Analysis of Differentially Expressed Proteins Involved in miR-449a for Hepatocellular Carcinoma by iTRAQ Proteomics.

ABSTRACT

BACKGROUND: To investigate the relationship between down-regulation of miR-449a and prognosis of hepatocellular carcinoma (HCC) and to elucidate the potential target proteins of miR-449a. MATERIAL AND METHODS: The expression of miR-449a in 142 HCC tissues was detected by RT-PCR. The correlation between down-regulation of miR-449a and prognosis of HCC was statistically analyzed during clinical follow-up. The Bel-7042 HCC cell line in miR-449a-mimic and miR-449a-inhihbitor model was used, and the potential target protein of miR-449a was screened by isobaric tags for relative and absolute quantitation (iTRAQ) technology. RESULTS: miR-449a was significantly down-regulated in HCC tissues, which was significantly associated with post-operative metastasis (p < 0.0001) and recurrence (p < 0.0001). The median overall survival time in the low-expression group of miR-449a was significantly lower than that of the high-expression group (19 months vs. 37 months, p = 0.001). In addition, the tumor-free survival time of the low-expression group was significantly lower than that of the high-expression group (14 months vs. 24 months, p = 0.001). iTRAQ analysis screened out 137 differential proteins, among which 88 were up-regulated and 49 were down-regulated. GO clustering, KEGG pathway, and STRING analysis were performed, suggesting that these differential proteins have complicated functions, such as ATP binding, metal ion binding, RNA binding, human papillomavirus infection, and Epstein-Barr virus infection. CONCLUSIONS: miR-449a was negatively correlated with HCC prognosis. The differential proteins screened by iTRAQ can provide the basis for studying the target proteins regulated by miR-449a and understanding the pathogenesis of HCC.