The anti-tumor effect of OP-B on ovarian cancer in vitro and in vivo, and its mechanism: An investigation using network pharmacology-based analysis

Ethnopharmacological relevance: Maidong (Liliaceae) is used as a yin-nourishing medication for the treatment of Cardiovascular Disease, inflammation, and assistant Cancer chemotherapy in the clinic. Ophiopogonin B (OP-B), a major saponin extracted from Maidong, is reported to have potential antitumor activities against various human cancers. However, the effects of OP-B on human ovarian Cancer (OC) and the potential mechanisms of action are yet elusive.

Aim of the study: In this study, we aimed to explore the potential molecular mechanisms of OP-B in the treatment of OC using network pharmacology. In vivo and in vitro experiments were conducted to further verify the therapeutic effects of OP-B on OC.

Materials and methods: To investigate the functions of OP-B against OC holistically, the related targets of OP-B and OC were each predicted based on four public databases. Subsequently, the identified PPI network was constructed to detect the hub potential targets. In addition, GO and KEGG enrichment analysis were applied by Metascape database. Furthermore, we simultaneously investigated the Anticancer effects of OP-B on SKOV3 and A2780 human ovarian Cancer cells using a cell viability assay, transwell assay, and an image-based cytometric assay. The quantitative Real-Time PCR and western-blot assay were used to validate the RNA and protein levels of target genes in OP-B treated OC cells. At last, SKOV3-bearing BALB/c nude mice were applied to observe the effectiveness and toxicity of OP-B.

Results: Through network pharmacological analysis, OP-B was found to play a critical role in OC via multiple targets and pathways, especially the STAT3 signaling pathways. In addition, in vitro experiments found OP-B suppressed SKOV3 and A2780 cells proliferation in a time and concentration dependent manner, and markedly impaired Cancer cell migration. Flow cytometry analysis revealed that OP-B significantly increased early and late Apoptosis, induced G2/M phase cell cycle arrest in SKOV3 cells and G0/G1 phase cell cycle arrest in A2780 cells. Moreover, OP-B administration down-regulated the expression of p-STAT3 protein, whereas the RNA expression and total protein levels of STAT3 were not altered. Finally, in vivo experiments confirmed the therapeutic effects of OP-B on OC in nude mice with low toxicity in heart, liver, lung, and kidney.

Conclusion: OP-B could efficiently suppress OC cellular proliferation, migration and induce Apoptosis, cell cycle arrest mainly via the regulation of STAT3 signaling pathway. This study provides a promising potential application for an alternative to chemotherapy in ovarian Cancer.