Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.
Acta Pharmacol Sin. 2012 Oct;33(10):1325-31. doi: 10.1038/aps.2012.93. Epub 2012 Sep 17.
To investigate whether luteolin, a highly prevalent flavonoid, reverses the effects of epithelial-mesenchymal transition (EMT) in vitro and in vivo and to determine the mechanisms underlying this reversal.
Murine malignant melanoma B16F10 cells were exposed to 1% O(2) for 24 h. Cellular mobility and adhesion were assessed using Boyden chamber transwell assay and cell adhesion assay, respectively. EMT-related proteins, such as E-cadherin and N-cadherin, were examined using Western blotting. Female C57BL/6 mice (6 to 8 weeks old) were injected with B16F10 cells (1×10(6) cells in 0.2 mL per mouse) via the lateral tail vein. The mice were treated with luteolin (10 or 20 mg/kg, ip) daily for 23 d. On the 23rd day after tumor injection, the mice were sacrificed, and the lungs were collected, and metastatic foci in the lung surfaces were photographed. Tissue sections were analyzed with immunohistochemistry and HE staining.
Hypoxia changed the morphology of B16F10 cells in vitro from the cobblestone-like to mesenchymal-like strips, which was accompanied by increased cellular adhesion and invasion. Luteolin (5-50 μmol/L) suppressed the hypoxia-induced changes in the cells in a dose-dependent manner. Hypoxia significantly decreased the expression of E-cadherin while increased the expression of N-cadherin in the cells (indicating the occurrence of EMT-like transformation), which was reversed by luteolin (5 μmol/L). In B16F10 cells, luteolin up-regulated E-cadherin at least partly via inhibiting the β3 integrin/FAK signal pathway. In experimental metastasis model mice, treatment with luteolin (10 or 20 mg/kg) reduced metastatic colonization in the lungs by 50%. Furthermore, the treatment increased the expression of E-cadherin while reduced the expression of vimentin and β3 integrin in the tumor tissues.
Luteolin inhibits the hypoxia-induced EMT in malignant melanoma cells both in vitro and in vivo via the regulation of β3 integrin, suggesting that luteolin may be applied as a potential anticancer chemopreventative and chemotherapeutic agent.
研究木樨草素（一种广泛存在的类黄酮）是否能逆转体外和体内的上皮-间充质转化（EMT）效应，并确定这种逆转的机制。
将小鼠恶性黑色素瘤 B16F10 细胞暴露于 1%的 O(2)中 24 小时。使用 Boyden 室 Transwell 分析和细胞黏附分析分别评估细胞迁移和黏附能力。使用 Western blot 检测 EMT 相关蛋白，如 E-钙黏蛋白和 N-钙黏蛋白。将 6 至 8 周龄的雌性 C57BL/6 小鼠（每只小鼠 0.2 mL 中注射 1×10(6)个 B16F10 细胞）通过尾静脉注射。用木樨草素（10 或 20 mg/kg，ip）每天处理 23 天。在肿瘤注射后第 23 天，处死小鼠，收集肺部，并拍摄肺表面的转移灶。用免疫组织化学和 HE 染色分析组织切片。
缺氧使 B16F10 细胞在体外的形态从鹅卵石样变为间充质样条带，同时细胞黏附和侵袭能力增加。木樨草素（5-50 μmol/L）以剂量依赖的方式抑制缺氧诱导的细胞变化。缺氧显著降低了细胞中 E-钙黏蛋白的表达，同时增加了 N-钙黏蛋白的表达（表明发生了 EMT 样转化），木樨草素（5 μmol/L）逆转了这一变化。在 B16F10 细胞中，木樨草素通过抑制 β3 整合素/FAK 信号通路至少部分地上调了 E-钙黏蛋白的表达。在实验性转移模型小鼠中，木樨草素（10 或 20 mg/kg）处理可使肺部的转移灶减少 50%。此外，该治疗增加了肿瘤组织中 E-钙黏蛋白的表达，同时降低了波形蛋白和 β3 整合素的表达。
木樨草素通过调节β3 整合素抑制体外和体内恶性黑色素瘤细胞的缺氧诱导的 EMT，表明木樨草素可能作为一种潜在的抗癌化学预防和化疗药物。
