Cripto-1 expression in patients with clear cell renal cell carcinoma is associated with poor disease outcome.

Background: Cripto-1 (CR-1) has been reported to be involved in the development of several human cancers. The potential role of CR-1 in clear cell renal cell carcinoma (ccRCC) is still not clear.
Methods: CR-1 expression was evaluated in ccRCC tissues by Real-time quantitative PCR, Western blot and immunohistochemistry. Serum levels of CR-1 were tested by enzyme-linked immunosorbent assay (ELISA). The clinical significance of CR-1 was analyzed. The effects of CR-1 on cell proliferation, migration, invasion and angiogenesis were investigated in ccRCC cell lines in vitro and in vivo, and markers of the epithelial -mesenchymal transition (EMT) were analyzed. The impact of CR-1 on Wnt/β-catenin signaling pathway was also evaluated in vitro and in vivo.
Results: CR-1 expression was elevated in ccRCC tumor tissues and serum samples. CR-1 expression was correlated with aggressive tumor phenotype and poor survival. Ectopic expression of CR-1 significantly promoted cell proliferation, migration, invasion and angiogenesis whereas knockdown of CR-1 inhibited these activities both in vitro and in vivo. Moreover, we found that CR-1 induced EMT and activated Wnt/β-catenin signaling pathway both in vitro and in vivo.
Conclusions: These results suggest that CR-1 is likely to play important roles in ccRCC development and progression, and that CR-1 is a prognostic biomarker and a promising therapeutic target for ccRCC.