Prenylated chromones and flavonoids isolated from the roots of Flemingia macrophylla and their anti-lung cancer activity.

BACKGROUND: The successful launch of icaritin, a therapeutic drug for liver cancer derived from Epimedium brevicornu, has provided new impetus for the development of prenylated flavonoids in the field of oncology. Flemingia macrophylla is reported to contain characteristic prenylated flavonoids which can regulate the p53 protein. We aimed to isolate these constituents and conduct activity evaluation, structure-activity relationship, and mechanism studies to provide candidate compounds for antitumor drug development. METHODS: In this study, chromatographic techniques combined with spectroscopic methods were used to separate, purify, and identify the constituents of Flemingia macrophylla methanol extract. The cytotoxic activity of the constituents was evaluated using an MTT assay with A549 and H1975 cells as the model. The binding mechanism between the compounds and the p53 protein was investigated with molecular docking and validated with cellular thermal shift assay (CETSA). Western blotting (WB) was employed to detect the expression of p53 protein and apoptosis-related proteins in cells. RESULTS: Chiral HPLC separation of racemates 1 and 7 provided two pairs of undescribed enantiomers (1a/1b and 7a/7b), along with eight known compounds (2 - 9) isolated from Flemingia macrophylla roots. Their structures were elucidated by spectroscopic analysis, and the absolute configurations of the enantiomers were determined from experimental and calculated electronic circular dichroism data. Compounds 1 - 7, and the non-prenyl analogues 10 - 13, were evaluated for cytotoxic activity against the human lung cancer A549 and H1975 cell line. Compounds 5 - 7 displayed better cytotoxicity than the positive control icaritin in A549 and H1975, with IC50 values ranging from 4.50 to 19.83 µmol·L-1 and < 5 µmol·L-1, respectively. The structure-activity relationships of the chromone or flavonoid analogues against A549 cells were discussed. Molecular docking results demonstrated that compound 7a has strong interaction with p53 and WB indicated that 7a induced apoptosis by increasing the p53 protein, decreasing the anti-apoptotic protein Bcl-2, and activating the caspase family in A549 cells. These results suggest that prenylated flavonoids are potential p53 protein activators. CONCLUSION: This study demonstrates that Flemingia macrophylla is rich in prenylated flavonoid constituents, among which compounds 5 and 7 exhibited significant cytotoxic activity against A549 cells and served as reference candidates for the design and development of prenylated compounds as antitumor therapeutic drugs.

The expression of lncRNA XIST in hepatocellular carcinoma cells and its effect on biological function.

PURPOSE: Hepatocellular carcinoma (HCC) is one of the common cancers, but its relationship with long non-coding (lnc)RNA XIST and microRNA (miR)-488 is still under investigation. Therefore, this study aimed to explore the correlation between miR-488 and XIST in HCC. METHODS: qRT-PCR was employed to quantify the lncRNA XIST and miR-488 in HCC tissues and cells, and miR-488 mimcs and lncRNA siRNA vectors were constructed for analysis of the roles of miR-488 and lncRNA XIST in HCC cells. Flow cytometry was applied to determine the cell cycle and apoptosis, Western blot assay to detect apoptosis-related proteins, and the MTT assay to detect cell viability. RESULTS: lncRNA XIST was highly expressed in HCC, while miR-488 was lowly expressed. Silencing lncRNA XIST gave rise to an increase in G0/G1 phase cells and a decrease in S-phase cells, promoted apoptosis, weakened cell viability, and induced up-regulation of Caspase-3, Caspase-9, and Bax, and up-regulating miR-488 led to similar results. The dual luciferase reporter gene assay confirmed that lncRNA XIST could bind to miR-488, and its inhibition could give rise to up-regulation of miR-488. It was also confirmed that lncRNA XIST was negatively correlated with miR-488. CONCLUSION: LncRNA XIST accelerates HCC cell growth by inhibiting miR-488, so inhibiting lncRNA XIST or up-regulating miR-488 has objective potential therapeutic value and may be helpful for the development of new HCC treatment strategies.

Auxin and Its Interaction With Ethylene Control Adventitious Root Formation and Development in Apple Rootstock.

Adventitious root (AR) formation is indispensable for vegetative asexual propagation. Indole-3-butyric acid (IBA) functioned indirectly as precursor of IAA in regulating AR formation. Ethylene affects auxin synthesis, transport, and/or signaling processes. However, the interactions between auxin and ethylene that control AR formation in apple have not been elucidated. In this study, we investigated the effects of IBA and its interaction with ethylene on AR development in apple. The results revealed that IBA stimulated the formation of root primordia, increased the number of ARs, and upregulated expression of genes (MdWOX11, MdLBD16, and MdLBD29) involved in AR formation. Comparison of different periods of IBA application indicated that IBA was necessary for root primordium formation, while long time IBA treatment obviously inhibited root elongation. RNA-seq analysis revealed that many plant hormone metabolism and signal transduction related genes were differentially expressed. IBA stimulated the production of ethylene during AR formation. Auxin inhibiting ARs elongation depended on ethylene. Together, our results suggest that the inhibitory role of auxin on AR elongation in apples is partially mediated by stimulated ethylene production.