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Abstract Background Although fibroblast growth factor 19 (FGF19) can promote liver carcinogenesis in mice, its involvement in human hepatocellular carcinoma (HCC) has not been well investigated. FGF19, a member of the FGF family, has unique specificity for its receptor FGFR4. This study aimed to clarify the involvement of FGF19 in the development of HCC. Methods We investigated human FGF19 and FGFR4 expression in 40 hepatocellular carcinoma specimens using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) analysis and immunohistochemistry. Moreover, we examined the expression and the distribution of FGF19 and FGFR4 in 5 hepatocellular carcinoma cell lines (HepG2, HuH7, HLE, HLF, and JHH7) using RT-PCR and immunohistochemistry. To test the role of the FGF19/FGFR4 system in tumor progression, we used recombinant FGF19 protein and small interfering RNA (siRNA) of FGF19 and FGFR4 to regulate their concentrations. Results We found that FGF19 was significantly overexpressed in HCCs as compared with corresponding noncancerous liver tissue (P < 0.05). Univariate and multivariate analyses revealed that the tumor FGF19 mRNA expression was an independent prognostic factor for overall and disease-free survival. Moreover, we found that the FGF19 recombinant protein could increase the proliferation (P < 0.01, n = 12) and invasion (P < 0.01, n = 6) capabilities of human hepatocellular carcinoma cell lines and inhibited their apoptosis (P < 0.01, n = 12). Inversely, decreasing FGF19 and FGFR4 expression by siRNA significantly inhibited proliferation and increased apoptosis in JHH7 cells (P < 0.01, n = 12). The postoperative serum FGF19 levels in HCC patients was significantly lower than the preoperative levels (P < 0.01, n = 29). Conclusions FGF19 is critically involved in the development of HCCs. Targeting FGF19 inhibition is an attractive potential therapeutic strategy for HCC.

A transcriptional factor, CCAAT/enhancer binding protein-beta (C/EBP-beta), regulates a variety of cell functions in normal and neoplastic cells. Although the involvement of C/EBP-beta in metastasis has been demonstrated clinicopathologically in several types of human cancer, the mechanism by which it functions during the multistep process of metastasis remains largely unknown. We investigated the role of C/EBP-beta in the intravascular step of hematogenous metastasis in a rat pancreatic tumor cell line, AR42J-B13, as this step profoundly affects metastatic efficiency. C/EBP-beta-transfected AR42J-B13 (betaB13) cells acquired considerable resistance against serum toxicity, which was primarily mediated by apoptosis in vitro. Upregulated expression of Bcl-2 and Bcl-xL was seen in betaB13 cells. Enhanced early survival of intraportally injected betaB13 cells in the BALB/c nu/nu male mice liver, detected by the mRNA of a vector-specific gene, was observed. Nick-end labeling analysis of the tumor-injected liver revealed significantly lower rates of apoptosis among intravascular betaB13 tumor cells than among empty vector-transfected AR42J-B13 (mB13) cells. Finally, intrasplenically injected betaB13 cells established a larger number of colonies in the liver than did the mB13 cells. These findings suggest that C/EBP-beta may enhance hematogenous metastasis and its antiapoptotic effects may promote the survival of intravascular tumor cells.

Aim: To study the effects of obstructive jaundice on liver regeneration after partial hepatectomy., Methods: Hepatocyte growth factor (HGF), its receptor, c-Met, vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1) mRNA expression in both liver tissue and isolated liver cells were investigated after biliary obstruction (BO) by quantitative reverse-transcription polymerase chain reaction (RT-PCR) using a LightCycler. Immunohistochemical staining for desmin and alpha-smooth muscle actin (alpha-SMA) was also studied. Regenerating liver weight and proliferating cell nuclear antigen (PCNA) labeling index, and growth factor expression were then evaluated after 70% hepatectomy with concomitant internal biliary drainage in BO rats or sham-operated rats., Results: Hepatic TGF-beta1 mRNA levels increased significantly 14 days after BO, and further increased with duration of cholestasis. Meanwhile, HGF and VEGF tended to increase, but was not significant. In cell isolates, TGF-beta1 mRNA was found mainly in the hepatic stellate cell (HSC) fraction. Immunohistochemical studies revealed an increased number of HSCs (desmin-positive cells) and activated HSCs (alpha-SMA-positive cells) in portal areas after BO. In a hepatectomy model, liver regeneration was delayed in BO rats, as compared to sham-operated rats. TGF-beta1 mRNA was significantly up-regulated up to 48 h after hepatectomy, and the earlier HGF mRNA peak was lost in BO rats., Conclusion: BO induces HSCs proliferation and activation, leading to up-regulation of TGF-beta1 mRNA and suppression of HGF mRNA in livers. These altered expression patterns may be strongly involved in delayed liver regeneration after hepatectomy with obstructive jaundice.

Aim: To study the regulatory mechanisms of sinusoidal regeneration after partial hepatectomy., Methods: We investigated the expression of angiopoietin (Ang)-1, Ang-2, Tie-2, and vascular endothelial growth factor (VEGF) in regenerating liver tissue by quantitative reverse-transcription polymerase chain reaction (RT-PCR) using a LightCycler (Roche Diagnostics) and also immunohistochemical staining after 70% hepatectomy in rats. In the next step, we isolated liver cells (hepatocytes, sinusoidal endothelial cell (SEC), Kupffer cell, and hepatic stellate cells (HSC)) from regenerating liver tissue by in situ collagenase perfusion and counterflow elutriation, to determine potential cellular sources of these angiogenic factors after hepatectomy. Proliferation and apoptosis of SECs were also evaluated by proliferating cell nuclear antigen (PCNA) staining and the terminal deoxynucleotidyl transferase d-uridine triphosphate nick end labeling (TUNEL) assay, respectively., Results: VEGF mRNA expression increased with a peak at 72 h after hepatectomy, decreasing thereafter. The expression of Ang-1 mRNA was present at detectable levels before hepatectomy and increased slowly with a peak at 96 h. Meanwhile, Ang-2 mRNA was hardly detected before hepatectomy, but was remarkably induced at 120 and 144 h. In isolated cells, VEGF mRNA expression was found mainly in the hepatocyte fraction. Meanwhile, mRNA for Ang-1 and Ang-2 was found in the SEC and HSC fractions, but was more prominent in the latter. The PCNA labeling index of SECs increased slowly, reaching a peak at 72 h, whereas apoptotic SECs were detected between 120 h and 144 h., Conclusion: Ang-Tie system, together with VEGF, plays a critical role in regulating balance between SEC proliferation and apoptosis during sinusoidal regeneration after hepatectomy. However, the VEGF system plays a more important role in the early phase of sinusoidal regeneration than angiopoietin/Tie system.