Investigation of inhibitory effects of quercetin and resveratrol through Sirt-1 regulation in Human breast cancer cell(MCF-7) metastasis

Most of polyphenol compounds have ability to protect normal cells and reduce tumor growth. Different types of polyphenols might have different mechanisms. Quercetin (Qu), which can be extracted from various natural plants and foods, is known as a flavonoid-type polyphenol. However, the effect of regulation of Quercetin on mammary cancer is still unclear. In this study, the mechanism of Quercetin’s influence on metastasis ability of MCF-7 was investigated. In order to observe and compare the effect on metastasis of MCF-7, Resveratrol, a stilbenes-type polyphenol compound with qualities most similar to Quercetin, was chosen as the control group in comparison. The results show below: (1) In wound healing assay, both Quercetin and Resveratrol (10, 20, 40, 80 100 μM) have ability of inhibition on wound healing of MCF-7 after reacting 24 or 48 hours with a significant sifference. Along with the increase of the concentration of the agents, the inhibiting ability increases, showing that both Quercetin and Resveratrol have effect on inhibition of metastasis of MCF-7. In addition, since previous studies proposed that MMP-9 involved in invasion and metastasis of mammary cancer, we did a further investigation on whether MMP-9 of MCF-7 was influenced by medicine with West blot assay. (2) The result of Western blot assay shows MMP-9 was down-regulated both in the condition of 40 μM of Quercetin and Resveratrol. Furthermore, studies also proposed that Resveratrol, by up-regulating expressing quantity of Sirt-1, could regulate different signal paths to work biologically on regulating invasion and metastasis of cancers. For this reason, we also observed the effect of the medicine on Sirt-1 of MCF-7, and discovered both Quercetin and Resveratrol have influence on increasing the expressing quantity of Sirt-1. (3) In cell migration assay and cell invasion assay, in order to confirm that Quercetin and Resveratrol can reduce the ability of metastasis by regulating MMP-9, we did examination on two in vitro cell lines. It was realized beyond and doubt that Quercetin and Resveratrol can inhibit the invasion and metastasis of MCF-7. On the other hand, Quercetin and Resveratrol (40 μM) inhibited the metastasis of MDA-MB-231 in 6-hour reaction and the invasion of MDA-MB-231 in 24-hour reaction significantly as well. (4) The result of cell proliferation assay shows both Quercetin and Resveratrol (40 μM) can inhibit cell proliferation of human breast cancer cell line MCF-7. According to the results of our experiments, on the one hand, Quercetin can inhibit the invasion and metastasis of MCF-7 by down-regulating the expressing quantity of MMP-9. On the other hand, Quercetin can up-regulate the expressing quantity of Sirt-1 of MCF-7. Therefore, we can deduce that, like Resveratrol, Quercetin can inhibit the invasion and metastasis of MCF-7 by up-regulating the expressing quantity of Sirt-1. Besides, Quercetin can also inhibit the invasion and metastasis of MDA-MB-231, which was understood much powerful in metastasis.