Carthamus tinctorius L. is a
traditional Chinese medicine that activates blood circulation and dissipates blood stasis, and has been extensively used as antitumor treatment in a clinical setting in single or in compound preparation form. However, empirical evidence and a better understanding of the possible mechanisms involved are still required. Here, we investigated the role of
safflower yellow (SY), the active ingredient of C. tinctorius, in the pulmonary
metastasis of
breast cancer, and the underlying mechanism of action.
EGF-meditated time- and dose-dependent cell response profiles were applied to screen for the activity of SY in vitro, while orthotopic lung
metastasis and
intravenous injection were used to evaluate the antimetastatic role of SY in vivo. SY could dose-dependently inhibit
EGF-mediated time- and dose-dependent cell response profiles by inhibiting cytoskeletal rearrangement. We also found that SY significantly inhibited the migration of
breast cancer cells in vitro and pulmonary
metastasis of
breast cancer cells in vivo. Consistent with these phenotypes, formation of invadopodia and the expression of MMP-9 and p-Src
proteins were decreased after
EGF stimulation in MBA-MD-231 cells treat with SY, as well as in lung metastatic foci. Additionally,
circulating tumor cells retained in lung capillaries were also reduced. These results suggest that the antimetastatic effect of SY is due to its inhibition of invadopodia formation, which occurs mainly through Src-dependent cytoskeleton rearrangement. We suggest that SY should be considered as a potential novel therapeutic agent for the treatment of
breast cancer.