To develop a fluorescence polarization (FP)-based high-throughput screening (HTS) assay to identify novel small-molecule antagonists targeting β-catenin/TCF4 (T-cell factor 4) interaction, recombinant human β-catenin was expressed in Escherichia coli Rosetta (DE3) cells and purified by HisTrapTM column. The bioactivity of purified β-catenin was further analyzed by enzyme-linked immunosorbent assay (ELISA). According to FP principle, the β-catenin/TCF4 binding model was performed, and fluorescence isothiocyanate (FITC) labeled TCF4 peptide (FITC-TCF4) served as the molecular probe of adaptor for binding to β-catenin. The FITC-TCF4 and β-catenin working concentration were optimized, and the binding conditions (complex stability and dimethylsulfoxide (DMSO) tolerance) have been investigated yet for further hits screening. The results showed that recombinant human β-catenin was successfully expressed and purified β-catenin exhibited favorable bioactivity in ELISA binding assay. Subsequently, the FP-based HTS assay was performed using 20 nmol·L-1 FITC-TCF4 and 100 nmol·L-1 β-catenin. Under these optimized conditions, a high Zxfactor of 0.88 was achieved in a 384-well format and this FP-based HTS assay was very stable with regard to DMSO. Through screening of a natural-based product library (NBPL) using the established FP-based HTS assay, three hits (sanguinarine, chelerythrine, and compound S720) were identified as potential β-catenin/TCF4 interaction antagonists. Taken together, we have successfully developed a simple, robust and reliable FP-based HTS assay for screening of novel antagonists targeting β-catenin/TCF4 interaction.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |