Identification of AR-targeted Active Compounds from Euphorbia humifusa Willd for the Treatment of Prostate Cancer

Introduction: Euphorbia humifusa Willd (EH) is a traditional medicinal herb in China. However, the anti-prostate cancer active compounds of EH and their molecular mechanisms have yet to be elucidated. Methods: The peaks of EH water extract in the fingerprinting were analysed using liquid chromatography coupled to quadrupole time of flight mass spectrometry. The cell viability of 22RV1 cells was determined via MTT. The active compounds and potential targets were screened in silico. The prostate cancer-associated targets were collected from the GeneCards database. The herb-compound-target-disease (H-C-T-D) and PPI networks were constructed to predict key targets. The molecular docking analysis of the active compounds with key targets was conducted using Autodock Vina 1.1.2. Western blot analysis was performed to evaluate the protein expression. Results: LC-MS results demonstrated that EH water extract is a rich source of phenolics and flavonoids. EH water extract inhibited the viability of 22RV1 cells in a time-and dosedependent manner. Moreover, the in silico screening results identified 17 active compounds from EH with 518 prostate cancer-related key genes. Moreover, an H-C-T-D network analysis combined with the PPI network results effectively identified seven chemical compounds, oestrogen receptor 1, and androgen receptor (AR) to be highly related to prostate cancer. Furthermore, molecular docking results showed that 4′,5-dihydroxyflavone, ensaculin, luteolin, hypolaetin, quercetin, and kaempferol had a strong binding affinity with AR. Finally, Western blot results demonstrated that EH water extract, quercetin, kaempferol, and luteolin significantly down-regulated the AR protein expression in 22RV1 cells. Conclusion: These results suggest that EH may provide a new promising therapeutic for prostate cancer treatment.