Objective The study employed bioinformatics to identify prognostic genes associated with pancreatic adenocarcinoma (PAAD) and predict Chinese medicines and active ingredients that regulate these genes. Methods The integration of data from the TCGA, GTEx, and GEO databases was conducted, then screening the prognostic genes through differential gene analysis, COX regression analysis, and survival analysis. The subsequent step involves prognostic efficacy analysis and a verification of the expression trends of the identified key genes. Concurrently perform gene ontology (GO) functional and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses, as well as gene set enrichment analysis (GSEA), to identify potential pathways and biological processes. The impact of feature genes on the infiltration status of immune cells was analyzed, and their correlation with immune checkpoints was further investigated, and tumor immune escape capacity and tumor mutation burden were predicted. Validation of gene expression patterns at the single-cell level. The DSigDB, CTD, and HERB databases are used to predict the potential active ingredients of Chinese medicine and perform molecular docking. Additionally, pharmacokinetic analysis is conducted using Swiss ADME and prediction and analysis of Chinese medicine by Coremine Medical database. Cellular experiments were conducted to validate the regulatory effect of the key active ingredient on the characteristic gene. Results The investigation ultimately led to the identification of the key gene interferon alpha inducible protein 27 (IFI27), which exhibited significantly elevated expression levels in PAAD tissues. Patients exhibiting low IFI27 gene expression demonstrated superior overall survival. Enrichment analysis indicated its potential involvement in various biological processes, including apoptosis, ECM-receptor interaction, regulation of T cell activation, macrophage migration, and signaling pathways such as PI3K-Akt and NF-κB. Immune infiltration analysis indicates that IFI27 may regulate the infiltration status of various immune cells, such as B cells naive, T cells CD8⁺, T cells regulatory (Tregs), and macrophages M0, suggesting that it has an important function in regulating the tumor immune microenvironment. Meanwhile, the expression of IFI27 showed significant positive correlations with multiple immune checkpoint molecules. Further studies have revealed that low expression of IFI27 is significantly associated with the response to immunotherapy, supporting its value as a therapeutic target. Single-cell RNA sequencing verified IFI27 upregulation in PAAD, pinpointing its expression to macrophages and other immune cells. Experiments confirmed that fisetin significantly downregulated both mRNA and protein expression levels of IFI27 in pancreatic cancer cells. Furthermore, a total of 22 Chinese medicines, including Jianghuang (Curcumae Longae Rhizoma), Zaojiaoci (Gleditsiae Spina), and Yujin (Curcumae Radix), were predicted. The four qi encompass cold and warm, and the five flavors are primarily bitter, sweet, and pungent, with a focus on the liver, spleen, and stomach meridians. The main effects are activating blood and resolving stasis, moving qi to relieve pain, and clearing heat and detoxifying, combined with tonifying and inducing diuresis. Conclusion The results of this study imply that IFI27 may serve as a prognostic gene related to PAAD immunity, while fisetin and various Chinese medicines may serve as potential therapeutic drugs.

pancreatic adenocarcinoma  /  bioinformatics  /  IFI27  /  tumor microenvironment  /  immunotherapy  /  molecular docking  /  fisetin  /  Curcumae Longae Rhizoma  /  Gleditsiae Spina  /  Curcumae Radix