A network pharmacology approach and experimental validation to investigate the anticancer mechanism and potential active targets of ethanol extract of Wei-Tong-Xin against colorectal cancer through induction of apoptosis via PI3K/AKT signaling pathway

Abstract

Ethnopharmacological relevance: Wei-Tong-Xin (WTX), derives from the Chinese herbal decoction (CHD) of Wan-Ying-Yuan in ancient China, has been shown to be effective therapeutic herbal decoction for treating gastrointestinal diseases. Present studies have demonstrated that WTX had potential to alleviate the symptoms of gastrointestinal inflammation, gastric ulcer and improve gastric motility.

Aim of the study: The study primarily focused on exploring the therapeutic effect and possible pharmacological mechanism of WTX on colorectal cancer (CRC) based on network pharmacology, in vitro and in vivo experiments.

Materials and methods: Firstly, colorectal cancer and WTX associated with targets were searched from GeneCards database and TCM Systems Pharmacology Database and Analysis Platform (TCMSP) respectively. The protein-protein interaction (PPI) network also was constructed to screening key targets. In addition, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied to predict the underlying biological function and mechanism involving in the anti-colorectal cancer effect of WTX. Next, CCK-8, colony formation and transwell assays were performed to verify the influence of proliferation and metastasizing ability of HCT116 cells after treated with WTX. Cell cycle, apoptosis and reactive oxygen species (ROS) were analysis by flow cytometry. Hoechst 33258 staining was conducted to observe nuclear morphology changes. Protein expression of apoptosis and PI3K/AKT signaling as well as mRNA expression of ferroptosis and apoptosis were determined by Western Blotting and RT-qPCR. The effects of WTX and LY294002 combination on the PI3K/Akt/mTOR signaling pathway were measured by Western Blotting. Finally, the xenograft tumor mouse model was established by subcutaneous injection of CT26 cells to measure tumors volume and weight. Hematoxylin and eosin (HE) staining and immunohistochemical analysis were used to observe the pathological changes and the protein expression in tumor tissues.

Results: There were 286 potential treatment targets from 130 bioactive compounds in WTX, 1349 CRC-related targets were identified. Eleven core targets (TP53, AKT1, STAT3, JUN, TNF, HSP90AA1, IL-6, MAPK3, CASP3, EGFR, MYC) were found by PPI network analysis constructed of 142 common targets. The results of KEGG enrichment displayed PI3K/AKT signaling pathway as core pathway. After the treatment of WTX, the inhibitory of viability, metastases and cell cycle arrest at G2/M phase were observed in HCT116 cells. Moreover, WTX induced an increase in the expression of apoptosis proteins (Bak, cytochrome c, cleaved caspase-9/caspase-9 and cleaved caspase-3/caspase-3) and the levels of ROS and MDA, a decrease in the expression of PI3K/AKT signaling related proteins (PI3K, p-PI3K, p-AKT/AKT and p-mTOR/mTOR) and the level of SOD. WTX treatment significantly reduced the tumor weight, increased cleaved caspase-3 positive area and decreased that of ki67 in xenograft mouse model.

Conclusion: Through a network pharmacology approach and in vitro experiments, we predicted and verified the effect of WTX on colorectal cancer cells mainly depended on the regulation of intrinsic apoptosis via PI3K/AKT signaling pathway, and further animal experiments proved that WTX has a good anti-colon cancer effect in vivo.

Keywords: Apoptosis; CT26-Tumor model; Colorectal cancer; HCT116 cells; Network pharmacology; Wei-Tong-Xin.