Activated Platelets-Targeting Micelles with Controlled Drug Release for Effective Treatment of Primary and Metastatic Triple Negative Breast Cancer

The frequent relapse and metastasis characteristics of triple negative breast cancer (TNBC) make it a fraught issue with very poor prognosis in clinic. An effective treatment for TNBC should prevent and even eliminate metastasis as well as suppress primary lesion expansion. Recent progress reveals that platelets can be recruited and activated by tumor cells through intercellular adhesion molecules (ICAM), and help aggressive circulating tumor cells (CTCs) form metastasis. Therefore, activated platelets are considered with possession of tumor-homing, CTC-capturing, and metastasis-targeting abilities. In this work, a P-selectin (expressed on activated platelet surface) targeting peptide (PSN) is modified on a redox-responsive paclitaxel-loaded micelle (PSN-PEG-SS-PTX 4 micelle) to utilize activated platelets as a “bridge” for interaction with cancer cells. The PSN-modified micelle can easily adhere to the surface of activated platelets and subsequently capture CTCs in blood circulation. Compared to Taxol and PEG-SS-PTX 4 micelle, PSN-PEG-SS-PTX 4 micelle also exhibits enhanced primary TNBC/metastasis targeting and penetrating effect through binding with tumor infiltrating platelets and thus significantly improves treatment outcome. More importantly, PSN-PEG-SS-PTX 4 micelle potently suppressed lung metastasis of TNBC and reduced incidence of distant liver metastasis. The activated platelet-targeting redox-responsive micelle system provides a promising prospect for the omnidirectional treatment of metastatic cancer.