Combination of chemotherapy with low-dose doxorubicin/Lycium barbarum polysaccharide and photothermal therapy with polypyrrole nanoparticles for treating breast cancer

To decrease the toxicity of doxorubicin (DOX) and increase the impact of anti-breast cancer drugs, 1 mg/kg DOX combined with Lycium barbarum polysaccharides (LBPs) and photosensitive polypyrrole nanoparticles (PPY NPs) was selected for chemotherapy combined with photothermal local therapy. In vitro cell experiments demon-strated that LBPs promoted DOX uptake by 4T1 cells, whereas the addition of PPY NPs further increased DOX uptake under near-infrared photothermal conditions. In vivo experiments demonstrated that when 1 mg/kg DOX was used in combination with LBPs and PPY NPs for localised photothermal treatment, the tumour inhibition rate reached 80.25%. Meanwhile, the results of the biochemical analysis and hematoxylin and eosin staining indicated that the heart and liver injuries were alleviated (aspartate aminotransferase/alanine aminotransferase, 3.81 +/- 0.46 vs. 2.58 +/- 0.40) (P < 0.05), and the anti-tumour effect was enhanced. The results of the enzyme-linked immunoassay test also revealed that low-dose DOX could reduce the toxicity and enhance the efficacy (interleukin-10, tumour necrosis factor-alpha, interferon-gamma, immunoglobulin A, and reactive oxygen species). Therefore, combination therapy can also enhance anti-breast cancer activity and reduce toxicity when a low dose of DOX is administered.