Background: Esophageal cancer is the seventh most common and sixth deadliest cancer globally, threatening human health, especially among vulnerable groups. It is also a major cause of global cancer burden, and as a malignant tumor with high mortality and poor prognosis, its 5-year survival rate is less than 25%; currently, surgical resection, radiotherapy and chemotherapy are the main clinical treatments for esophageal cancer. However, conventional treatment outcomes are unsatisfactory, and only a limited number of individuals are able to achieve lasting benefits due to the elusive chemoresistance. Newly developed targeted therapies for esophageal cancer have been available over the past few decades, but have not had a meaningful clinical impact, resulting in minimal improvement in patient survival. Nevertheless, scientists still believe that novel treatments for esophageal cancer hold great promise, and it is therefore important to identify new drug targets from existing chemotherapy regimens for new drug development.
Methods: In this study, we screened potential targets of 5-FU by a multi-omics approach: predicting drug-acting genes based on PubChem, CTD, SwissTargetPrediction and TargetNet databases; differential expression analysis and pathway enrichment of esophageal cancer using GEO dataset GSE17351, and constructing a co-expression network by WGCNA to analyze the clinical and gene module correlations. clinical and gene module correlation. Finally, cell subpopulation distribution was analyzed based on GSE196756 single-cell sequencing data. For the experimental validation part, the KYSE150/TE1 human esophageal cancer cell line was used, with an untreated control group (NC) and a si-BUB1 interference group (two independent siRNA sequences), and the BUB1 function was detected by Western blot, cell scratch/Transwell and clone formation assays.
Results: KEGG enrichment significantly associated with the p53/PI3K-Akt pathway. Differential analysis showed that genes such as MMP10 and MYBL2 were up-regulated and SLC6A1 was down-regulated in esophageal cancer tissues, and GSEA based on the results of differential analysis suggested activation of the cancer cell cycle/DNA replication pathway. Subsequent drug-disease intersection screening identified 29 core genes, and PPI network and MCODE analysis targeted key nodes such as BUB1, CCNA2, CDK1, etc. TCGA data confirmed that BUB1 was highly expressed in esophageal cancers (p < 0.001) but had no correlation with TNM stage progression. The results showed inhibition of BUB1 protein expression, reduction of clone formation, significant reduction of scratch healing rate and Transwell migration number in the si-BUB1 group (p < 0.01).
Conclusions: This study revealed the important role of BUB1, one of the potential targets of 5-FU, in the development of esophageal cancer. Through bioinformatics analysis and experimental validation, we found that the high expression of BUB1 in esophageal cancer tissues was closely related to the biological properties of the tumor. the regulation of cell cycle by BUB1 and its role in the invasion and migration ability of the cells marked its potential as a new target for the treatment of esophageal cancer.
Keywords: 5-FU; BUB1; Esophageal cancer; Molecular interaction network.
© 2026. The Author(s).