Objective        To investigate the expression of PC cell-derived growth factor (PCDGF) in nasopharyngeal carcinoma tissues and determine the effect of small interfering RNA (siRNA) against PCDGF gene on the proliferation in nasopharyngeal carcinoma HNE-1 cell line.        Methods       Immunohistochemical staining was used to examine the expression of PCDGF protein in 34 tissue samples of nasopharyngeal

carcinoma and 20 samples of chronic nasopharyngeal inflammation. Two siRNA expression plasmids targeting PCDGF mRNA were constructed based on the nucleotide sequence of PCDGF and were respectively transferred into human nasopharyngeal carcinoma HNE-1 cells via Lipofectamine

TM

2000. The expression of PCDGF at mRNA and protein levels were analyzed by reverse transcription polymerase chain reaction (RT-PCR)

Western blotting and immunofluorescence assay

respectively. The cell proliferation was determined by MTT assay. The distribution of cell cycle was assessed by flow cytometry.        Results        The positive expression rate was 85.3% (29/34) in nasopharyngeal carcinoma

while only 15.0% (3/20) in chronic nasopharyngeal inflammation

with significant difference between each other（P0.01）. The 2 recombinant plasmids inhibited the expressions of PCDGF

and the siRNA-1 was demonstrated to have the strongest silencing effect on PCDGF expression in HNE-1 cells at 48 h after transfection. The expression of PCDGF were reduced by 64.7% and 69.8%

respectively at mRNA and protein levels. PCDGF silence resulted in the proliferation inhibitory ratio of (37.07±12.4)% and more cells arrested at G

0

/G

1

phase in HNE-1 cells.       Conclusion        Specific siRNA of PCDGF effectively inhibits the gene expression and observably suppresses cell proliferation in nasopharyngeal carcinoma HNE-1 cells.