Abstract
Breast cancer brain metastases (BCBM) represent a major cause of morbidity and mortality among patients with breast cancer. Systemic drug therapy, which is usually effective against peripheral breast cancers, is often ineffective on BCBM due to its poor penetration through the blood-brain tumor barrier (BTB). In this study, prostate-specific membrane antigen (PSMA) with internalization function was found to be specifically up-regulated on BCBM-associated BTB while barely detectable in normal blood-brain barrier (BBB). Here, a nanotechnology approach is reported that can overcome the BTB through ACUPA (A) and cyclic TT1 (cT) co-functionalized nanoparticles (A-NPs-cT). A-NPs-cT selectively target PSMA on BTB for specific BTB crossing and specially bind with p32 for BCBM targeting. We disclosed the effectual synergism of doxorubicin (DOX) and lapatinib (LAP) for BCBM combined therapy. A-NPs-cT exhibited boosted uptake than integrin-targeting RGD-modified NPs in BTB endothelial cells and displayed about 4.57-fold stronger penetration through the BCBM-associated BTB as compared to the normal BBB. In vivo studies showed specific BTB crossing, and remission of BCBM and prolonged survival with DOX and LAP combinatorial regimen. A-NPs-cT based DOX and LAP innovative combined therapy envisioned improved therapeutic intervention for clinical management of BCBM, for which surgery is generally inapplicable and insufficient.