The ethyl acetate extract from Trichoderma viride fermentation acts by downregulating the leukocyte transendothelial migration signaling pathway to induce ferroptosis in triple-negative breast cancer cells.

[PURPOSE] Triple-negative breast cancer (TNBC), characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, remains clinically challenging due to the lack of effective targeted therapies. This investigation revealed the anti-TNBC potential of Trichoderma viride ethyl acetate extract (TVEAE) from the endophytic fungus Trichoderma viride isolated from Coreopsis basalis.

[METHODS] Pharmacological validation of TVEAE's anti-TNBC efficacy was conducted through in vitro and in vivo pharmacological models. The cell death mechanisms were systematically investigated using Hoechst staining, reactive oxygen species (ROS) detection, and lipid peroxidation assays. Potential therapeutic targets and signaling pathways were identified by integrating network pharmacology, transcriptomics, and weighted gene co-expression network analysis (WGCNA). Furthermore, this study validated key tumor-related proteins involved in tumor progression and cell death pathways via Western blotting. Finally, chemical constituents were characterized through molecular network coupled with Global Natural Products Social Molecular Networking (GNPS) analysis.

[RESULTS] Both in vitro and in vivo models established TVEAE's significant anti-TNBC efficacy. Mechanistic interrogation established TVEAE-mediated ferroptosis induction via selective modulation of leukocyte transendothelial migration (TEM) signaling cascades. Integrative analysis combining transcriptomics, WGCNA, and network pharmacology identified IL-6/TNF-α/HSP90AA1 as core therapeutic targets regulating TEM pathway dynamics. GNPS-assisted molecular networking uncovered six structurally novel anti-TNBC metabolites, including N-lauryldiethanolamine, erucamide, and Gliotoxin.

[CONCLUSION] This study provides the first evidence of TVEAE's anti-TNBC activity through multi-target engagement along the leukocyte TEM signaling axis, effectively triggering ferroptosis. The mechanistic elucidation advances TNBC therapeutic development, offering a multi-dimensional targeting strategy against this recalcitrant malignancy.