Kayode Olumide, Huang Zunnan, Soares Alexei S, Caulfield Thomas R, Dong Zigang, Bode Ann M, Radisky Evette S
Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, Florida, United States of America.
The Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America.
PLoS One. 2017 May 2;12(5):e0176694. doi: 10.1371/journal.pone.0176694. eCollection 2017.
PRSS3/mesotrypsin is an atypical isoform of trypsin, the upregulation of which has been implicated in promoting tumor progression. To date there are no mesotrypsin-selective pharmacological inhibitors which could serve as tools for deciphering the pathological role of this enzyme, and could potentially form the basis for novel therapeutic strategies targeting mesotrypsin. A virtual screen of the Natural Product Database (NPD) and Food and Drug Administration (FDA) approved Drug Database was conducted by high-throughput molecular docking utilizing crystal structures of mesotrypsin. Twelve high-scoring compounds were selected for testing based on lowest free energy docking scores, interaction with key mesotrypsin active site residues, and commercial availability. Diminazene (CID22956468), along with two similar compounds presenting the bis-benzamidine substructure, was validated as a competitive inhibitor of mesotrypsin and other human trypsin isoforms. Diminazene is the most potent small molecule inhibitor of mesotrypsin reported to date with an inhibitory constant (Ki) of 3.6±0.3 μM. Diminazene was subsequently co-crystalized with mesotrypsin and the crystal structure was solved and refined to 1.25 Å resolution. This high resolution crystal structure can now offer a foundation for structure-guided efforts to develop novel and potentially more selective mesotrypsin inhibitors based on similar molecular substructures.
PRSS3/间胰蛋白酶是一种非典型的胰蛋白酶同工型，其上调与促进肿瘤进展有关。迄今为止，尚无间胰蛋白酶选择性药理抑制剂可作为解析该酶病理作用的工具，也无法作为针对间胰蛋白酶的新型治疗策略的基础。利用间胰蛋白酶的晶体结构，通过高通量分子对接对天然产物数据库（NPD）和美国食品药品监督管理局（FDA）批准的药物数据库进行了虚拟筛选。根据最低自由能对接分数、与间胰蛋白酶关键活性位点残基的相互作用以及商业可得性，选择了12种高分化合物进行测试。双脒苯脲（CID22956468）以及另外两种具有双苯甲脒亚结构的类似化合物被确认为间胰蛋白酶和其他人类胰蛋白酶同工型的竞争性抑制剂。双脒苯脲是迄今为止报道的最有效的间胰蛋白酶小分子抑制剂，其抑制常数（Ki）为3.6±0.3 μM。随后，双脒苯脲与间胰蛋白酶共结晶，并解析了晶体结构，将其精修至1.25 Å分辨率。这种高分辨率晶体结构现在可为基于类似分子亚结构开发新型且可能更具选择性的间胰蛋白酶抑制剂的结构导向研究提供基础。
