AB094. C1QBP negatively regulates the activation of oncoprotein YBX1 in the renal cell carcinoma as revealed by interactomics analysis

BACKGROUND: The Y-box-binding protein 1 (YBX1) plays a critical role in tumorigenesis by promoting cell proliferation, overriding cell cycle check points, and enhancing genomic instability. METHODS: The interactome of YBX1 in renal cell carcinoma (RCC) was analyzed by coimmunoprecipitation and mass spectrometry. The interaction between C1QBPand YBX1 was confirmed by immunoprecipitation and Western blotting. The clinical significance of these two proteins by IHC. RESULTS: A total of 129 proteins were identified as potential YBX1 binding partners. Knockdown of C1QBP enhanced the phosphorylation of YBX1 and its nuclear translocation. Expression of YBX1 was markedly elevated. Meanwhile, the level of C1QBP in the carcinoma tissues was significantly lower. CONCLUSIONS: These data suggest that C1QBP is a novel regulator of YBX1, and the expression of C1QBP and the nuclear expression of YBX1 could both be used as independent prognostic makers for cancer progression in the RCC patients.