Wnt Signaling Inhibits the Growth of Primary Cilia and Activates CyclinD1, Snail and VEGFA Expression in Breast Cancer Cell Line MDA-MB-231

Although Wnt/β-catenin signaling has been shown to be essential in the process of cancer formation, it is unclear how Wnt3a signaling pathway regulates abnormal proliferation and differentiation of breast cancer cells. Here, we found overexpression of Wnt3a stimulated the expression of the Wntsignaling’s downstream genes such as LRP6, Naked, Axin1, DVL-2, β-catenin, and TCF-1 in breast cancer cell line MDA-MB-231.Primarycilia is deemed as sensory cell antennae thatcoordinates a large number of cellular signaling pathways, sometimes coupling cell division and differentiation. Primary cilia were found on the surface of this cell line. Overexpression of Wnt3a decreased the formation of primary cilia. Inhibition of Wnt3a with Calphostin C facilitated growth of primary cilia. Wnt3a activated cell proliferation gene of CyclinD1. In contrary, Calphostin C decreased the promotional effect on proliferation of MDA-MB-231. The Snail family of transcription factor has previously been implicated in the differentiation of epithelial cells into mesenchymal cells (epithelial-mesenchymal transitions) during embryonic development. Wnt3a promoted MDA-MB-231 induced expression of Snail, whose effect was inhibited by Calphostin-C. VEGFA activity was originally referred to as vascular permeability factor and had been shown to stimulate endothelial cell mitogenesis and cell migration and increased microvascular permeability. Wnt3a facilitated MDA-MB-231 induced expression of VEGFA, as well as Calphostin-C suppressed its effect. Taken together, these results suggested thatWnt3a signaling played an important role in regulating the formation of breast cancer.