The role of urokinase type plasminogen activator (u-PA) and u-PA receptor (u-PAR) in the invasion of human hepatocellular carcinoma cell lines

Background Tumor invasiveness is a factor that influences the prognosis of patients with hepatocellular carcinoma. Urokinase-type plasminogen activator (u-PA) and its receptor (u-PAR) play an important role in malignant invasion. This study estimated the invasion potential of u-PA and u-PAR by hepatocellular carcinoma cells in vitro. Methods Human hepatocellular carcinoma cell lines, HLE, HLF and HC-4 were used. The Invasion Index (II) was determined with the Transwell insert, which was coated with extracellular matrix (Matrigel) in vitro. Results The HLE II was the highest of the 3 cell lines. The second was HLF cell line, and the third was HC-4 cell line. The greater the production of u-PA and u-PAR, the stronger the cell line's invasiveness. The invasiveness of HLF and HC-4 was augmented by the addition of exogenous u-PA. However, this addition did not increase the HLE II, which produced the highest amount of u-PA. This may be due to the full occupation of its receptors with endogenous u-PA. Conclusion These data suggested that the production of u-PAR and u-PA, are linked with invasion of human hepatocellular carcinoma cell lines.