Background Halofuginone hydrobromide (HF) is a synthetic analogue of the naturally occurring quinazolinone alkaloid febrifugine, which has potential therapeutic effects against breast cancer, however, its poor water solubility greatly limits… Click to show full abstract
Background Halofuginone hydrobromide (HF) is a synthetic analogue of the naturally occurring quinazolinone alkaloid febrifugine, which has potential therapeutic effects against breast cancer, however, its poor water solubility greatly limits its pharmaceutical application. D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) is a water-soluble derivative of vitamin E, which can self-assemble to form polymeric micelles (PMs) for encapsulating insoluble anti-tumor drugs, thereby effectively enhancing their anti-cancer effects. Methods HF-loaded TPGS PMs (HTPMs) were manufactured using a thin-film hydration technique, followed by a series of characterizations, including the hydrodynamic diameter (HD), zeta potential (ZP), stability, drug loading (DL), encapsulation efficiency (EE), and in vitro drug release. The anti-cancer effects and potential mechanism of HTPMs were investigated in the breast cell lines MDA-MB-231 and MCF-7, and normal breast epithelial cell line Eph-ev. The breast cancer-bearing BALB/c nude mouse model was successfully established by subcutaneous injection of MDA-MB-231 cells and used to evaluate the in vivo therapeutic effect and safety of the HTPMs. Results The optimized HTPMs had an HD of 17.8±0.5 nm and ZP of 14.40±0.1 mV. These PMs exhibited DL of 12.94 ± 0.46% and EE of 90.6 ± 0.85%, along with excellent storage stability, dilution tolerance and sustained drug release in pH-dependent manner within 24 h compared to free HF. Additionally, the HTPMs had stronger inhibitory effects than free HF and paclitaxel against MDA-MB-231 triple-negative breast cancer cells, and little toxicity in normal breast epithelial Eph-ev cells. The HTPMs induced cell cycle arrest and apoptosis of MDA-MB-231 by disrupting the mitochondrial membrane potential and enhancing reactive oxygen species formation. Evaluation of in vivo anti-tumor efficacy demonstrated that HTPMs exerted a stronger tumor inhibition rate (68.17%) than free HF, and exhibited excellent biocompatibility. Conclusion The findings from this study indicate that HTPMs holds great clinical potential for treating triple-negative breast cancer.
               
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