Musashi2 promotes the development and progression of pancreatic cancer by down-regulating Numb protein

Musashi2-Numb interaction plays a vital role in the progression of myeloid leukemia. However, its potential role in solid cancers has rarely been reported. We investigated the coordinate function of Musashi2-Numb in the development of pancreatic cancer (PC) in vitro and vivo. Both Musashi2 protein and mRNA levels were higher in PC tissues than that in paired normal pancreas (P<0.05). Musashi2 overexpression and Numb positive expression were positively and negatively associated with tumor size and UICC stage, respectively (P<0.05). Multivariate analysis identified Musashi2 and Numb as adverse and favorable independent indicators for the survival of PC patients. Moreover, patients with high Musashi2 expression combining with negative Numb expression had a significantly worse overall survival (P=0.001). The negative relationship between Musashi2 and Numb was found at both PC tissue and cell levels. These two endogenous proteins can be co-immunoprecipitated from PC cell lines, and Musashi2 silence up-regulated Numb protein in vitro and vivo. Meanwhile, its silence decreased cell invasion and migration in vitro and inhibited the growth of subcutaneous tumors and the frequency of liver metastasis in vivo. However, Numb knockdown significantly reversed the decrease of cell invasion and migration induced by Musashi2 silence. Musashi2 promotes the development and progression of pancreatic cancer by down-regulating Numb protein. The interaction of Musashi2-Numb plays a significant role in the development and progression of PC.