Celastrol increases anoikis sensitivity to suppress triple-negative breast cancer via EGFR pathway and p-EMT state regulation

Faced with the highly malignant threat of metastatic triple-negative breast cancer (TNBC), the effect of traditional chemical agents is limited, and new anti-metastasis drug remains to be explored. Celastrol (Cel) is a bioactive compound derived from <i>Tripterygium wilfordii</i> with significant anti-neoplastic effects in various cancers. In this study, we investigated the potential anti-metastatic effects of Cel on anoikis resistant TNBC cells (TNBC-AR) cells, including MDA-MB-231-AR cells and BT-549-AR cells. Using CCK-8 and colony formation assay, we demonstrated that Cel could inhibit the proliferation of MDA-MB-231-AR cells and BT-549-AR cells with IC₅₀ value of 1.510 μM and 1.673 μM, respectively. The results of wound healing and transwell assays showed that Cel could potently inhibit the invasion and migration of TNBC-AR cells. Aggregation and flow cytometry experiments showed that Cel could inhibit the clusters formation and enhance the anoikis of TNBC-AR cells on the suspension conditions. Then we conducted bioinformatics analysis, Western blotting, and intervention experiments to explore the molecular mechanisms of Cel's anti-metastasis effects. The results of these experiments discovered that Cel treatment suppressed the p-EMT state in TNBC-AR cells, and this effect correlated with a reduction in EGFR/MEK/ERK pathway activation. Our findings suggest that Cel may be a promising candidate for therapeutic treatments of metastatic TNBC.