| Breast cancer is one of the leading causes of cancer death. Approximately 90% of cancer deaths resulted from tumor metastasis. Some Chinese herbal medicines have been found to be effective in inhibiting tumor propagation. For anti-tumor metastasis, zoledronate (ZOL) is commonly used in treatment of bone destruction caused by metastatic spread. However, long-term use of ZOL leads to the osteonecrosis of jaw and femoral insufficiency fracture. In this study, we aim to: (1) evaluate the anti-tumor and anti-metastasis effects of water extracts of four selected Chinese medicines, Camellia sinensis (CS), Coriolus versicolor (CV), Hedyotis diffusa (HD) and Scutellaria baicalensis (SB); (2) comparatively study the anti-tumor and anti-osteolysis effects of conventional and metronomic regimens of ZOL; (3) investigate the anti-tumor, anti-metastasis and anti-osteolysis effects of the combined use of the potent herbal extract CS and metronomic ZOL.;In this study, the in vitro anti-tumor and anti-metastatic effects were evaluated in mammary cancer cells (4T1, MDA-MB-231-TXSA-TGL and/or MDA-MB-231) using cell viability, scratch wound and transwell migration assays. Annexin-V FITC/PI staining and caspase-3 activity assays were employed to assess the induction of apoptosis, and western blot and gelatin zymography were used to investigate the underlying mechanisms. Besides, the in vivo 4T1 mouse mammary tumor model and MDA-MB-231-TXSA-TGL intratibial breast cancer induced-osteolysis model were employed to evaluate the anti-tumor, anti-metastasis and anti-osteolysis effects of herbal extracts and ZOL. The combined use of the potent herbal extract CS and metronomic ZOL against tumor burden and metastasis were investigated in both animal models.;Our results demonstrated that the water extracts of CS, CV, SB and HD had potent anti-migration and anti-invasion abilities in vitro. In animal study, CS and CV extracts were effective in decreasing tumor weight and lung metastasis in mice bearing 4T1 tumors, also showed significant effects in bone protection. Cytokines production analysis showed that CV and HD extracts had potent immunomodulatory effects, especially in stimulating IL-2, TNF-alpha and IFN-gamma. Underlying mechanistic study of CS demonstrated apoptosis induction and suppression of MMP-9 and MMP-2 in 4T1 and MDA-MB-231-TXSA-TGL cells. Besides, metronomic regimen of ZOL was firstly demonstrated to be effective in reducing tumor burden and did not promote lung or liver metastasis in both metastatic and primary breast cancer against MDA-MB231-TXSA-TGL cells, as compared with conventional ZOL. In addition, the novel application of herbal extract CS and metronomic ZOL promoted the anti-tumor, anti-metastasis and anti-osteolysis effects against metastatic breast cancer. Furthermore, the inhibitory effect of CS on cell migration and apoptosis induction was strengthened by ZOL in 4T1 and MDA-MB231-TXSA-TGL cells.;In conclusion, we presented the first evidence on anti-tumor and anti-metastasis effects of the water extracts of CS, CV, HD and SB against breast cancer 4T1 tumors. Metronomic dose of ZOL was firstly demonstrated to be effective in decreasing iii tumor burden and metastasis in MDA-MB231-TXSA-TGL mouse models, as compared with conventional regimen. In addition, the combined use of CS extract and metronomic ZOL demonstrated promising effects against metastatic breast cancer, and suggested potential clinical application in breast cancer patients. |
