Sonic Hedgehog stimulates migration of MCF-7 breast cancer cells through Rac1

As one of the most common tumors in women, breast cancer has drawn considerable interest from investigators and clinicians in recent years. Despite early diagnosis and best therapeutic regimens available, the prognosis of malignant or metastatic breast cancer patients is still not optimistic. Hedgehog signaling, a classical pathway indispensable to embryonic development, participates in the growth of a variety of tumors. In the present study, the effect of Sonic Hedgehog (Shh) on breast cancer cells was investigated. We identified that Shh signal stimulated the migration of MCF-7 breast cancer cells. Smo and Gli1 were involved in Shh-stimulated migration of MCF-7 cells. Activating Smo and Gli1 induced cell migration, which was blocked by their specific antagonists. The effect of Shh signaling on MCF-7 cells was independent of Wnt5a, Dvl2 and Rab35, but directly dependent on Rac1. In conclusion, our study suggested that Shh promotes breast cancer cell migration via Rac1 independently of the non-canonical Wnt signaling pathway, which may represent a rational molecular target for combination medication in breast cancer.