Expression And Regulation Mechanism Of Fructose-1,6-bisphosphatase In Heptocelluar Carcinoma

Objective:To quantity the expression level of FBP1(fructose-1,6-bisphosphatase) in hepatocellular carcinoma and adjacent tissues. Determine its effect on the prognosis of patients. Analysis the relationship between expression of histone deacetylase 1(HDAC1), histone deacetylase 2(HDAC2) and FBP1. and detect FBP1 effect on the biological behavior of liver cancer cells.Methods:Firstly, tissues from 90 cases of heptocellular carcinoma were evaluated for the expression of FBP1 using immunohistochemistry. The association of clinical parameters with expression level of FBP1 was evaluated using chi-square test. Kaplan-Meier test and Log-rank test were used to determine the association of the expression level of FBP1 with the overall survival of patient. Secondly, in order to investigate the regulation mechanism of FBP1 in liver cancer, Hep G2 cells and SK-Hep1 cells were treated with HDAC inhibitors including Na Bu, SAHA, LBH, or knocked down HDAC1 and HDAC2. Western blot and real-time PCR were used to exam the protein and m RNA level of FBP1. In addition, Hep G2 cells and SK-Hep1 cells were treated with Na Bu, SAHA, or knocked down HDAC1 and HDAC2. The binding of HDAC to FBP1 gene was determined by chromatin immunoprecipitation(Ch IP) assay. We established the stable transfected Hep G2 cells and SK-Hep1 cells, including pc DNA3.1, p Lenti6.3/FBP1, NS sh RNA and FBP1 sh RNA. Glucose test kit was used to detect the glucose consumption level of the stable transfection cells. MTS and generation of hepatocellular carcinoma xenogragts in mice were preformed to detect the effect of FBP1 on the proliferation of liver cancer cells. The relationship between expression of HDAC1, HDAC2 and FBP1 was determined by IHC staining.Results:FBP1 expression level in tumor tissues was significantly lower than in adjacent tissues(Z=7.952, P<0.01). Expression of FBP1 was much lower in HCC(Heptocelluar carcinoma) tissues with tumor size larger than 3cm(P<0.01). According to AJCC(American Joint Committee on Cancer) stage, FBP1 expression was lower in Ⅲ to Ⅳ stage patients(P=0.001). The average survival time of patients with low FBP1 expression level was much shorter than FBP1 high expression patients(15.29 month vs. 50.17 month, P<0.05). FBP1 protein and m RNA level increased with concentration of HDACIs treatment. Knocking down HDAC1 or HDAC2 individually, the protein and m RNA levels of FBP1 were both slightly increased. Transfection of HDAC1-specific si RNA plus HDAC2-specific si RNA could significantly elevated the FBP1 m RNA and protein level. HDAC1 and HDAC2 regulated FBP1 expression at transcriptional level by binding to its enhancer. Over-expression of FBP1 could decrease the consumption of glucose and reduce the proliferation of liver cancer cells. There were negative co-relationship between HDAC1, HDAC2 and FBP1(r=-0.64, P<0.05;r=-0.61, P<0.05).Conclusion:Loss of expression of FBP1 was an reference index for poor prognosis of heptocellular carcinoma. HDAC1 and HDAC2 regulate the expression of FBP1 by inhibiting acetylation level of H3K27 in the enhancer area of FBP1. We also found that FBP1 interfered with glycolysis of liver cancer cells, decreased the energy supply, and inhibited tumor cell proliferation.