Dual-Targeting of Tumor Cells and Tumor-Associated Macrophages by Palmitic Acid Modified Albumin Nanoparticles for Antitumor and Antimetastasis Therapy

Tumor-associated macrophages (TAMs), the most abundant immune cells in the tumor microenvironment (TME), profoundly affect the occurrence and development of tumors. To overcome the common limitations of TAMs-targeted delivery systems, such as off-target toxicity, high cost, and transformation probability, we fabricated pirarubicin (THP)-loaded palmitic acid modified human serum albumin nanoparticles (THP-PSA NPs) for dual-targeting of tumor cells and TAMs via acidic secretory proteins rich in cysteine (SPARC) and scavenger receptor-A (SR-A), respectively. In vitro, the THP-PSA NPs exhibit stronger cytotoxicity against 4T1 and M2 macrophages compared with THP-loaded human serum albumin nanoparticles (THP-HSA NPs). In vivo, the infiltration of myeloid-derived suppressor cells (MDSCs) and the secretion of immunosuppressive cytokines significantly decrease after effective elimination of the TAMs through the THP-PSA NPs treatment; this is accompanied by an increase in the immunostimulatory cytokine expression level. Moreover, the antitumor and antimetastasis experimental results indicate that the tumor volumes in mice treated with the THP-PSA NPs are effectively controlled, resulting in an inhibition rate of 81.0% and almost no metastases in the lung tissues. Finally, in terms of biological safety, the THP-PSA NPs perform similar to THP-HSA NPs, causing no damage to the liver or kidney.