Objectives: To observe the expression of macrophage migration inhibition factor (MIF) and p27 in hepatocellular carcinoma tissue, and to investigate the effect of MIF on the expression of p27 in hepatocellular carcinoma (HCC) cells.
Methods: Immunohistochemistry and quantitative RT-PCR were performed to detect the expression of MIF and p27 in HCC tissues and peri-tumor tissues. Specific small interfering RNA (siRNA) targeting MIF gene was chemically synthesized and then transfected at the concentration of 50 nmol/L and 100 nmol/L into PLC cells and Hep3B cells. The mRNA levels of MIF and p27 after MIF siRNA treatment were quantified by real-time RT-PCR.
Results: MIF protein and mRNA were over-expressed in the HCC tumor tissues compared to these in the peri-tumor tissues (P less than 0.01). The expression of p27 protein and mRNA was significantly lower in the HCC tumor tissues compared to these in the peri-tumor tissues (P less than 0.01). Compared to normal liver cell line L-02, HCC cell lines expressed higher level of MIF (F=61.036, P less than 0.01) and lower level of p27 (F=529.853, P less than 0.01). In MIF siRNA treated PLC and Hep3B cells, the MIF mRNA was decreased in a dose-dependent manner (F=320.1, P less than 0.01; F=201.2, P less than 0.01). The p27 mRNA was significantly up-regulated in MIF siRNA treated PLC and Hep3B cells compared to control siRNA transfected cells (F=419.4, P less than 0.01; F=459.9, P less than 0.01).
Conclusions: MIF is over-expressed in HCC tumor tissues, and the expression of p27 is repressed by MIF.