• • DDY reduced pulmonary metastatic nodules to 2.4 per lung versus 21 in controls and 6.6 for free desloratadine in a 4T1 orthotopic breast tumor model (p < 0.01), demonstrating a >8-fold suppression of metastasis; this matters clinically because metastasis, not primary tumor size, drives mortality in triple-negative breast cancer.
• • Immunohistochemical analysis showed drastic decreases in SLC7A11 and GPX4 levels in DDY-treated tumors, confirming ferroptosis as the mechanism of action; this provides a biomarker strategy for patient selection and suggests combination with ferroptosis inducers may overcome resistance.
• • DDY exhibited selective toxicity against MCF-7, MDA-MB-231, and 4T1 tumor cells at concentrations up to 20.0 μM, while sparing normal MCF-10A breast cells; this selectivity index is critical for reducing off-target toxicity and enabling dose escalation in vivo.
• • DDY administration significantly inhibited tumor growth to the smallest tumor volume and weight among groups and suppressed distal liver metastasis, with no significant effect on mouse body weight; this indicates a favorable therapeutic window and potential for chronic dosing in metastatic settings.