Hassan Mujtaba, Baussière Floriane, Guzelj Samo, Sundin Anders P, Håkansson Maria, Kovačič Rebeka, Leffler Hakon, Tomašič Tihomir, Anderluh Marko, Jakopin Žiga, Nilsson Ulf J
Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
Department of Medicinal Chemistry, Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia.
ACS Med Chem Lett. 2021 Nov 2;12(11):1745-1752. doi: 10.1021/acsmedchemlett.1c00371. eCollection 2021 Nov 11.
Galectin-8 is a carbohydrate-binding protein that plays a crucial role in tumor progression and metastasis, antibacterial autophagy, modulation of the immune system, and bone remodeling. The design, synthesis, and protein affinity evaluation of a set of C-3 substituted benzimidazole and quinoline d-galactal derivatives identified a d-galactal-benzimidazole hybrid as a selective ligand for the galectin-8 N-terminal domain (galectin-8N), with a of 48 μM and 15-fold selectivity over galectin-3 and even better selectivity over the other mammalian galectins. X-ray structural analysis of galectin-8N in complex with one benzimidazole- and one quinoline-galactal derivative at 1.52 and 2.1 Å together with molecular dynamics simulations and quantum mechanical calculations of galectin-8N in complex with the benzimidazole derivative revealed orbital overlap between a NH LUMO of Arg45 with electron rich HOMOs of the olefin and O4 of the d-galactal. Such overlap is hypothesized to contribute to the high affinity of the d-galactal-derived ligands for galectin-8N. A (3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2-tetrazolium) (MTS) assay evaluation of the d-galactal-benzimidazole hybrid and an analogous galactoside derivative on a panel of cell lines with MTS assay showed no effect on cell viability up to 100 μM concentration. A subsequent functional assay using the MDA-MB-231 cell line demonstrated that the d-galactal-benzimidazole hybrid and the analogous galactoside derivative reduced the secretion of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in a dose-dependent manner. Therefore, these compounds represent potential probes for galectin-8N pharmacology investigations and possibly promising leads for the design and synthesis of potent and selective galectin-8 inhibitors as potential antitumor and anti-inflammatory agents.
半乳糖凝集素-8是一种碳水化合物结合蛋白，在肿瘤进展和转移、抗菌自噬、免疫系统调节以及骨重塑中发挥关键作用。一组C-3取代的苯并咪唑和喹啉d-半乳糖衍生物的设计、合成及蛋白亲和力评估确定了一种d-半乳糖-苯并咪唑杂化物是半乳糖凝集素-8 N端结构域（galectin-8N）的选择性配体，其解离常数为48 μM，对半乳糖凝集素-3的选择性为15倍，对其他哺乳动物半乳糖凝集素的选择性甚至更高。在1.52 Å和2.1 Å分辨率下对galectin-8N与一种苯并咪唑和一种喹啉-半乳糖衍生物复合物进行的X射线结构分析，以及对galectin-8N与苯并咪唑衍生物复合物进行的分子动力学模拟和量子力学计算表明，精氨酸45的NH最低未占分子轨道与烯烃的富电子最高已占分子轨道以及d-半乳糖的O4之间存在轨道重叠。据推测，这种重叠有助于d-半乳糖衍生配体对galectin-8N的高亲和力。使用（3-(4,5-二甲基噻唑-2-基)-5-(3-羧基甲氧基苯基)-2-(4-磺基苯基)-2-四氮唑）（MTS）检测法对d-半乳糖-苯并咪唑杂化物和一种类似的半乳糖苷衍生物在一组细胞系上进行评估，结果表明在浓度高达100 μM时对细胞活力无影响。随后使用MDA-MB-231细胞系进行的功能检测表明，d-半乳糖-苯并咪唑杂化物和类似的半乳糖苷衍生物以剂量依赖性方式降低促炎细胞因子白细胞介素-6（IL-6）和IL-8的分泌。因此，这些化合物代表了用于半乳糖凝集素-8N药理学研究的潜在探针，并且可能是设计和合成强效且选择性的半乳糖凝集素-8抑制剂作为潜在抗肿瘤和抗炎药物的有前景的先导化合物。
