Rhein and hesperidin nanoparticles remodel tumor immune microenvironment by reducing CAFs and CCL2 secreted by CAAs for efficient triple-negative breast cancer therapy.

In triple-negative breast cancer (TNBC), the tumor immune microenvironment (TIME) is a highly heterogeneous ecosystem that exerts indispensable roles in tumorigenesis and tumor progression. Cancer-associated fibroblasts (CAFs) and cancer-associated adipocytes (CAAs) are the main matrix components in the TIME of TNBC. CAFs mediate the edesmoplastic response, which is a major driver of the immunosuppressive microenvironment to promote tumor growth. In addition, CAAs, a type of tumor-educated adipocyte, participate in crosstalk with breast cancer and are capable of secreting various cytokines, adipokines and chemokines, especially C-C Motif Chemokine Ligand 2 (CCL2), resulting in changes of cancer cell phenotype and function. Therefore, how to treat tumors by regulating the CAFs and the secretion of CCL2 by CAAs in TIME is investigated here. Our research group previously found that rhein (Rhe) has been identified as effective against CAFs, while hesperidin (Hes) could effectively diminish CCL2 secretion by CAAs. Inspired by the above, we developed unique PLGA-based nanoparticles loaded with Rhe and Hes (RH-NP) using the emulsion solvent diffusion method. The RH-NP particles have an average size of 114.1 ± 0.98 nm. RH-NP effectively reduces CAFs and inhibits CCL2 secretion by CAAs, promoting increased infiltration of cytotoxic T cells and reducing immunosuppressive cell presence within tumors. This innovative, safe, low-toxic, and highly effective anti-tumor strategy could be prospective in TNBC treatment.