Objective: To investigate the effects of quercetin on tumour growth, cell proliferation and apoptosis in transplantation tumor of breast cancer cell line MCF-7 in nude mice.
Methods: MCF-7 cells were inoculated into the mammary fatty pad of nude mice to establish breast cancer model, then twenty-four BALB/c nude mice with xenograft tumor were randomized into four groups: Control group, Quercetin group, 5-Fu group and Quercetin + 5-Fu group. After 15 days treatment, samples of tumor were collected. The sections of tumor were observed under light microscope and electron microscope. Cell apoptosis in situ was examined by a Tunel assay, and the expressions of ki67 antigen and B-cell lymphoma/leukemia-2 (Bcl-2) were detected by immunohistochemistry.
Results: 1. The tumor weight of Control group was significantly higher than those of Quercetin group, 5-Fu group and Quercetin + 5-Fu group (P < 0.05). 2. Immunohistochemical staining of ki67 showed that the ki67 label index (ki67-LI) displayed significant difference between Control group and Quercetin group, 5-Fu group, Quercetin + 5-Fu group, and so did the staining of Bcl-2. 3. Detection of apoptosis in situ showed that apoptosis index (AI) was significantly higher in Quercetin group, 5-Fu group and Quercetin + 5-Fu group than in control group (P < 0.01), and higher AI was observed in Quercetin + 5-Fu group as compared with the AI in Quercetin group and 5-Fu group (P < 0.05).
Conclusion: Quercetin can inhibit the growth of transplantation tumor of breast cancer cell line MCF-7 in nude mice.