Ferroportin in the progression and prognosis of hepatocellular carcinoma

Abstract

Background: Hepatocellular carcinoma (HCC) is the fifth most common malignant tumor in men and the seventh in women and understanding the molecular mechanisms of HCC and establishing more effective therapies are critical and urgent issues. Our objective was to study the expression of ferroportin in hepatocellular carcinoma (HCC) tissue samples and the relationship between ferroportin expression and HCC characteristics.

Methods: Sixty HCC tissues and their corresponding para-cancer liver tissues (PCLT) were obtained from sixty HCC patients who had undergone hepatectomy in the Second Xiangya Hospital of Central South University. Ten normal liver tissue samples were also obtained as a control. Immunohistochemistry (IHC) was performed to analyze the ferroportin expression in HCC, and the relationship between ferroportin expression and HCC clinical pathological characteristics also was analyzed. For the evaluation of IHC results, the comprehensive scoring criteria were met according to the staining intensity and the number of positive staining cells. Western blotting was performed to detect the expression level of ferroportin in HCC cell lines.

Results: Ferroportin expression in HCC tissue was significantly lower compared to PCLT and normal liver tissue (P <0.05). Moreover, ferroportin expression was related to liver cancer cell de-differentiation, the severity degree in TNM staging, Edmondson-Steiner grading, intrahepatic metastasis and portal vein invasion. In addition, high expression of ferroportin was observed in normal human liver cell lines L02 and HL7702, whereas weak positive expression and even negative expression of ferroportin were observed in HCC cell lines FOCUS, MHCC-97H, HepG2 and SMMC-7721. Furthermore, among the four kinds of HCC cell lines, the expression level of ferroportin was the lowest in MHCC-97H cells.

Conclusions: Ferroportin expression level declines along with the progression of liver cancer, suggesting that the reduction of ferroportin may serve as an important marker for poor HCC prognosis and as a new therapeutic target.

Figure 1

Immunohistochemistry (IHC) of the ferroportin expression in hepatocellular carcinoma (HCC) tissue sections (100 bp). A) Normal liver tissue cytoplasm and cell membrane presented positive ferroportin staining. B) Para-cancer liver tissues (PCLT) cytoplasm and cell membrane presented positive ferroportin staining. C) and D) Ferroportin positive staining has not been found in HCC tissue sections. A brownish black staining or brown orange staining shows ferroportin positive staining.

Figure 2

The expression level of ferroportin in different cell lines. A) Western blotting: 1, Normal human liver cell line L02; 2, FOCUS; 3, HepG2; 4, MHCC-97H; 5, SMMC-7721. βMactin was shown as the loading control. B) Statistical graph of the expression level of ferroportin in different cell lines. **The expression difference of ferroportin between normal human liver cell line and hepatocellular carcinoma (HCC) cell lines all had statistical significance, P <0.01. *The difference of ferroportin expression between MHCC-97H and other HCC cell lines had statistical significance, P <0.05 (for convenience, the single asterisk has only been shown between MHCC-97H and FOCUS; it is the same consequence for the comparison between MHCC-97H and HepG2/ SMMC-7721).