R-Spondin 2 Promoted Proliferation, Invasion and Migration of Triple Negative Breast Cancer Cells Through Activating Wnt/β-Catenin Signaling Pathway After Axin2 Inhibition

Protein R-spondin 2, which is known as roof plate-specific spondin 2, is an extracellular matrix secreted protein that participates in a wide range of biological processes. However, the expression of R-spondin 2 in triple negative breast cancer (TNBC) and its specific mechanism have not been reported. In this study, RT-qPCR and western blot were used to detect the expression of R-spondin 2 and Axin2 in cells. Cell transfection techniques were used to overexpress Axin2 and interfere with the expression of R-spondin 2. CCk-8 and clone formation assay were used to detect cell viability. Wound healing and Traswell techniques were used to test the rate of invasion and migration of TNBC cells. Western blot was used to detect the expression of related proteins. The results showed that the expression of R-spondin 2 in TNBC cell lines was significantly increased compared with normal breast cancer cells. After interfering with the expression of R-spondin 2 in TNBC cell lines, the rate of cell viability, invasion and migration were decreased. It was also found that the expressions of Axin2 and β-catenin and Cyclin-D1, which are wnt/β-catenin pathway related proteins, were significantly decreased. Subsequently, the overexpression of Axin2 can inhibit the proliferation, invasion and migration that were ever promoted by R-spondin 2 of TNBC cells. Moreover, the overexpression of Axin2 inhibited the activation of wnt/β-catenin signaling pathway, which was also activated by R-spondin 2 in TNBC cells. In a word, R-spondin 2 promoted proliferation, invasion and migration of triple negative breast cancer cells through activating wnt/β-catenin signaling pathway after Axin2 inhibition.