Heat/pH-boosted release of 5-fluorouracil and albumin-bound paclitaxel from Cu-doped layered double hydroxide nanomedicine for synergistical chemo-photo-therapy of breast cancer.

Considerable attention has been devoted to nanomedicine development for breast cancer therapy, while the therapeutic efficiency is far from satisfactory owing to non-specific biodistribution-caused side effects and limitation of single modal treatment. In this study, we have developed a novel nanomedicine for efficient combination breast cancer therapy. This nanomedicine was based on copper-doped layered double hydroxide (Cu-LDH) nanoparticles loaded with two FDA-approved anticancer drugs, i.e. 5-fluorouracil (5-FU) and albumin-bound paclitaxel (nAb-PTX) with complementary chemotherapeutic actions. The 5-FU/Cu-LDH@nAb-PTX nanomedicine showed pH-sensitive heat-facilitated therapeutic on-demand release and demonstrated the moderate-to-strong synergy of photothermal therapy and chemotherapy in inducing apoptosis of breast cancer cells (4 T1). This nanomedicine had a high colloidal stability in saline and serum, and efficiently accumulated in the tumor tissue. Remarkably, this nanomedicine nearly eliminated 4 T1 tumors in vivo after a two-course treatment under mild 808 nm laser irradiation (0.75 W/cm, 3 min) at very low doses of 5-FU and nAb-PTX (0.25 and 0.50 mg/kg, 8-50 times less than that used in other nanoformulations), without observable side effects. Therefore, this research provides a novel approach to designing multifunctional nanomedicines for on-demand release of chemotherapeutics to cost-effectively treat breast cancer with minimal side effects in future clinic applications.