Reactive oxygen species produced by photodynamic therapy enhance docosahexaenoic acid lipid peroxidation and induce the death of breast cancer cells.

Breast cancer remains a serious threat to women's physical and emotional health. The combination therapies can overcome the deficiency of single therapy, enhance the therapeutic effects and reduce the side effects at the same time. In this study, we synthesize a novel nanomedicine that enhanced the therapeutic effects of breast cancer treatment by combining photodynamic therapy and chemotherapy. The doxorubicin (DOX) and photosensitizer methyl pyropheophorbide-a (MPPa) are loaded into the nano-drug delivery system as DPSPFA/MPPa/DOX. In response to near-infrared (NIR) laser, the drugs were quickly released to the cancer cells. The MPPa produces reactive oxygen species (ROS) under the action of photodynamics. Unsaturated fatty acids with ROS promotes lipid peroxidation and the combination of chemotherapy and photodynamic therapy. The data shows that the DPSPFA/MPPa/DOX has a spherical shape, good dispersibility and stability, and the particle size is roughly 200 nm. The drug loading capability of DOX is about 13 %. Both of MCF7 cell model in vitro and breast cancer model in vivo, DPSPFA/MPPa/DOX showed an excellent anti-tumor effect of 86.9 % and without any obvious side effects. These findings might offer potential for a new approach for breast cancer treatment.