Mechanism investigation of Forsythoside A against esophageal squamous cell carcinoma in vitro and in vivo.

Context: Forsythoside A (FSA) was extracted from Forsythia suspensa, a traditional Chinese medicine, which has been demonstrated to exert anti-inflammatory, antibacterial, and other pharmacological effects. However, the anticancer effect of FSA in esophageal squamous cell carcinoma (ESCC) has not been documented.

Objective: The present study aimed to elucidate the mechanism of FSA against ESCC.

Materials and methods: Network pharmacology and molecular docking were employed to predict the mechanism. FSA was utilized to treat ESCC cell lines KYSE450 and KYSE30, followed by CCK-8 assay, cell cloning formation assay, flow cytometry, Western blot, RNA-seq analysis, and subsequent in vivo experiments.

Results: Network pharmacology and molecular docking predicted that the therapeutic effect of FSA in ESCC is mediated through proteins such as BCL2 and BAX, influencing KEGG pathways associated with apoptosis. In vitro experiments showed that FSA inhibited cell proliferation and plate clone formation, promoted cell apoptosis and impacted the cell cycle distribution of G2/M phase by regulating BCL2, BAX, and p21. Further RNA-seq in KYSE450 cells showed that FSA regulated the expression of 223 genes, specifically affecting the biological process of epidermal development. In vivo experiments showed that gastric administration of FSA resulted in notable reductions in both tumor volume and weight by regulating BCL2, BAX, and p21. 16S rRNA sequencing showed that FSA led to significant changes of beta diversity. Abundance of 11 specific bacterial taxa were considerably changed following administration of FSA.

Conclusions: This study presents a novel candidate drug against ESCC and establishes a foundation for future clinical application.