Comprehensive Evaluation of Usnic Acid as a Potential Drug Candidate for Triple-Negative Breast Cancer: Insights from Transcriptomic, Proteomic, and In Vivo Analyses.

BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options, prompting extensive research into novel therapeutics. This study presents a comprehensive molecular characterization of usnic acid in TNBC using transcriptomic, proteomic, and in vivo analyses. RESULTS: Transcriptome profiling identified 974 differentially expressed genes (201 upregulated, 773 downregulated; p ≤ 0.05, FC ≥ 2) between control and usnic acid-treated MDA-MB-231 cells, while 4956 DEGs were detected between usnic acid-treated normal epithelial and TNBC cells. Proteomic analysis revealed significant changes in 372 proteins (50 upregulated and 322 downregulated). Functional enrichment analyses indicated that usnic acid modulates key oncogenic pathways, including gonadotropin, CCKR, integrin-ECM signaling, and lipid/energy metabolism. Flow cytometry confirmed increased apoptosis, evidenced by upregulation of pro-apoptotic genes and suppression of anti-apoptotic genes. In vivo xenograft models further validated the tumor-suppressive effects of usnic acid. CONCLUSIONS: In light of the findings, this study constitutes the first comprehensive integrated transcriptomic and proteomic evaluation of usnic acid in TNBC, supported by functional and in vivo validation. Collectively, the results position usnic acid as a compelling therapeutic candidate that has successfully passed key in vitro and in vivo preclinical evaluations, warranting further investigation in advanced preclinical models and potential translation toward clinical development for TNBC.