过度激活的 Wnt 信号介导的癌症（如结肠癌）的有效小分子化合物，我们建立了基于哺乳动物细胞系的报告基因筛选系统。该筛选揭示了一种二萜衍生物 15-氧螺旋霉素内酯（NC043），它能抑制 HEK293T 细胞中 Wnt3a 或 LiCl 刺激的 Top-flash 报告基因活性，以及结肠癌细胞 SW480 和 Caco-2 的生长。NC043 处理 SW480 细胞会导致 Wnt 靶基因 Axin2、Cyclin D1 和 Survivin 的 mRNA 和/或蛋白表达减少，以及 Cdc25c 和 Cdc2 的蛋白水平降低。NC043 不影响细胞质-核分布和可溶性 β-连环蛋白的蛋白水平，但会减少 SW480 细胞中β-连环蛋白/TCF4 的结合。此外，NC043 抑制了 SW480 细胞的非锚定依赖性生长和异种移植肿瘤发生。综上所述，这些结果表明 NC043 是一种抑制β-连环蛋白稳定性下游经典 Wnt 信号的新型小分子化合物，可能是治疗结直肠癌的潜在化合物。
