Objective: To observe the effects of rukangyin (RKY) on the lymphangiogenesis and lymph node metastasis of breast cancer transplantation tumor mice, thus exploring its anti-tumor metastasis mechanisms.
Methods: Human breast cancer cell line MDA-MB-435S were in situ implanted into the mammary fat pad of 30 female nude mice to establish breast cancer transplantation tumor spontaneous metastasis model. They were randomly divided into six groups, i.e., the model control group, the 5-FU control group, the small, medium, large dose RKY groups, and the medium dose RKY +5-FU group, 5 in each. Normal saline was given to mice in the model control group at the daily dose of 0.4 mL/kg by gastrogavage. 5-FU was given to mice in the 5-FU control group at the daily dose of 30 mg/kg by peritoneal injection. RKY was given to mice in the small, medium, large dose RKY groups at the daily dose of 18, 45, and 90 g/kg by gastrogavage. 5-FU 30 mg/kg (by peritoneal injection) + RKY 45 g/( kg x d) (by gastrogavage) was given to mice in the medium dose RKY +5-FU group. All medication was carried out once daily for 6 successive weeks. The tumor volume, the tumor inhibition ratio, and the inhibition ratio of axillary lymph node metastasis were detected after medication. The lymphatic microvessel density (LMVD) and expressions of vascular endothelial growth factor-C (VEGF-C) and vascular endothelial growth factor receptor-3 (VEGFR-3) of the breast cancer tissues were detected using immunohistochemical assay.
Results: Compared with the model control group, the tumor volume was markedly reduced in the small, medium, large dose RKY groups, and the medium dose RKY +5-FU group, the expressions of VEGF-C and VEGFR-3 were significantly down-regulated and LMVD were obviously lowered, showing statistical difference (P < 0.05, P < 0.01). The inhibition rates of tumor and axillary lymph node metastasis were highest and the LMVD was the lowest in the medium dose RKY +5-FU group, showing statistical difference when compared with other medication groups (P < 0.05, P < 0.01).
Conclusion: RKY might inhibit the lymph node metastasis of breast cancer possibly through intervening the expressions of VEGF-C and VEGFR-3, and suppressing lymphangiogenesis.