Rosmarinic acid inhibits norepinephrine-induced metastatic capacity of triple negative breast cancer cells by Src kinase inactivation.

Chronic psychological stress promotes cancer metastasis through catecholamine-mediated activation of β-adrenergic signaling. This study aimed to evaluate the inhibitory effects of rosmarinic acid (RA) on norepinephrine (NE)-induced migration and invasion in triple-negative breast cancer (TNBC) cells and to elucidate the underlying molecular mechanisms. Cell viability was assessed using an MTT assay. Migration and invasion were evaluated by Transwell assays in MDA-MB-231 and BT-20 cells treated with NE in the presence or absence of RA. Src phosphorylation and EMT-related protein expression were analyzed by Western blotting. Molecular docking was performed to predict the binding of RA to Src kinase. Constitutively active Src transfection was used to confirm the role of Src. A network pharmacology-based analysis was conducted to identify RA-associated targets and enriched pathways. RA significantly suppressed NE-induced migration and invasion in TNBC cells. RA markedly reduced NE-induced Src phosphorylation, and docking analysis predicted stable binding of RA within the ATP-binding pocket of Src. Constitutive Src activation abrogated the anti-migratory and anti-invasive effects of RA, confirming Src as a key molecular target. RA also attenuated NE-induced EMT by reducing mesenchymal marker expression. Network pharmacology analysis revealed enrichment of RA-associated targets in cancer-related pathways and identified several hub genes that converge on Src-related signaling cascades. RA suppresses NE-induced metastatic phenotypes in TNBC cells primarily through inhibition of Src kinase and partial modulation of the EMT program, highlighting its potential as a therapeutic candidate for stress-associated TNBC metastasis.