Network Pharmacology-Based Prediction and Verification of the Mechanism of Shikonin in the Treatment of Colorectal Cancer

Abstract Background: Zicao is the dried root of Lithospermum erythrorhizon Sieb, et Zucc, Arnebia euchroma (Royle) Johnst, or Arnebia guttata Bunge and is commonly used to treat viral infection, inflammation, arthritis, and cancer in traditional Chinese medicine. Shikonin (SKN), a naturally occurring naphthoquinone, is a major active chemical component isolated from Zicao and exhibits anticancer activity according to previous research. However, the underlying mechanism has not been elucidated, so further research is necessary to verify its traditional application. The purpose of the present study was to investigate the antitumor mechanism of SKN in colorectal cancer (CRC) through network pharmacology and experiments. Methods: The SymMap database and GeneCards were adopted to predict the potential targets of SKN and CRC, while cotargets were obtained via a Venn diagram. The cotargets were imported from the String and DAVID websites, the protein-protein interaction (PPI) network was constructed, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. With regard to the prediction of KEGG by DAVID, the compound-target-pathway network was generated by connecting potential pathways with the corresponding targets. According to the network pharmacological analysis, cytological experiments, real-time PCR (RT-PCR), and Western blot (WB) were used to verify the key signaling pathway. Results: According to the network pharmacological analysis, the most relevant target of SKN to the treatment of colorectal cancer was IL6. GO and KEGG enrichment analyses indicated that various kinases and the PI3K/AKT signaling pathway were the most enriched molecules and pathways. SKN inhibited CRC cell (HT29 and HCT116) proliferation, migration, and invasion and promoted cell apoptosis by targeting IL6 and inhibiting the IL6R/PI3K/AKT signaling pathway. Conclusions: SKN promotes apoptosis and suppresses CRC cell (HT29 and HCT116) activities through the PI3K-Akt signaling pathway. This research not only provides a theoretical and experimental basis for more in-depth studies but also offers an efficient method for the rational utilization of a series of traditional Chinese medicines as anti-CRC drugs.