pH-responsive Sulfated Hyaluronic Acid Nanoparticles Targeting Tumor Cells and CAFs for the Treatment of Breast Cancer.

Background: Tumor metastasis is a main cause of death in patients with breast cancer. The cross-talk between cancer-associated fibroblasts (CAFs) and tumor cells plays an important role in promoting tumor invasion and metastasis. It is important to develop a novel delivery system to inhibit tumor development by simultaneously targeting both CAFs and tumor cells.

Objectives: The main objective of this research was to prepare nanoparticles to inhibit tumor proliferation and migration by blocking the cross-talk of tumor-CAFs. Additionally, a novel "MCF- 7+NIH/3T3" mixed cell model was established to mimic the tumor microenvironment (TME).

Methods: In this study, the pH-responsive nanoparticles (MIF/DOX-sul-HA NPs) based on sulfated hyaluronic acid (sul-HA) polymers were prepared for co-delivery of doxorubicin (DOX) and mifepristone (MIF). The effects of anti-proliferation and anti-metastasis of MIF/DOX-sul-HA NPs were investigated both in vitro and in vivo.

Results: The results showed that MIF/DOX-sul-HA NPs were nearly spherical in shape with narrow particle size distribution and pH-responsive drug release, and could be taken up by both MCF-7 and NIH/3T3 cells. Compared with MCF-7 cells alone, the anti-tumor effect of single DOX was weak in the "MCF-7+NIH/3T3" mixed cell model. MIF/DOX-sul-HA NPs exhibited strong effects of anti-proliferation and anti-metastasis than the free single drug.

Conclusion: The sul-HA nanoparticles for co-delivery of DOX and MIF could be a promising combined therapy strategy for the treatment of breast cancer.