(S)-Erypoegin K, an isoflavone isolated from Erythrina poeppigiana, is a novel inhibitor of topoisomerase IIα: Induction of G2 phase arrest in human gastric cancer cells

[Studies on the Isolation and Molecular Mechanisms of Bioactive Phytochemicals]

Studies on the isolation and molecular mechanisms of phytochemicals with anti-tumor or anti-inflammatory properties are important to developing new drugs for cancer and neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. In the course of a study to screen bioactive isoflavones from Erythrina poeppigiana (Leguminosae), we isolated an isoflavone with potent apoptosis-inducing activity against human leukemia HL-60 cells. It was designated erypoegin K. The studies demonstrated an enantiomer, (S)-erypoegin K, displayed selective cytotoxic activity, was a novel inhibitor of topoisomerase II, and possessed anti-tumor activity both in vitro and in vivo. We identified other apoptosis-inducing isoflavones with the ability to inhibit glyoxalase I. Dimeric acridone alkaloids, carbazole alkaloids, and coumarin and quinoline derivatives-all obtained mainly from plants in the family Rutaceae-induced apoptosis of HL-60 cells via the production of reactive oxygen species and mitochondrial dysfunction. We also identified terpenoid coumarins, carbazole quinones, rotenoid derivatives, and quinolone alkaloids with anti-inflammatory activities. These compounds reduced nitric oxide (NO) production from RAW264.7 macrophage cells stimulated with lipopolysaccharides and interferon-γ. Some of the compounds displayed neuroprotective activity by reducing NO production. This review primarily describes our recent studies on erypoegin K, and other compounds with apoptosis-inducing and anti-inflammatory activities.

Potential molecular target screening and bioinformatics analysis of cholangiocarcinoma based on GEO database

BACKGROUND

Cholangiocarcinoma is a highly malignant tumor with a poor prognosis. Targeted therapy is important for the treatment of cholangiocarcinoma, and it is therefore of great clinical importance to identify novel molecular targets for targeted therapy of this malignancy.

AIM

To identify potential molecular targets for the treatment of cholangiocarcinoma and identify the key genes involved in cholangiocarcinoma by bioinformatics analysis.

METHODS

We downloaded two sets of cholangiocarcinoma expression profile data from GEO database. GEO2R online analysis tool was used to screen differentially expressed genes in cholangiocarcinoma tumor tissues and normal tissues, and we performed GO enrichment analysis, KEGG pathway analysis, and protein interaction network for differentially expressed genes. We used Cytoscape software to calculate key genes. The GEPIA database was used to verify the expression of hub genes in cholangiocarcinoma tissues.

RESULTS

A total of 158 differentially expressed genes were identified. GO enrichment analysis showed that these differential genes were mainly involved in the cellular response to zinc ion, negative regulation of growth, cell adhesion, metabolic process, and protein homotetramerization. They were enriched in exosomes, extracellular spaces, elastic fibers, and organelle membranes. The main molecular functions are related to heparin binding, cysteine-type endopeptidase inhibitor activity, protein homodimerization activity, receptor binding, and pyridoxal phosphate binding. KEGG pathway analysis showed that differential genes are mainly involved in processes such as mineral absorption, carbon and propanoate metabolism, PPAR signaling pathway, and fatty acid degradation. A protein interaction network diagram was constructed based on the String database, and the CytoHubba plug-in of the Cytoscape software was used to calculate the key genes. The key genes were all up-regulated ones. GEPIA analysis verified that the expression of key genes in cholangiocarcinoma tissues was significantly higher than that in normal tissues.

CONCLUSION

In this study, eight key genes related to cholangiocarcinoma were identified, including NUSAP1, TOP2A, RAD51AP1, MCM4, KIAA0101, CDCA5, TYMS, and ZWINT. These genes provide new ideas for in-depth study of the targeted therapy of cholangiocarcinoma, and are expected to become new molecular therapeutic targets.