RAP1B, a DVL2 binding protein, activates Wnt/beta-catenin signaling in esophageal squamous cell carcinoma.

RAP1B is a small GTPase, which regulates multiple cellular processes. Up-regulation of RAP1B has been observed in several cancer types. Although previous study has shown that miR-518 inhibited the proliferation and invasion of esophageal squamous cell carcinoma (ESCC) cells possibly by targeting RAP1B, the expression pattern and the functions of RAP1B in ESCC are not fully understood. Here, we have fund that the expression of RAP1B was up-regulated in ESCC clinical samples. Gain-of-function and loss-of-function assays demonstrated that RAP1B promoted the growth, migration and metastasis of the ESCC cells. Moreover, the mechanism study showed that RAP1B interacted with DVL2, an important upstream regulator for beta-catenin/TCF signaling, and activated beta-catenin/TCF signaling. Taken together, our study demonstrated the oncogenic roles of RAP1B in ESCC, and suggested that RAP1B might be a therapeutic target.