The improved targeting of an aspirin prodrug albumin-based nanosystem for visualizing and inhibiting lung metastasis of breast cancer.

Lung metastasis is the principal reason for the majority of deaths from breast cancer. The nonsteroidal anti-inflammatory drug aspirin can prevent lung metastasis in breast tumors via inhibiting heparanase. However, the lack of specific targets and limited accumulation at the site of the tumor have thus far hindered the use of aspirin in oncotherapy. In this study, we developed the nanoplatform FA-BSA@DA and loaded it with the versatile aspirin prodrug DA to visualize and inhibit breast cancer metastasis via targeting heparanase. This nanosystem can be effectively targeted to folic acid (FA)-positive tumor cells, and would then subsequently release a high dose of DA, whose ester bond is specifically ruptured by H2O2 in the tumor microenvironment to afford the therapeutic drug aspirin and near-infrared (NIR) fluorescent reporter DCM. The released aspirin can effectively prevent breast cancer lung metastasis through the inhibition of heparanase activity, and the NIR fluorescent signals emitted from DCM can be used to monitor and evaluate the metastasis levels of breast cancer. Our results showed that the expression of heparanase was significantly decreased, and lung metastasis from breast cancer was effectively monitored and inhibited after treatment with FA-BSA@DA. Furthermore, the collaborative therapy nanoplatform FA-BSA@DA/DOX exhibited strong therapeutic effects in the treatment of breast cancer in vitro and in vivo via the introduction of doxorubicin (DOX) to the system, which resulted in an even stronger result due to its synergistic effects with aspirin. This heparanase-reliant strategy has profound significance for the extended development of nanoplatforms based on versatile aspirin prodrugs, which may offer a solution to clinically prevent breast cancer recurrence and lung metastasis.