Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Emory University School of Medicine, Atlanta, Georgia, United States of America.
PLoS One. 2013 Sep 12;8(9):e75069. doi: 10.1371/journal.pone.0075069. eCollection 2013.
Though clinicians can predict which patients are at risk for developing metastases, traditional therapies often prove ineffective and metastatic disease is the primary cause of cancer patient death; therefore, there is a need to develop anti-metastatic therapies that can be administered over long durations to specifically inhibit the motility of cancer cells. Withaniasomnifera root extracts (WRE) have anti-proliferative activity and the active component, Withaferin A, inhibits the pro-metastatic protein, vimentin. Vimentin is an intermediate filament protein and is part of the epithelial to mesenchymal transition (EMT) program to promote metastasis. Here, we determined whether WRE standardized to Withaferin A (sWRE) possesses anti-metastatic activity and whether it inhibits cancer motility via inhibition of vimentin and the EMT program. Several formulations of sWRE were created to enrich for Withaferin A and a stock solution of sWRE in EtOH could recover over 90% of the Withaferin A found in the original extract powder. This sWRE formulation inhibited breast cancer cell motility and invasion at concentrations less than 1µM while having negligible cytotoxicity at this dose. sWRE treatment disrupted vimentin morphology in cell lines, confirming its vimentin inhibitory activity. To determine if sWRE inhibited EMT, TGF-β was used to induce EMT in MCF10A human mammary epithelial cells. In this case, sWRE prevented EMT induction and inhibited 3-D spheroid invasion. These studies were taken into a human xenograft and mouse mammary carcinoma model. In both models, sWRE and Withaferin A showed dose-dependent inhibition of tumor growth and metastatic lung nodule formation with minimal systemic toxicity. Taken together, these data support the hypothesis that low concentrations of sWRE inhibit cancer metastasis potentially through EMT inhibition. Moreover, these doses of sWRE have nearly no toxicity in normal mouse organs, suggesting the potential for clinical use of orally administered WRE capsules.
尽管临床医生可以预测哪些患者有发展转移的风险，但传统疗法往往证明无效，转移性疾病是癌症患者死亡的主要原因；因此，需要开发能够长期使用的抗转移疗法，以特异性抑制癌细胞的运动性。印度萝芙木根提取物 (WRE) 具有抗增殖活性，活性成分醉茄内酯 A 抑制促转移蛋白波形蛋白。波形蛋白是一种中间丝蛋白，是促进转移的上皮间质转化 (EMT) 程序的一部分。在这里，我们确定 WRE 标准化的醉茄内酯 A (sWRE) 是否具有抗转移活性，以及它是否通过抑制波形蛋白和 EMT 程序来抑制癌症运动性。创建了几种 sWRE 制剂来富集醉茄内酯 A，而 sWRE 的乙醇溶液可以回收原始提取物粉末中发现的醉茄内酯 A 的 90%以上。这种 sWRE 制剂在低于 1µM 的浓度下抑制乳腺癌细胞的运动性和侵袭性，而在该剂量下具有可忽略的细胞毒性。sWRE 处理破坏了细胞系中的波形蛋白形态，证实了其波形蛋白抑制活性。为了确定 sWRE 是否抑制 EMT，用 TGF-β 诱导 MCF10A 人乳腺上皮细胞 EMT。在这种情况下，sWRE 阻止 EMT 诱导并抑制 3-D 球体侵袭。这些研究被应用于人异种移植物和小鼠乳腺癌模型。在这两种模型中，sWRE 和醉茄内酯 A 均表现出剂量依赖性抑制肿瘤生长和转移肺结节形成，且全身毒性极小。综上所述，这些数据支持低浓度 sWRE 通过 EMT 抑制抑制癌症转移的假说。此外，这些剂量的 sWRE 在正常小鼠器官中几乎没有毒性，表明口服 WRE 胶囊具有临床应用的潜力。
