Overexpression of PSF1 is correlated with poor prognosis in hepatocellular carcinoma patients

PSF1 is a subunit of the GINS complex which is essential for establishment of DNA replication forks, and the progression of the replisome. Previous studies have shown a close relationship between PSF1 and cell cycle in the proliferation of immature cells as well as tumors. The purpose of this study was to measure PSF1 expression in hepatocellular carcinoma (HCC) tissues, and determine the effects of down-regulation of PSF1 expression on growth of cancer cells, the cell cycle, apoptosis and cell invasiveness.

Samples from 137 HCC tissues, 67 from adjacent nontumor tissue and 15 from normal liver were studied using immunochemistry. The HepG2 cell line was used for knockdown experiments studied by RT-PCR, real-time PCR, apoptosis and invasiveness assays.

PSF1 was overexpressed in HCC tissues compared with normal liver tissues. High PSF1 expression correlated with a more aggressive phenotype as well as worse prognosis in HCC patients. Knockdown of PSF1 expression using small interfering RNA (siRNA) slowed the growth of cancer cell by suppressing the cell cycle progression as well as increasing apoptosis, especially early apoptosis. In addition, the invasiveness of HepG2 cells was also reduced by down-regulation of PSF1.

These results suggest that the inhibition of PSF1 might provide new therapeutic approaches for HCC.