Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
Nat Commun. 2023 May 9;14(1):2659. doi: 10.1038/s41467-023-38352-5.
Calcium-selective oncochannel TRPV6 is the major driver of cell proliferation in human cancers. While significant effort has been invested in the development of synthetic TRPV6 inhibitors, natural channel blockers have been largely neglected. Here we report the structure of human TRPV6 in complex with the plant-derived phytoestrogen genistein, extracted from Styphnolobium japonicum, that was shown to inhibit cell invasion and metastasis in cancer clinical trials. Despite the pharmacological value, the molecular mechanism of TRPV6 inhibition by genistein has remained enigmatic. We use cryo-EM combined with electrophysiology, calcium imaging, mutagenesis, and molecular dynamics simulations to show that genistein binds in the intracellular half of the TRPV6 pore and acts as an ion channel blocker and gating modifier. Genistein binding to the open channel causes pore closure and a two-fold symmetrical conformational rearrangement in the S4-S5 and S6-TRP helix regions. The unprecedented mechanism of TRPV6 inhibition by genistein uncovers new possibilities in structure-based drug design.
钙选择性肿瘤通道 TRPV6 是人癌症细胞增殖的主要驱动因素。尽管在合成 TRPV6 抑制剂的开发方面投入了大量精力，但天然通道阻滞剂在很大程度上被忽视了。在这里，我们报告了与人 TRPV6 复合物的结构，该复合物与来源于 Styphnolobium japonicum 的植物雌激素染料木黄酮结合，已在癌症临床试验中显示出抑制细胞侵袭和转移的作用。尽管具有药理学价值，但染料木黄酮抑制 TRPV6 的分子机制仍然是个谜。我们使用 cryo-EM 结合电生理学、钙成像、突变和分子动力学模拟表明，染料木黄酮结合在 TRPV6 通道的细胞内半部分，并作为离子通道阻滞剂和门控修饰剂。染料木黄酮与开放通道的结合导致孔关闭，并在 S4-S5 和 S6-TRP 螺旋区域引起两倍对称的构象重排。染料木黄酮抑制 TRPV6 的前所未有的机制为基于结构的药物设计开辟了新的可能性。
