Nanomodulators Targeting Endothelial WNT and Pericytes to Reversibly Open the Blood-Tumor Barrier for Boosted Brain Tumor Therapy.

The blood-brain barrier (BBB)/blood-tumor barrier (BTB) impedes brain entry of most brain-targeted drugs, whether they are water-soluble or hydrophobic. Endothelial WNT signaling and neoplastic pericytes maintain BTB low permeability by regulating tight junctions. Here, we proposed nitazoxanide (NTZ) and ibrutinib (IBR) co-loaded ICAM-1-targeting nanoparticles (NI@I-NPs) to disrupt the BTB in a time-dependent, reversible, and size-selective manner by targeting specific ICAM-1, inactivating WNT signaling and depleting pericytes in tumorassociated blood vessels in breast cancer brain metastases. At the optimal NTZ/IBR mass ratio (1:2), BTB opening reached the optimum effect at 48-72 h without any sign of intracranial edema and cognitive impairment. The combination of NI@I-NPs and chemotherapeutic drugs (doxorubicin and etoposide) extended the median survival of mice with breast cancer brain metastases. Targeting BTB endothelial WNT signaling and tumor pericytes via NI@I-NPs could open the BTB to improve chemotherapeutic efficiency against brain metastases.