Blockage of MDM2-mediated p53 ubiquitination by yuanhuacine restrains the carcinogenesis of prostate carcinoma cells by suppressing LncRNA LINC00665

Prostate cancer (PCa) is a challenging issue for men's health worldwide due to its uncontrolled proliferation and high metastatic potential. Increasing evidence has supported plant extracts and natural plant derivatives as promising antitumor therapy with less toxic side effects. Yuanhuacine is an active component isolated from Daphne genkwa and can effectively suppress the tumorigenesis of several cancers. However, its role in PCa remains unclear. In this study, yuanhuacine dose-dependently inhibited the proliferation and induced apoptosis of PCa cells. Moreover, yuanhuacine also restrained the invasion and migration of PCa cells. Mechanically, yuanhuacine decreased the ubiquitination and degradation of p53 protein, and ultimately increased p53 levels, which was regulated by inhibiting the phosphorylation and total protein levels of mouse double minute 2 (MDM2). Moreover, elevation of MDM2 reversed the suppressive efficacy of yuanhuacine in PCa cell viability, invasion, and migration. The network pharmacologic and bioinformatics analysis confirmed that MDM2 might be a common target of D. genkwa and LINC00665. Furthermore, yuanhuacine inhibited LINC00665 expression. Upregulation of LINC00665 reversed yuanhuacine-mediated inhibition in MDM2 protein expression and suppressed p53 levels by enhancing its ubiquitination in yuanhuacine-treated cells. Importantly, the inhibitory effects of yuanhuacine on cell viability and metastatic potential were offset after LINC00665 elevation. Together, the current findings highlight that yuanhuacine may possess tumor-suppressive efficacy by inhibiting LINC00665-mediated MDM2/p53 ubiquitination signaling. Therefore, this study indicates that yuanhuacine may be a promising candidate for the treatment of PCa.     

Evaluation of Daphne genkwa diterpenes: fingerprint and quantitative analysis by high performance liquid chromatography

Daphne genkwa contains a novel class of anticancer diterpene esters that inhibit DNA topoisomerase I. Fingerprint and quantitative analysis by HPLC were performed in order to characterise and evaluate D. genkwa. A standard fingerprint of Daphne diterpene esters from the root extract was first established by HPLC-UV, and the major peaks in the fingerprint profile were preliminarily determined using HPLC-MS. The principal Daphne diterpene esters, yuanhuacine (1), yuanhuadine (2), yuanhuajine (3) and yuanhuagine (4), were isolated and identified using a combination of UV, IR, MS, 1H-NMR and 13C-NMR spectral data. Quantitative analysis indicated that 1 was the principal component in the root, and that 2 was the major component in the buds. The average extraction rates of 1 and 2 were 0.0151 and 0.0033% (n=10) from the root, respectively, and 0.0020 and 0.0078% (n=3) from the buds, respectively.