Abstract

Epithelial–mesenchymal transition (EMT) has recently been associated with cancer invasion, metastasis, and resistance. In our previous study, we discovered nanaomycin K, a natural growth inhibitor for EMT-induced Madin Darby canine kidney (MDCK) cells, from the cultured broth of actinomycetes. However, the screening method was undeveloped, because the activity of nanaomycin K was discovered accidentally. In this study, we established a screening method by analyzing the characteristics of nanaomycin K in MDCK cells. Nanaomycin K showed the characteristic growth inhibitory activity on MDCK cells cultured under four conditions: medium containing dimethyl sulfoxide, SB431542, TGF-β, and a mixture of SB431542 and TGF-β. The activity was stronger in TGF-β-treated cells than in DMSO-treated cells. In the mixture of SB431542 and TGF-β-treated cells, the activity of nanaomycin K was suppressed. The anti-cancer agents, mitomycin C, cisplatin, and staurosporine, lacked the characteristics as that of nanaomycin K for these four treatment conditions. Since these four conditions distinguish between the effects of nanaomycin K and other anti-cancer agents in EMT-induced cells, the screening method was established. Among the 13,427 plant extracts tested, Piper betle leaf extract displayed growth inhibitory activity against EMT-induced cells. Through the purification of the extract via bio-guided fractionation, hydroxychavicol was isolated as an active compound. The cytotoxic activity of hydroxychavicol was stronger in EMT-induced MDCK cells than in control cells. However, its cytotoxic activity was suppressed in EMT-inhibited cells. Furthermore, hydroxychavicol exhibited same activity against SAS cells (human squamous cell carcinoma of the tongue). Thus, we have successfully established a screening method for growth inhibitors of EMT-induced cells and have discovered an inhibitor from plant-based sources.

Graphical abstract

中文翻译：

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通过植物来源的 TGF-β 筛选上皮-间质转化诱导细胞的生长抑制剂，鉴定出来自 Piper bitle 的活性化合物羟基胡椒粉酚

摘要

最近，上皮-间质转化（EMT）与癌症侵袭、转移和耐药性相关。在我们之前的研究中，我们从放线菌培养液中发现了纳霉素 K，它是 EMT 诱导的 Madin Darby 犬肾 (MDCK) 细胞的天然生长抑制剂。然而，由于纳米霉素K的活性是偶然发现的，筛选方法尚未开发出来。在本研究中，我们通过分析MDCK细胞中纳米霉素K的特性，建立了筛选方法。Nanaomycin K 对在四种条件下培养的 MDCK 细胞表现出特征性的生长抑制活性：含有二甲基亚砜、SB431542、TGF-β 以及 SB431542 和 TGF-β 混合物的培养基。TGF-β处理的细胞中的活性比DMSO处理的细胞中的活性更强。在SB431542和TGF-β处理的细胞的混合物中，纳霉素K的活性被抑制。抗癌药物丝裂霉素C、顺铂和星形孢菌素缺乏纳米霉素K针对这四种治疗条件的特性。由于这四个条件区分了纳霉素 K 和其他抗癌药物在 EMT 诱导细胞中的作用，因此建立了筛选方法。在测试的 13,427 种植物提取物中，蒌叶提取物对 EMT 诱导的细胞表现出生长抑制活性。通过生物引导分级分离纯化提取物，分离出羟基胡椒酚作为活性化合物。羟基胡椒粉酚在 EMT 诱导的 MDCK 细胞中的细胞毒活性强于对照细胞。然而，其细胞毒活性在 EMT 抑制的细胞中受到抑制。此外，羟基胡椒酚对 SAS 细胞（人舌鳞状细胞癌）也表现出相同的活性。因此，我们成功建立了EMT诱导细胞生长抑制剂的筛选方法，并发现了一种植物来源的抑制剂。

图形概要