Objective       To determine the expression pattern of glypican-5 (GPC5) gene in the lung adenocarcinoma cell lines and the effects of its over-expression or silencing on the biological behaviors in lung adenocarcinoma cell lines.       Methods       The expression of GPC5 gene at mRNA and the protein levels in 4 lung adenocarcinoma cell lines (A549

H1299

H358 and H1975) and 1 strain of normal lung epithelial cell line (HBE) was determined by reverse transcription PCR (RT-PCR)

real-time quantitative PCR (qRT-PCR) and Western blotting. Over-expression vectors of GPC5 gene and its interference plasmids were

constructed

and then transfected respectively into A549 cells (lower expression of the gene) or H1299 cells (higher expression) to over-express or silence the gene. Cell counting kit-8 (CCK-8) assay was performed to measure the proliferation of the lung adenocarcinoma cell lines. Cell cycle and apoptosis were detected by flow cytometry.       Results       Compared with the expression level of GPC5 in normal cells (HBE)

the level was lower in A549 cells and highly in H1299 cells

with its protein level consistent with the mRNA level. Over-expression of GPC5 in A549 cells gene resulted in inhibition of cell growth and arrest of cells at G

1

/S phase. On the other hand

interference of GPC5 in H1299 cells promoted cell growth and improved cell cycle. Over-expression and interference of GPC5 gene significantly affected the cell apoptosis in the lung adenocarcinoma cell lines.       Conclusion       GPC5 gene affects the biological behaviors of lung adenocarcinoma cell lines. It may be a tumor suppressor gene

and its specific molecular mechanism is worth of further research.