Effects of Water Extract of Cynanchum paniculatum (Bge.) Kitag. on Different Breast Cancer Cell Lines

Cynanchum paniculatum (Bge.) Kitag. (CP) is an important medicinal herb used in Chinese herbal medicine, with a variety of biological activities including anticancer property. In this study, we explored the water extract of CP, for its anticancer effects against breast cancer cells with different mutation types. Cells were grouped as untreated (Control); CP direct treatment (dir-CP); Conditioned medium from CP treated (sup-CP), and untreated cells (sup-Control). Effects of dir-CP and sup-CP were compared to corresponding untreated cells on cytotoxicity, cell migration, and protein expression (cleaved caspase-3, caspase-9, and MMP-2 and 9). CP treatment showed time-dependent decrease in cell number of MDA-MB-231 and SK-Br-3 (both ER(−) PR(−)), while the decrease in cell number was not as significant in MCF-7 and ZR-75-1 cells (both ER(+) PR(+)). sup-CP treatment inhibited the cell migration of MDA-MB-231 and MCF-7 (Her2(−)) in a 24 h scratch assay. Our data suggested that ER(−) PR(−) cells are more sensitive to the CP in terms of direct cytotoxicity, which is not regulated by caspase-3. CP inhibited the migration of the two Her2(−) cells, and this correlated with MMP-2 regulation. The migration of ER(−) PR(−) cells was more sensitive to conditioned medium with CP treatment than to direct CP, and this is not regulated by MMP-2. Our data suggested that CP has anticancer potential on various breast cancer cells through different mechanisms and is specifically effective in inhibiting the migration of the triple negative MDA-MB-231. Our data provide insight into the mechanism of CP against breast cancer progression and would benefit the medical practitioners in better management with CP usage.