The Evolution of Safe and Effective Coaguligands for Vascular Targeting and Precision Thrombosis of Solid Tumors and Vascular Malformations

Externalization of Mitochondrial PDCE2 on Irradiated Endothelium as a Target for Radiation-Guided Drug Delivery and Precision Thrombosis of Pathological Vasculature

Endothelial cells are highly sensitive to ionizing radiation, and exposure leads to multiple adaptive changes. Remarkably, part of this response is the translocation of normally intracellular proteins to the cell surface. It is unclear whether this ectopic expression has a protective or deleterious function, but, regardless, these surface-exposed proteins may provide unique discriminatory targets for radiation-guided drug delivery to vascular malformations or tumor vasculature. We investigated the ability of an antibody–thrombin conjugate targeting mitochondrial PDCE2 (E2 subunit of pyruvate dehydrogenase) to induce precision thrombosis on irradiated endothelial cells in a parallel-plate flow system. Click-chemistry was used to create antibody–thrombin conjugates targeting PDCE2 as the vascular targeting agent (VTA). VTAs were injected into the parallel-plate flow system with whole human blood circulating over irradiated cells. The efficacy and specificity of fibrin-thrombus formation was assessed relative to non-irradiated controls. The PDCE2-targeting VTA dose-dependently increased thrombus formation: minimal thrombosis was induced in response to 5 Gy radiation; doses of 15 and 25 Gy induced significant thrombosis with equivalent efficacy. Negligible VTA binding or thrombosis was demonstrated in the absence of radiation or with non-targeted thrombin. PDCE2 represents a unique discriminatory target for radiation-guided drug delivery and precision thrombosis in pathological vasculature.

Erythrocyte Membrane-Coated Invisible Acoustic-Sensitive Nanoparticle for Inducing Tumor Thrombotic Infarction by Precisely Damaging Tumor Vascular Endothelium

Selective induction of tumor thrombus infarction is a promising antitumor strategy. Non-persistent embolism due to non-compacted thrombus and activated fibrinolytic system within the tumor large blood vessels and tumor margin recurrence are the main therapeutic bottlenecks. Herein, an erythrocyte membrane-coated invisible acoustic-sensitive nanoparticle (TXA+DOX/PFH/RBCM@cRGD) is described, which can induce tumor thrombus infarction by precisely damaging tumor vascular endothelium. It is revealed that TXA+DOX/PFH/RBCM@cRGD can effectively accumulate on the endothelial surface of tumor vessels with the help of the red blood cell membrane (RBCM) stealth coating and RGD cyclic peptide (cRGD), which can be delivered in a targeted manner as nanoparticle missiles. As a kind of phase-change material, perfluorohexane (PFH) nanodroplets possess excellent acoustic responsiveness. Acoustic-sensitive missiles can undergo an acoustic phase transition and intense cavitation with response to low-intensity focused ultrasound (LIFU), damaging the tumor vascular endothelium, rapidly initiating the coagulation cascade, and forming thromboembolism in the tumor vessels. The drugs loaded in the inner water phase are released explosively. Tranexamic acid (TXA) inhibits the fibrinolytic system, and doxorubicin (DOX) eliminates the margin survival. In summary, a stealthy and acoustically responsive multifunctional nanoparticle delivery platform is successfully developed for inducing thrombus infarction by precisely damaging tumor vascular endothelium.