State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, China; Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China; Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin, China.
Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Science, Hebei University of Technology, Tianjin, China.
J Biol Chem. 2021 Sep;297(3):101016. doi: 10.1016/j.jbc.2021.101016. Epub 2021 Jul 28.
As a calcium-activated chloride channel regulated by the intracellular Ca concentration and membrane potential, TMEM16A has attracted considerable attention and has been proposed as a novel anticancer drug target. We have previously reported that the pocket above the ion conductance pore could be a nonselective inhibitor-binding pocket. However, whether this pocket is druggable remains unexplored. In this study, we performed virtual screening to target the presumed inhibitor-binding pocket and identified a highly effective TMEM16A inhibitor, theaflavin (TF: a tea polyphenol in black tea). Molecular dynamics simulations revealed that theaflavin adopts a "wedge insertion mode" to block the ion conduction pore and induces pore closure. Moreover, the binding mode showed that the TF pedestal plays an important role in pore blockade, and R515, R535, T539, K603, E623, and E633 were determined to be most likely to interact directly with the pedestal. Mutagenesis experiment results corroborated the mechanism through which TF binds to this pocket. Combined with the quantitative calculation results, our data indicated that the three hydroxyl groups on the pedestal may be the most crucial pharmacophores for TMEM16A inhibition by TF. Finally, antitumor experiments revealed that TF could target TMEM16A to inhibit the proliferation and migration of LA795 cells, indicating the potential therapeutic effect of TF on the growth of lung adenocarcinoma with high TMEM16A expression. The successful application of drug screening strategies based on this binding pocket highlights new directions for discovering superior modulators and contributes to the development of novel therapeutics for lung adenocarcinoma.
TMEM16A 是一种钙激活氯离子通道，受细胞内 Ca 浓度和膜电位调节，它已引起广泛关注，并被提议作为一种新的抗癌药物靶点。我们之前曾报道过，离子电导孔上方的口袋可能是一个非选择性抑制剂结合口袋。然而，这个口袋是否具有成药性仍未被探索。在这项研究中，我们进行了虚拟筛选以针对假定的抑制剂结合口袋，并鉴定出一种高效的 TMEM16A 抑制剂，茶黄素（TF：红茶中的一种茶多酚）。分子动力学模拟表明，茶黄素采用“楔形插入模式”来阻断离子传导孔并诱导孔关闭。此外，结合模式表明 TF 基架在孔阻断中起重要作用，并且 R515、R535、T539、K603、E623 和 E633 被确定最有可能与基架直接相互作用。突变实验结果证实了 TF 结合该口袋的机制。结合定量计算结果，我们的数据表明基架上的三个羟基可能是 TF 抑制 TMEM16A 的最关键药效团。最后，抗肿瘤实验表明 TF 可以靶向 TMEM16A 抑制 LA795 细胞的增殖和迁移，表明 TF 对高 TMEM16A 表达的肺腺癌生长具有潜在的治疗效果。基于该结合口袋的药物筛选策略的成功应用为发现更优调节剂指明了新方向，并为肺腺癌的新型治疗方法的开发做出了贡献。
