Repurposing maduramicin as a novel anticancer and anti-metastasis agent for triple-negative breast cancer as enhanced by nanoemulsion.

Triple-negative breast cancer (TNBC) is featured by aggression and metastasis and remains an unmet medical challenge due to high death rate. We aimed to repurpose maduramicin (MAD) as an effective drug against TNBC, and develop a nanoemulsion system to enhance anticancer efficacy of MAD. MDA-MB-231 and 4 T1 cells were used as in vitro model, and cell viability was determined by performing cell counting kit-8 and a colony-formation assay. Furthermore, MAD loaded nanoemulsion (MAD-NEs) was manufactured and characterized by a series of tests. The anticancer and anti-metastasis mechanism of MAD-NEs were assessed by performing cell cycle, apoptosis, wound-healing, transwell assay and Western blotting assays. Herein, MAD was firstly demonstrated to be an effective agent to suppress growth of TNBC cells. Subsequently, the optimized MAD-NEs were shown to have stability and high encapsulation efficiency, and could arrested cells in G0/G1 phase and induced apoptosis in TNBC cells. More importantly, MAD-NEs significantly impeded the metastasis of tumor cells, which was further demonstrated by the significant altered expression of epithelial-mesenchymal transition and extracellular matrix markers in vitro and in vivo. Moreover, compared to MAD, MAD-NEs exhibited higher efficacy in shrinking breast tumor size and repressing liver and lung metastasis in vivo, and showed excellent biocompatibility in tumor-bearing mice. The successfully prepared MAD-NEs are expected to be harnessed to suppress tumor growth, invasion and metastasis in the battle against malignant TNBC.

Orally Administered Halofuginone-Loaded TPGS Polymeric Micelles Against Triple-Negative Breast Cancer: Enhanced Absorption and Efficacy with Reduced Toxicity and Metastasis.

Background: Halofuginone (HF)-loaded TPGS polymeric micelles (HTPM) were successfully fabricated using the thin-film hydration technique. HTPM via intravenous injection have been demonstrated to exert an excellent anticancer effect against triple-negative breast cancer (TNBC) cells and subcutaneous xenografts. In the present study, we further explored the potential treatment effect and mechanism of orally administered HTPM alone and in combination with surgical therapy on TNBC in subcutaneous and orthotopic mouse models. Methods: Herein, the stability and in vitro release behavior of HTPM were first evaluated in the simulated gastrointestinal fluids. Caco-2 cell monolayers were then used to investigate the absorption and transport patterns of HF with/without encapsulation in TPGS polymeric micelles. Subsequently, the therapeutic effect of orally administered HTPM was checked on subcutaneous xenografts of TNBC in nude mice. Ultimately, orally administered HTPM, combined with surgical therapy, were utilized to treat orthotopic TNBC in nude mice. Results: Our data confirmed that HTPM exhibited good stability and sustained release in the simulated gastrointestinal fluids. HF was authenticated to be a substrate of P-glycoprotein (P-gp), and its permeability across Caco-2 cell monolayers was markedly enhanced via heightening intracellular absorption and inhibiting P-gp efflux due to encapsulation in TPGS polymeric micelles. Compared with HF alone, HTPM showed stronger tumor-suppressing effects in subcutaneous xenografts of MDA-MB-231 cells when orally administered. Moreover, compared with HTPM or surgical therapy alone, peroral HTPM combined with partial surgical excision synergistically retarded the growth of orthotopic TNBC. Fundamentally, HTPM orally administered at the therapeutic dose did not cause any pathological injury, while HF alone led to weight loss and jejunal bleeding in the investigated mice. Conclusion: Taken together, HTPM could be applied as a potential anticancer agent for TNBC by oral administration.

Encapsulating Halofuginone Hydrobromide in TPGS Polymeric Micelles Enhances Efficacy Against Triple-Negative Breast Cancer Cells.

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.