Abstract

Hepatocellular carcinoma is the fifth most common neoplasm and the most important cause of death in patients with liver cirrhosis in the world. lipopolysaccharide (LPS) stimulates the hepatocyte cells and increases the production of inducible cytokine with the high production of nitric oxide and ROS. Chronic inflammation caused by lipopolysaccharide directly activates immune system and indirectly, through COX-2 interferes in the formation of malignant disease. In this study, the rate change of COX-2 was searched by adding LPS and also the effect of inhibition of this inflammatory enzyme by Celecoxib and combined effect of this in HepG2 cancer cells was assessed. Salmonellaenteritidis lipopolysaccharide is extracted by methanol-chloroform method and the Sodium dodesyl sulfate poly acryl-amide gel electrophoresis (SDS-PAGE) electrophoresis bands were stained by silver nitrate. Four treatment groups of HepG2 cells were stimulated with 100 ng/ml LPS, 500 µM Celecoxib as inhibitor and were incubated for 12 and 24 h. Variables including both increase and decrease inflammatory factor, COX-2, was assayed. The obtained results showed that initial activity of COX-2 in not stimulated in HepG2 cell, 1.957 ng/ml after stimulation  with LPS for 12 and 24 h (1.383 and 0.618 ng/ml) decreased and the effect of this inhibitor was also studied. The data showed that the reduction of COX-2 in HepG2 cells was correlated with the cell density and duration of incubation with LPS. Inhibition of enzyme associated with inflammation, with inhibitor substance; celecoxib, observed as well as LPS. We can potentially design drugs to treat a variety of diseases and cancers.

Key words: Cyclooxygenase-2, HepG2 Cell, Salmonella enteritidis,lipopolysaccharide, Sodium dodesyl sulfate poly acryl-amide gel electrophoresis (SDS-PAGE).