Laboratory of Protein Chemistry, Proteomics and Epigenetic Signalling (PPES), Department of Biomedical Sciences, University of Antwerp (UA), Belgium.
Hematology, Department Internal Medicine, Ghent University, Ghent, Belgium.
J Proteomics. 2018 May 15;179:17-29. doi: 10.1016/j.jprot.2018.02.013. Epub 2018 Feb 13.
Withaferin A (WA), a natural steroid lactone from the plant Withania somnifera, is often studied because of its antitumor properties. Although many in vitro and in vivo studies have been performed, the identification of Withaferin A protein targets and its mechanism of antitumor action remain incomplete. We used quantitative chemoproteomics and differential protein expression analysis to characterize the WA antitumor effects on a multiple myeloma cell model. Identified relevant targets were further validated by Ingenuity Pathway Analysis and Western blot and indicate that WA targets protein networks that are specific for monoclonal gammopathy of undetermined significance (MGUS) and other closely related disorders, such as multiple myeloma (MM) and Waldenström macroglobulinemia (WM). By blocking the PSMB10 proteasome subunit, downregulation of ANXA4, potential association with HDAC6 and upregulation of HMOX1, WA puts a massive blockage on both proteotoxic and oxidative stress responses pathways, leaving cancer cells defenseless against WA induced stresses. These results indicate that WA mediated apoptosis is preceded by simultaneous targeting of cellular stress response pathways like proteasome degradation, autophagy and unfolded protein stress response and thus suggests that WA can be used as an effective treatment for MGUS and other closely related disorders.
Multifunctional antitumor compounds are of great potential since they reduce the risk of multidrug resistance in chemotherapy. Unfortunately, characterization of all protein targets of a multifunctional compound is lacking. Therefore, we optimized an SILAC quantitative chemoproteomics workflow to identify the potential protein targets of Withaferin A (WA), a natural multifunctional compound with promising antitumor properties. To further understand the antitumor mechanisms of WA, we performed a differential protein expression analysis and combined the altered expression data with chemoproteome WA target data in the highly curated Ingenuity Pathway database. We provide a first global overview on how WA kills multiple myeloma cancer cells and serve as a starting point for further in depth experiments. Furthermore, the combined approach can be used for other types of cancer and/or other promising multifunctional compounds, thereby increasing the potential development of new antitumor therapies.
来自植物睡茄的天然甾体内酯 Withaferin A（WA）因其抗肿瘤特性而经常被研究。尽管已经进行了许多体外和体内研究，但 WA 的蛋白质靶标鉴定及其抗肿瘤作用机制仍不完整。我们使用定量化学蛋白质组学和差异蛋白质表达分析来描述 WA 对多发性骨髓瘤细胞模型的抗肿瘤作用。通过使用 Ingenuity 通路分析和 Western blot 进一步验证了鉴定出的相关靶标，并表明 WA 靶向特定于单克隆丙种球蛋白病的未确定意义（MGUS）和其他密切相关疾病的蛋白质网络，如多发性骨髓瘤（MM）和瓦尔登斯特伦巨球蛋白血症（WM）。通过阻断 PSMB10 蛋白酶体亚基，下调 ANXA4，与 HDAC6 潜在关联并上调 HMOX1，WA 对蛋白质毒性和氧化应激反应途径造成严重阻断，使癌细胞无法抵御 WA 诱导的应激。这些结果表明，WA 介导的细胞凋亡之前，同时靶向细胞应激反应途径，如蛋白酶体降解、自噬和未折叠蛋白应激反应，因此表明 WA 可用于治疗 MGUS 和其他密切相关疾病。
多功能抗肿瘤化合物具有很大的潜力，因为它们降低了化疗中多药耐药的风险。不幸的是，缺乏对多功能化合物所有蛋白质靶标的描述。因此，我们优化了 SILAC 定量化学蛋白质组学工作流程，以鉴定具有良好抗肿瘤特性的天然多功能化合物 Withaferin A（WA）的潜在蛋白质靶标。为了进一步了解 WA 的抗肿瘤机制，我们进行了差异蛋白质表达分析，并将改变的表达数据与高度注释的 Ingenuity 通路数据库中的化学蛋白质组 WA 靶标数据相结合。我们提供了 WA 如何杀死多发性骨髓瘤癌细胞的第一个全局概述，并为进一步的深入实验提供了起点。此外，该联合方法可用于其他类型的癌症和/或其他有前途的多功能化合物，从而增加开发新的抗肿瘤疗法的潜力。
