OBJECTIVE: To evaluate the effects of Huangqi (Radix Astragali Mongolici)-Ezhu (Rhizoma Curcumae Phaeocaulis) (HQEZ) on colorectal cancer therapies and to elucidate the potential mechanisms of HQEZ, especially in combination with 5-Fluorouracil (5-FU).

METHODS: The anti-tumor effects of HQEZ were evaluated in colorectal cancer models both in vivo and in vitro. The network pharmacological assay was used to investigate potential mechanisms of HQEZ. Potential target genes were selected by Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, protein-protein interaction network (PPI) and molecular docking. Within key targets, potential targets related to drug sensitivity, especially the sensitivity to 5-FU, were evaluated in HCT116 in vitro by immunofluorescence, quantitative real-time polymerase chain reaction (qPCR) and Western-blot. Then, changes in potential targets were assessed in tumors from tumor-bearing mice and the expression of these targets was also evaluated in colorectal cancer (COAD) patients from the Cancer Genome Atlas Program (TCGA) database.

RESULTS: HQEZ significantly enhanced the anti-tumor activity of 5-FU in vivo and inhibit the growth of HCT116 in vitro. By network pharmacological analysis, key targets, such as protein kinase B (AKT1), epidermal growth factor receptor (EGFR), adenosine triphosphate (ATP) binding cassette subfamily B member 1 (ABCB1, also named multidrug resistance protein 1, MDR1), ATP binding cassette subfamily G member 2 (ABCG2), thymidylate synthetase (TYMS, also named TS), prostaglandin-endoperoxide synthase 2 (PTGS2), matrix metallopeptidase 2 (MMP2), MMP9, toll like receptor 4 (TLR4), TLR9 and dihydropyrimidine dehydrogenase (DPYD), were identified. Additionally, 4 potential core active ingredients (Folate, Curcumin, quercetin and kaempferol) were identified to be important for the treatment of colorectal cancer with HQEZ. In key targets, chemoresistance related targets were validated to be affected by HQEZ. Furthermore, 5-FU sensitivity related targets, including MDR1, TS, EGFR, ribonucleotide reductase catalytic subunit M1, Breast and Ovarian Cancer Susceptibility Protein 1 (BRCA1) and mutl homolog 1 were also significantly reduced by HQEZ both in vitro and in vivo. Finally, these validated key targets and 5-FU sensitivity related targets were demonstrated to be up-regulated in COAD patients based on TCGA database.

CONCLUSION: HQEZ has synergistic effects on the anti-tumor activity of 5-FU in the treatment of colorectal cancer both in vivo and in vitro. The beneficial effect of HQEZ results from the inhibition of the drug sensitivity targets associated with 5-FU. The combination therapy of HQEZ with 5-FU or other chemotherapeutic drugs will also improve the anti-tumor efficacy of chemotherapy.